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diff --git a/old/11204-8.txt b/old/11204-8.txt new file mode 100644 index 0000000..4b9fdc2 --- /dev/null +++ b/old/11204-8.txt @@ -0,0 +1,15805 @@ +Project Gutenberg's Diseases of the Horse's Foot, by Harry Caulton Reeks + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Diseases of the Horse's Foot + +Author: Harry Caulton Reeks + +Release Date: February 21, 2004 [EBook #11204] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + + + + +Produced by Juliet Sutherland, Leonard D Johnson and the Online +Distributed Proofreading Team. + + + + + +DISEASES OF THE HORSE'S FOOT + +By +H. CAULTON REEKS + +Fellow of the Royal College of Veterinary Surgeons +Author of 'The Common Colics of the Horse' + + + +1906 + + +To +J. MacQueen, F.R.C.V.S., + +Professor of Surgery at the Royal Veterinary College, London, as a slight +acknowledgment of his ability as a teacher, and in return for many kindly +services, this volume is gratefully inscribed by + +THE AUTHOR. + + +PREFACE + + +Stimulated by the reception accorded my 'Common Colics of the Horse,' both +in this country and in America, and assured by my publishers that a work on +diseases of the foot was needed, I have been led to give to the veterinary +profession the present volume. + +While keeping the size of the book within reasonable limits, no effort +has been spared to render it as complete as possible. This has only been +achieved by adding to my own experience a great deal of the work of others. +To mention individually those who have given me permission to use their +writings would be too long a matter here. In every case, however, where the +quotation is of any length, the source of my information is given, either +in the text or in an accompanying footnote. A few there are who will, +perhaps, find themselves quoted without my having first obtained their +permission to do so. They, with the others, will, I am sure, accept my +hearty thanks. + +The publishers have been generous in the matter of illustrations and +diagrams, and although to the older practitioner some of these may appear +superfluous, it is hoped they will serve to render the work an acceptable +textbook for the student. + +H. CAULTON REEKS. + +SPALDING, _January, 1906_. + + +CONTENTS + + +CHAPTER I + +INTRODUCTION + + +CHAPTER II + +REGIONAL ANATOMY + +A. The Bones +B. The Ligaments +C. The Tendons +D. The Arteries +E. The Veins +F. The Nerves +G. The Complementary Apparatus of the Os Pedis +H. The Keratogenous Membrane +I. The Hoof + + +CHAPTER III + +GENERAL PHYSIOLOGICAL AND ANATOMICAL OBSERVATIONS + +A. Development of the Hoof +B. Chemical Properties and Histology of Horn +C. Expansion and Contraction of the Hoof +D. The Functions of the Lateral Cartilages +E. Growth of the Hoof + + +CHAPTER IV + +METHOD OF EXAMINING THE FOOT + + +CHAPTER V + +GENERAL REMARKS ON OPERATIONS ON THE FOOT + +A. Methods of Restraint +B. Instruments required +C. The Application of Dressings +D. Plantar Neurectomy + History of the Operation + Preparation of the Subject + The Operation + After-treatment +E. Median Neurectomy +F. Length of Rest after Neurectomy +G. Sequelæ of Neurectomy + Liability of Pricked Foot going undetected + Loss of Tone in the Non-sensitive Area + Gelatinous Degeneration + Chronic Oedema of the Leg + Persistent Pruritus + Fracture of the Bones + Neuroma + Reunion of the Divided Nerve + The Existence of an Adventitious Nerve-supply + Stumbling +H. Advantages of the Operation +I. The Use of the Horse that has undergone Neurectomy + + +CHAPTER VI + +FAULTY CONFORMATION + +A. Weak Heels +B. Contracted Foot + (_a_) Contracted Heels + (_b_) Local or Coronary Contraction +C. Flat-foot +D. Pumiced-foot, Dropped Sole, or Convex Sole +E. 'Ringed' or 'Ribbed' Hoof +F. The Hoof with Bad Horn + (_a_) The Brittle Hoof + (_b_) The Spongy Hoof +G. Club-Foot +H. The Crooked Foot + (_a_) The Foot with Unequal Sides + (_b_) The Curved Hoof + + +CHAPTER VII + +DISEASES ARISING FROM FAULTY CONFORMATION + +A. Sand-crack + Definition + Classification + Causes + Complications + Treatment + Surgical Shoeing for Sand-crack + +B. Corns + Definition + Classification + Causes + Pathological Anatomy and Histology + Treatment + Surgical Shoeing for Corn + +C. Chronic Bruised Sole + + +CHAPTER VIII + +WOUNDS OF THE KERATOGENOUS MEMBRANE + +A. Nail-bound + Definition + Causes + Symptoms + Treatment + +B. Punctured Foot + Definition + Causes + Common Situations of the Wound + Classification + Symptoms and Diagnosis + Complications + Prognosis + Treatment + +C. Coronitis (Simple) + + 1. Acute + Definition + Causes + Symptoms + Complications + Prognosis + Treatment + + 2. Chronic + Definition + Causes + Symptoms + Treatment + +D. False Quarter + Definition + Causes + Treatment + +E. Accidental Tearing off of the Entire Hoof + + +CHAPTER IX + +INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS + +A. ACUTE + Acute Laminitis + Definition + Causes + Symptoms + Pathological Anatomy + Complications + Diagnosis and Prognosis + Treatment + Broad's Treatment for Laminitis + Smith's Operation for Laminitis + +B. CHRONIC + + 1. Chronic Laminitis + Definition + Causes + Symptoms + Pathological Anatomy + Treatment + + 2. Seedy-Toe + Definition + Causes + Symptoms + Treatment + + 3. Keraphyllocele + Definition + Causes + Symptoms + Treatment + + 4. Keratoma + + 5. Thrush + Definition + Causes + Symptoms + Treatment + + 6. Canker + Definition + Causes, Predisposing and Exciting + Symptoms and Pathological Anatomy + Differential Diagnosis and Prognosis + Treatment + Malcolm's, Lieutenant Rose's, Bermbach's, Hoffmann's + and Imminger's Treatment for Canker + + 7. Specific Coronitis + Definition + Causes + Symptoms + Treatment + + +CHAPTER X + +DISEASES OF THE LATERAL CARTILAGES + +A. Wounds of the Cartilages + +B. Quittor + Definition + Classification + + 1. Simple or Cutaneous Quittor + Definition + Causes + Symptoms + Pathological Anatomy + Prognosis + Complications + Treatment, Preventive and Curative + + 2. Sub-horny Quittor + Definition + Causes + Symptoms and Diagnosis + Complications + Necrosis of the Lateral Cartilage + Pathological Anatomy of the Diseased Cartilage + Necrosis of Tendon and of Ligament + Ossification of the Cartilage + Treatment + Operations for Extirpation of the Cartilage + +C. Ossification of the Lateral Cartilages (Side-bones) + Definition + Symptoms and Diagnosis + Causes + Treatment + Smith's Operation for Ossification of the Lateral Cartilages + + +CHAPTER XI + +DISEASES OF THE BONES + +A. Periostitis and Ostitis + 1. Periostitis + (_a_) Simple Acute Periostitis + (_b_) Suppurative Periostitis + (_c_) Osteoplastic Periostitis + + 2. Ostitis + (_a_) Rarefying Ostitis + (_b_) Osteoplastic Ostitis + (_c_) Caries and Necrosis + +Treatment of Periostitis + +Recorded Cases of Periostitis + +B. Pyramidal Disease, Buttress Foot, or Low Ringbone + Definition + Symptoms and Diagnosis + Pathological Anatomy + Treatment + Recorded Cases of Buttress Foot + +C. Fractures of the Bones + 1. Fractures of the Os Coronæ + Recorded Cases of Fractures of the Os Coronæ + + 2. Fractures of the Os Pedis + Recorded Cases of Fractures of the Os Pedis + + 3. Fractures of the Navicular Bone + Recorded Case of Fracture of the Navicular Bone + + Treatment of Fractures of the Bones of the Foot + + +CHAPTER XII + +DISEASES OF THE JOINTS + +A. Synovitis + (_a_) Simple + (1) Acute + (2) Chronic + (_b_) Purulent or Suppurative +B. Arthritis + (_a_) Simple or Serous + (_b_) Acute + (_c_) Purulent or Suppurative + (_d_) Anchylosis + +C. Navicular Disease + Definition + History + Pathology + Changes in the Bursa + Changes in the Cartilage + Changes in the Tendon + Changes in the Bone + Causes + Heredity + Compression + Concussion + A Weak Navicular Bone + An Irregular Blood-supply to the Bone + Senile Decay + Symptoms and Diagnosis + Differential Diagnosis + Prognosis + Treatment + +D. Dislocations + +LIST OF ILLUSTRATIONS + +1. The Bones of the Phalanx +2. The Os Coronæ (Anterior View) +3. The Os Coronæ (Posterior View) +4. The Os Pedis (Postero-lateral View) +5. The Os Pedis (viewed from Below) +6. The Navicular Bone (viewed from Below) +7. The Navicular Bone (viewed from Above) +8. Ligaments of the First and Second Interphalangeal Articulations + (Lateral View). (_After Dollar and Wheatley_) +9. Ligaments of the First and Second Interphalangeal Articulations + (viewed from Behind). (_After Dollar and Wheatley_) +10. The Flexor Tendons and the Extensor Pedis. (_After + Haübner_) +11. The Flexor Perforans and Perforatus +12. The Flexor Perforans and Perforatus (the Perforans cut through and + deflected) +13. Median Section of Normal Foot +14. The Arteries of the Foot +15. The Veins and Nerves of the Foot +16. The Lateral Cartilage +17. The Keratogenous Membrane (viewed from the Side) +18. The Keratogenous Membrane (viewed from Below) +19. The Wall of the Hoof +20. Internal Features of the Hoof +21. Inferior Aspect of the Hoof +22. Hoof with the Sensitive Structures removed +23. Section of Epidermis +24. Section of Skin with Hair Follicle and Hair +25. Section of Human Nail and Nail-bed +26. Section of Foot of Equine Foetus. (_Mettam_) +27. Section from Foot of Sheep Embryo. (_Mettam_) +28. Section from Foot of Calf Embryo. (_Mettam_) +29. Section from Foot of Equine Foetus. (_Mettam_) +30. Section through Hoof and Soft Tissues of a Foal at Term. (_Mettam_) +31. Perpendicular Section of Horn of Wall +32. Horizontal Section of Horn of Wall +33. Horizontal Section through the Junction of the Wall with the Sole +34. Section of Frog. (_Mettam_) +35. Professor Lungwitz's Apparatus for Examining the Foot Movements +36. Professor Lungwitz's Apparatus for Examining the Foot Movements +37. The Movements of the Solar and Coronary Edges of the Hoof illustrated. + (_Lungwitz_) +38. The Blind +39. The Side-line +40. Method of securing the Hind-foot with the Side-line +41. The Hind-foot secured with the Side-line +42. The Casting Hobbles +43. Method of securing the Hind-leg upon the Fore +44. The Hind-leg secured upon the Fore +45. The Drawing-knife (Ordinary Pattern) +46. Modern Forms of Drawing-knives +47. Symes's Knife +48-51. Illustrating Colonel Nunn's Method of applying a Poultice to the + Foot +52. Poultice-boot of Canvas and Steel +53. Poultice-boot of Cocoa-fibre +54. Foot-swab +55. The Shoe with Plates +56. Quittor Syringe +57. The Esmarch Bandage and Tourniquet +58. Tourniquet with Wooden Block +59. Neurectomy Bistoury +60. Neurectomy Needle +61. Double Neurectomy Tenaculum +62. Adventitious Nerve-supply to Foot. (_Sessions_) +63. Tip Shoe +64. The Tip Shoe 'let in' to the Foot +65. The Thinned Tip +66. Drawing-knife for Charlier Shoeing +67. The Foot prepared for the Charlier Shoe +68. Bar Shoe +69. Rubber Bar Pad on Leather +70. The Bar Pad applied with a Half-shoe +71. Frog Pad +72. Frog Pad applied +73. Smith's Expansion Shoe for Contracted Feet +74. A Contracted Foot treated with Smith's Shoe +75. De Fay's Vice +76. Hartmann's Expanding Shoe +77. Broué's Slipper Shoe. (_Gutenacker_) +78. Einsiedel's Slipper and Bar-clip Shoe. (_Gutenacker_) +79. Hoof showing Coronary Contraction. (_Gutenacker_) +80. Flat-foot (Solar Surface). (_Gutenacker_) +81. Hoof showing Laminitis Rings on the Wall. _(Gutenacker)_ +82. Hoof showing 'Grass' Rings on the Wall. (_Gutenacker_) +83. Club-foot. (_Gutenacker_) +84. Shoe with extended Toe-piece. (_Gutenacker_) +85. A Crooked Foot in Cross-section. (_Gutenacker_) +86. Sand-crack Firing-iron +87. Sand-crack Forceps and Clamp. (_Vachette's_) +88. McGill's Sand-crack Clamp +89. Koster's Sand-crack Clamp +90. Sand-crack Belt +91. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +92. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +93. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +94 96. Grooving the Wall in the Treatment of Sand-crack +97. Removing the Wall in the Treatment of Sand-crack +98. Removing the Wall in the Treatment of Sand-crack +99. Horizontal Section of Corn. (_Gutenacker_) +100. Inner Surface of the Wall, showing Changes in Chronic Corn. + (_Gutenacker_) +101. Perpendicular Section of the Wall in a Case of Chronic Corn. + (_Gutenacker_) +102. Three-quarter Shoe +103. Three-quarter Bar Shoe +104. Shoe with a 'Dropped' Heel +105. Shoe with a 'Set' Heel +106. Curette, or Volkmann's Spoon +107. Resection of the Terminal Portion of the Perforans Tendon + (_Gutenacker_) +108. Shoe with extended Toe-piece. (_Colonel Nunn_) +109. Mesian Section of Foot with Lesions following Coronitis. + (_Gutenacker_) +110. Toe of Ordinary Hind-shoe +111. Toe of Hind-shoe Bevelled for the Prevention of Overreach +112. Hoof showing Lesion in the Wall following Coronitis. + (_Gutenacker_) +113. Foot with Lesions of Chronic Coronitis. (_Gutenacker_) +114. Hoof Accidentally Tom from Foot. (_Cartledge_) +115. Hoof Accidentally Tom from Foot. (_Rogerson_) +116. Section of Foot with Laminitis of Eight Days' Duration. +(_Gutenacker_) +117. Section of Foot with Laminitis of Fourteen Days' Duration. + (_Gutenacker_) +118. Chronic Ostitis of the Os Pedis in Laminitis. +119. Broad's Rocker Bar Shoe for Laminitis. +120. The Foot showing Grooves made in the Wall for Treatment of Laminitis + (Anterior Surface). +121. The Foot showing Grooves made for the Treatment of Laminitis (Solar + Surface). +122. Foot with Chronic Laminitis. (_Gutenacker_) +123. Inferior Aspect of Foot with Chronic Laminitis. (_Gutenacker_) +124. Section of Foot with Laminitis of Three Weeks' Duration. + (_Gutenacker_) +125. Section of Foot with Laminitis of Several Years' Duration. + (_Gutenacker_) +126. Diagram showing Position of the Abnormal Growth of Horn in Chronic + Laminitis. +127. Diagram showing the same Abnormal Growth of Horn Removed prior to + Shoeing. +128. Shoe with Heel-clip. +129. Internal Seedy-Toe. +130. External Seedy-Toe. (_Colonel Nunn_) +131. External Seedy-Toe. (_Colonel Nunn_) +132. A Keraphyllocele on the Inner Surface of the Horn of the Wall at the +Toe. (_Gutenacker_) +133. Os Pedis showing Absorption of Bone caused by the Pressure of a + Keraphyllocele. (_Gutenacker_) +134. Foot with Canker of the Frog and Heels. (_Gutenacker_) +135. Foot with Canker extending to the Wall. (_Malcolm_) +136. Foot with Advanced Canker. (_Gutenacker_) +137. Feet affected with Specific Coronitis. (_Taylor_) +138. Fore-foot with Specific Coronitis. (_Taylor_) +139. Excision of the Lateral Cartilage (Old Method). (_Gutenacker_) +140. Excision of the Lateral Cartilage. (_After Moller and Frick_). + (_Gutenacker_) +141. Excision of the Lateral Cartilage. (_After Bayer_.) + (_Gutenacker_) +142. Partial Excision of the Lateral Cartilage +143. Ossified Lateral Cartilages, or Side-bones. +144. Smith's Side-bone Saw (Old Pattern). +145. Smith's Side-bone Saw (Improved Pattern). +146. Smith's Hoof Plane. +147. Hodder's Hoof Chisel. +148. Foot showing the Grooves made in Smith's Operation for Side-bones + (viewed from the Side). +149. Foot showing the Grooves made in Smith's Operation for Side-bones + (viewed from Below). +150. Periostitis involving the Pedal and Navicular Bones. (_Litt_) +151. Periostitis involving the Pedal and Navicular Bones. (_Litt_) +152. Effects of Periostitis on the Os Pedis. (_Smith_) +153. Effects of Periostitis on the Os Pedis. (_Smith_) +154. Effects of Periostitis on the Os Pedis. (_Jones_) +155. Effects of Periostitis on the Os Pedis. (_Jones_) +156. Case of Buttress Foot. (_Routledge_) +157. Foot showing Fracture of the Pyramidal Process in a Case of Buttress + Foot. (_Routledge_) +158. Fracture of the Os Coronæ. (_Crawford_) +159. Fracture of the Os Coronæ. (_Crawford_) +160. Fractured Os Pedis. (_Freeman_) +161. Navicular Bone showing Lesions of Navicular Disease. + (_Gutenacker_) +162. Foot with the Seat of Navicular Disease exposed (showing Lesions). + (_Gutenacker_) +163. Navicular Bone showing Lesions of Navicular Disease (a Case of + Long-standing). (_Gutenacker_) +164. Frog Seton Needle. +165. Diagram showing Course of the Needle in Setoning the Frog. + + + +DISEASES OF THE HORSE'S FOOT + + + +CHAPTER I + +INTRODUCTION + + +The importance of that branch of veterinary surgery dealing with diseases +of the horse's foot can hardly be overestimated. That the animal's +usefulness is dependent upon his possession of four good feet is a fact +that has long been recognised. Who, indeed, is there to be found entirely +unacquainted with one or other of such well-known aphorisms as: 'Whoever +hath charge of a horse's foot has the care of his whole body'; 'As well a +horse with no head as a horse with no foot'; or the perhaps better known, +and certainly more epigrammatic, 'No foot, no horse.' + +Without taking these sayings literally, it will be admitted by almost +everyone that they contain a vast amount of actual truth. This allowed, it +at once becomes clear that a ready understanding of the diseases to which +the foot is liable, the means of holding them in check, and the correct +methods of treating them should figure largely in the knowledge at the +command of the veterinary surgeon. + +In the very great majority of instances the horse's ability to perform +labour is the one thing that justifies his existence, and to that end the +presence of four good, sound feet is an almost indispensable qualification. +And yet how many circumstances do we see tending to militate against that +one essential. + +Even in colthood the foot, if neglected, may become a source of trouble. +Unless periodically examined and properly trimmed, its shape is liable to +serious alteration. From that in which it is best calculated to withstand +the effects of the wear it will be called upon to endure in after life, it +may become so changed for the worse as to seriously affect the animal's +value. + +In the matter of feeding, too, trouble is likely to ensue. Particularly is +this the case where the colt shows points of exceptional merit. He is 'got +up' for show, and the feet are likely to fall victims to the mismanagement +that frequent exhibition so often carries with it. An extra allowance of +peas, beans, wheat, or other equally injurious food is given. The result is +a severe attack of laminitis, and an otherwise valuable and promising colt +is permanently ruined. + +Exposed as it is, too, to injury, the foot of a young horse, even at grass, +is frequently the seat of injuries from picked up nails, stakes, or other +agents which, unless detected and carefully treated, may terminate in a +troublesome case of quittor and incurable lameness. + +With the passing of colthood, and the coming into effect of the evils of +further domestication, the troubles to which the foot is open become more +numerous. Foremost among them will come those having their starting-point +in errors of practice originating in the forge; for, in spite of attempts +at their education, smiths, as a class, are as yet grievously unversed in +even the elementary knowledge of the delicate construction of the member +that is entrusted to their care. + +This fact has been dilated on in books devoted to shoeing, and in the +prefatory note to the last edition of Fleming's manual on this subject we +find the following statement: 'The records of all humane societies show +that, of prosecutions for cruelty to animals, an overwhelming majority +refer to the horse; and of these, a large proportion are for working horses +while suffering from lameness in one form or other. + +'So frequent are such cases that observers have concluded that their +prevalence must result from some specific cause, and, not unnaturally, +attention has thus been directed to the various modes of management +practised in relation to the horse's foot, to the manner of shoeing, and, +in particular, to the way in which the foot is prepared for the shoe.' + +It must be remembered, however, that although harm in the forge may +frequently arise from culpable roughness or carelessness, such is not +necessarily always the case, and that quite as much injury may result from +careful and conscientious workmanship when it is unfortunate enough to be +based upon principles wrong in themselves to commence with. + +It so happens, too, that shoeing, in itself a necessary evil, may be +responsible for injuries in the causation of which the smith can have +played no part. Take, for example, the ill effects following upon the +animal's attendant allowing him to carry his shoes for too long a time. +In this case the natural growth of the horn carries the heel of the shoe +further beneath the foot than is safe for a correct bearing; in fact, +anterior to the point of inflection of the wall. The shoe, at the same +time, is greatly thinned from excessive wear. Result, a sharp and +easily-bended piece of iron situate immediately under the seat of corn. +Pressure or actual cutting of the sole is bound to occur, and the animal is +lamed. + +Again, apart from the question of negligence or otherwise on the part of +the smith or the animal's attendant, it must be remembered that the nailing +on to the foot of a plate of iron is not giving to the animal an easier +means of progression. The reverse is the case. In place of the sucker-like +face of the natural horn is substituted a smooth, and, with wear, +highly-polished surface. Slipping and sliding attempts to gain a foothold +become frequent, and strains of the tendons and ligaments follow in their +wake. + +As, however, this treatise is not intended to deal with the art of shoeing, +the reader must be referred to other works for further information. In +addition to Fleming's, there may be mentioned, among others, Hunting's 'Art +of Horse Shoeing,' and the very excellent volume of Messrs. Dollar and +Wheatley on the same subject. Leaving the forge, we may next look to the +nature of the animal's work, and the conditions under which he is kept, for +active causes in the production of disorders of the foot. From the yielding +softness of the pasture he is called to spend the bulk of his time upon the +hard macadamized tracks of our country roads, or the still more hard and +more dangerous asphalt pavings or granite sets of our towns. The former, +with the bruises they will give the sole and frog from loose and scattered +stones, and the latter, with the increased concussion they will entail on +the limb, are active factors in the troubles with which we are about to +deal. Upon these unyielding surfaces the horse is called to carry slowly or +rapidly, as the case may be, not only his own weight, but, in addition, is +asked to labour at the hauling of heavy loads. The effects of concussion +and heavy traction combined are bound primarily to find the feet, and such +diseases as side-bones, ringbones, corns, and sand-cracks commence to make +their appearance. + +Again, as opposed to the comparative healthiness of the surroundings when +at grass, consideration must be given to the chemical changes the foot is +frequently subjected to when the animal is housed. + +Only too often the bedding the animal has to stand upon for several hours +of the twenty-four can only be fitly described as 'filthy in the extreme.' +The ammoniacal exhalations from these collected body-discharges must, and +do, have a prejudicial effect upon the nature of the horn, and, though slow +in its progress, mischief is bound sooner or later to occur in the shape of +a weakened and discharging frog, with its concomitant of contracted heels. +Lucky it is in such a case if canker does not follow on. + +Observers, too, have chronicled the occurrence in horse's feet of disease +resulting from the use of moss litter. Tenderness in the foot is first +noticeable, which tenderness is afterwards followed by a peculiar softening +of the horn of the sole and the frog. What should be a dense, fairly +resilient substance is transformed into a material affording a yielding +sensation to the fingers not unlike that imparted by a soft indiarubber, +and as easily sliced as cheese-rind. + +Lastly, though the foot is extremely liable to suffer from the effects +of extreme dryness or excessive humidity, especially with regard to the +changes thus brought about in the nature of the horn, it is perforce +exposed at all times to the varying condition of the roads upon which it +must travel. The intense dryness of summer and the constant damp of winter, +each in their turn take part in the deteriorating influences at work upon +it. + +Though this subject might be indefinitely prolonged, this brief résumé of +the adverse circumstances to which the foot of the horse is exposed +is sufficient to point out the extreme importance of its study to the +veterinary surgeon. So long as the horse is used as a beast of burden so +long will this branch of veterinary surgery offer a wide and remunerative +field of labour. + + + +CHAPTER II + +REGIONAL ANATOMY + + +Considered from a zoological standpoint, the foot of the horse will include +all those parts from the knee and hock downwards. For the purposes of this +treatise, however, the word foot will be used in its more popular sense, +and will refer solely to those portions of the digit contained within +the hoof. When, in this chapter on regional anatomy, or elsewhere, the +descriptive matter or the illustrations exceed that limit, it will be with +the object of observing the relationship between the parts we are concerned +with and adjoining structures. + +Taking the limit we have set, and enumerating the parts within the hoof +from within outwards, we find them as follows: + +A. THE BONES.--The lower portion of the second phalanx or os coronæ; the +third phalanx, os pedis, or coffin bone; and the navicular or shuttle bone. + +B. THE LIGAMENTS.--The ligaments binding the articulation. + +C. THE TENDONS.--The terminal portions of the extensor pedis and the flexor +perforans. + +D. THE ARTERIES. + +E. THE VEINS. + +F. THE NERVES. + +G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS. + +H. THE KERATOGENOUS MEMBRANE. + +I. THE HOOF. + + +A. THE BONES. + +THE SECOND PHALANX, OS CORONÆ, OR SMALL PASTERN BONE.--This belongs to +the class of small bones, in that it possesses no medullary canal. It is +situated obliquely in the digit, running from above downwards and from +behind to before, and articulating superiorly with the first phalanx or os +suffraginis, and inferiorly with the third phalanx and the navicular bone. + +[Illustration: FIG. 1.--THE BONES OF THE PHALANX. 1, The os suffraginis; 2, +the os coronæ; 3, the os pedis; 4, the navicular bone, hidden by the wing +of the os pedis, is in articulation in the position indicated by the barbed +line.] + +[Illustration: FIG. 2.--SECOND PHALANX OR OS CORONÆ (ANTERIOR VIEW). +1, Anterior surface; 2, superior articulatory surface; 3, inferior +articulatory surface; 4, pits for ligamentous attachment.] + +[Illustration: FIG. 3.--SECOND PHALANX OR OS CORONÆ (POSTERIOR VIEW). 1, +Posterior surface; 2, gliding surface for passage of flexor perforans; 3, +lower articulatory surface.] + +Cubical in shape, it is flattened from before to behind, and may be +described as possessing six surfaces: _An anterior surface_, covered with +slight imprints; _a posterior surface_, provided above with a transversely +elongated gliding surface for the passage of the flexor perforans; _two +lateral surfaces_, each rough and perforated by foraminæ, and each bearing +on its lower portion a thumb-like imprint for ligamentous attachment, and +for the insertion of the bifid extremity of the perforatus tendon; _a +superior surface_, bearing two shallow articular cavities, separated by an +antero-posterior ridge, for the accommodation of the lower articulating +surface of the first phalanx; _an inferior surface_, also articulatory, +which in shape is obverse to the superior, bearing two unequal condyles, +separated by an ill-defined antero-posterior groove, which surface +articulates with the os pedis and the navicular bone. + +_Development_.--The bone usually ossifies from one centre, but often there +is a complementary nucleus for the upper surface. + +THE THIRD PHALANX, OS PEDIS, OR COFFIN BONE.--This also belongs to the +class of short bones. It forms the termination of the digit, and, with the +navicular bone, is included entirely within the hoof. For our examination +it offers _three surfaces_, _two lateral angles_, and _three edges_. + +_The Anterior or Laminal Surface_, following closely in contour the wall of +the hoof, is markedly convex from side to side, nearly straight from above +to below, and closely dotted with foraminæ of varying sizes. On each side +of this surface is to be seen a distinct groove, the _preplantar groove_, +or _preplantar fissure_, which, commencing behind, between the basilar and +retrossal processes, runs horizontally forwards from the angles or wings of +the bone, and terminates anteriorly in one of the larger foraminæ. As the +name 'laminal' indicates, it is this surface which in the fresh state is +covered by the sensitive laminæ. + +_The Inferior or Plantar Surface_, hollowed in the form of a low arch, +presents for our inspection two regions, an anterior and a posterior, +divided by a well-marked line, the _Semilunar Crest_, which extends forward +in the shape of a semicircle. The anterior region, as is the laminal +surface, is covered with foraminæ; in this case more minute. In the recent +state it is covered by the sensitive sole. The posterior region, lying +immediately behind the semilunar crest, shows on each side of a median +process a large foramen, the _Plantar Foramen_. From this foramen runs the +_Plantar Groove_, a channel, bounded above by the superior edge, and below +by the semilunar crest of the bone, which conducts the plantar arteries +into the _Semilunar Sinus_, a well-marked cavity in the interior of the +bone. + +_The Superior or Articular Surface_ consists of two shallow depressions, +divided by a slight median ridge. Its posterior part shows a transversely +elongated facet for articulation with the navicular bone. + +_The Superior Edge_, outlining the superior margin of the laminal surface, +describes a curve, with the convexity of the curve forward. In the centre +of the curve is a triangular process, the _Pyramidal Process_, which serves +as the point of attachment of the extensor pedis. + +_The Inferior Edge_, the most extensive of the three, separates the laminal +from the solar surface. It is semicircular in shape, sharp, and finely +dentated, and is perforated by eight to ten large foraminæ. + +_The Posterior Edge_, very slightly concave, divides the small, +transversely elongated facet of the superior surface from the posterior +region of the inferior surface. + +_The Lateral Angles_ of the bone, also termed the _Wings_, are two +projections directed backwards. Each is divided by a cleft into an upper, +the _Basilar Process_, and a lower, the _Retrossal Process_. In old animals +the posterior portion of the cleft separating the two processes gradually +becomes filled in with bony deposit, thus transforming the cleft into a +foramen, which gives passage to the preplantar artery. We may mention +in passing that the lateral angles give attachment to the lateral +fibro-cartilages, and that the lateral angles themselves in old horses +become increased in size owing to ossification of portions of the adjacent +lateral cartilages. + +_Development_.--The os pedis ossifies from two centres, one of which is for +the articular surface; but this epiphysis fuses with the rest of the bone +before birth. + +[Illustration: FIG. 4.--THIRD PHALANX OR OS PEDIS (POSTERO-LATERAL VIEW). +1, Anterior or laminal surface; 2, preplantar foramen; 3, preplantar +groove; 4, basilar process of the wing; 5, retrossal process of the wing; +6, foramen caused by the ossifying together posteriorly of the basilar and +retrossal processes.] + +[Illustration: FIG. 5.--THIRD PHALANX OR OS PEDIS (VIEWED FROM BELOW). 1, +Plantar surface; 2, plantar foramen and plantar groove; 3, semilunar crest; +4, tendinous surface; 5, retrossal processes of the wings.] + +THE NAVICULAR BONE, SHUTTLE BONE, OR SMALL SESAMOID.--Placed behind +the articulating point of the second and third phalanges, this small +shuttle-shaped bone assists in the formation of the pedal articulation. It +is elongated transversely, flattened from above to below, and narrow at its +extremities. In it we see two surfaces, and two borders. + +_The Superior or Articular Surface_ of the bone, which may easily be +recognised by its smoothness, is moulded upon the lower articular surface +of the second phalanx, being convex in its middle, and concave on either +side. + +_The Inferior or Tendinous Surface_ resembles the preceding in form, but +is broader and less smooth. In the recent state it is covered with +fibro-cartilage for the passage of the flexor perforans. + +_The Anterior Border_ possesses above a small transversely elongated facet +for articulation with the os pedis, and below a more extensive grooved +portion, perforated by numerous foraminæ, affording attachment to the +interosseous ligaments of the articulation. + +_The Posterior Border_, thick in the middle, but thinner towards the +extremities, is roughened for ligamentous attachment. + +_Development_.--The bone ossifies from a single centre. + + +B. THE LIGAMENTS. + +THE ARTICULATION OF THE FIRST WITH THE SECOND PHALANX, OR THE PASTERN +JOINT.--Adhering to the limit we have set, this articulation should not +receive our attention. As, however, we shall in a later page be concerned +with fractures of the os coronæ, which fractures may affect the +articulation above mentioned, a brief note of its formation will not be out +of place. + +It is an imperfect hinge-joint, permitting of extension and flexion, +allowing the first phalanx to pivot on the second, and admitting of the +performance of slight lateral movements. It is formed by the opposing of +the inferior surface of the os suffraginis with the superior surface of the +os coronæ. The articulating surface of the os coronæ is supplemented by +the addition behind of a thick piece of _fibro-cartilage (the glenoid_) +attached inferiorly to the posterior edge of the upper articulatory surface +of the os coronæ, and superiorly by means of three fibrous slips on each +side to the os suffraginis. The innermost of these three slips becomes +attached to about the middle of the lateral edge of the suffraginis, and +the remaining two, beneath the first, attach themselves to nearer the lower +end of that bone. The posterior surface of the complementary cartilage +forms a gliding surface for the passage of the perforans. + +[Illustration: FIG. 6.--THE NAVICULAR BONE (VIEWED FROM BELOW). 1, Inferior +surface (smooth for the passage of the flexor perforans); 2, anterior edge +of inferior surface; 3, posterior edge of inferior surface.] + +[Illustration: FIG. 7.--THE NAVICULAR BONE (VIEWED FROM ABOVE, THE BONE +TILTED POSTERIORLY TO SHOW ITS ANTERIOR BORDER). 1, Superior articulatory +surface; 2, anterior border (grooved portion of); 3, anterior border +(articulatory portion of).] + +[Illustration: FIG. 8.--LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL +ARTICULATIONS (VIEWED FROM THE SIDE). (AFTER DOLLAR AND WHEATLEY.) 1, +Outermost slip from the glenoidal fibro-cartilage; 2, lateral ligament of +the first interphalangeal articulation; 3, prolongations of the lateral +ligament of the first interphalangeal articulation attached to the end of +the navicular bone to form the postero-lateral ligament of the pedal joint; +4, end of the navicular bone; 5, antero-lateral ligament of the pedal +joint.] + +_The Lateral Ligaments_.--These are large and thick, an outer and an inner, +running obliquely from above downwards and backwards. Each is inserted +superiorly into the lateral tubercle of the lower end of the first phalanx, +and inferiorly to the side of the second phalanx, their most inferior +fibres becoming finally fixed to the extremities of the navicular bone, +where they form the postero-lateral ligaments of the pedal articulation. +In front of the joint the extensor pedis plays the part of an additional +ligament. + +_The Synovial Membrane_.--This is limited in front by the tendon of the +extensor pedis, on each side by the lateral ligaments of the joint, and +behind by the glenoid fibro-cartilage. At this point it is prolonged +upwards as a pouch behind the lower extremity of the first phalanx. + +THE ARTICULATION OF THE SECOND PHALANX WITH THE THIRD, THE PEDAL, OR THE +COFFIN JOINT.--This also is an imperfect hinge-joint, permitting only of +flexion and extension, which movements are more restricted than in the +previous articulation. Three bones enter into its formation: the second +phalanx, the third phalanx, and the navicular bone. The lower articulatory +surface is formed by the third phalanx and the navicular bone combined. +To effect this the navicular is closely and firmly attached to the third +phalanx by an interosseous ligament. The two bones, as one, are then +connected to the second phalanx by four lateral ligaments, an anterior and +a posterior on each side. + +_The Interosseous Ligament_ consists of extremely short fibres running from +the extensively grooved portion of the anterior surface of the navicular +bone to become attached to the os pedis immediately behind its articular +surface. + +_The Antero-lateral Ligaments_ are attached by their superior extremities +to the lateral surfaces of the second phalanx, and by their inferior +extremities into the depressions on either side of the pyramidal process of +the os pedis. + +_The Postero-lateral Ligaments_.--As mentioned when describing the first +interphalangeal articulation, these are in reality continuations of the +lateral ligaments of that joint. Running obliquely downwards and backwards +from their point of attachment to the first phalanx they curve round the +lower part of the side of the second phalanx and end on the extremities and +posterior surface of the navicular bone. Having reached that position, they +send short attachments to the retrossal process of the os pedis and to the +inner face of the lateral cartilage. + +[Illustration: FIG. 9.--LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL +ARTICULATIONS (VIEWED FROM BEHIND). (AFTER DOLLAR AND WHEATLEY.) 1, +Suspensory ligament; 2, innermost slip from complementary cartilage of +pastern joint; 3, middle slip from complementary cartilage of pastern +joint; 4, outermost slip from complementary cartilage of pastern joint; 5, +glenoid or complementary cartilage of pastern joint; 6, postero-lateral +ligaments of the pedal joint; 7, the navicular bone; 8, interosseous +ligaments of the pedal joint; 9, semilunar crest of os pedis; 10, plantar +surface of os pedis.] + +_Synovial Membrane_.--This extends below the facets uniting the navicular +to the pedal bone, and offers for consideration two sacs. A large one +posteriorly running up behind the second phalanx to nearly adjoin the +sesamoidean bursæ, and a small one, a prolongation of the synovial membrane +between the antero-lateral and postero-lateral ligaments of the same side. +This latter is often distended, and on account of its close proximity to +the seat of operation, is liable to be accidentally opened in excision of +the lateral cartilage for quittor. + + +C. THE TENDONS + +In order to convey an intelligent understanding of the tendons it will be +wise to briefly describe the course of their parent muscles from their +commencement. + +THE EXTENSOR PEDIS.--The extensor pedis arises from the lower extremity +of the humerus in two distinct portions of unequal size, a muscular and a +tendinous. These are succeeded by two tendons passing in common through a +vertical groove at the lower end of the radius. Lower in the limb these +tendons separate, the outer and smaller joining the tendon of the extensor +suffraginis, and the inner and main tendon continuing its course downwards. +With the exception of the navicular, it is attached to all the bones of the +foot, and is covered internally by the capsular ligaments of the joints +over which it passes, those with which we are concerned being the pastern +joint and the pedal joint. Before its attachment to the os pedis it +receives on each side of the middle of the first phalanx reinforcement in +the shape of a strong band descending obliquely over the fetlock from the +suspensory ligament. Widening out in fanlike fashion, it is inserted into +the pyramidal process of the os pedis. + +_Action_.--The action of this muscle is to extend the third phalanx on the +second, the second on the first, and the first on the metacarpus. It also +assists in the extension of the foot on the forearm. + +[Illustration: FIG. 10.--THE FLEXOR TENDONS AND EXTENSOR PEDIS. (AFTER +HAÜBNER.) 1, Tendon of flexor perforans; 2, its supporting check-band from +the posterior ligament of the carpus; 3, tendon of the flexor perforatus; +4, ring and sheath of the flexor perforatus; 5, widening out of the flexor +perforatus to form the plantar aponeurosis; 6, suspensory ligament; 7, +reinforcing band from the suspensory ligament to the extensor pedis; 8, the +extensor pedis.] + +THE FLEXOR PEDIS PERFORATUS, OR THE SUPERFICIAL FLEXOR OF THE +PHALANGES.--In common with the perforans, this muscle arises from the inner +condyloid ridge of the humerus. It is reinforced at the lower end of the +radius by the superior carpal ligament, passes through the carpal and +metacarpo-phalangeal sheaths, and, arriving behind the fetlock, forms a +ring for the passage of the flexor perforans. Its termination is bifid, and +it is inserted on either side to the lateral surface of the second phalanx. + +[Illustration: FIG. 11.--THE FLEXOR PERFORANS AND FLEXOR PERFORATUS +TENDONS. The metacarpo-phalangeal sheath and the ring of the perforatus +laid open posteriorly, and the cut edges reflected to show the passage +of the perforans. 1, Reflected cut edges of the perforatus ring and the +metacarpo-phalangeal sheath; 2, the perforans tendon; 3, point of insertion +of the perforans tendon into the semilunar crest of the os pedis (this +widened and thickened extremity of the perforans is known as the plantar +aponeurosis).] + +[Illustration: FIG. 12.--THE FLEXOR PERFORATUS AND FLEXOR PERFORANS +TENDONS. The metacarpo-phalangeal sheath and the ring of the perforatus +laid open posteriorly, and the cut edges reflected; the flexor perforans +cut through at about the region of the sesamoids, and its inferior portion +deflected. 1, Superior end of severed perforans tendon; 2, inferior end of +severed perforans tendon; 3, insertion of flexor perforans into +semilunar crest of os pedis; 4, the cut and reflected edges of the +metacarpo-phalangeal sheath and perforatus ring; 5, the bifid insertion of +the flexor perforatus into the lateral surfaces of the os corona; 6, +the capsular ligament of the pedal joint; 7, the navicular bone; 8, the +posterior surface and glenoid fibro-cartilage of the os coronæ.] + +_Action_.--This muscle flexes the second phalanx on the first, the first on +the metacarpus, and the entire foot on the forearm. Mechanically, it +acts as a stay when the animal is standing by maintaining the +metacarpo-phalangeal angle. + +[Illustration: FIG. 13.--MEDIAN SECTION OF FOOT. _A_, Os suffraginis; _B_, +os coronæ; _C_, os pedis; _D_, navicular bone; _E_, tendon of the extensor +pedis; _F_, insertion of the extensor pedis into the pyramidal process of +the os pedis; _G_, the tendon of the flexor perforatus; _H_, insertion of +perforatus into the os coronæ; _I_, tendon of the flexor perforans; _J_, +its passing attachment to the os coronæ; _K_, its final insertion into the +semilunar crest of os pedis; _a_, section of coronary cushion; _b_, section +of plantar cushion; _c_, semilunar sinus of os pedis.] + +THE FLEXOR PEDIS PERFORANS, OR THE DEEP FLEXOR OF THE PHALANGES.--This +muscle consists of three easily-divided portions: an ulnar, a humeral, and +a radial, and has for points of origin the olecranon process of the ulna, +the inner condyloid ridge of the humerus, and the posterior surface of the +radius. These portions are continued by a common tendon which enters the +carpal sheath with the tendon of the perforatus, and continues with it +through the synovial sheath of the metacarpo-phalangeal region. Like the +last-named tendon, it receives a supporting check-band, in this case from +the posterior ligament of the carpus. Passing down between the suspensory +ligament in front, and the perforatus tendon behind, it glides over the +sesamoid pulley and passes through the ring formed by the perforatus. +Continuing its course, it passes between the bifurcating portions of the +extremity of the perforatus, glides over the smooth posterior surface of +the supplementary glenoid cartilage of the articulation of the first and +second phalanges, plays over the inferior surface of the navicular bone, +and finally becomes inserted into the semilunar crest of the os pedis. On +reaching the posterior border of the navicular bone it widens out to form +the plantar aponeurosis. + +In connection with the lower portion of this tendon must be noticed the +Navicular Sheath. This is a synovial sheath lining the deep face of the +tendon, and reflected on to the navicular bone and the interosseous +ligament of the pedal joint. This will be of particular interest when we +come to deal with cases of pricked foot from picked up nails. Above, it is +in connection with the synovial membrane of the pedal articulation and that +of the metacarpo-phalangeal sheath. + +_Action_.--The action of the perforans is to flex the third on the second, +and the second on the first phalanx. The latter it flexes in turn on the +metacarpus. It also assists in the flexion of the entire foot on the +forearm, and in supporting the angle of the metacarpo-phalangeal +articulation when the animal is standing. + + +D. THE ARTERIES. + +So far as the arteries supplying the foot are concerned, we shall be +interested in following up the distribution of the two digitals, which are +the terminal branches of the Large Metacarpal. + +THE LARGE METACARPAL, OR COLLATERAL ARTERY OF THE CANNON.--This, the larger +terminal branch of the posterior radial artery, needs brief mention, for +the reason that we shall be afterwards concerned with it in the operation +of neurectomy. Its point of origin is the inside of the inferior extremity +of the radius. Descending in company with the flexor tendons, and passing +behind the carpus and beneath the carpal sheath, it continues its descent, +in company with the internal plantar nerve and the internal metacarpal +vein, on the inner side of the flexor tendons until just above the fetlock. +At this point it bifurcates into the digital arteries. + +From the carpus downwards the large metacarpal artery, the internal +metacarpal vein, and the internal plantar nerve are in close relation with +each other. The vein holds the anterior position. The artery is between the +two, and has the nerve in close contact with it behind. + +THE DIGITAL ARTERIES, OR COLLATERAL ARTERIES OF THE DIGIT.--These are of +large volume, and carry the blood to the keratogenous apparatus of the +foot. They separate from each other at an acute angle, and pass over the +side of the fetlock, one to the inside, the other to the outside, to reach +the internal face of the basilar process of the os pedis, where they +bifurcate to form the _Plantar_ and _Preplantar_ arteries. In the whole +of their course the digital arteries follow the flexor tendons, and are +related in front to the digital vein, and behind to the posterior branch of +the plantar nerve. This is the nerve implicated in the lower operation of +neurectomy, and its relation to adjoining structures will be detailed +under Section F. of this chapter. During its course the digital artery +gives off branches in the following positions: + +1. _At the Fetlock_ numerous branches to the metacarpo-phalangeal +articulation, the sesamoid sheath, and the tendons. + +2. _At the Upper Extremity of the First Phalanx_ branches for the supply of +the surrounding tissues, and for the tissues of the ergot. + +3. _Towards the Middle of the Third Phalanx_, the _Perpendicular_ artery +of Percival. This arises at a right angle from the main vessel, and +immediately divides into two series of ramifications--an ascending and +a descending. The ramifications of these series freely anastomose with +corresponding vessels of the opposite side. + +4. _At the Superior Border of the Lateral Cartilage_, the _Artery of the +Plantar Cushion_. This is directed obliquely downwards and backwards, under +cover of the cartilage, and is distributed to the middle portion of the +complementary apparatus of the os pedis, as well as to the villous tissue +and the coronet. A branch of it is turned forwards to join with the +coronary circle in forming the _circumflex artery of the coronet_. + +[Illustration: FIG. 14.--THE ARTERIES OF THE FOOT. The digital; 2, the +perpendicular--(_a_) its ascending branch, (_b_) its descending branch; +3, circumflex artery of coronary cushion; 4, the preplantar (ungual) +artery--this is seen issuing from the preplantar foramen, and distributing +numerous ascending (_c_) and descending (_d_) branches (the latter concur +in forming the circumflex artery of the toe); 5, the circumflex artery +of the toe; 6, at the point marked (*) the terminal branch of the +digital--namely, the plantar ungual--is hidden behind the lateral +cartilage; 7, the lateral cartilage.] + +5. _Under the Lateral Cartilage_ two transverse branches, an anterior and +a posterior, to form the _Coronary Circle_. The numerous ramifications +of these branches anastomose both anteriorly and posteriorly with their +corresponding branches of the artery of the opposite side. This circle +closely embraces the os coronæ. Among the larger branches given off from +its anterior portion are two descending, one on each side of the extensor +pedis, to assist in the formation of the _Circumflex Artery of the Coronary +Cushion_. The formation of this last-named artery is completed posteriorly +by the before-mentioned branch from the artery of the plantar cushion. + +THE PREPLANTAR (UNGUAL[A]) ARTERY.--This, the smaller of the two terminal +branches of the digital, is situated inside the basilar process of the os +pedis. It turns round this to gain the fissure between the basilar and +retrossal processes, and becomes lodged in the preplantar fissure. Here +it terminates in several divisions which bury themselves in the os pedis. +Before leaving the inner aspect of the pedal wing it supplies a deep branch +to the heel and the villous tissue. Gaining the outer aspect of the +wing, it distributes a further backward branch, which passes behind the +circumflex artery of the pedal bone, and, during its passage in the +preplantar fissure, gives off ascending and descending branches, which +ramify in the laminal tissue. + +THE PLANTAR (UNGUAL[A]) ARTERY.--This, the larger of the two terminals +of the digital, may be looked upon as a continuation of the main vessel. +Running along the plantar groove, it gains the plantar foramen. Here it +enters the interior of the bone (the semilunar sinus) and anastomoses with +the corresponding artery of the opposite side. The circle of vessels so +formed is called the _Plantar Arch_ or the _Semilunar Anastomosis_. + +[Footnote A: The epithet 'ungual' is added by Chauveau to distinguish +these arteries from the properly so-called plantar arteries--the terminal +divisions of the posterior tibial artery.] + +From the semilunar anastomosis radiate two main groups of arterial +branches, an ascending group and a descending one. The _ascending_ branches +penetrate the substance of the os pedis, and emerge by the numerous +foraminæ on its laminal surface. The _descending_ branches, larger in size, +also penetrate the substance of the pedal bone, and emerge in turn from +the foraminæ cribbling its outer surface--in this case the set of larger +foraminæ opening on its inferior edge. Having gained exit from the bone, +their frequent anastomosis, right and left, with their fellows forms a +large vessel following the contour of the inferior edge of the os pedis. +This constitutes the _Circumflex Artery of the Toe_. + + +E. THE VEINS. + +These commence at the foot with a series of plexuses, which may be +described as forming (1) AN INTERNAL OR INTRA-OSSEOUS VENOUS SYSTEM, and +(2) AN EXTERNAL OR EXTRA-OSSEOUS VENOUS SYSTEM. + +1. THE INTRA-OSSEOUS VENOUS SYSTEM.--This is a venous system within the +structure of, and occupying the semilunar sinus of the os pedis. It follows +in every respect the arrangement of the arteries as before described in the +same region. Efferent vessels emerge from the plantar foraminæ, follow the +plantar fissures, and ascend within the basilar processes of the os pedis. +Here they lie under shelter of the lateral cartilages, and assist in the +formation of the deep layer of the coronary plexus of the extra-osseous +system. + +2. THE EXTRA-OSSEOUS VENOUS SYSTEM.--This may be regarded as a close-meshed +network enveloping the whole of the foot. Although a continuous system, it +is best described by recognising in it three distinct parts: + + _(a) The Solar Plexus_. + _(b) The Podophyllous Plexus_. + _(c) The Coronary Plexus_. + +_(a) The Solar Plexus_.--The veins of this plexus discharge themselves in +two directions: (1) _By a central canal_ or canals running along the bottom +of the lateral lacunæ of the plantar cushion to gain the deep layer of the +coronary plexus. (2) _By the Circumflex or Peripheral Vein of the Toe_, a +canal formed by ramifications from the solar and the podophyllous plexuses, +and following the direction of the artery of the same name. The circumflex +vein terminates by forwarding branches to concur in the formation of the +superficial coronary plexus. + +_(b) The Podophyllous or Laminal Plexus_.--The podophyllous veins +anastomose below with the circumflex vein of the solar plexus, and above +with the veins of the coronary plexus. + +_(c) The Coronary Plexus_.--This proceeds from the podophyllous, the +intra-osseous, and the solar networks, and consists of a _central_ and _two +lateral parts_. + +The _central_ portion lies between the lateral cartilages and immediately +under the coronary cushion. The _lateral portions_ are ramifications on +both surfaces of the lateral cartilages. The ramifications on the lateral +cartilages may be again distinguished as _superficial_ and _deep_. The +superficial layer is distributed over the external face of the cartilage, +forming thereon a dense network, and finally converges towards the superior +limit of the plexus to form ten or twelve principal branches, which again +unite to form two large vessels. These vessels, by their final fusion at +the lower end of the first phalanx, constitute the digital vein. The deep +layer is formed, as before described, by ascending branches from the +posterior parts of the podophyllous and solar plexuses, and by branches +from the intra-osseous system of the pedal bone. The veins of this deep +layer finally drain into the two vessels proceeding from the superficial +layer, which go to the formation of the digital vein. + +THE DIGITAL VEINS--These arise from the network formed on the surfaces of +the lateral cartilages, and ascend in front of the digital arteries to +unite above the fetlock, where they form an arch between the deep flexor +and the suspensory ligament. From this arch (named the _Sesamoidean)_ +proceed the Metacarpal Veins. + +THE METACARPAL VEINS.--Three in number, they are distinguished as an +_Internal_ and an _External Metacarpal_, and a _Deep_ or _Interosseous +Metacarpal_. As we shall be concerned with these in the higher operation of +neurectomy, we may give them brief mention. + +THE INTERNAL METACARPAL VEIN, the largest of the three, has relations +with the internal metacarpal artery and the internal plantar nerve. These +relations were shortly discussed under the section devoted to the arteries, +to which the reader may refer. + +THE EXTERNAL METACARPAL VEIN.--This ascends on the external side of the +flexor tendons in company with the external plantar nerve. + +_The Interosseous Vein_.--This is an irregular vessel running up between +the suspensory ligament and the posterior face of the large metacarpal +bone. + + +F. THE NERVES. + +THE PLANTAR NERVES.--These are two in number, and are distinguished as +Internal and External. + +THE INTERNAL PLANTAR NERVE lies behind and in close contact with the great +metacarpal artery during that vessel's course down the region of the +cannon. A point of interest is that it gives off at about the middle of +the cannon a branch which bends obliquely downwards and behind the flexor +tendons to join its fellow of the opposite side--namely, the external +plantar. This it joins an inch or more above the bottom of the splint bone. +Measured in a straight line, this is about 2-1/2 inches below its point +of origin. Near the fetlock, at the level of the sesamoids, the internal +plantar nerve ends in several digital branches. + +THE EXTERNAL PLANTAR NERVE.--This holds a position to the outside of the +metacarpal region, analogous to that of the internal plantar nerve on +the inside of the limb, running down on the external edge of the flexor +tendons. Unlike the internal nerve, it is accompanied by a single vessel +only, the external metacarpal vein, behind which it lies. At the level of +the sesamoid bones it divides, as does the _internal_ nerve, into three +main branches--the digital nerves. + +[Illustration: FIG. 15.--THE VEINS AND NERVES OF THE FOOT. 1, The digital +vein; 2, its main tributaries, draining the podophyllous plexus, and +concurring to form the digital; 3. the digital artery (the main trunk only +of this is shown, in order to show its relationship with the vein and +nerve); 4, the plantar nerve, with its three branches--(_a_) the anterior +digital, (_b_) the middle digital, (_c_) the posterior digital; 5, the +podophyllous plexus; 6, superficial portion of the coronary plexus; 7, the +peripheral or circumflex vein of the toe.] + +THE DIGITAL NERVES.--These are distinguished as Anterior, Middle, and +Posterior. + +_The Anterior Branch_ descends in front of the vein, distributing cutaneous +branches to the front of the digit, and terminating in the coronary +cushion. + +_The Middle Branch_ descends between the artery and the vein, and freely +anastomoses with the two other branches. It terminates in the coronary +cushion and the sensitive laminæ. + +_The Posterior Branch_.--This is the largest of the three, and may be +regarded as the direct continuation of the plantar. At the fetlock it is +placed immediately above the digital artery, but afterwards takes up a +position directly behind that vessel. Together with the digital artery it +descends to near the basilar process of the os pedis. Here it passes with +the plantar artery into the interior of the os pedis, and continues its +main branch, with the preplantar artery, in the fissure of the same name, +to finally furnish supply to the os pedis and the sensitive laminæ. It is +this nerve which is divided in the low operation of neurectomy. + +Beyond the fact of this branch descending, in the region of the pastern, 1 +inch behind the digital artery, a further point of interest presents itself +to the surgeon, and one to which attention must be paid. This is the +presence in close proximity to the nerve of the Ligament of the Pad +(Percival), or the Ligament of the Ergot (McFadyean). This is a +subcutaneous glistening cord originating in the ergot of the fetlock, +passing in an oblique direction downwards and forwards, and crossing over +on its way both the digital artery and the posterior branch of the digital +nerve. + +In the foregoing description of the anatomy, we have taken the fore-limb as +our guide. In the hind-limb, where they reach the foot, the counterparts of +the tendons, arteries, veins, and nerves differ in no great essential from +their fellows in the fore. They will therefore need no special mention. + + +G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS. + +This consists of two lateral pieces, the LATERAL CARTILAGES or +_Fibro-cartilages_ of the pedal bone, united behind and below by the +_Plantar Cushion_. + +1. THE LATERAL CARTILAGES.--Each is a flattened plate of cartilage, +possessing two faces and four borders separated by four angles. + +The external face is convex, covered by a plexus of veins, and slightly +overhangs the pedal bone. The internal face is concave, and covers in +front the pedal articulation and the synovial sac, already mentioned as +protruding between the antero- and postero-lateral ligaments of that joint. +We have already remarked that this is a point of interest to be remembered +in connection with the operation for quittor. Below and behind, the +internal face of the cartilage is united to the plantar cushion. + +[Illustration: FIG. 16.--EXTERNAL FACE OF THE OUTER LATERAL CARTILAGE. 1, +External face of cartilage--(_a_) its upper border, (_b_) its posterior +border, (_c_) its anterior border, (_d_) its inferior border; 2, the os +pedis; 3, wing of os pedis.] + +The upper border, sometimes convex, sometimes straight, is thin and +bevelled, and may easily be felt in the living animal. It is this border +that the digital vessels cross to gain the foot, and the border is often +broken by a deep notch to accommodate them. The inferior border is attached +in front to the basilar and retrossal processes, behind which it blends +with the plantar cushion. The posterior border is oblique from before to +behind, and above to below, and joins the preceding two. The anterior +border is oblique in the same direction, and is intimately attached to the +antero-lateral ligament of the pedal articulation. The cartilages of the +fore-feet are thicker and more extensive than those of the hind. + +2. THE PLANTAR CUSHION on FIBRO-FATTY FROG.--Composed of a fibrous +meshwork, in the interstices of which are lodged fine elastic and +connective fibres and fat cells, this wedge-shaped body occupies the space +between the two lateral cartilages, the extremity of the perforans tendon, +and the horny frog. It offers for consideration an antero-superior and an +infero-posterior face, a base, an apex, and two borders. + +The antero-superior face is in contact with the terminal expansion of the +perforans tendon. The infero-posterior face is covered by the keratogenous +membrane, and follows closely the shape of the horny frog, on whose inner +surface it is moulded. It presents, therefore, at its centre a single +conical prolongation, the _Pyramidal Body_, which is continued behind, as +is the horny frog, in the shape of two lateral ridges divided by a median +cleft. The _base_ of the cushion lies behind, and consists of two lateral +masses, _the Bulbs of the Plantar Cushion_. In front these are continuous +with the ridges of the pyramidal body, while behind they become confounded +with the lateral cartilages and the coronary cushion. The _apex_ is fixed +into the plantar surface of the os pedis, in front of its semilunar ridge. +The _borders_, right and left, are wider behind than before, and are in +relation with the inner faces of the lateral cartilages. + + +H. THE KERATOGENOUS MEMBRANE. + +THE KERATOGENOUS, OR HORN-PRODUCING MEMBRANE, is in reality an extension +of the dermis of the digit. It covers the extremity of the digit as a sock +covers the foot, spreading over the insertion of the extensor pedis, the +lower half of the external face of the lateral cartilages, the bulbs of the +plantar cushion, the pyramidal body, the anterior portion of the plantar +surface of the os pedis, and over the anterior face of the same bone. In +turn, as the human foot with its sock is covered by the boot, this is +encased by the hoof, the formation of which we shall study later. + +To expose the membrane for study the hoof must be removed. This may be done +in two ways. By roasting in a fire, and afterwards dragging off the horny +structures with a pair of pincers, a knife having first been passed round +the superior edge of the horny box. Or by maceration in water for several +days, when the hoof will become loosened by the process of decomposition, +and may be easily removed by the hands. The latter method is less likely +to injure the sensitive structures, and will expose them with a fresh +appearance for observation. + +For purposes of description the keratogenous membrane is divided into three +regions: + + 1. The Coronary Cushion. + 2. The Velvety Tissue. + 3. The Podophyllous Tissue, or the Sensitive laminæ. + +1. THE CORONARY CUSHION. In the foot stripped of the hoof the coronary +cushion is seen as a rounded structure overhanging the sensitive laminæ +after the manner of a cornice. It extends from the inner to the outer bulbs +of the plantar cushion, and is bounded above by the perioplic ring, and +below by the laminæ. + +When _in situ_ it is accommodated by the _Cutigeral Groove_, a cavity +produced by the bevelling out of the superior portion of the inner face of +the wall of the hoof. Its superior surface is covered by numerous elongated +papillæ, set so closely as to give the appearance of the 'pile' of velvet. +This is observed to the best advantage with the foot immersed in water. + +_The Superior Border_ of the cushion is bounded by the _Perioplic Ring_, +the cells of which have as their function the secreting of the _Periople_, +a layer of thin horn to be noted afterwards as covering the external face +of the wall. From the perioplic ring the cushion is separated by a narrow +and shallow, though well-marked, groove. + +The inferior border is bounded by the sensitive laminæ. + +[Illustration: FIG. 17.--THE KERATOGENOUS MEMBRANE (VIEWED FROM THE SIDE). +(THE HOOF REMOVED BY MACERATION.) 1. The sensitive laminæ, or podophyllous +tissue; 2, the coronary cushion; 3, the perioplic ring; 4, portion of +plantar cushion; 5, groove separating perioplic ring from coronary cushion; +6. the sensitive sole.] + +The upper portions of the laminæ, those in contact with the cushion, are +pale in contrast with the portions immediately below, and thus there is +given the appearance of a white zone adjoining the inferior border of the +cushion. + +Widest at its centre, the cushion narrows towards its extremities, which, +arriving at the bulbs of the plantar cushion, bend downwards into the +lateral lacunæ of the pyramidal body, where they merge into the velvety +tissue of the sole and frog. + +The papillæ of the coronary cushion secrete the horn tubules forming the +wall, and the papillæ of the perioplic ring secrete the varnish-like veneer +of thin horn covering the outside surface of the hoof. + +[Illustration: FIG. 18.--THE KERATOGENOUS MEMBRANE (VIEWED FROM BELOW). +(THE HOOF REMOVED BY MACERATION.) 1, The sensitive sole; 2, the sensitive +frog[A]--(a) its median lacuna, (6) its lateral lacuna; 3. V-shaped +depression accommodating the toe-stay; 4, the sensitive laminæ which +interleave with the horny laminæ of the bar.] + +[Footnote A: The sensitive frog thinly invests the plantar cushion or +fibre-fatty frog, the outline of which is here indicated.] + +2. THE VELVETY TISSUE.--This is the portion of the keratogenous membrane +covering the plantar surface of the os pedis and the plantar cushion. To +the irregularities of the latter body--its bulbs, pyramidal body, and its +lacunæ--it is closely adapted. Its surface may, therefore, be divided into +_(a) The Sensitive Frog_, and _(b) The Sensitive Sole_. + +_(a) The Sensitive Frog_ is that part of the velvety tissue moulded on the +lower surface of the plantar cushion. The shape of the plantar cushion has +already been described as identical with that of the horny frog. It only +remains to state that, like the coronary cushion, the surface of the +sensitive frog is closely studded with papillæ. The cells clothing the +papillæ are instrumental in forming the horny frog. + +_(b) The Sensitive Sole_.--As its name indicates, this is the portion of +the keratogenous membrane that covers the plantar surface of the os pedis. +It also is clothed with papillæ, which again give rise to the formation of +that part of the horny box to which they are adapted--namely, the sole. + +3. THE PODOPHYLLOUS TISSUE, OR SENSITIVE LAMINÆ.--This portion of the +keratogenous membrane is spread over the anterior face and sides of the os +pedis, limited above by the coronary cushion, and below by the inferior +edge of the bone. It presents the appearance of fine longitudinal streaks, +which, when closely examined with a needle, are found to consist of +numerous fine leaves. These extend downwards from the lower border of the +coronary cushion to the inferior margin of the os pedis. At this point each +terminates in several large villous prolongations, which extend into the +horny tubes at the circumference of the sole. At the point of the toe this +membrane sometimes shows a V-shaped depression, into which fits a inverted +V-shaped prominence on the inner surface of the wall at this point. + +The sensitive laminæ increase in width from above to below. Their free +margin is finely denticulated, while their sides are traversed from top to +bottom by several folds (about sixty), which, examined microscopically, are +seen to consist of secondary leaves, or _laminellæ_. + +Examined on the foot, deprived of its horny covering, the sensitive laminæ +are, the majority of them, in close contact with each other. In the normal +state this is not so. The interstices between the leaves are then occupied +by the horny leaves, to be afterwards described as existing on the inner +surface of the wall. + +Reaching and rounding the heels, the sensitive laminæ extend forward for a +short distance, where they interleave with the horny laminæ of the bars. + +Much discussion has centred round the point as to whether or no the cells +of the sensitive laminæ take any share in the formation of the horn of the +wall. This will be alluded to in a future chapter. + + +I. THE HOOF. + +Removed from the foot by maceration a well-shaped hoof is cylindro-conical +in form, and appears to the ordinary observer to consist of a box or case +cast in one single piece of horn. Prolonged maceration, however, will show +that the apparently single piece is divisible into three. These are known +as (1) THE WALL, (2) THE SOLE, and (3) THE FROG. In addition to these, we +have also an appendage or circular continuation of the frog named (4) THE +PERIOPLE, or CORONARY FROG BAND. These various divisions we will study +separately. + +1. THE WALL is that portion of the hoof seen in front and laterally when +the horse's foot is on the ground. Posteriorly, instead of being continued +round the heels to complete the circle, its extremities become suddenly +inflected downwards, forwards, and inwards. These inflections can only be +seen with the foot lifted from the floor, and form the so-called _Bars_. It +will be noticed, too, with the foot lifted, that the wall projects beyond +the level of the other structures of the plantar surface, taking upon +itself the bearing of the greatest part of the animal's weight. + +The horn of the wall, viewed immediately from the front, is known as the +_Toe_, which again is distinguished as _Outside Toe_ or _Inside Toe_, +according as the horn to its inner or outer aspect is indicated. The +remainder of the external face of the wall, that running back to the heels, +is designated the _Quarters_. + +In the middle region of the toe, the wall following the angle of the bones +is greatly oblique. This obliquity decreases as the quarters are reached, +until on reaching the heels the wall is nearly upright. + +[Illustration: FIG. 19.--THE WALL OF THE HOOF. 1, The toe; 2, inner toe; 3, +outside toe; 4, the quarter; 5, entigeral groove; 6, horny laminæ.] + +For observation the wall offers two faces, two borders, and two +extremities. + +_The External Face_ is convex from side to side, but straight from the +upper to the lower border. Examined closely, it is seen to be made up of +closely-arranged parallel fibres running in a straight line from the upper +to the lower border, and giving the surface of the foot a finely striated +appearance. In addition to these lines, which are really the horn tubules, +the external face is marked by a series of rings which run horizontally +from heel to heel. These are due to varying influences of food, climate, +and slight or severe disease. This will be noted again in a later page. In +a young and healthy horse the whole of the external face of the wall +is smooth and shining. This appearance is due to a thin layer of horn, +secreted independently of the wall proper, termed the periople. + +[Illustration: FIG. 20.--INTERNAL FEATURES OF THE WALL, FROG, AND SOLE +(MESIAN SECTION OF HOOF). 1, Horny laminæ covering internal face of wall; +2, superior border of wall; 3, junction of wall with horny sole; 4, the +cutigeral groove; 5, the horny sole; 6, the horny frog (that portion of +it known as the 'frog-stay'); 7, inverted V-shaped ridge on wall and sole +(known as the 'toe-stay'); 8, anterior face of wall; 9, inferior border of +wall.] + +_The Internal Face_ of the wall, that adapted to the sensitive laminæ, +is closely covered over its entire surface with white parallel leaves +_(Keraphyllæ_, or horn leaves, to distinguish them from the _Podophyllæ_, +or sensitive leaves). These keraphyllæ dovetail intimately with the +sensitive laminæ, covering the os pedis. Running along the superior portion +of the inner face is the _Cutigeral Groove_. This cavity has been mentioned +before as accommodating the coronary cushion, whose shape and general +contour it closely follows, being widest and deepest in front, and +gradually decreasing as it proceeds backwards. It is hollowed out at the +expense of the wall, and shows on its surface numberless minute openings +which receive the papillæ of the coronary cushion. + +At the bottom of the internal face, at the point where the toe joins the +sole, will be noted the before-mentioned inverted V-shaped prominence. +Its position will be clearly understood when we say that it gives the +appearance of having been forced there by the pressure of the toe-clip of +the shoe. This will be noted again when dealing with the sole. + +_The Inferior Border_ of the wall offers little to note. It is that portion +in contact with the ground, and subject to wear. A point of interest is its +union with the sole. This will be noticed in a foot which has just been +pared as a narrow white or faint yellow line on the inner or concave face +of the wall at its lower portion. It marks the point where the horny leaves +of the wall terminate and become locked with corresponding leaves of the +circumference of the sole. + +_The Superior Border_ follows closely the line marked by the perioplic ring +and the groove separating the latter from the coronary cushion. + +_The Extremities_ of the wall are formed by the abruptly reflected portions +of the wall at the heels. Termed by some the 'Inflexural Nodes,' they are +better known to us as the '_Points of the Heels_.' + +2. THE SOLE.--The sole is a thick plate of horn which, in conjunction +with the bars and the frog, forms the floor of the foot. In shape it is +irregularly crescentic, its posterior portion, that between the horns of +the crescent, being deeply indented in a V-shaped manner to receive the +frog. Its upper surface is convex, its lower concave. It may be recognised +as possessing two faces and two borders. + +_The Superior or Internal Face_ is adapted to the sole of the os pedis. Its +highest point, therefore, is at the point of its V-shaped indentation. From +this point it slopes in every direction downwards and outwards until near +the circumference. Here it curves up to form a kind of a groove in which +is lodged the inferior edge of the os pedis. In the centre of its anterior +portion--that is to say, at the toe--will be seen a small inverted V-shaped +ridge, which is a direct continuation of the same shaped prominence before +mentioned on the internal face of the wall. This Fleming has termed the +toe-stay, from a notion that it serves to maintain the position of the os +pedis. The whole of the superior face of the sole is covered with numerous +fine punctures which receive the papillæ of the sensitive sole. + +_The Inferior Face_ is more or less concave according to circumstances, its +deepest part being at the point of the frog. Sloping from this point to its +circumference, it becomes suddenly flat just before joining the wall. Its +horn in appearance is flaky. + +[Illustration: FIG. 21.--INFERIOR ASPECT OF HOOF. _a_ The inferior face of +horny sole; _b_, inferior border of the wall; _c_, body or cushion of the +frog; _d_, median lacuna of the frog; _e_, lateral lacuna of the frog; _f_, +the bar; _g_, the quarter; _h_, the point of the frog; _i_ the heel.] + +_The External Border_ or Circumference is intimately dovetailed with the +horny laminæ of the wall. At its circumference the sole, if unpared, is +ordinarily as thick as the wall. This thickness is maintained for a short +distance towards its centre, after which it becomes gradually more thin. + +_The Internal Border_ has the shape of an elongated V with the apex +pointing forwards. It is much thinner than the external border, and, +like it, is dovetailed into the horny laminæ of the inflections of the +wall--namely, the bars. In front of the termination of the bars it is +dovetailed into the sides and point of the frog. Where unworn by contact +with the ground, the horn of the sole is shed by a process of exfoliation. + +3. THE FROG.--Triangular or pyramidal in shape, the frog bears a close +resemblance to the form of the plantar cushion, upon the lower surface of +which body it is moulded. It offers for consideration two faces, two sides, +a base, and a point or summit. + +[Illustration: FIG. 22.--HOOF WITH THE SENSITIVE STRUCTURES REMOVED. 1, +Superior face of horny frog; 2, the frog-stay; 3, the lateral ridges of +the frog's superior surface; 4, the horny laminæ at the inflections of the +wall.] + +_The Superior Face_ is an exact cast of the lower surface of the plantar +cushion. It shows in the centre, therefore, a triangular depression, with +the base of the triangle directed backwards. Posteriorly, the depression +is continued as two lateral channels divided by a median ridge. The median +ridge widens out as it passes backwards, forming the larger part of the +posterior portion of the frog. This median ridge fits into the cleft of the +plantar cushion. It serves to prevent displacement of the sensitive from +the horny frog, and has been rather aptly termed the '_Frog-stay_.' + +_The Inferior Surface_ is an exact reverse of the superior. The triangular +depression of the superior surface is represented in the inferior surface +by a triangular projection, and the ridge-like frog-stay of the upper +surface is represented below by a median cleft, the _Median Lacuna_ of the +frog. The triangular projection in front of the median lacuna is the +body or cushion of the frog. It is continued backwards as two ridge-like +branches, which, at the points of the heels, form acute angles with the +bars. On the outer side of each lateral ridge is a fissure. These are known +as the Lateral Lacunæ. + +_The Sides_ of the frog are flat and slightly oblique. They are closely +united to the bars and to the triangular indentation in the posterior +border of the sole. + +_The Base_ of the frog is formed by the extremities of its branches, which, +becoming wider and more convex as they pass backwards, form two rounded, +flexible, and elastic masses separated from each other by the median +lacuna. These constitute the 'glomes' of the frog. They are continuous with +the periople. + +_The Point of the Frog_ is situated, wedge-like, within the triangular +notch in the posterior border of the sole. + +4. THE PERIOPLE, OR CORONARY FROG BAND.--This is a continuation of the +substance of the frog around the extreme upper surface of the hoof. It is +widest at the heels over the bulbs or glomes of the frog, and gradually +narrows as it reaches the front of the hoof. It is, in reality, a thin +pellicle of semi-transparent horn secreted by the cells of the perioplic +ring. When left untouched by the farrier's rasp it serves the purpose, by +acting as a natural varnish, of protecting the horn of the wall from the +effects of undue heat or moisture. + + + +CHAPTER III + +GENERAL PHYSIOLOGICAL AND ANATOMICAL OBSERVATIONS + + +The matter embraced by the heading of this chapter will offer for +discussion many subjects of great interest to the veterinary surgeon. +Around some of them debate has for many years waxed more than keen. Of the +points in dispute, some of them may be regarded as satisfactorily settled, +while others offer still further room for investigation. + +In this volume we can only hope to deal with them in brief, and must select +such as appear to have the greatest bearing on the veterinarian's everyday +practice. + +Always prolific of heated discussion has been one question: 'Are the horny +laminæ secreted by the sensitive?' To answer this satisfactorily, it will +be best to give a short account of the mode of production of the hoof in +general. + + +A. DEVELOPMENT OF THE HOOF. + +Starting with the statement that it is epidermal in origin, we will +first consider the structure of the skin, and follow that with a brief +description of the structure and mode of growth of the human nail, a short +study of which will greatly assist us when we come to investigate the +manner of growth of the horse's hoof. + +THE SKIN is composed of two portions, the EPIDERMIS and the CORIUM. + +THE EPIDERMIS is a stratified epithelium. The superficial layers of the +cells composing it are hard and horny, while the deeper layers are soft and +protoplasmic. These latter form the so-called _Retae Mucosum_ of Malpighi. + +[Illustration: FIG. 23.--VERTICAL SECTION OF EPIDERMIS (HUMAN). (AFTER +RANVIER) _A_, The horny layer of the epidermis; _B_, the rete mucosum; +_a_, the columnar pigment-containing cells of the rete; _b_, the polyhedral +cells; _c_, the stratum granulosum; _d_, the stratum lucidum; _e_, swollen +horny cells; _f_ the stratum squamosum.] + +Commencing from below and proceeding upwards, we find that the lowermost +cells of the rete mucosum, those that are set immediately on the corium, +are columnar in shape. In animals that have a coloured skin these cells +contain pigment granules. Directly superposed to these we find cells which +in shape are polyhedral. Above them, and forming the most superficial layer +of the rete mucosum, is a series of flattened, granular-looking cells known +as the _stratum granulosum_. + +Immediately above the stratum granulosum the horny portion of the epidermis +commences. In the human skin this is formed of three distinct layers. +Undermost a layer of clear compressed cells, the _stratum lucidum_. +Next above it a layer of swollen cells, the nuclei of which are +indistinguishable. Finally, a surface layer of thin, horny scales, the +_stratum squamosum_, which become detached and thrown off in the form of +scurf or dandruff. In the skin of the horse, except where it is thickest, +these layers are not clearly defined. + +It is the Malpighian layer of the epidermis that is most active in cell +division. As they are formed the new cells push upwards those already +there, and the latter in their progress to the surface undergo a chemical +change in which their protoplasm is converted into horny material. This +change, as we have already indicated, takes place above the stratum +granulosum. + +In addition to its constant formation of cells to replace those cast +off from the surface, the active proliferation of the elements of the +Malpighian layer is responsible for the development of the various +appendages of the skin, the hairs with their sebaceous glands, the sweat +glands, horny growths and the hoof, and, in the human subject, the nail. +These occur as thickenings and down-growths of the epithelium into the +corium. + +The epidermis is devoid of bloodvessels, but is provided with fine nerve +fibrils which ramify between the cells of the rete mucosum. + +THE CORIUM is composed of dense connective tissue, the superficial layer +of which bears minute papillæ. These project into the epidermis, which is +moulded on them. For the most part the papillæ contain looped capillary +vessels, rendering the superficial layer of the corium extremely vascular. +Why this must be a moment's reflection will show. The epidermis, as we have +already said, is devoid of bloodvessels. It therefore depends entirely for +its nourishment upon the indirect supply it receives from the vessels of +the corium. The need for extreme vascularity of the corium is further +explained when we call to mind the constant proliferation and casting off +of the cells of the epidermis, the growth of the hairs, the production of +the horn of the hoof, and the work performed by the numerous sweat and +other glands. + +Others of the papillæ contain nerves, ending here in tactile corpuscles, or +continuing, as we have mentioned before, to ramify as fine fibrils in the +rete mucosum of the epidermis. + +THE HAIRS are growths of the epidermis extending downwards into the deeper +part of the corium. Each is developed in a small pit, the _Hair Follicle_, +from the bottom of which it grows, the part lying within the follicle being +known as the _Root_. It is important to note their structure, as it will be +seen later that they bear an extremely close relation to the horn of the +hoof. + +Under a high power of the microscope, and in optical section, the central +portion of a hair is tube-like. In some cases the cavity of the tube is +occupied by a dark looking substance formed of angular cells, and known as +the _Medulla_. The walls of the tube, or the main substance of the hair, is +made up of a pigmented, _horny, fibrous material_. This fibrous structure +is covered by a delicate layer of finely imbricated scales, and is termed +the _Hair Cuticle_. + +The root of the hair, that portion within the follicle, has exactly the +same formation save at its extreme end. Here it becomes enlarged into +a knob-like formation composed of soft, growing cells, which knob-like +formation fits over a vascular papilla projecting up in the bottom of the +follicle. + +We have already stated that the hairs are down-growths of the epidermis. +It follows, therefore, that the hair follicles, really depressions +or cul-de-sacs of the skin itself, are lined by epithelial cells and +connective tissue. So closely does the epidermal portion of the follicle +invest the hair root that it is often dragged out with it, and is known +as the _Root Sheath_. This is made up of an outer layer of columnar cells +(_the outer root sheath_) corresponding to the Malpighian layer of the +epidermis, and of an inner horny layer, next to the hair, corresponding to +the more superficial layer of the epidermis, and known as the _inner root +sheath_. + +The hair grows from the bottom of the follicle by a multiplication of the +cells covering the papilla upon which its root is moulded. When a hair is +cast off a new one is produced from the cells covering the papilla, or, in +case of the death or degeneration of the original papilla, the new hair is +produced from a second papilla formed in place of the first at the bottom +of the follicle. + +[Illustration: FIG. 24.--SECTION OF SKIN WITH HAIR FOLLICLE AND HAIR. _a_, +The hair follicle; _b_, the hair root; _c_, the medulla; _d_, the hair +cuticle; _e_, the outer root sheath; _f_, the inner root sheath; _g_, the +papilla from which the hair is growing; _h_, a sebaceous gland; _i_, a +sudoriferous gland.] + +THE SEBACEOUS GLANDS are small saccular glands with their ducts opening +into the mouths of the hair follicles. They furnish a natural lubricant to +the hairs and the skin. + +THE SUDORIFEROUS OR SWEAT GLANDS are composed of coiled tubes which lie in +the deeper portion of the skin, and send up a corkscrew-like duct to open +on the surface of the epidermis. They are numerous over the whole of the +body. + +[Illustration: FIG. 25.--LONGITUDINAL SECTION THROUGH NAIL AND NAIL-BED OF +A HUMAN FOETAL FINGER.[A] _a_, The nail; _b_, the rete mucosum; _c_, the +longitudinal ridges of the corium.] + +[Footnote A: Seeing that the section is a longitudinal one, it would appear +from the way the ridges cut that they are running transversely beneath the +nail. Their extreme delicacy, however, prevents a single one showing itself +along the length of the section, and their constant accidental cutting +makes them _appear_ to run transversely (H.C.R.).] + +THE HUMAN NAILS are thickenings of the lowermost layer of the horny portion +of the epidermis, the stratum lucidum. They are developed over a modified +portion of the corium known as the nail-bed. The horny substance of the +nail is composed of clear horny cells, and rests immediately upon a +Malpighian layer similar to that found in the epidermis generally. Instead +of the papillæ present elsewhere in the skin, the corium of the nail-bed is +marked by longitudinal ridges, a similar, though less distinct, arrangement +to that found in the laminæ of the horse's foot. + +Having thus paved the way, we are now in a better position to discuss our +original question (Are the horny laminæ secreted by the sensitive?), +and better able to appreciate the work that has been done towards the +elucidation of the problem. + +A most valuable contribution to this study is an article published in 1896 +by Professor Mettam.[A] Here the question is dealt with in a manner that +must effectually silence all other views save such as are based upon +similar methods of investigation--namely, histological examination of +sections of equine hoofs in various stages of foetal development. + +[Footnote A: The _Veterinarian_, vol. lxix., p.1.] + +Professor Mettam commences by drawing attention to the error that has +been made in this connection by studying the soft structures of the foot +separated by ordinary putrefactive changes from the horny covering. "In +this way," the writer points out, "a wholly erroneous idea has crept in +as to the relation of the one to the other, and the two parts have been +treated as two anatomical items, when, indeed, they are portions of one +and the same thing. As an illustration, and one very much to the point at +issue, the soft structures of the foot are to the horny covering what the +corium of the skin and the rete Malpighii are to the superficial portions +of the epidermis. Indeed, the point where solution of continuity occurs in +macerating is along the line of the soft protoplasmic cells of the rete." + +In the foregoing description of the skin we have seen that the corium +is not a _plane_ surface, but that it is studded by numerous papillary +projections, and that these projections, with the depressions between them, +are covered by the cells of the epidermis. + +The corium of the horse's foot, however, although possessed of papillæ in +certain positions (as, for example, the papillæ of the coronary cushion, +and those of the sensitive frog and sole), has also most pronounced ridges +(laminæ) which run down the whole depth of the os pedis. Each lamina again +carries ridges (laminellæ) on its lateral aspects, giving a section of +a lamina the appearance of being studded with papillæ. We have already +pointed out the ridge-like formation of the human nail-bed, and noted that, +with the exception that the secondary ridges are not so pronounced, it is +an exact prototype of the laminal formation of the corium of the horse's +foot. + +The distribution of the laminæ over the foot we have discussed in the +chapter devoted to the grosser anatomy. In a macerated foot the sensitive +laminæ of the corium interdigitate with the horny laminæ of the hoof; that +is to say, there is no union between the two, for the simple reason that it +has been destroyed; they simply interlock like the _unglued_ junction of +a finely dovetailed piece of joinery. But no further, however, than the +irregularities of the underneath surface of the epidermis of the skin can +be said to interlock with the papillæ of the corium does interlocking of +the horny and sensitive laminæ occur. It is only apparent. The horny laminæ +are simply beautifully regular epidermal ingrowths cutting up the corium +into minute leaf-like projections. + +In a macerated specimen, then, the exposed sensitive structures of the +foot exhibit the corium as (1) the _Coronary Cushion_, fitting into the +cutigeral groove; (2) the _Sensitive Laminæ_, clothing the outer surface of +the terminal phalanx, and extending to the bars; (3) the _Plantar Cushion_, +or sensitive frog; and (4) the _Sensitive Sole_. + +The main portion of the wall is developed from the numerous papillæ +covering the corium of the coronary cushion. We have in this way numberless +down-growing tubes of horn. Professor Mettam describes their formation in +a singularly happy fashion: "Let the human fingers represent the coronary +papillæ, the tips of the fingers the summits of the papillæ, and the folds +of skin passing from finger to finger in the metacarpo-phalangeal region +the depressions between the papillæ. Imagine that all have a continuous +covering of a proliferating epithelium. Then we shall have a more or less +continuous column of cells growing from the tip of the finger or papilla (a +hollow tube of cells gradually moving from off the surface of the finger +or papilla like a cast), and similar casts are passing from off all the +fingers or papillæ." + +From this description it will be noticed that each down-growing tube of +horn bears a striking resemblance to the growth of a hair, described on p. +47. In fact, the horn tube may be regarded as what it really is, a modified +hair. + +We next continue Professor Mettam's illustration, and note how the modified +hairs or horn tubes become as it were matted together to form the hoof +wall. The cells lining the depressions are also proliferating, and their +progeny serve to cement together the hollow casts of the papillæ, thus +giving the _inter_-tubular substance. We have thus produced hollow tubes, +united together by cells, all arising from the rete Malpighii of the +coronary corium. Section of the lower part of the horn tubes shows them to +contain a cellular debris. + +Thus, in all, in the horn of the wall we find a tubular, an intertubular, +and intratubular substance. In fact, hairs matted together by intertubular +material, and only differing from ordinary hairs in their development in +that they arise, not from papillæ sunk in the corium, but from papillæ +projecting from its surface. + +Although this disposes of the wall proper, there still confronts us the +question of the development of the horny laminæ. To accurately determine +this point it is absolutely essential to examine, histologically, the feet +from embryos. + +In the foot of any young ungulate in the early stages of intra-uterine +life horizontal sections will show a covering of epidermis of varying +thickness.[A] This may be only two or three cells thick, or may consist of +several layers. Lowermost we find the cells of the rete Malpighii. As some +criterion of the activity with which these are acting, it may be noted that +with the ordinary stains their nuclei take the dye intensely. The cells of +this layer rest upon a basement membrane separating the epidermis from the +corium. At this stage _the corium has a perfectly plane surface_. + +[Footnote A: Equine foetus, seventy-seven days old.] + +[Illustration: FIG. 26.--SECTION OF FOOT OF EQUINE FOETUS, SEVENTY-SEVEN +DAYS OLD. The rete Malpighii rests on a plane corium; the rent in the +section is along the line of the cells of the rete (Mettam).] + +[Illustration: FIG. 27.--SECTION FROM FOOT OF SHEEP EMBRYO. It shows a +pronounced epithelial ingrowth into the corium (Mettam).] + +The next stage will demonstrate the first step in the formation of the +sensitive laminæ.[A] The plain surface of the corium has now become broken +up, and what is noticed is that the broken-up appearance is due to the +epithelial cells irrupting and advancing _en échelon_ into its connective +tissue. Each point of the ingrowing lines of the _échelon_ has usually +one cell further advanced into the corium than its neighbours, and may be +termed the _apical cell_. The fine basement membrane separating epithelium +from corium is still clearly evident. This epidermal irruption of the +corium takes place at definite points right round the foot. It is extremely +probable, however, that it commences first at the toe and spreads +laterally. + +[Footnote A: Sheep embryo, exact age unknown.] + +As yet, these cellular ingrowths (which are destined to be the _horny_ +laminæ, and cut up the corium into _sensitive_ laminæ) are free from +irregularities or secondary laminæ. Before these are to be observed other +changes in connection with the ingrowths are to be noticed. + +[Illustration: FIG. 28.--SECTION FROM CALF EMBRYO. The epithelial ingrowths +hang down from the epidermis into the corium like the teeth of a comb +(Mettam).] + +The first is merely that of elongation of the epithelial processes into the +connective tissue, until the rete Malpighii gives one the impression that +it has hanging to its underneath surface and into the corium a number of +thorn-like processes. These extend all round the front of the foot, and +even in great part behind. Accompanying this elongation of the processes +is a condensation of the epithelial cells immediately above the rete +Malpighii, with a partial or total loss of their nuclei. This is the first +appearance of true horn, and its commencement is almost coincident with the +first stages of ossification of the os pedis. + +[Illustration: FIG. 29.--SECTION OF AN EPITHELIAL INGROWTH FROM AN EQUINE +FOETUS. It shows commencing secondary laminar ridges. In the centre are +epithelial cells which are undergoing change into horny elements to form +the horn core, or 'horny laminæ' (Mettam).] + +With the appearance of horn comes difficulty of sectioning. The last +specimen that Professor Mettam was able to satisfactorily cut upon the +microtome was from a foetus between three and four months old. In this the +secondary laminar ridges were clearly indicated, and the active layer of +the rete Malpighii could be traced without a break from one ingrowing +epithelial process to the next, and around this, following all the +irregularities of its outline, and covering the branches of the nascent +laminæ. The laminæ mostly show this branching as if a number of different +growing points had arisen, each to take on a function similar to the +epithelial process as it at first appeared. + +In the centre of the processes a few nuclei may be observed, but they are +scarce, and stain only faintly; they have arisen from the cells of the rete +Malpighii which have grown into the corium. In fact, the active cells are +passing their daughters into the middle of the process, and these pass +through similar stages as those derived from the ensheathing epidermis. In +other words, the daughter cells of the constituents of the rete Malpighii +which have grown into the corium pass through a degeneration precisely +similar to that undergone by cells shed at desquamation, or those which +eventually give rise by their agglutination to a hair. + +This is the real origin of the horny laminæ, and the thickness of these is +increased merely by an increase in the area covered by the cells of the +rete Malpighii--i.e., by the development of secondary laminar ridges. If +a section from a foal at term be examined, the processes will be found far +advanced into the corium, and, occupying the axis of each process, will +be seen a horny plate, continuous with the horn of the wall. No line of +demarcation can be observed between the horn so formed and the intertubular +material of the wall. They merge into and blend with each other, with no +indication of their different origins. The cells that have invaded the +corium have thus _not lost their horn-forming function_. There has merely +been an increase in the area for horn-producing cells. The horny processes +are continuous with the hoof proper at the point where the epithelial +ingrowth first commenced to invade the corium, and fuses here with the +horn derived from the cells of the rete Malpighii which have _not_ grown +inwards, and which are found between the processes in the intact foot. From +this it is clear that some considerable portion of the horn of the wall is +derived from the cells of the rete Malpighii covering the corium of the +foot. It becomes even more clear when we remember the prompt appearance of +horn in cases where a portion, or the whole, of the wall has been removed +by operation or by accident (see reported cases in Chapter VII.). + +The activity of the cells of the rete Malpighii of the corium covering the +remainder of the foot will be quite as necessary as the activity of the +cells of the coronary papillæ which form the horn tubes themselves. 'For,' +in Professor Mettam's own words, 'I am inclined to believe that much of the +"white line" which is found uniting the wall of the hoof to the sole has +been derived from the horn formed from the rete of the foot corium. This +origin will explain the absence of pigment from this thin uniting "line," +as it does from the horn lining the interior of the wall. The cells of the +rete are free of colouring matter.' + +[Illustration: FIG. 30.--SECTION THROUGH HOOF AND SOFT TISSUES OF A FOAL AT +TERM. The horn of the wall is shown, and the horn-core ('horny laminæ') of +the epithelial ingrowth. The latter has advanced far into the corium, and +is now provided with abundant secondary laminar ridges (Mettam).] + +From the matter here given us it is easy to understand how, in a macerated +foot, the appearance is given of interlocking of the sensitive and horny +laminæ. We see that the horny laminæ are ingrowths of the rete Malpighii, +ploughing into and excavating the corium into the shape of leaves--the +sensitive laminæ. Putrefactive changes simply break into two separate +portions what originally was one whole, by destroying the cells along its +weakest part. This part is the line of soft protoplasmic cells of the rete +Malpighii. Thus the more resistant parts (the horn on the one hand, and the +corium covering the foot on the other) are easily torn asunder. + +As a result of the evidence we have quoted, we are able to answer our +original question in the affirmative. Seeing that the horny and the +sensitive laminæ are both portions of the same thing--namely, a modified +skin, in which the epidermis is represented by the horny laminæ, and the +corium by the sensitive--it is clear to see that the cells covering the +inspreading horny laminæ are dependent for their growth and reproduction +upon the cells with which they are in immediate contact--namely, those +of the sensitive laminæ--and that therefore the sensitive laminæ are +responsible for the growth of the horny. + + +B. CHEMICAL PROPERTIES AND HISTOLOGY OF HORN. + +Horn is a solid, tenacious, fibrous material, and its density in the hoof +varies in different situations. It is softened by alkalies, such as caustic +potash or soda and ammonia, the parts first attacked being the commissures, +then the frog, and afterwards the sole and wall. Strong acids, such as +sulphuric acid and nitric acid, also dissolve it. + +The chemical composition of the hoof shows it to be a modification of +albumin, its analysis yielding water, a large percentage of animal matter, +and materials soluble and insoluble in water. The proportions of these, as +existing in the various parts of the hoof, have been given by Professor +Clement as follows: + + Wall. Sole. Frog. + Water 16.12 36.0 42.0 + Fatty matter 0.95 0.25 0.50 + Matters soluble in water 1.04 1.50 1.50 + Insoluble salts 0.26 0.25 0.22 + Animal matter 81.63 62.0 55.78 + +Horn appears to be identical with epidermis, hair, wool, feathers, and +whalebone, in yielding 'keratin,' a substance intermediate between albumin +and gelatine, and containing from 60 to 80 per cent. of sulphur. + +That horn is combustible everyone who has watched the fitting of a hot shoe +knows. That it is a bad conductor of heat, the absence of bad after-effects +on the foot testifies. + +[Illustration: FIG. 31.--PERPENDICULAR SECTION OF HORN OF WALL.] + +In a previous page we have described the manner of growth of the horn +tubules, and noted the direction they took in the wall; also, we have +noticed the existence between them of an intertubular horn or cement. + +Those who wish to give this subject further study will find an excellent +series of articles by Fleming in the _Veterinarian_ for 1871. We +shall content ourselves here with introducing one or two diagrams and +photo-micrographs, and dealing with the histology very briefly. + +Under the microscope the longitudinal striation of the wall is found to be +due to the direction taken by the horn tubules. + +Fig. 31 is a magnified perpendicular section of the wall. In it the +parallel dark striæ are the horn tubules in longitudinal section. The +lighter striæ represent the intertubular material. + +Fig. 32 gives us the wall in horizontal section. To the left of this +picture we find the horn tubules cut across, and standing out as so many +concentrically ringed circles. In the centre of the figure are seen the +horny laminæ, with their laminellæ, and the sensitive laminæ. The right +portion of the figure pictures the corium. + +[Illustration: FIG. 32.--HORIZONTAL SECTION OF HORN OF WALL.] + +Fig. 33 is, again, a horizontal section, cut this time at the junction of +the wall with the sole. To the left are seen, again, the horn tubules of +the wall, and to the centre the horny laminæ. In this position, however, +the structures interdigitating with the horny laminæ are not sensitive, but +are themselves horny. As the diagram shows, they contain regularly arranged +horn tubules cut across obliquely. It is this horn which forms the 'white +line.' To the extreme right of the figure are seen the horn tubules of the +sole. + +There remains now but to notice the arrangement of the horn tubules in the +frog. The peculiar, indiarubber-like toughness of this organ is well known. +Histological examination gives a reason for this. + +[Illustration: FIG. 33.--HORIZONTAL SECTION OF HORN THROUGH THE JUNCTION OF +THE WALL WITH THE SOLE. _a_, Horn tubule of the wall; _b_, horn tubule of +the sole; _c, d_, horny laminæ.] + +[Illustration: FIG. 34.--SECTION OF FROG THROUGH CORIUM AND HORN. The long +finger-like projections of corium into epidermis are sections of the long +papillæ from which the horn-tubes of the sole grow. In the stainable +portion of the epidermis are to be clearly seen light and dark streaks +pointing out the alternate strata-like arrangement of cells mentioned in +the text (Mettam).] + +The horn tubules of the frog are sinuous in their course. This is accounted +for by the fact that in the horn of the frog there is a large amount of +intertubular material, this having the effect of frequently turning the +horn tubules from the straight. In addition to this, the intertubular +material has a peculiar arrangement of the cells composing it. These +are laid down in alternating striæ (1) of cells with their long axes +longitudinal, and (2) of cells with their long axes horizontal. This is +seen in Fig. 34, between the long papillæ of the corium, where the lines of +longitudinally arranged cells in horizontal section stand out darker than +the adjoining strata in which their arrangement is horizontal. The tortuous +direction of the horn tubules, and the almost interlocking nature of the +alternating strata of the intertubular material, together combine to give +the frog its characteristic toughness and resiliency. + + +C. EXPANSION AND CONTRACTION OF THE HOOF. + +Among other questions productive of heated argument come those relating to +expansion of the horse's hoof. In the past many observers have strenuously +insisted on the fact that expansion and contraction regularly occur during +progression. Opposed to them have been others equally firm in the belief +that neither took place. Quite within recent times this question also +has been settled once and for all by the experiments of A. Lungwitz, of +Dresden. His conclusions were published in an article entitled 'Changes in +Form of the Hoof under the Action of the Body-weight.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +iv., p. 191. The whole of the matter in this article, from which we have +borrowed Figs. 35 and 36, is too long for reproduction here. It forms, +however, most instructive reading, and its careful perusal will well repay +everyone interested in this most important question (H.C.R.).] + +In connection with this it is interesting to note how, all unconsciously, +two separate observers were simultaneously arriving by almost identical +means at an equally satisfactory answer to the question. Prior to the +publication of Lungwitz's article on the subject, Colonel F. Smith, A.V.D., +had arrived at similar conclusions by working on the same methods. + +[Illustration: Fig. 35. I. Electric Bell with Dry Element. a, Under +part, with box, for the dry element; 6, roller for winding up the +conducting-wires; c, dry element, with screw-clamp for attachment of the +conducting-wires; c', conducting-wire leading to the screw-clamp, with +contact-spring in c', Fig. 2, or to the wall in Fig. 3; d, upper part, with +bell; d', conducting-wire to the shoe d' in Figs. 2 and 3; e, strap for +slinging the apparatus around the body of the assistant or rider; f, +connecting-wire between bell and dry element.] + +[Illustration: Fig. 35. II. Hoof Shod with Shoe provided with Toe-piece and +Calkins; Wall of the Hoof covered with Tinfoil. a, Heel angle, with b, the +contact-screws; c, screw-clamp, with contact-spring (isolated from +the shoe); c' conducting-wire from the same; d, screw-clamp, with +conducting-wire (d') screwed into the edge of the shoe; e, nails isolated +by cutting a small window in the tinfoil.] + +[Illustration: Fig. 35. III. Hoof Shod with Plain Shoe; Horny Wall covered +with Tinfoil. a, Toe and heel angle, with b, the contact-screws; c, +conducting-wire passing from the tinfoil on the wall; d, conducting-wire +passing from the shoe; c', d', ends of the conducting-wires, which must be +imagined connected with the ends c', d', passing from the apparatus.] + +It is unnecessary for our purpose here to minutely describe the exact +_modus operandi_ of these two experimenters. Briefly, the method of inquiry +adopted in each case was the 'push and contact principle' of the ordinary +electric bell, and the close attention which was paid to detail will be +sufficiently gathered from Figs. 35 and 36. + +[Illustration: Fig. 36. I. LEFT FORE-FOOT SHOD AND MOUNTED TO RECOGNISE THE +SINKING OF THE SOLE. _a_, Iron plate covering the inner half of the horny +sole; _b_, openings in the same, with screw-holes for the reception of the +contact-screw _c_ (the part of the sole under the plate is covered with +tinfoil, which at _d_ passes out under the outer branch of the shoe, and +becomes connected with the tinfoil of the wall; in order to give the +freshly applied tinfoil a better hold, copying-tacks are at _e_ passed +through it into the horn, and one is similarly used to protect the tinfoil +at the place where the contact-screw touches the latter); _f_, holes +with screw thread for the fastening of the angle required to measure the +movement of the wall, and also for the fastening of the conducting-wire, +_g; h_, conducting-wire passing from the tinfoil; _i_, isolated nails.] + +[Illustration: Fig. 36. II. BAR-SHOE WITH OPENINGS. _a_, Near the inner +margin and in the longitudinal bar; _b_, for the reception of the +contact-screw _c; d_, openings for fastening the angle and the +conducting-wires.] + +After numerous experiments with the depicted contact-screws, moved to the +various positions indicated in the drawings, the following conclusions were +arrived at: + +1. BEHAVIOUR OF THE CORONARY EDGE.--During uniform weighting of all four +hoofs the coronary edge shows a tendency to contraction in the anterior and +lateral regions of the hoof, and a tendency to expansion posteriorly. With +heavy weighting of the hoof, which is shown by a backward inclination of +the fetlock, contraction in the anterior and lateral regions is slight, but +the expansion behind, in the region of the heels, is distinct, commencing +gradually in front, becoming stronger, and diminishing again posteriorly. +The coronary edge of the heels becomes slightly bulged outwards. The bulbs +of the heels swell up and incline a little backwards and downwards. + +When the fetlock is raised the expansion of the coronary edge of the heels +disappears from behind forwards, passing forwards like a fluid wave. In +the lateral and anterior regions of the coronary edge the contraction +disappears; and when the weight is thrown off the foot it passes into a +gentle expansion of the coronary edge of the toe. During the opposite +movement of the fetlock, that of sinking backwards, this change of form is +executed in the converse manner. + +In short, the coronary edge resembles a closed elastic ring, which yields +to pressure, even the most gentle, of the body-weight, in such a way that a +bulging out of any one part is manifested by an inward movement of another +part. + +In Fig. 37, _b_, the dotted line represents the changes of form in +comparatively well-formed and sound hoofs at the moment of strongest +over-extension[A] of the fetlock-joint. + +[Footnote A: The term 'over-extension,' as employed by Lungwitz, is +intended to indicate that position assumed by the fetlock-joint when the +opposite foot is raised from the ground.] + +2. BEHAVIOUR OF THE SOLAR EDGE.--Under the action of the body-weight this +is somewhat different from that of the coronary edge. Anteriorly, and at +the sides, as far as the wall forms an acute angle with the ground, +the tendency to expansion exists, but the change of form first becomes +measurable in the region where the lateral cartilages begin. Quite +posteriorly the expansion again diminishes. + +Fig. 37, _a_, by the dotted line represents the expansion at the moment of +over-extension of the fetlock-joint. This expansion is itself rather less +than at the coronary edge, and it shows itself distinctly _only when the +weighted hoof is exposed to a counter-pressure on the sole and frog_, no +matter whether the counter-pressure is produced naturally or artificially. +Thus anything tending to the removal of the pressure from below, such as +a decayed condition of the frog or excessive paring in the forge, will +diminish the extent of expansion of the solar edge. + +Contraction of the solar edge of the heels occurs at the moment of greatest +over-extension of the fetlock-joint--that is, in a foot with pressure +from below absent. On the face of it, this appears impossible. Lungwitz, +however, has perfectly demonstrated it; and, when dealing with the +functions of the lateral cartilages in a later paragraph, we shall show +reason for why it is but a simple and natural result of the foot dynamics. + +3. BEHAVIOUR OF THE SOLE.--The horny sole becomes flattened under the +action of the body-weight. This is most distinct at the solar branches, and +gradually shades off anteriorly and towards the circumference. As might be +supposed, width of hoof and thickness of the solar horn exert an influence +on the extent of this movement. The sinking of the horny sole is most +marked in flat hoofs. + + +D. THE FUNCTIONS OF THE LATERAL CARTILAGES.[A] + +[Footnote A: Extracted from a paper by J.A. Gilruth, M.R.C.V.S., in the +_Veterinary Record_, vol. v., p. 358.] + +We have just referred to contraction of the heels as taking the place of a +normal expansion in those cases where ground frog-pressure was absent. We +shall readily understand this when we bear in mind the anatomy of the +parts concerned, especially that of the plantar cushion. This wedge-shaped +structure we have already described as occupying the irregular space +between the two lateral cartilages, the extremity of the perforans tendon, +and the horny frog. + +Now, when weight or pressure is exerted from above on to this organ, and +the _frog is in contact with the ground below_, it is clear from the +position the cushion occupies that, whatever change of form pressure from +above will cause it to take, it must certainly be limited in various +directions. + +[Illustration: FIG. 37. _a_, The dotted lines in this diagram represent the +expansion of the solar edge of the hoof at the moment of over-extension of +the fetlock-joint; _b_, the dotted line represents the change in form of +the coronary edge under similar circumstances.] + +Because of the shape of the cushion its change of form cannot be forwards +(simultaneous pressure from above and below on to this wedge with its apex +forwards must tend to give it a backward change of form). Because of the +pastern being horizontal, and aiding in the downward pressure, its +change of form cannot be upwards. And because of the ground it cannot be +downwards. It follows, therefore, that the movement must be backwards and +outwards, being especially directed outwards because of its shape and the +median lacuna in its posterior half--this latter, the lacuna, accommodating +as it does the frog-stay, preventing the tendency to backward movement +becoming excessive, and directing the change of form to the sides. Where +the greatest pressure is transmitted, then, is to the inner aspects of the +flexible lateral cartilages. The coronary cushion being continuous with the +plantar, the backward and outward movements of the latter will tend to pull +upon and tighten the former, especially _in front_. This will account for +the contraction noted by Lungwitz in the _anterior half_ of the coronary +edge of the hoof. + +Remove the body-weight, and naturally the elastic nature of the lateral +cartilages and the coronary and plantar cushions, with, in a less degree, +that of the hoof, cause things to assume their normal position. + +Repeat the weighting of the hoof, in this second case _without +frog-pressure_, and we shall see at once that we have done away with one of +the greatest factors in determining the outward and backward movements of +the plantar cushion--namely, the pressure from below on its wedge-shaped +mass. The movement of the plantar cushion will now be _downwards_ as well +as backwards; and, seeing that it is attached to the inner aspect of each +lateral cartilage, we shall expect these latter, by the downward movement +of the plantar cushion, to be drawn _inwards_. This Lungwitz has shown to +occur. + +The chief function of the lateral cartilages, therefore, is to _receive +the concussion engendered by locomotion_, which concussion is directed +backwards and outwards by the pad-like plantar cushion. + +In addition to this, the lateral cartilages, together with the plantar and +coronary cushions, _play the part of a valve to the whole of the veins of +the foot_. + +It is in this way: We have only to refer to the chapter on anatomy to see +that the whole of the foot is covered with a tissue of extreme vascularity. +Thus we find papillæ--the over the coronary cushion; enlarged and modified +papillæ sensitive laminæ--covering the anterior face of the os pedis; and +numberless papillæ again covering the sole. There can be no doubt that the +quantity of fluid brought by the bloodvessels of these papillæ to the foot +acts largely as a means of hydraulic protection to the soft structures.[A] +In like manner as that delicate organ, the brain, is best protected by +being floated upon the cerebro-spinal fluid and bloodvessels (which fluids +transmit waves of concussion or pressure _through_ the organ without injury +to the delicate cells forming it), so, in like manner, does the extreme +vascularity of the foot protect the cells of its softer structures from the +effects of pressure and concussion. + +[Footnote A: The _Veterinary Record_, vol. iii., p. 518.] + +That this law of hydraulics may operate in the horse's foot to the best +advantage, the veins must be provided with valves, and valves of no +mean strength. These we know to be absent. It is here that the lateral +cartilages and the elastic substances of the coronary and plantar cushions +step in to supply the deficiency. + +At the time when weight is placed upon the foot (with, of course, a +tendency to drive the blood upwards in the limb), and, therefore, the time +when a valvular apparatus is needed to retain the fluid in the foot, we +find the wanting conditions supplied by the pressure outwards of the +plantar cushion compressing the large plexuses of veins on each side of the +lateral cartilages, to which plexuses, it will be remembered, the bulk +of the venous blood from the foot was directed. A more perfect valvular +apparatus, automatic and powerful, it would be difficult to imagine. + + +E. GROWTH OF THE HOOF. + +We will conclude this chapter with a few brief remarks on the growth of +the hoof. That the rate of growth is slow is a well-known fact to every +veterinarian, and it will serve for all practical purposes when we state +that, roughly, the growth of the wall is about 1/4 inch per month. This +rate is regular all round the coronet, from which it follows that the time +taken for horn to grow from the coronary edge to the inferior margin +will vary according as the toe, the quarters, or the heels are under +consideration. + +As might naturally be expected, the rate of growth will depend on various +influences. Any stimulus to the secreting structures of the coronet, such +as a blister, the application of the hot iron, or any other irritant, +results in an increased growth. Growth is favoured by moisture and by +the animal going unshod, as witness the effects of turning out to grass. +Exercise, a state of good health, stimulating diets--in fact, anything +tending to an increased circulation of healthy blood--all lead to increased +production of horn. With the effects of bodily disease and of ill-formed +legs and feet on the wear of the hoof, and the growth of horn, we shall be +concerned in a future chapter. + + + +CHAPTER IV + +METHOD OF EXAMINING THE FOOT + + +As a general rule, it may be taken that most diseases of the foot are +comparatively easy of diagnosis. When, however, the condition is one which +commences simply with an initial lameness, the greatest care will have to +be exercised by the practitioner. + +What remarks follow here should rightly be confined to a treatise on +lameness. This much, however, we may state: As compared with lameness +arising from abnormal conditions in other parts of the limb, that emanating +from abnormalities of the foot is easy of detection. With a case of +lameness before him, concerning which he is in doubt, the practitioner +remembers that a very large percentage may safely be referred to the foot, +and, if wise, subjects the foot to a rigorous examination. + +Much may be gathered by first putting the animal through his paces. When +at a trot, notice the peculiarity of the 'drop,' whether any alteration in +going on hard or soft ground, and watch for any special characteristic in +gait. At the same time inquiry should be made as to the history of the +case; its duration; whether pain, as evidenced by lameness, is constant or +periodic; the effect of exercise on the lameness; and the length of time +elapsed since the last shoeing. + +This failing to reveal adequate cause for the lameness in any higher part +of the limb, one is led, by a process of negative deduction, to suspect +the foot. If 'pointing' is a symptom, its manner is noticed. The foot is +compared with the other for any deviation from the normal. In some cases +the two fore or the two hind feet may differ in size. Though this may not +necessarily indicate disease, it may, nevertheless, be taken into account +if the lameness is not easily referable to any other member. Measurement +with calipers will then be of help, and a pronounced increase in size, +especially if marked in one position only, given due consideration. The +hand is used upon each foot alternately to look for change of temperature, +to detect the presence of growths small enough to escape the eye, and to +discover evidence of painful spots along the coronet. + +At this stage the method of percussion recommends itself, and in many cases +no more useful diagnostic agent is to be found than the ordinary hammer. As +a preliminary, the foot of the sound limb should be always tapped first. +This precaution will serve to bring to light what is frequently met +with--the aversion nervous animals sometimes exhibit to this manner of +manipulation of the hoof. Unless this is done, the ordinary objection to +interference is apt to be read as evidence of pain. No aversion to the +method being shown, the suspected foot is gently tapped in various places +round the wall, a keen look-out being kept for any manifestation of +tenderness. This may vary from a slight resentment to each tap, indicated +by a sudden lifting and setting down again of the foot, to a complete +removal of the foot from the ground, and a characteristic pawing of the air +that points out clearly enough the seat of pain. + +Evidence of pain once given, the tapping is persisted in until, in some +cases, the exact position of the tender spot is definitely located. + +Failing evidence obtained from percussion, attention should next be given +to the shoeing. We may add here that, even when difficulties have to be +encountered in doing it, it is always a wise plan to have the shoe removed. + +The nails should be removed one by one, the course they have taken, their +point of emergence on the wall, and the condition of their broken ends all +being carefully noted as they are withdrawn. + +The removed shoe should next be examined as to the coarseness or fineness +of its punching and the 'pitch' of its nail-holes, and close attention +given to the shape of its bearing surface. + +From that we may pass to a consideration of the underneath surface of +the foot. The drawing-knife should be run lightly over the whole of its +surface, the first thing to be noticed being the point of entrance of the +nails as compared with the coarseness or fineness of the punching, and the +staining or otherwise of the horn immediately around. We may thus be guided +towards mischief arising from tight nailing apart from actual prick of the +foot. + +This done, more than usual care should be taken in following up any other +small prick or dark spot that may show itself upon the white surface of the +cleaned sole. In any case, a suspicious-looking speck should be followed up +with the searcher until it is either cut out or is traced to the sensitive +structures. + +While this is done, we should also have noticed the condition of the horn +at the seat of corn; should have noticed the shape of the heels, contracted +or otherwise; and the appearance of the frog, clean or discharging. + +A point to be remembered in making this exploratory paring of the foot is +the peculiar consistency of the horn of the frog, and its tendency to hide +the existence of punctures. In like manner, as a pin pierces a piece of +indiarubber, and leaves no clearly visible trace of the hole it has made, +so does a nail or other sharp object penetrate the frog, leaving but little +to show for the mischief that has been done. + +After all, even though we may have fully decided the foot is at fault, our +case of lameness may remain obscure so far as a cause is concerned. Nothing +remains, then, but to acknowledge the inability to discover it, to advocate +poulticing, or some other expectant palliative measure, and to bring the +case up for further examination at no distant date. Where, though we +may have suspected the foot, we have not been able to definitely assure +ourselves that there the mischief is to be found, a further method of +examination presents itself--namely, subcutaneous injections of cocaine +along the course of the plantar nerves. + +The salt of cocaine used is the hydrochlorate, 2-1/2 grains for a pony, +4 grains for a medium-sized animal, and 6 grains for a large horse. A +solution of this is made in boiled water (about 3 drams), and injected at +the seat of the lower operation of neurectomy. + +It is advisable to first render aseptic the seat of operation, and to +sterilize both the needle and the syringe by boiling. A suitable point to +choose for the injection is exactly over the upper border of the lateral +faces of the two sesamoids, the needle being introduced behind the cord +formed by the nerve and accompanying vessels, and parallel with it. + +It is possible that the vein or the artery may be wounded, but such +accident is of little importance. All that is necessary in that case is to +partly withdraw the needle and again insert it. It is advisable to use a +twitch. + +When the needle is in position, the injection should be made slowly, and +at the same time the point of the needle should be made to describe a +semicircular sweep, so as to spread the solution over as wide an area as is +possible. + +Anæsthesia ensues in from six to twenty minutes, and if the cause of the +lameness is below the point of injection the animal moves sound. + +Regarding this method of diagnosis, Professor Udriski of Bucharest, after a +series of trials, sums up as follows: + +1. For the diagnosis of lameness cocaine injections are of very +considerable value. + +2. These injections should be made along the course of the nerves. + +3. Solutions heated to 40° or 50° C. produced quicker, deeper, and longer +anæsthesia than equally strong cold solutions. + +4. In the sale of horses cocaine injections conceal fraud. + +Cocaine being an irritant, it must be remembered that after the anæsthesia +the lameness is somewhat more marked than before. + +To the cocaine other practitioners add morphia in the following +proportions: + + Cocaine hydrochlorate 2-1/2 grains. + Morphia 1-1/2 " + Aqua destil 1-1/2 drams. + +As a diagnostic this mixture of the two is said to be far superior to +either cocaine or morphia alone. + +In connection with this subject, Professor Hobday has published, among +others, the following cases illustrating the practical value of this method +of diagnosis:[A] + +[Footnote A: The _Journal of Comparative Pathology and Therapeutics_ vol. +viii., pp. 27, 43.] + +CASE I.--Cab gelding. Seat of lameness somewhat obscure; navicular disease +suspected. Injected 2 grains of cocaine in aqueous solution on either side +of the limb, immediately over the metacarpal nerves. + +_Five Minutes_.--Lameness perceptibly diminished. + +_Ten Minutes_.--Lameness scarcely perceptible. + +CASE II.--Mare. Obscure lameness; foot suspected. Injected 30 minims of a 5 +per cent. solution on either side of the leg just above the fetlock. + +_Ten Minutes_.--No lameness, thus proving that the seat of lameness was +below the point of injection. + +CASE III.--Cab gelding, aged, free clinique; Messrs. Elme's and Moffat's +case. Obscure lameness; foot suspected of navicular disease; very lame. +Injected 30 minims of a 5 per cent. solution of cocaine on either side of +the leg over the metacarpal nerves. + +_Six Minutes_.--Lameness perceptibly less; there was no response whatever +on the inside of the leg to the prick of a pin. On the outside, which had +not been injected so thoroughly, there was sensation, although not so much +as in a healthy foot. + +_Ten Minutes_.--Lameness had almost disappeared; so much so, that the +opinion as to navicular disease was confirmed, and neurectomy was +performed. Immediately after this operation there was no lameness whatever. + +The same author also reports numerous cases among horses and cattle, dogs +and cats, pointing out the toxic properties of the drug. The symptoms +following an overdose are interesting enough to relate here, and I select +the following case of Professor Hobday's as being fairly typical:[A] + +[Footnote A: _Loc. cit_.] + +CASE IV.--Cart gelding. Free clinique; navicular disease. Injected +subcutaneously over the metacarpal nerves on each side 6 grains of cocaine +in aqueous solution. During the operation the animal manifested no signs +of pain whatever, not even when the nerve was cut. This animal received +altogether 12 grains of cocaine (3 grains were given on either side first, +then fifteen minutes afterwards the same dose repeated). The effect was +manifested on the system in ten minutes after the second injection by +clonic spasms of the muscles of the limbs (the legs being involuntarily +jerked backwards and forwards at intervals of about twenty seconds), which +materially interfered with the performance of the operation. The animal was +also continually moving the jaws, and was very sensitive to sounds, moving +the ears backwards and forwards. This hyperæsthesia, as evinced by the +movement of the ears, lasted for some considerable time after the animal +had been allowed to get up. + +Cocaine hydrochlorate solutions, if intended to be kept for any length of +time, should have added to them when freshly made 1/200 part of boric acid +in order to preserve them. Even then they are liable to spoil, and should, +for subcutaneous injection, be made up just before needed for use. + + + +CHAPTER V + +GENERAL REMARKS ON OPERATIONS ON THE FOOT + + +A. METHODS OF RESTRAINT. + +Many of the simple operations on the foot, such as the probing of a sinus, +the paring out of corns, or the searching of pricks, may most suitably be +performed with the animal's leg held by the operator as a smith holds it +for shoeing. According to the temperament of the animal, even the operation +for the removal of a portion of the sole, or the injection of sinuses with +caustics, may be carried out with the animal simply twitched. + +When the operation is still a simple one, casting inconvenient or +impossible, and the animal restive, the twitch must be supplemented by some +other method. The most simple and one of the most effective is the blind, +cap, or bluff (Fig. 38). With it the most vicious animal or the most +nervous is in many instances either cowed into submission or soothed into +quietness. + +At the same time, more forcible means than the operator's own strength +must be taken to hold the animal's foot from the ground. If the foot is a +fore-foot, and the point desired to be operated on is to the outside, the +pastern should be firmly lashed to the forearm by means of a thin, short +cord, or a leather strap and buckle. Much may then be done in the way of +paring and probing that would otherwise be impossible. + +[Illustration: Fig. 38--The BLIND.] + +[Illustration: Fig. 39--THE SIDE-LINE.] + +If the foot is a hind one, one of the many methods of using what is +termed by Liautard, in his 'Manual of Operative Veterinary Surgery,' the +plate-longe, must be adopted. This, in its most useful form, is a length of +closely-woven cotton webbing, from about 2 to 2-1/2 inches wide, and from 5 +to 6 yards long, provided with a small loop formed on one of its ends, and +perhaps better known to English readers as a 'side-line.' If webbing be not +available, a length of soft cotton rope, or a rope plaited and sold for the +purpose, as Fig. 39, will serve equally well. One of the most convenient +methods of using the side-line for securing the hind-foot is depicted in +Figs. 40 and 41. + +[Illustration: FIG. 40.--THE SIDE-LINE ADJUSTED PREPARATORY TO SECURING THE +NEAR HIND-FOOT.] + +[Illustration: FIG. 41.--THE NEAR HIND-FOOT SECURED WITH THE SIDE-LINE.] + +Here the side-line has formed upon it a loop sufficiently large to form a +collar. This is placed round the animal's neck, the free end of the line +run round the pastern of the desired foot, and the foot drawn forward, as +in Fig. 40. + +The loose end of the line is then twisted once or twice round the tight +portion, and finally given to an assistant to hold (see Fig. 41). The foot +is thus held from the ground, and violent kicking movements prevented. + +Where the operation is a major one, restraint of a distinctly more forcible +nature becomes imperative. Many of the more serious operations can most +advantageously be performed with the patient secured in some form or other +of stock or trevis, and the foot suitably fixed. It is not the good fortune +of every veterinary surgeon, however, to be the lucky possessor of one of +these useful aids to successful operating. Perforce, he must fall back on +casting with the hobbles (Fig. 42). + +[Illustration: FIG. 42.--CASTING HOBBLES.] + +With the use of these we will assume our readers to be conversant, and will +imagine the animal to be already cast. It remains, then, but to detail the +most suitable means for firmly fixing the foot to be operated on. + +Here the side-line is again brought into use. Care should previously have +been taken when casting to throw the animal so that the portion of the foot +to be operated on, whether inside or outside, falls uppermost, and that the +buckle of the hobble on that particular foot is placed so that it also is +within easy reach when the animal is down. + +In the case we are illustrating the point of operation was the outside of +the near hind coronet. We will, therefore, describe the mode of fixing the +near hind-foot upon the cannon of the near fore-limb. + +[Illustration: FIG. 43.--PHOTOGRAPH ILLUSTRATING METHOD OF ADJUSTING THE +SIDE-LINE PREPARATORY TO FIXING THE HIND-LEG UPON THE FORE.] + +The side-line is first adjusted as follows: It is fixed upon the cannon of +the near hind-leg (A) by means of its small loop. From there it is passed +under the forearm of the same limb, over the forearm, under the rope +running from A to B; from there over and under the thigh, to be finally +brought in front of the thigh, and below the portion of rope running from +arm to thigh. The loose end of the side-line is then given to an assistant +standing behind the animal's back, the buckle of the hobble restraining the +foot unloosed, and strong but steady traction brought to bear from behind +upon the line. The operator should now stand in front of the fore-limbs, +and, by placing a hand on the rope passing round the arm, prevent the line +from slipping below the knee. + +By this means the hind-limb is pulled forward until the foot projects +beyond the cannon of the front-limb. When that position is reached, the +operator grasps the hock firmly with one hand, and, directing the side-line +to be slackened, gently slides downward the coils of rope round the arm +and thigh until they encircle the cannons of both limbs. The cannon of the +hind-limb is firmly lashed to the cannon of the fore, and the foot firmly +and securely fixed in the best position for operating (see Fig. 44). + +[Illustration: FIG. 44.--PHOTOGRAPH SHOWING THE NEAR HIND-FOOT SECURED UPON +THE CANNON OF THE NEAR FORE-LIMB.] + +Similarly, with the horse still on his off side, the off hind-limb may be +fixed to the near fore, and the near fore and the off fore to the near +hind. + +With the animal on his near side, we may fix the near hind and the off hind +to the off fore, and the off fore and near fore to the near hind. + +The points to be remembered in fixing the limbs thus are: (1) The side-line +should always commence upon the cannon of the limb to be operated on; (2) +it should next pass under and over (or over and under, it is immaterial +which) first the arm and then the thigh, or the thigh and the arm, as the +case may be; (3) in every case, whether rounding the thigh and the arm from +above or below, the piece of rope completing the round should always finish +below that portion preceding it, so that traction upon it from behind the +animal's back should tend to keep all portions of it from slipping below +the knee and the hock. + +With the uppermost fore-limb secured to the hind-limb in the manner we have +described, we have the underneath fore-limb suitably exposed for both the +higher and lower operations of neurectomy. The position for this operation +will be made better still if the lowermost limb (the one to be operated on) +is removed from the hobbles and drawn forward by an assistant by means of a +piece of rope fastened to the pastern. + +Taking what we have described as a general guide, other modifications of +thus securing the foot will suggest themselves to the operator to meet the +special requirements of the case with which he is dealing. + +Regarding the administration of chloroform, no description of the method +is needed here, as it will be found fully detailed in most good works on +general surgery. Where great immobility is needed, it is one of the most +valuable means of restraint we have. Apart from that, its use in any +serious operation is always to be advocated, if only on the score of humane +consideration for the dumb animal helpless under our hands. + + +B. INSTRUMENTS REQUIRED. + +In addition to those required for operations on the softer structures--such +as scalpels, forceps, artery forceps, directors, scissors, etc.--the +surgery of the foot demands instruments specially adapted for dealing with +the horn. + +A great deal will depend upon the operator as to whether these are few or +many. The average man of resource will deem a smith's rasp and one or two +strong drawing-knives amply sufficient, and on no account should they be +omitted from the list of those ready to hand. + +[Illustration: FIG. 45.--THE ORDINARY DRAWING-KNIFE.] + +The ordinary smith's drawing-knife (Fig. 45) is well known to almost +everyone, and is well suited for much of the rougher part of the work. +The careful following up of pricks, however, and some of the more special +operations demanding removal of portions of the lateral cartilages call for +instruments of a more delicate character and peculiar construction. These +are to be found in the so-called sage-knife, and the modern (French) +pattern of drawing-knife. + +[Illustration: FIG. 46. _a, b_, Modern forms of drawing-knife; _c, d, e_, +sage-knives.] + +The modern drawing-knife differs from the smith's instrument in being +attached to a straight, instead of a curved, handle, and in usually being +sharp on both edges instead of only on one. These are made in various sizes +(Fig. 46, _a, b_), and the blades flat, curved on the flat, or curved at an +angle with the edges of the haft. + +The sage-knife, as its name indicates, is a knife with a lanceolate-shaped +blade. These also may be obtained in varying forms and sizes (Fig. 46, _c, +d, e_). Fig. 46, _c_, is a single-edged, right-handed sage-knife. Fig. +46, _d_, is a left-handed instrument of the same type. The double-edged +sage-knife is represented in Fig. 46, _e_. + +[Illustration: FIG. 47.--SYMES'S ABSCESS-KNIFE.] + +It may be mentioned too, in passing, that the ordinary Symes's +abscess-knife (Fig. 47) is a most useful instrument when performing the +operation of partial excision of the lateral cartilages, its peculiar shape +lending itself admirably to the niceties of the operation. + +One or two good-shaped firing-irons will also be found useful. They will +lighten the labour of tediously excavating grooves with the knife, +where that procedure is necessary; and, used in certain positions to be +afterwards described, will afford just that necessary degree of stimulus to +the horn-secreting structures of the foot, which the use of the knife alone +will not. + +The man in country practice will also be well advised in carrying to every +foot case a compact outfit, such as that carried by the smith. This will +consist of hammer and pincers, drawing-knife and buffer. Much valuable time +is then often saved which would otherwise be wasted in driving round for +the nearest smith. + +There are other special operations requiring the use of specially-devised +instruments for their successful carrying out. These we shall mention when +we come to a consideration of the operations in which they are necessary. + + +C. THE APPLICATION OF DRESSINGS. + +One of the most common methods of applying a dressing to the foot is +poulticing. Usually resorted to on account of its warmth-retaining +properties, the poultice may also be medicated. In fact, a poultice, +strongly impregnated with perchloride of mercury or other powerful +antiseptic, is a useful dressing in a case of a punctured foot, or a +wise preliminary to an operation involving the wounding of the deeper +structures. The poultice may consist of any material that serves to retain +heat for the longest time. Meal of any kind that contains a fair percentage +of oil is suitable. Crushed linseed, linseed and bran, or linseed-cake dust +are among the best. + +To prepare it, all that is necessary is to partly fill a bucket with the +material and pour upon it boiling water. The hot mass is emptied into a +suitable bag, at the bottom of which it is wise to first place a thin layer +of straw, in order to prevent the bag wearing through, and then secured +round the foot. This is generally done by means of a piece of stout cord, +or by straps and buckles fastened round the pastern and above the fetlock. + +An improved method of fastening has been devised by Lieutenant-Colonel +Nunn: + +'A thin rope or stout piece of cord about 5 feet long is doubled in two, +and a knot tied at the double end so as to form a loop about 5 or 6 inches +long, this length depending on the size of the foot (as at A, Fig. 48). The +poultice or other dressing is applied to the foot, and the cloth wrapped +round in the ordinary way, the loop of the cord being placed at the back of +the pastern (as in A, Fig. 49); the ends of the cord are passed round, one +on the inside and the other on the outside, towards the front (as in B, +Fig. 49). These ends are then twined together down as far as the toe (see C +in Fig. 49). The foot is now lifted up, and the ends of the cord (CC, Fig. +49), are passed through the loop A (as at D, Fig. 49), and then drawn +tight. The ends of the cord are now separated, and carried up to the +coronet (as at EE, Fig. 49), one on the outside, the other on the inside of +the foot. They are then again twisted round each other once or twice (as at +F, Fig. 50), and are passed round the pastern once or twice on each side. +They are now passed under the cord (E, Fig. 49), and then reversed, so +as to tighten up E, and are finally tied round the pastern in the usual +manner. The arrangement of the cords on the sole is shown in Fig. 51, which +is a view from the posterior part. + +[Illustration: FIGS. 48, 49, 50, 51.--ILLUSTRATING LIEUTENANT-COLONEL +NUNN'S METHOD OF APPLYING A POULTICE TO THE FOOT.] + +'The advantages of this method of fastening have been found to be: (1) It +does not chafe the skin; (2) if properly applied it has never been known +to come undone; (3) it is the only way we know that a poultice can be +satisfactorily applied to a mule's hind-foot; (4) horses can be exercised +when the poultice is on the foot, which is almost impossible with the +ordinary leather boot; (5) the sacking or canvas does not cut through so +quickly.' + +[Illustration: FIGS. 52, 53.--TWO FORMS OF POULTICE-BOOT.] + +A further method of applying the poultice is by using one of the +poultice-boots made for that purpose (see Figs. 52 and 53). + +These have an objection. They are apt to be allowed to get extremely dirty, +and so, by carrying infective matter from the foot of one animal to that of +another, undo the good that the warmth of the poultice is bringing about. +The advantage of the ordinary sacking or canvas is that it may be cast +aside after the application of each poultice. Where the boot is kept clean, +however, it will save a great deal of time and trouble to the attendant. + +While on the subject of poulticing, it is well to remark that in many cases +it may be more advantageous to supply the necessary warmth and moisture to +the foot by keeping it immersed in a narrow tub of water maintained at the +required temperature. By this means the warmth is carried further up the +limb (sometimes an important point), and the water can more conveniently be +medicated with whatever is required than can the poultice. In fact, it is +the author's general practice, where the attendants can be induced to take +the necessary pains, to always advise this latter method. + +[Illustration: FIG. 54.--SWAB FOR APPLYING MOISTURE TO THE FOOT.] + +Where a dressing is relied upon by some practitioners on account of the +warmth it gives, others, even in identical cases, will depend upon the +effects of cold. This may be applied by means of what are called 'swabs.' +In their simplest form swabs may consist only of hay-bands or several +layers of thick bandage bound round the foot and coronet, and kept cool by +having water constantly poured upon them. In many cases the form of swab +depicted in Fig. 54 will be found more convenient. + +When only one foot is required to be dressed, and a water-supply is +available, by far the preferable method is to attach one end of a length +of rubber tubing to the water-tap, and fasten the other just above the +coronet, allowing the water to trickle slowly over the foot. In cases where +a forced water-supply is unobtainable, and the case warrants the extra +trouble, much may be done with a medium-sized cask of water placed +somewhere over the animal, and the rubber tubing connected with that. + +Where the dressing is desired to be kept applied to the sole and frog only, +there is no method more satisfactory than the shoe with plates. + +[Illustration: FIG. 55.--THE SHOE WITH PLATES. _A_, The plates in position; +_B_, the plates separated from the shoe.] + +[Illustration: FIG. 56.--THE QUITTOR SYRINGE.] + +The plates are of metal, preferably of thin sheet iron or zinc, and are +slipped between the upper surface of the shoe and the foot after the manner +shown in Fig. 55. The plates themselves are shaped as depicted in Fig. +55, _a, b, c, a_ and _b_ curved to meet the outlines of the shoe, and _c_ +shaped so as to wedge tightly over the posterior ends of the side plates, +and between them and the shoe. A distinct advantage of the plate method of +dressing is that a certain amount of pressure may be maintained on the sole +and frog, a very important consideration in connection with some of the +diseases with which we shall later deal. + +When dealing with sinuous wounds of the foot, another favourite mode of +applying dressings is by means of the syringe, and no better instrument for +all cases can be found than that known as a quittor syringe (Fig. 56). + +A further mode of applying dressing, and one frequently practised +in connection with the foot, is known as 'plugging.' This is almost +sufficiently indicated by its name. It consists in rolling portions of +the dressing into little cylinders, wrapped round with thin paper, and +introduced into a sinus or other position where considered necessary. + + +D. PLANTAR NEURECTOMY. + +As a last resort in the treatment of many diseases of the foot the +operation of neurectomy is often advised. It will be wise, therefore, to +insert a description of the operation here. + +_Derivation of the Word_.--For many years the operation was known simply as +'nerving' or 'unnerving,' and it was not until 1823, at the suggestion +of Dr. George Pearson, that Percival introduced the word _neurotomy_ +to signify the operation with which we are now about to deal. The word +neurotomy, however, used strictly, means the act or practice of dissection +of nerves, and, when applied to the operation as practised to-day, +describes only a step in the procedure. + +As the operation really consists in cutting down upon, and afterwards +excising a portion of the nerve, the modern appellation of +_neurectomy_--from the Greek _neuron_, a nerve; and _tome_, a cutting, +signifying the cutting out of a nerve or the portion of a nerve--is far +more suitable. + +According as the nerve operated on is the plantar or the median, the +operation is known as plantar or median neurectomy. + +_History of the Operation_.--It is to two English veterinarians that we +owe the introduction of the operation to the veterinary world. In 1819 +Professor Sewell announced himself as the originator of neurotomy. This +claim was disputed by Moorcraft, who appears to have successfully +shown himself to be the real person entitled to that honour, he having +satisfactorily performed the operation on numerous animals for fully +eighteen years prior to Professor Sewell's announcement. It appears that +Moorcraft left this country for India in 1808, having practised the +operation in more or less obscurity for some six or seven years previous +to that. After his departure neurectomy, as introduced by him, either died +away in repute, or was not made by him sufficiently public to become a +matter of general knowledge. To Professor Sewell, therefore, although not +the actual originator of the operation, belongs the honour of making it +public to the veterinary profession. + +In 1824, five years after Sewell's introduction, we find it practised on +the Continent by Girard. We gather, however, from the writings of Percival +and Liautard, that both in this country and on the Continent the operation +was for several years largely in the stage of experiment. Unsuitable +subjects were operated on; the work afterwards given to the animal +improperly adjusted to his altered condition; and the bad after-results of +the operation almost ignored by some, and greatly exaggerated by others. +In fact, some long time elapsed before veterinary surgeons allotted to the +operation that measure of credit which the results following it warranted. + +_The Object of the Operation_ is to render the foot insensitive to pain, +and to give to an otherwise incurably lame animal a further period of +usefulness. After the operation, as time goes on, this object may become +defeated by the reunion of the divided ends of the nerve. In that case, +neurectomy must necessarily be performed again. + +_The Operation_.--Two forms of neurectomy are recognised--the high +operation and the low. The low operation deals with the posterior digital +branch of the plantar nerve, and the high operation with the plantar +itself. + +It is the latter operation with which we shall deal first. In our opinion +it is that most likely to be followed by satisfactory results. The area +supplied by the posterior digital is mainly the posterior portion of the +digit. Thus, unless the cause of the lameness is diagnosed with certainty +to be situated somewhere in the posterior region of the foot, section of +the posterior digital alone will not give total insensibility to pain. +Added to that, we may remember this: Below the point at which the digitals +branch off from the plantar there is always more likelihood of the part +we are attempting to render insensible being supplied by another and +adventitious branch, or a branch that, as regards its direction, is +abnormally distributed. As a last consideration, we may say that the higher +operation is the easier to perform. + +Percival, in his works on lameness, has some very sage remarks to make by +way of a preliminary, and we cannot do better than quote them here. He +says: + +'To command success in neurectomy three considerations demand attention: + +'1. The subject must be fit and proper; in particular, the disease for +which neurectomy is performed should be suitable in kind, seat, stage, etc. + +'2. The operation must be skilfully and effectually performed. + +'3. The use that is made of the patient afterwards should not exceed what +his altered condition appears to have fitted him for. + +'The veterinarian who is guided by considerations such as those will find +that he has restored to work horses who would otherwise have been utterly +useless. A plain and safe argument wherewith to meet the objections to +neurectomy is simply to ask the question what the animal is worth, or to +what useful purpose he can be put, that happens to be the subject of such +an operation. + +'If the horse can be shown to be still serviceable and valuable, then he is +not a legitimate subject for the operation. The rule of procedure I have +laid down is to operate on no other but the _incurably lame horse_; and +whenever this has been attended to, not only has success been the more +brilliant, but indemnification from blame or reproach has been assured.' + +_Preparation of the Subject_.--But little in the way of medicinal +preparation is necessary. When the animal is a gross, heavy feeder, and +carries a more than ordinary amount of cupboard, all that is needed is to +withhold his usual allowance of food for some time prior to the operation, +simply to avoid risk of rupture when casting. If considered advisable, a +dose of physic may also be administered. + +To the seat of operation, however, careful attention should be given. On +the day previous to the operation the hair should be closely removed with +the clipping machines, and the skin thoroughly cleansed with warm water +and soap. After this, a bandage soaked in a 4 per cent, watery solution +of carbolic acid should be wrapped lightly round the limb, and allowed to +remain in position until the animal is cast and ready for the operation the +following morning. On removing the bandage prior to operating, the part +should again be bathed with a cold 5 per cent. solution of carbolic acid +and swabbed dry. Attention to these details will serve to leave the wound +in that favourable condition in which it heals nicely, and with the minimum +amount of trouble. + +_Preliminary Steps_.--By some practitioners the operation is performed with +the animal standing, local anæsthesia having been first obtained by the use +of cocaine, or an ethyl chloride spray. There is no gainsaying the fact, +however, that the operation of neurectomy is a painful one, and that, with +most operators, success will be more fully guaranteed with the animal cast +and the limb held in a suitable position by an assistant. + +The animal is thrown by the hobbles upon the side of the leg which is to be +operated on. The cannon of the upper fore-limb is then fixed to the cannon +of the upper hind, as described under the section of this chapter devoted +to the methods of restraint, and the lower limb freed from the hobbles and +drawn forward by an assistant by means of a stout piece of cord round the +pastern. + +An alternative method of holding the limb is to bind both fore-legs +together above the knee by means of the side-line run round a few times in +the form of the figure 8, and then fastened off. As in the former method, +the lower foot is then removed from the hobble, and again held forward by +an assistant. By either method the inside of the limb is operated on first. + +[Illustration: FIG. 57.--THE ESMARCH RUBBER BANDAGE AND TOURNIQUET.] + +Although it is not absolutely necessary, it is an advantage, especially to +the inexperienced operator, to apply before operating an Esmarch's bandage +and tourniquet (Fig. 57). This expels the greater part of the blood from +the limb, and renders the operation comparatively bloodless. + +[Illustration: FIG. 58.--RUBBER TOURNIQUET WITH WOODEN BLOCK.] + +The Esmarch bandage is composed of solid rubber, and with it the limb is +bandaged tightly from below upwards. On reaching the knee the tourniquet is +stretched round the limb, fastened by means of its buckle and strap, and +the bandage removed. Those who feel they can dispense with the bandage use +the tourniquet alone. For this purpose the form depicted in Fig. 58, and +the one in general use at the Royal Veterinary College, is more suitable, +on account of its wooden block, which may be placed so as to press on the +main artery of supply. + +[Illustration: Fig. 59. NEURECTOMY BISTOURY.] + +_Instruments Required_.--These should be at hand in an earthenware or +enamelled iron tray containing just sufficient of a 5 per cent. solution +of carbolic acid to keep them covered. Those that are necessary will be a +sharp scalpel, or, if preferred, one of the many forms of bistoury devised +for the purpose (see Fig. 59), a pair of artery forceps, a needle ready +threaded with silk or gut, one of the patterns of neurectomy needle (see +Fig. 60), and a pair of blunt-pointed scissors curved on the flat. It is +also an advantage, when once the incision through the skin is made, to +employ one of the forms of elastic, self-adjusting tenacula (see Fig. 61) +for keeping the edges of the wound apart while searching for the nerve. + +[Illustration: FIG. 60. NEURECTOMY NEEDLE.] + +_Incision through the Skin_.--We remember that the plantar nerve of the +inner side is in close relation with the internal metacarpal artery, and +that both, in company with the internal metacarpal vein, run down the limb +in close proximity with the inner border of the flexor tendons. Also, we +remember that the external plantar nerve has no attendant artery, although, +like its fellow, it is to be found in close touch with the edge of the +flexor tendons. + +Bearing these landmarks in mind, we feel for the nerve in the hollow +just above the fetlock-joint by noting the pulsations of the artery, and +determining the edge of the flexor tendons. This done, a clean incision is +made with the bistoury or the scalpel in the direction of the vessels. The +incision should be made firmly and decisively, so that the skin may be +cleanly penetrated with one clear cut. If judiciously made, little else in +the shape of dissection will be needed. + +[Illustration: FIG. 61.--DOUBLE TENACULUM.] + +It is now that the double tenaculum (Fig. 61) is applied. One clip is fixed +to the anterior edge of the wound, and the other carried beneath the limb +and made to grasp the posterior edge. If found desirable to keep the +edges of the wound apart, and no tenaculum to hand, the same end may be +accomplished by means of a needle and silk. In like manner as is the +tenaculum, the silk is attached to one edge of the wound, carried under the +limb, and firmly secured to the other. + +Having made the incision, the wound should be wiped free from blood by +means of a pledget of cotton-wool previously soaked in a carbolic acid +solution and squeezed dry. At the bottom of the wound will now be seen +the glistening white sheath, containing the vein, artery, and nerve. This +should be picked up with the forceps, and a further incision made with the +bistoury. Care should be exercised in making this second incision, or the +artery may accidentally be opened. If an ordinary scalpel is used, the +lower end of the sheath should be picked up and the point of the scalpel +inserted through it. With the cutting edge of the scalpel turned towards +the opening of the wound, the sheath is then slit from below upwards. The +second incision satisfactorily made, the wound is again wiped dry, and the +nerve seen as a piece of white, curled string in the posterior portion of +the wound. + +At this stage it is advisable to accurately ascertain whether what we have +taken to be the nerve actually is it. This is done by taking it up with the +forceps and giving it a sharp tweeze. A sudden struggle on the part of the +patient will then leave no doubt in the operator's mind that it is the +nerve he has interfered with. + +_Section of the Nerve_.--The neurectomy needle (Fig. 60) is now taken, and, +excluding the other structures, passed under the nerve. A piece of stout +silk or ordinary string is then threaded through the eye of the needle, the +needle withdrawn, and the silk left in position under the nerve. The silk +is now tied in a loop, and the nerve by this means gently lifted from its +bed. With the curved scissors or the scalpel it is severed as high up as is +possible. The lower end of the severed nerve is then grasped firmly with +the forceps, pulled downwards as far as possible, and then cut off. At +least an inch of the nerve should be excised. + +The animal is then turned over, and the opposite side of the limb operated +on in the same manner. + +The tourniquet is now removed, and the wound is examined for bleeding +vessels. If the hæmorrhage is only slight, the wound should be merely +dabbed gently with the antiseptic wool until it has stayed. A larger vessel +may be taken up with the artery forceps and ligatured, or the hæmorrhage +stopped by torsion. On no account, unless it it done to stay hæmorrhage +that is otherwise uncontrollable, should the wound be sutured with blood in +it. With the wound once dry and clean, it is well to insert three or four +silk sutures, but care must be taken not to draw them too tightly. This +done, the patient may be allowed to get up. _After-treatment_.--This is +simple. Over each wound is placed a pledget of antiseptic cotton-wool or +tow, and the whole lightly covered with a bandage soaked in an antiseptic +solution. For the first night the animal should be tied up short to the +rack, and the following morning the bandages removed. A little boracic +acid or iodoform, or a mixture of the two combined with starch (starch and +boracic acid equal parts, iodoform 1 drachm to each ounce) should now be +dusted over the wounds, the antiseptic pledgets renewed, and the bandage +readjusted over all. + +At the end of three or four days the bandages may be dispensed with. All +that is necessary now is an occasional dusting with an antiseptic powder, +and, as far as possible, the restriction of movement. At the end of a week +the sutures may be removed, and the animal turned into a loose box or out +to pasture. + + +E. MEDIAN NEURECTOMY. + +As a palliative for lameness when confined to the foot, one would imagine +that the plantar operation would be all sufficient. There are operators, +however, who state that the results following section of the median nerve +have been such as to cause them to entirely abandon the lower operation in +its favour. If only for that reason a brief mention of the operation must +be made here. + +The operation was first performed in this country in October, 1895, the +subject being one of the out-patients at the Royal Veterinary College Free +Clinique. + +For five or six years following this date Professor Hobday performed the +operation some several hundred times, and was certainly instrumental in +bringing the operation into prominence. Though so recently introduced here, +it appears to have been practised for several years on the Continent, +originating in Germany as early as 1867. In that country a first public +account of it was published in 1885 by Professor Peters of Berlin, while in +France it was introduced by Pellerin in 1892. In this operation a portion +of the median nerve is excised on the inside of the elbow-joint just below +the internal condyle of the humerus. Here the nerve runs behind the artery, +then crosses it, and descends in a slightly forward direction behind the +ridge formed by the radius. + +The position of the limb most suitable for the operation is exactly that we +have described as most convenient for the plantar excision. The animal is +cast, preferably anæsthetized, and the limb removed from the hobbles, and +held as far forward as is possible by an assistant with the side-line. + +Professor Hobday's description of the operation is as follows: + +'A bold incision is made through the skin and aponcurotic portion of +the pectoralis transversus and panniculus muscles, about 1 to 3 inches +(depending on the size of the horse) below the internal condyle of the +humerus, and immediately behind the ridge formed by the radius. This +latter, and the nerve which can be felt passing over the elbow-joint, form +the chief landmarks. The hæmorrhage which ensues is principally venous, and +is easily controlled by the artery forceps. In some cases I have found it +of advantage to put on a tourniquet below the seat of operation, but this +is not always advisable, as it distends the radial artery. We now have +exposed to view the glistening white fascia of the arm, which must be +incised cautiously for about an inch. This will reveal the median nerve +itself situated upon the red fibres of the flexor metacarpi internus +muscle. If not fortunate enough to have cut immediately over the nerve, it +can be readily felt with the finger between the belly of the flexor muscle +and the radius.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. ix., +p. 181.] + +The nerve exposed, the remainder of the operation is exactly as that +described in removing the portion of the nerve in the plantar operation. +The wound is sutured and suitably dressed, and a fair amount of exercise +afterwards allowed the patient. + + +F. LENGTH OF REST AFTER NEURECTOMY. + +This is placed by the majority of surgeons at about three weeks to a +month. Within that period no excessive exertion should be undergone by +the patient. A certain amount of quiet exercise, however, is beneficial, +facilitating the healing of the wounds, and accustoming the animal to the +altered condition of his limb. + + +G. SEQUELÆ OF NEURECTOMY. + +These we shall relate collectively, making no distinction between those +following excision of the plantar nerve and those succeeding section of the +median. It must be remembered by the surgeon, however, that the unfortunate +sequelæ we are now about to describe are likely to be far more grave when +following section of the larger nerve. + +_Liability of Pricked Foot going undetected_.--On account of the warning +they convey to the surgeon, first place among the sequelæ of neurectomy +must be given to accidents following loss of sensation. Take, for example, +punctured foot. In any case, in the sense of being unforeseen, it is +accidental. In the neurectomized foot it becomes doubly accidental, in that +not only is it unforeseen, but that it is for some time indiscoverable. +With the foot deprived of sensation, a nail may be picked up, or a prick +sustained at the forge, and no intimation given to the attendant until pus +has underrun the horn, and broken out at the coronet. What follows, then, +is that the hoof as a whole, or the greater part of it, sloughs off. + +No neurectomy should be undertaken unless this contingency has been allowed +for. The owner should be advised of it by the surgeon, who should at the +same time enjoin on his client the absolute necessity of giving to the +neurectomized foot daily and careful attention. + +_Loss of Tone in the Non-sensitive Area_.--In addition to the mischief +resulting from a wound going undetected, it must be remembered that the +loss of tone resulting from the operation gives to every wound (however +slight), in the region supplied by the removed nerve, a sluggish and +troublesome character. Difficult to deal with as wounds about the foot +ordinarily are, they are rendered more so by a previous neurectomy. + +_Gelatinous Degeneration_. This is a condition liable to occur in cases +where the operation has been too long deferred, and when considerable +structural alteration has already taken place in the shape of diseased bone +or tendon, more especially in navicular disease. It consists in a peculiar +softening of the structures of the limb, accompanied with enlargement, +due to swelling of the connective tissues, the enlargement and softening +generally making itself first apparent by a soft, pulpy swelling in the +hollow of the heel. + +From this onwards the enlargement increases, and lameness becomes +excessive, the animal going more and more on his heels, until, finally, no +portion of the solar surface of the foot comes to the ground at all. + +The case is hopeless, and destruction should be advised. + +_Reported Case_.--'The patient, a brown carriage gelding, was brought to +the Royal Veterinary College infirmary in a cart on December 31, the only +previous history obtainable being that it had suddenly fallen lame a month +before. + +'The symptoms presented were excessive lameness of the near fore-limb. On +being trotted, the toe was elevated each time the foot reached the ground, +progression being entirely on the heels. Separation of the hoof for about 2 +inches at the hinder part of the coronet; oedematous swelling from foot to +knee, extending during the next three days to the elbow. Great tenderness +between the knee and the fetlock; below this no sensation whatever, as a +pin was inserted in several places round the coronet without causing any +symptoms of pain. On further examination, two unnerving scars were found. +No treatment was adopted, and the horse was destroyed on January 6. + +'On dissecting the leg, the following appearances presented themselves: + +'The limb was very much enlarged, due to thickening of the connective +tissue, the skin being removed only with difficulty. The tendons were soft +and much thickened. A rupture of the skin at the coronet, just where the +skin meets the wall of the foot. Large extravasations of blood at the back +of the tendons, situated in the lower half. _External_ nerve trunk had +become reunited, at the point of junction there being a hard lump about +the size of a walnut. _Internal_ nerve trunk also had become reunited, and +presented a thickened portion at the point of junction, but not so large as +that of the outer side, and situated in the lower half of the tendon, about +2 inches higher than that on the external nerve. This nerve trunk was +atrophied below the thickening, and had undergone gelatinous degeneration. +Judging from the scars on the skin, this side had evidently been unnerved a +week or ten days previously to that on the outer side. The band stretching +across the back of the perforatus, between the external and internal +nerves, appeared on the inside to have become firmly fixed into the tendon. + +'On removing the hoof, under the sole there appeared a large quantity of +very foetid pus; the laminæ were very much inflamed in patches. There +was an enormous thickening of connective tissues in the heel. On cutting +longitudinally through the perforatus tendon, there was exposed a large +blood-coloured mass, of a gelatinous appearance, situated on the perforatus +tendon, the latter being very much thickened, and growing to the navicular +bone. The underneath surface of the superior suspensory ligament was much +thickened, and firmly adherent to the bone; at the posterior surface of +the metacarpus there was a quantity of gelatinous substance. The anterior +ligament of the fetlock-joint was thickened; the navicular bone was entire, +but showed lesions of navicular disease, being ulcerated. Section through +the bone did not reveal anything further. It may be here remarked that the +ulcerations were on either side of the central ridge, and not at all on the +ridge itself. + +'Microscopic examination of the tissue joining the two ends of the nerve +together revealed a few nerve fibres; the general appearance was that +of granulation tissue, containing capillary vessels, which were fairly +plentiful, and comparatively large in size.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 386 (Hobday)] + +_Chronic Oedema of the Leg_.--In some cases there is a distinct swelling +of the leg some time after the operation. This exposes the limb to the +infliction of sores from striking with the opposite foot, with, of course, +the difficulty in healing we have just described. + +_Persistent Pruritus_.--This annoying sequel occurs in the neurectomized +limb, with or without gelatinous degeneration, and appears to be without a +remedy. The itching in some cases is so intense as to lead the animal to +constantly gnaw at the top of the foot. As one observer has remarked, the +animal may begin literally biting pieces out of his limb. The result of the +irritation and gnawing is fatal. Great sloughing of the parts takes place, +and the animal has eventually to be slaughtered. + +_Fracture of the Bones_.--The sudden loss of sensation in a foot may cause +the animal to use violently the limb he has for months past been carefully +nursing. It may be that the lameness for which the operation has been +performed has been due to disease existing in the navicular bone, and +extending, perhaps, to the os pedis. By the disease the bone has already +been made brittle, its substance and ligamentous attachments perchance +weakened and broken up by a slow-spreading caries, and rarefaction of the +remaining bone substance rendered almost certain. In this instance, the +free use of the foot, and the application to the diseased structures of an +unwonted pressure immediately after the operation results in fracture. With +the rupture of the structures we get the elevated toe and soft swelling in +the heel, as described in gelatinous degeneration. Treatment, of course, is +out of the question. + +_Neuroma_.--A further sequel is the appearance at the seat of the operation +of what is termed an 'amputational neuroma.' This is a tumour-like +growth occurring on the end of the divided nerve. It is composed of +connective-tissue elements permeated by nerve fibres which have grown out +from the axis-cylinders of the nerve stump. It may vary in size from a pea +to a hazel-nut, and is frequently the cause of much pain. This must be cut +down upon and cleanly removed, taking away at the same time as much of the +nerve as is possible. + +_Reunion of the Divided Nerve_.--We may say at once that 'reunion' in the +popular sense of the word does not take place. At a varying period after +section, however, we do get a return of sensation. This is brought about in +the following manner: The axis-cylinder of the nerve, still in connection +with the spinal cord, swells somewhat, and hypertrophies. The cells of this +hypertrophied portion show a great tendency to proliferate and produce +new nerve structure. This growing point splits, and gives rise to several +fibrils, which are new axis-cylinders. These commence to grow towards the +periphery, and, in so doing, grow through the cicatricial tissue that has +formed at the seat of the operation. + +After passing through the cicatricial tissue (the amount of which tissue, +of course, controls the length of time that insensibility remains), the +growing axis-cylinders reach the degenerated portions of the nerve below +the point of section. It is along the track of the old nerve that the new +growths from the stump reproduce themselves. + +The fact of the new growths having to pass through the fibrous tissue of +the cicatrix before they can gain the course of the old nerve, along which +latter their progress of growth is comparatively easy, affords ample +illustration that as large a portion as is possible of the nerve should be +removed when operating, in order to convey insensibility for the longest +time. After reunion, of course, nothing remains but to repeat the +operation. + +_The Existence of an Adventitious Nerve-supply_.--While not exactly a +sequel of the operation, the fact that it is not discovered until after the +operation has been performed warrants us in mentioning it here. It is +not an uncommon thing in the lower operation to find that sensation and +symptoms of lameness still persist after section of the nerve. In many +cases this has been traced to the existence of an abnormal nerve branch. +In the higher operation this is not so likely to be met with. That it may +occur, however, is shown by the following interesting case related by +Harold Sessions, F.R.C.V.S.:[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +xii., p. 343.] + +'In June of 1898 I saw a hunter suffering from navicular disease. After +carefully examining the leg, I advised the owner to have the operation of +neurectomy performed upon him. This he decided to do, and the horse was +sent to me about the beginning of July. + +[Illustration: FIG. 62.--DISSECTED EXTERNAL METACARPAL NERVE AND BRANCHES. +_a_, Metacarpal; _b_, anterior plantar; _c_, extra branch (probably from +the internal metacarpal), conveying sensation after division of the +external metacarpal.] + +'The operation was performed in the ordinary way, without any difficulty +whatever. The wounds healed nicely, but the horse still continued to go +lame. Careful examination showed that there was still sensation on the +outside of the foot. Thinking that possibly there might be two external +metacarpal nerves, the horse was again cast, the operation being performed +slightly lower down. Only the main branch of the external metacarpal nerve +could be found. A piece of this was taken out, and the horse let up. On +examination, sensation was still found in the posterior part of the outside +of the foot. It was very evident that there was some abnormal distribution +of the nerve, as sensation was still being conveyed to that part of the +foot. + +'As the horse was absolutely useless, and would have to be shot unless this +piece of nerve could be found, he was again thrown, and after he had been +anæsthetized I determined to follow the course of the nerve down, until I +found where the accessory branch came from. This I found a little below the +fetlock, about 1/2 inch below the point where the anterior plantar nerve is +given off from the metacarpal nerve. It was about 1/2 inch below the spot +where the anterior plantar nerve passes between the artery and vein of the +foot, and it was somewhat difficult to get at it. + +'Fig. 62 shows the exact size and distribution of the nerves. After the +separation of the accessory branch, sensation was taken from the foot, and +the horse went perfectly sound.' + +_Stumbling_.--In addition to the sequelæ we have mentioned, it is urged +against the operation of neurectomy that one of the first effects of +depriving the foot of the sense of touch is a tendency on the part of +the animal to stumble. From the cases we have seen we cannot regard +this objection as a serious one. Nevertheless, as veterinarians, with a +knowledge of the physiology of the structures with which we are dealing, +we must treat the objection with respect, for, after all, we are bound to +allow that stumbling, and a bad form of it, would be but a natural sequence +of the operation we have just performed. The real fact remains, however, +that cases of stumbling, even immediately after the operation, are +rare; and that even when they do occur, the animal seems easily able to +accommodate himself to the altered condition, and as readily uses the +comparatively inert mass at the end of his limb as he did previously the +intact foot. + + +H. ADVANTAGES OF THE OPERATION. + +From the prominence we have given to the unfortunate sequelæ of the +operation it might possibly be inferred that, while not giving it our +absolute condemnation, we regard neurectomy with a certain amount of +distrust. That we may contradict any such false impression, we state here +that in many cases the operation is the only measure which will offer +relief from pain, and restore to work an otherwise useless animal. In +support of that we will now quote the recognised advantages of the +operation. + +That in many cases, when all other methods--surgical and medicinal--have +failed, there is an immediate and total freedom from pain and lameness no +one will deny. This, if it restores to active work an animal that would +otherwise have had to have been cast aside, is ample justification for +giving the operation, in spite of its many unfortunate terminations, a real +place among the more highly favoured remedial measures to our hand. + +'For _Contracted Hoofs_, viewing them in the light of idiopathic disease, +or as being the immediate cause of the existing lameness in the uninflamed +condition of the foot, and when consequential changes of its organism have +taken place which bid defiance to therapeutic measures, _neurotomy_ is a +_warrantable resource_' (Percival). + +'For _Ringbone_ neurotomy has been practised with perfect success, after +blistering and firing had both failed, notwithstanding the work the animal +had to perform afterwards was of the most trying nature' (_ibid_.). + +For _Navicular Disease_, when that malady is diagnosed, the earlier +neurectomy is performed the better. The greater work given to the diseased +bursa and bone, and the return of the contracted heels to the normal, +brought about by the greater freedom with which the foot is used, are +claimed by many to effect a cure. + +Writing of navicular disease, and mentioning his belief in the possibility +of the diseased bone effecting its own repair after the operation, Harold +Leeney, M.R.C.V.S., says: + +'The expansion of the heel, and rapid development of the frog (in this and +many other cases) immediately after the operation, has not, I venture to +think, attracted so much attention as it deserves, and may have something +to do with those cases which appear to be actually _cured_, not merely made +to go sound by absence of pain.'[A] + +[Footnote A: _Veterinary Record_, vol. xi., p. 297.] + +Speaking of the median operation before a meeting of the Central Veterinary +Medical Society, Professor Hobday says:[A] + +[Footnote A: _Veterinary Record_, vol. xiii., p. 427.] + +'For old-standing lamenesses, when due to splints, exostoses, chronically +sprained, thickened, and painful perforans and perforatus tendons, or cases +of that kind which cause pain by pressing on the adjacent nerve structures, +after all other known methods have failed, median neurectomy is the +operation which will be most likely to give the animal a new lease of life +and usefulness.' + +'Of the _Humanity and Utility of Neurectomy_ there can be no question +whatever, and provided the cases are well selected, and the operation +is efficiently performed, the advantages to be derived from it are most +striking as well as enduring. But the disadvantages attending the loss of +sensation in the foot have been brought forward on many occasions as +an argument against neurectomy, and no one can deny that the foot with +sensation is better than one without that faculty. But in a long experience +of the operation I have never found these disadvantages outweigh the great +advantages which have immediately followed it.'[A] + +[Footnote A: _Veterinary Journal_, vol. ix., p. 178 (Fleming).] + +Beyond these, the direct advantages of neurectomy, are other and more +indirect advantages which claim attention. + +The most astonishing among them is the fact noted by many writers of repute +that exostoses (ringbones, side-bones, splints, etc.) rapidly diminish in +size. This is vouched for by such well-known authorities as Zundel and +Nocard. + +Percival, too, mentions at some length the effect of the removal of pain on +the oestral and generative functions, quoting a case of a brood cart-mare +by reason of bony deposits being stayed from breeding for some years. Two +months after the operation she went to work, and moved sound, her altered +condition leading her to breed several healthy foals. + + +I. THE USE OF THE HORSE THAT HAS UNDERGONE NEURECTOMY. + +No operation is of any considerable value to the veterinary surgeon unless +he is able to show that after it he has left his patient workable. The +alleviation of pain alone, commendable as it is from a humanitarian +standpoint, is of no interest to the average owner of horse-flesh, unless +with it he sees his animal capable of justifying his existence by the +amount of labour performed. + +Criticised in this way, is the operation of neurectomy justifiable? Upon +that point the opinions of many practitioners, even at the present day, +differ. We have already partly answered the objections likely to be raised +on this score by stating that the work afterwards allotted the animal +should be fixed to suit his altered condition. It may be taken as a general +rule that in all cases where the animal's usefulness depends upon his +delicacy of touch, as, for example, animals used solely for hacking or +hunting, his future usefulness in that special sphere of work will be done +away with. + +Percival himself, always a strong advocate for the operation, fully +recognises this. 'Does the neurotomized horse maintain the same step +as before?' he asks. 'To this important question,' he replies, 'I +unhesitatingly answer no; he does not. There can be no doubt but that the +horse _feels_ the ground upon which he is treading, and that he regulates +his action in consonance with such feeling, so as to render his step the +least jarring and fatiguing to himself, and therefore the easiest and +pleasantest to his rider.... Such impressions'--those of touch--'being +in the neurotomized subject, so far as regards the feeling of the foot, +altogether wanting, a bold, fearless projection of the limb in action will +be the consequence, followed by a putting down of the hoof flat upon the +ground, as though it were a block, creating a sensation alike unpleasant +both to horse and rider.' + +Emphatic as Percival is upon this point, there are, nevertheless, others +who maintain with equal stoutness that the unnerved animal is positively as +safe, if not safer, than the animal who has not been so treated. + +'That the tactile sense in the horse's foot is useful, it would be idle to +deny; but that it is absolutely essential, even to safe progression, no one +who has paid attention to the results of plantar neurectomy will maintain. +On several occasions for years I have hunted, hacked, and driven horses +which have been deprived of sensation in their fore-feet, and never had an +accident with them. Their action has not been impaired by the operation; on +the contrary, it has been vastly improved compared with what it had been +previous to it. And my opinion has not been single in this respect, as many +competent horsemen can give like evidence after long and severe trials of +neurotomized horses. The opponents of neurotomy were, probably, not aware +that there is in progression a _muscular_ as well as a _tactile sense_.' + +This latter contention is supported by numerous cases, reported at the time +when the operation of neurectomy was at the heyday of its popularity. Two I +select from writings of a later period: + +_Recorded Cases_.--1. 'Two of the finest among the many fine horses in the +Second Life Guards were so lame from navicular disease, when I joined the +regiment, that they were unsafe and unsightly to ride, and were therefore +entered on the list to be cast off and sold. One was so crippled that it +could scarcely be moved out of its stable. Peeling sorry at having to get +rid of such good horses, and anxious to give another blow to the mistaken +theory that unnerved animals were unsafe, I obtained the consent of my +commanding officer, who patronizes practical conclusions, to perform +neurotomy. This was carried out on both horses about eighteen months ago. +Within a fortnight they were at their duty, absolutely free from lameness, +and with first-rate action, and one of them, from being troublesome and +unsteady in the ranks--probably from the pain in its feet--had become quite +steady and tractable. Instead of being lame, blundering, and unsafe, both +were sound, free in movement, and secure, and, the pain being abolished, +they looked improved in condition. + +'During the month of July the regiment attended the summer drills at +Aldershot, and five days every week for a month these horses carried a +weight of about 22 stones each over the roughest and most dangerous ground, +nearly always at a fast pace, and for four, five, or six hours each day; +and yet they never fell or blundered, and the troopers who rode them had +unbounded confidence in their sure-footedness. They returned to Windsor, at +the end of the month's severe test, as sound in their paces as when they +left, and certainly now offer no indication whatever that they are less +safe to ride than any other horse in the regiment. The effects of the +relief from pain are also most marked, not only in the altered gait out of +doors, but also in the stable.'[A] + +[Footnote A: _Veterinary Journal, vol_. ix., p. 178 (George Fleming, +F.B.C.V.S.).] + +2. 'Some years ago I operated upon a valuable hunter, the property of a +gentleman in Kildare, the animal having shown unmistakable symptoms +of navicular disease for some months previously, and which had been +unsuccessfully combated by the milder forms of treatment for the disease +without any benefit. Although the horse went sound, the owner feared to +ride him, and sent him to be sold in Dublin, where he was disposed of for a +small price, and I then lost sight of him. The following Punchestown +Races, to my surprise, amongst a group of horses walking round the paddock +previous to saddling for an important race, I recognised my old patient, +bandaged, clothed, and trained, ready to take his part in the cross-country +contest, and surrounded by a host of admirers willing to back him at any +price. + +'Having satisfied myself that it was no other than the same animal, my +first impulse was at once to find out the jockey who was to ride him, and +warn him of his danger by telling him his mount was devoid of feeling +in both fore-feet; but the saddling-bell had already rung, and in a few +moments more the jockey emerged from the weighing-room and the next view of +the horse was his tearing up the course in the preliminary, and "pulling +double." I was sorry for the jockey if he felt as I did at that moment, for +if he did I fear he and his horse would have parted company at the first +fence, as I was certain there would be a smash before the end of the long +and difficult three miles of the Kildare Hunt Cup course. It was not until +I saw him again in the front rank passing the stand, in the first round, +that I breathed freely, and even then I felt very guilty, and, had he come +to grief badly, I don't think I should ever have operated on another horse +except in such a way as would have left unmistakable traces after it. + +'"The old horse wins!" screamed a thousand voices as the competitors safely +cleared the last bank (now taken away for a gorse fence) the last time +round, and from that moment the operation went up in my estimation a +hundredfold, and I almost lost all interest in the finish (and it was a +close one, with my patient a good third), resolving I would operate for the +future on every animal, young and old, which showed symptoms of navicular +disease. + +'Neither owner nor jockey knew the horse had been operated on, and he was +soon after, on the strength of his performance, sold for a good price to +come to England. It is idle to think that all cases are as successful as +this was, as experience soon told me; but I consider that, in careful +hands, the advantages well outweigh the disadvantages of the operation, and +I have selected this instance merely as a practical example.'[A] + +[Footnote A: _Veterinary Journal_, vol. iii., p. 254 (W. Pallin, +M.B.C.V.S.).] + +It is solely with the object of ventilating both sides of the question +that we quote the last two cases. In our opinion, the colours in which +the results of the operation are there painted are far too rosy. The +practitioner who has before him the task of satisfying a client as to what +will or what will not be the results of an operation he has suggested will +do well to weigh each side of the argument carefully, and endeavour in his +explanation to strike the happy mean. + +We hold, further, that the animal who has previously been accustomed to +fast work, and to work entailing a large call upon the sense of touch when +passing over rough and uneven ground, will be far more likely, in his +neurectomized condition, to give satisfaction to his owner if put to a +slower and a more suitable means of earning his living. + + + +CHAPTER VI + +FAULTY CONFORMATION + + +Under this heading we shall deal with such formations of the feet as depart +sufficiently from the normal to render them serious. Faulty conformation +may be either congenital or acquired, and acquired gradually as the result +of slowly operating causes, or suddenly as the sequel to previous acute +disease. Whether congenital or acquired, serious in its nature or +comparatively of no account, the veterinary surgeon will often find that +the matter of conformation is one which will have a direct bearing on many +of his 'foot' cases, and, furthermore, that it is one upon which he will +often be called to give advice. + + +A. WEAK HEELS. + +_Definition_.--That condition of the wall in which, owing to the softness +of the horn and the oblique direction of the horn fibres, the heels are +unable properly to bear the body-weight, and, as a consequence, curve in +beneath the sole. We give the condition first mention, not because of its +greater importance, but for the reason that it is frequently the forerunner +of the condition to be next described--namely, contracted feet. + +_Symptoms_.--The extreme point of the heel is not affected unless the foot +has been greatly neglected, and the condition allowed to develop. Where, +however, the foot has been uncared for, curving in of the wall takes place +to an alarming degree, and the heels curl underneath the foot to such an +extent as to grow over the sole and the bars. By the pressure they exert on +the sole corns result, and the animal is lamed. + +_Causes_.--In the main this defect is hereditary. It is seen commonly in +connection with flat-foot, and where the horn of the wall is thin and +shelly. + +_Treatment_.--In the case of weak or 'turned in' heels no suitable bearing +is offered for the shoe in the posterior half of the foot. Any attempt to +induce the heels to bear weight is immediately followed by their bending +in. It follows from this that the best shoe to be used here is one in which +the bearing is confined to the anterior half of the wall, the heels being +relieved by being sufficiently pared. As might be expected, this bearing on +the anterior half only of the foot is insufficient; pressure must be given +the frog. This latter end is best gained by a bar shoe (Fig. 68). With it +the anterior portions of the wall, the whole of the bars, and the whole +of the frog may be in contact, and the heels only so pared as to take no +bearing at all. A few such shoeings sees the defect remedied. In every +instance paring of the sole should be discouraged, as it serves but to +increase the deformity. + + +B. CONTRACTED FOOT. + +_(a)_ GENERAL CONTRACTION--CONTRACTED HEELS. + +_Definition_. By the term contracted foot, otherwise known as hoof-bound, +is indicated a condition in which the foot, more especially the posterior +half of it, is, or becomes, narrower from side to side than is normal. + +It must be borne in mind, however, that certain breeds of horses have +normally a foot which nearer approaches the oval than the circular in form, +and that a narrow foot is not necessarily a contracted foot. + +The contraction may be bilateral when affecting both heels of the same foot +and extending to the quarters, or unilateral when the inside or outside +heel only is affected. + +In some cases contraction is confined to one foot, while in others it may +be noticed equally bad in both. It is a matter of common knowledge that +contraction is usually seen in the fore-feet, while the hind seldom or +never suffer from it, a fact which, to our minds, seems difficult of +adequate explanation. Zundel explains this by stating that contraction is +principally _observed_ in the fore-feet, by reason of the fact that when +lameness arises from it alteration in action will more readily be detected +in front than behind. Percival, on the other hand, suggests that the +greater expansive powers of the hind-foot, by reason of the impetus of its +action, is able to overcome any influence operating towards contraction. It +may be, however, that given a cause for contraction, such as the removal of +the frog's counter-pressure with the ground by faulty shoeing or excessive +paring, the fore-feet, by reason of their being called upon to bear the +greater part of the body-weight, are the first to suffer. + +Flat feet with weak heels are those most frequently affected, and, as we +have already intimated, the condition may exist with or without other +disease of the foot. + +Depending upon its degree, contracted foot may vary from a simple +abnormality, non-inflammatory and painless, to a condition in which it +becomes a veritable disease, giving rise to a bad form of lameness, and +bringing about a withered and sometimes discharging and cankerous affection +of the frog. + +_Symptoms_.--In its early stages contraction is difficult of detection, and +where both feet are affected may for some time go unsuspected. With only +one foot undergoing change, the early stages may the more readily be +marked, for in this case comparison with the other and sound foot will at +once reveal the alteration in shape. If lameness in the suspected foot is +present, then any lingering doubt will be quickly dispelled. + +When far advanced, contraction offers signs that cannot well be missed. The +converging of the heels narrows the V-shaped indentation in the sole for +the reception of the frog. As a consequence of this, the frog itself +becomes atrophied by reason of the _continual_ pressure exerted upon it by +the ingrowing horn of the wall and the bars. The median and lateral lacunæ +of this organ, from being fairly broad and open channels, become pressed +into mere crack-like openings (see the commencing of this condition in Fig. +80, and a badly wasted frog in Fig. 74A). As the case goes on, the lateral +branches of the frog entirely disappear, and all that is left of the organ +is a remnant of its body or cushion, now wedged in tightly between the +bars. Following upon the disappearance of the frog, we find that the bars +are in contact, or, in some cases, actually overlapping each other at their +posterior extremities. + +At this stage, perhaps, the whole condition has become aggravated by a foul +discharge from the place originally occupied by the frog, and the foot, +especially in the region of the heels, has become hot and tender--really a +form of local and subacute laminitis. + +The long-continued inflammation, although only of a low type, renders the +horn of the hoof hard and dry, and only with difficulty will the ordinary +foot instruments cut it. This in its turn leads to cracks and fissures in +various places, but more especially in the bars and what is left of the +frog. Often, too, cracks will appear in the horn of the quarters, and a +troublesome and incurable form of sand-crack results. + +An animal with contraction advanced as far as this, especially if confined +to one foot, goes unmistakably lame. With both feet affected, he ordinarily +starts out from the stable in a manner that is commonly called 'groggy.' In +other words, the gait is uncertain, and feeling; and stumbling is frequent. +Anyone who has had the misfortune to drive an animal with feet in this +condition knows full well that every little irregularity in the road at +once makes itself felt to the feet, and that the animal, as time goes on, +learns to carefully avoid any suspicious-looking group of stones he may +see. To drive an animal like this is to keep one's self continually on +tenter-hooks, for, sooner or later, the inevitable happens, and the animal +comes down. + +Up to now we have described the changes of form in the hoof as seen when +the contracted foot is viewed from the solar surface. With those changes as +evident as we have depicted them, there will be no difficulty in detecting +the alterations in the form of the wall. + +In addition to a narrowing from side to side there will be noticed an +abnormal straightness of the quarters, with a turning in, more or less +sudden, of the heels. This effect is given in these cases by the smith +maintaining the shoe of a length and width that should normally fit a foot +of that particular animal's size and substance. This is probably done with +the idea of deceiving anyone examining the solar surface. Viewed from this +position, the width of the shoe at the heels gives the impression that it +is attached to a foot of normal breadth. This deception is heightened if +at the same time has been practised the process of 'opening up the heels.' +That expression indicates that the bars have been removed, and the lateral +lacunæ of the frog made to continue the concavity of the sole. The arch of +the latter is thus made to appear of much greater extent than it really is, +and the heels, by reason of their being abruptly cut off when removing the +bars, also convey the false impression of being wide apart. + +The practitioner unversed in the tricks of the forge will best guard +against this by viewing the foot, while on the ground, from behind. From +that position he will be able to detect the lowness of the quarters, and +the projecting portion of the shoe, that the hoof, by reason of its sudden +bending inwards, does not touch. + +The 'feeling' manner of the gait before alluded to, together with the +disinclination to put the foot firmly and squarely forward, will sometimes +lead the examiner to over-look the contraction, and diagnose his case as +one of shoulder lameness. In many cases, too, such consequent conditions +as 'thrushy frogs' and 'suppurating corns' are often treated with utter +disregard of the contraction that has really brought them about. But above +all, the disease most likely to be confounded with simple contraction is +navicular disease. More than probable it is that many cases of so-called +'navicular' have in reality been nothing more than contraction brought +about by one or other of the causes we shall afterwards enumerate--cases +where a due attention to the prime cause of the mischief would, in all +likelihood, have remedied the lameness. + +_Changes in the Internal Structures_.--It follows as a matter of course +that the changes we have described in the form of the hoof itself carry +with them alterations in the bones and sensitive structures beneath it. The +tissues, as a whole, become atrophied. The os pedis becomes deformed, loses +its circular shape, and gradually becomes more or less oval in contour. +At the same time, its structure becomes more compact, the cribriform +appearance of its anterior and lateral faces more or less destroyed, and +the few remaining openings apparently increased in size. This atrophy of +the os pedis is best noted at the wings. + +In the plantar cushion the effects of the atrophy are noted in the +smallness of the organ, in its becoming whiter in colour than normal, and +more resistant to pressure. + +The coronary cushion is also affected in the same way, where the changes +are noted most in its posterior portions. + +A further effect of the narrowing of the heels, and their consequent +tendency to drop downwards, is the exertion of a continual pressure on the +sensitive sole. In course of time, and especially in flat feet, this leads +to the appearance of corns. + +The navicular bone and bursa and the tendon of the perforans also suffer +from the effects of compression. The movement of the tendon is restricted, +and arterial supply to the adjacent structures rendered deficient. The +tissues of the bone and bursa are insufficiently nourished, and the +secretion of synovia lessened. In this way it is conceivable that navicular +disease may follow the condition of simple contracted heels. + +In common with the other structures, the lateral cartilages also suffer +from the continual pressure. Their blood-supply is lessened, their +functions interfered with, and side-bones result. + +_Causes_.--Upon the causation of contraction a very great deal has been +written, both by early veterinarians and by those of the present day. Many +and widely differing opinions have been advanced, but a careful résumé of +only a few will lead one to certain fixed conclusions. + +We may consider the causes of contraction under two headings--predisposing +and exciting. + +_Predisposing Causes of Contraction_.--Among these we will first mention +heredity, although it is possible it should not be deemed of so great +account as it is by some. That the shape of certain feet, especially those +with low heels and abnormally sloping walls, predisposes to contraction no +one will deny. So long, however, as the animal goes unshod, so long does +the foot maintain a normal condition of the heels. In other words, it +is not until the tendency to contraction already there is aggravated by +careless shoeing and the effects of work that it operates to any noticeable +extent. + +The degree of contraction will also be very largely governed by the amount +of the development of the frog. With a frog of good size, low down, and +taking part in the pressure of the foot on the ground, contraction will +be prevented. On the other hand, an ill-developed frog, one wasted by +long-continued and spreading thrush, or one robbed of its normal function +by excessive paring in the forge, is a common starting-point of the +condition we are considering. We have already referred to this in Chapter +III., when considering the experiments of Lungwitz in this connection. What +we have to bear in mind in these experiments is that the application of +a pad to the frog, in such a manner that effective ground-pressure is +obtained, results always in a marked expansion of the heels, and that, with +counter-pressure with the ground absent, expansion occurs to little or +no extent. This is proof positive of the enormous part the frog plays in +maintaining an open and elastic condition of the heels--a fact so insisted +on by Coleman. + +It is worthy of mention, however, that loss of the frog's function does not +operate to nearly so serious an extent in horses with high, upright heels +as in those with the heels low and excessively sloping. + +In illustrating this, Mr. Dollar, in his work on shoeing, mentions the case +of a pair of trotting horses of similar age, size, and weight, each having +weak fore-heels. In one case the hoofs were flat, in the other upright. The +horse with the flat hoofs suffered from contraction, while the other did +not. + +The reason appears to be that in the animal with upright hoofs the +proportion of body-weight borne by the heels is considerably less than in +those with the hoofs flat and sloping. + +Certain conditions of the horn-producing membranes also predispose to +contraction. For example, in horses reared on marshy soils, and afterwards +transferred to standing in town stables, we find that a dry and brittle +condition of the horn supervenes. This we may regard as a low form of +laminitis, brought about by the heat of the material upon which the animal +is standing, and the congestion of the feet engendered by his enforced +standing for long periods in one position, as opposed to the more or less +continuous exercise when at pasture. With the hoof in this condition it +loses by evaporation the moisture that normally it should contain, and, as +we might expect, a certain degree of contraction of its structure is the +inevitable result. + +We thus see that contraction brought about in this way is not so much +caused by the heat of the stable, as it is by the decreased ability of the +horn to retain its own moisture. + +On the other hand, it cannot be denied that excessive warmth and dryness +combined tend also to an undue abstraction of moisture, even from the horn +of the healthy foot; and this explains in great measure how it is that +lameness, as a rule, and especially that proceeding from contracted heels, +is far more frequent and of greater intensity in the hot, dry months of +summer, than in the cooler and more humid atmosphere of winter. It is +interesting to note, too, that an alternation of humidity and dryness +is far more liable to injure the quality of the horn and tend to its +contraction than the long-continued effects of dryness alone. A common +illustration of this is to be found in the effects of the ordinary +poultice. Everyone knows that when, after a few days' application, they are +discontinued, we get as a result an abnormally dry and brittle state of +the horn. This is doubtless due to the poultice removing the thin, +varnish-like, and protective pellicle known as the periople, and thereby +allowing the process of evaporation to act on the water normally contained +in the hoof. + +_Exciting Causes of Contraction_.--Among these, first place must +undoubtedly be given to shoeing. This does not necessarily imply shoeing +more than ordinarily faulty, nor a faulty preparation of the foot, but +shoeing as it is generally practised. No ordinary shoe, except a few +devised for the purpose, such as the Charlier or the tip, allows the frog +to come in contact with the ground. This we take to be the main factor in +the causation of contracted heels, especially with a predisposition already +present in the foot itself. In the words of Lungwitz: 'Regarded from this +point of view, there is no greater evil than shoeing. It abolishes the +necessary counter-pressure, and thus interferes with expansion. Bars, sole, +and frog cannot perform the functions that naturally belong to them as they +would do without the shoe.' + +In addition to the evil of the shoe itself, errors of practice in the forge +contribute to the causation of contraction. Taking first the preparation of +the foot, we find that often the heels are lowered far too much, and the +toe allowed to remain too long. This can have but one effect--that of +throwing a greater proportion of the animal's weight upon the heels than +properly they should bear, with, what we now know to be the consequence of +that, a corresponding pushing inwards and downwards of the horn; in other +words, contraction. + +Excessive paring of the bars, to which we have already partly alluded, is +also an active agent in bringing about an inward growth of the horn of the +heels and quarters. The bar, or inflexion of the wall at the heel, by means +of its close contact with the frog, communicates the outward movements +of that organ to the wall of the hoof. With the bar removed, the outward +movements of the frog under pressure are naturally rendered of no account, +and a proper and intermittent expansion of the wall denied it. The same +evil follows, though to a less extent, excessive paring of the sole. + +The shape of the bearing surface of the shoe is often to be blamed. Where +this is concave--'seated'--and the 'seating' is carried back to the +heels, it is easy to see that, when weight is on the foot, there is an +ever-present tendency for the bearing edge of the wall to slide down +towards the inner edge of the shoe. This tendency, operating on both the +inner and outer wall simultaneously, must strongly favour contraction. + +A further wrong practice is that of continuing the nailing too far towards +the heels. In our opinion this is not now often met with. When it occurs +its effect is, of course, to prevent those movements of expansion of the +wall which we now know to be normal and most marked at the heels. + +It may be remarked of the build of the shoe, or of errors in the +preparation of the foot, that neither are of much moment. Neither are +they. But when one stays to consider that errors of this description are +practised not only once, but each time the horse goes to the forge, and +that with some of them--those relating to the build of the shoe--the injury +thereby brought about is inflicted not only once, but every day that +particular shoe is worn, then it is not to be wondered at that, sooner or +later, ill consequences more or less grave result. + +_Prognosis_.--This will depend to a very large extent upon the conformation +of the limb, and upon the previous duration of the contraction. Contraction +of long standing, where atrophy of the sub-lying, soft structures and the +pedal bone may be expected, will prove obstinate to treatment. Especially +will this be so if the lateral cartilages have become ossified. Neither may +we look for much benefit from treatment if the contraction has occurred in +animals with an oblique foot axis and flat hoofs. + +On the other hand, if the case is comparatively recent, if the limb +is straight and the form of the hoof is upright, and if matters are +uncomplicated by side-bones, or other serious alteration in the internal +structures, then treatment may be rewarded with some measure of success. + +[Illustration: FIG. 63.--TIP SHOE. The dotted portions represent the length +of the branches removed.] + +_Treatment_.--The greater part of the treatment of contracted foot will +almost suggest itself as a corollary of the causes we have enumerated. The +normal width of the heels may be renewed, and development of the wasted +frog brought about by one of three methods: + +1. By restoring the pressure from below to the frog. + +2. By the use of an expansion shoe. + +3. By operative measures upon the horn of the wall. + +1. _By Restoring the Pressure from Below to the Frog_. + +This may be accomplished as follows: + +_(a) By Shoeing with Tips_.--This method is advocated by Percival, by A.A. +Holcombe, D.V.S., Inspector. Bureau of Animal Industry, U.S.A., by Dollar +in his work on horseshoeing, and by many others. + +Though requiring more care than in fitting the ordinary shoe, the +application of a tip is simple. In reality, the tip is just an ordinary +shoe shortened by truncating the heels. + +Before applying the tip, the horn of the wall at the toe should be +shortened sufficiently to prevent any undue obliquity of the hoof, and the +foot should be so prepared as to allow the heels of the tip to sink flush +with the bearing edge of the wall behind it. + +When the foot does not allow of the removal of much horn at the toe, what +is termed a 'thinned' tip is to be preferred. Its shape is sufficiently +shown by the accompanying figure (Fig. 65). + +With the tip the posterior half of the foot is allowed to come into contact +with the ground, and the object we are striving for--namely, frog pressure, +and greater facilities for alternate expansion and contraction of the +heels--is thus brought about. + +[Illustration: FIG. 64.--THE TIP SHOE 'LET IN THE FOOT.] + +[Illustration: FIG. 65.--THE THINNED TIP.] + +_(b) By Shoeing with the Charlier_.--The results brought about by the use +of a tip may be arrived at by the application of a Charlier or preplantar +shoe, or by a modified Charlier or Charlier tip. + +Briefly described, a Charlier is a shoe that allows the sole and the frog +to come to the ground exactly as in the unshod foot. This is accomplished +by running a groove round the inferior edge of the hoof by removing +a portion of the bearing edge of the wall with a specially devised +drawing-knife. Into this groove is fitted a narrow and somewhat deep shoe, +made, preferably, of a mixture of iron and steel, and forged in such a +manner that its front or outer surface follows the outer slope of the wall. + +The Charlier should have the inner edge of its upper surface very slightly +bevelled, in order to prevent any pressure on the sensitive sole, and +should be provided with from four to six nail-holes. These latter should be +small in size and conical in shape. The nails themselves should be small, +and have a conical head and neck, to fit into the nail-hole of the shoe. + +[Illustration: FIG. 66.--THE SPECIAL DRAWING-KNIFE (FLEMING'S) FOR +PREPARING THE FOOT FOR THE CHARLIER SHOE.] + +The modified Charlier, or Charlier tip, perhaps the better of the two for +the purpose we are describing, is really a shortened Charlier, and bears +the same relation to the Charlier proper as the tip does to the ordinary +shoe. It is let into the solar surface of the foot in exactly the same +manner as its larger fellow, but it does not extend backwards beyond the +commencement of the quarters. By its use greater opportunity for expansion +is given to the heels than is done by the Charlier with heels of full +length. + +[Illustration: FIG. 67.--FOOT PREPARED FOR THE CHARLIER SHOE.] + +We do not here intend to deal at any length with the arguments for and +against the Charlier as regards its adoption for general use. These will be +found fully set out in any good work on shoeing. + +The point that it is correct in theory it would be idle to attempt to +evade; but that it is generally practicable, or that it offers any very +pronounced advantages, as compared with the disadvantages urged against it, +over the shoes in ordinary use, the limited favour it has drawn to itself, +since its introduction in 1865, seems sufficiently to deny. + +_(c) By the Use of a Bar Shoe_.--Where the frog is not excessively wasted +benefit will be derived from the use of a bar shoe. + +[Illustration: FIG. 68.--BAR SHOE.] + +The transverse portion at the back, termed the 'bar,' and which gives +the shoe its name, is instrumental in bringing about from below that +counter-pressure on the frog that we now know to be so necessary a factor +in remedying contraction. When the frog, by wasting or disease, is +so deficient as to be unable to reach the 'bar,' this shoe must be +supplemented by a leather or rubber sole. + +In the event of corn or sand-crack existing with the contraction, the shoe +known as a 'three-quarter bar' is preferable (see Fig. 103). The break here +made in the contour of the shoe allows of dressing the corn, and, in the +case of sand-crack, removes the bearing from that portion of the wall. +_(d) By the Use of a Bar Pad and a Heelless or 'Half' Shoe_.--The bar +pad consists of a shape of rubber composition firmly fixed to a leather +foundation, which shape of rubber takes the place of the 'bar' of the bar +shoe. + +[Illustration: FIG. 69.--RUBBER BAR PAD ON LEATHER.] + +[Illustration: FIG. 70.--THE BAR, PAD APPLIED WITH A HALF-SHOE.] + +For habitual use in such cases as prove obstinate to treatment, or where +a complete cure was never from the commencement expected, the bar pad is +undoubtedly one of the most useful inventions to our hand. The animal's +'going' is improved, the tender frog is protected from injury by loose +stones, and greater comfort given to both the horse and the driver. + +[Illustration: FIG. 71.--FROG PAD.] + +[Illustration: FIG. 72.--FROG PAD APPLIED.] + +_(e) By the Use of a Frog Pad and a Shoe of Ordinary Shape_.--The shape of +rubber on this pad is designed to cover the frog only. Its shape and mode +of application is sufficiently shown in the accompanying illustrations. + +_(f) By turning out to Grass_.--Where the expense of keep is no object, a +return of contracted feet to the normal may be brought about by removing +the shoes and turning the animal out to pasture, thus giving the feet the +advantages to be derived from a more or less continuous operation of the +normal movements of expansion and contraction. In this case the treatment +must extend from three to four, or possibly six months. + +2. _By the Use of Some Form of Expansion Shoe_. + +[Illustration: FIG. 73.--SMITH'S EXPANSION SHOE SEEN FROM ITS GROUND +SURFACE AND FROM THE SIDE. _a_, The screw, with a fine-cut thread; _b_, nut +which travels along it; _c_, a hollow thimble into which the screw passes +at one end, the other being cut out V-shaped to catch into a slot (_d_) on +the shoe; _e, e_, the grip[A] for the bars, the length and direction of +which depend upon the shape of the foot; _f, f_, the counter-sunk rivets +forming the hinge (_f_'); _g_, the counter-sunk rivet of the expanding +piece.] + +[Footnote A: The inventor of this shoe uses the word 'grip' to denote what, +in describing other expansion shoes, we term the 'clip' (H.C.R.).] + +_(a) Smith's_.--For many years past continental writers have been +practising this method. So far as we know, however, Lieutenant-Colonel Fred +Smith was the first English veterinarian to use a shoe of his own devising, +and to report on its effects. This shoe we will, therefore, give first +mention. + +The above figure, with its accompanying letterpress, sufficiently explains +the nature of the shoe. In fitting the shoe, care must be taken to have the +hinges (_f, f_) far enough back, or the shoe will have a tendency to spring +at the heels, and the grips _(e, e)_, which catch on the bars, will have +a difficulty in biting. This trouble will be avoided by having the hinges +about 1-1/2 to 2 inches from the heels. + +After the shoe has been firmly nailed to the foot, the travelling nut _b_ +is driven forward on the screw _a_ so as to cause the grips to just catch +on the inside of the bars of the foot. According to the inventor, the +amount of pressure to be exerted must be learned by experience, and he +says: + +'I screw up very gradually until I see the cleft of the frog just beginning +to open. I now trot the horse up, and if he goes sound it is certain that +the pressure I have exercised will not give rise to trouble. The animal is +sent to work to assist in the expansion of the foot. On examining the shoe +next day, the grip is found to be quite loose, the foot has enlarged, and +the nut is turned once more until the grip on the bars is tightened, the +horse being again trotted to ascertain that no injurious pressure is +exerted. + +'Every day or two I repeat this process, making measurements in all cases +before widening the heels. The increase in width of the foot which results +is astonishing, 1/4 to 3/8 inch during the first week may be safely +predicted, and in a month to six weeks it is impossible to recognise in the +large healthy frog and wide heels, the shrivelled-up organ of a short time +before.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 98.] + +It is pointed out by the writer of the above (and his observations, +doubtless, apply to the use of all other expansion shoes in which the bars +are gripped and forcibly expanded) that the whole secret of success lies +in avoiding injurious pressure by exerting too great an expansion at one +operation. After each manipulation of the expanding apparatus the horse +should trot sound and the frog remain cool. Should the foot become hot, and +lameness supervene, then tension should at once be relaxed. + +_Recorded Cases of the Use of the Shoe_.--The inventor of the shoe relates +two cases of contracted foot treated by these means in which the heels +of one, after thirty-nine days' treatment, had increased in width to the +extent of 1 inch, and the heels of the other, after twenty-four days', had +enlarged 5/8 inch. Of the first case he gives the drawings in Fig. 74. + +A represents the foot before treatment; B the same foot after nine days' +treatment, when the heels had widened 3/4 inch; and C the same foot at +the end of the thirty-nine days' treatment, at which date the frog was an +excellent-looking one, and the foot had increased an inch in width.[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 100] + +[Illustration: FIG. 74.--THE CHANGES IN FORM OF A CONTRACTED FOOT TREATED +WITH SMITH'S EXPANSION SHOE] + +In 1893, at a meeting of the Midland Counties Veterinary Medical +Association, the late Mr. Olver said he had applied this shoe to a valuable +hunter that had gone so lame that he could scarcely put his foot to the +ground. After a fortnight's application, and by the assistance of the +double screw in the shoe, the heel was forced out. Then the horse was put +to work with the shoe on, and he had hunted the whole of the last season in +a perfectly sound condition.[A] + +[Footnote A: _Veterinary Record_, vol. vi., p. 143] + +F.D. McLaren, M.R.C.V.S., writes:[A] 'I resolved to try one of Captain +Smith's shoes in a case where the hoof was badly contracted, and where the +frog had entirely disappeared, there being also slight lameness. The roof +rapidly expanded, and every other day the nut was moved on a bit to keep +the cross-piece tight. I then had the cross-piece bent downwards a little +_to prevent the nut pressing on the rapidly-growing frog_.[B] After another +fortnight or so, I had a shoe made with clips resting against the inside of +the bars,[C] and the next time he was shod these were also dispensed with. +It is now a year ago since the animal recovered his frog, and he still has +the largest frog in the stable, and the hoof shows no sign of contraction.' + +[Footnote A: _Ibid_., vol. vi., p. 183] + +[Footnote B: The italics are mine (H.C.R.).] + +[Footnote C: The expanding shoe itself was here evidently dispensed with, +and an ordinary shoe with bar-clips used in its stead (H.C.R.).] + +_(b) De Fay's_.--Among other shoes of the expansion class may be mentioned +that of De Fay. Like the preceding, it is a shoe with a flat bearing +surface, and provided with bar-clips. It is, however, _un_ hinged. The +requisite degree of periodic expansion is in this case arrived at by a +forcible widening of the heels of the shoe, accomplished by bending +the substance of which it is made, and for this purpose the instrument +illustrated in Fig. 75 is employed. + +The foot is first properly trimmed by levelling the heels and thinning +the sole on each side of the frog. The shoe is then fixed by nails in the +ordinary manner, taking care that the last nails come not too far back, and +that the clips rest evenly and firmly on the inside of the bars. + +The dilator, hoof-spreader, or vice, as it is variously called, is then +applied, its two jaws (_a_ and _b_) fitting against the inner edge of +the shoe at the heels. Careful note is taken of the width of the hoof as +measured on the graduated scale (_e_, _e_), and the double screw (_g_, _h_) +revolved by means of the wrench (k), until the opening of the jaws thus +obtained registers an expansion of 1/12 to 1/8 inch. + +The dilatation is repeated at intervals of from eight to ten days, until, +at the expiration of a month or six weeks, the amount of total expansion of +the heels registers nearly an inch. That the method requires the greatest +care may be gathered from the reports of continental writers. They state +that frequently the pain and consequent lameness keep the patient confined +to the stable for several days. + +Numerous and but slightly differing forms of the dilator are on the market. +As in principle they are all essentially the same, and are to be found +illustrated in any reliable instrument catalogue, they need no description +here. + +[Illustration: FIG. 75.--DE FAY'S VICE.] + +_(c) Hartmann's_.--A further useful expansion shoe is that of Hartmann's +(Fig. 76), in that it may be adapted for either unilateral or bilateral +contraction. This shoe is also provided with bar-clips, and forcibly +expanded at the heels by means of a dilator. The expansion is governed by +saw-cuts through the inner margin of the shoe directed towards its outer +margin, and running only partially through the inner half of the web (see +Fig. 76). + +According as the contraction is confined to the inner or outer heel, the +saw-cuts, one or two in number, are placed to the inner or outer side of +the toe-clip. When the contraction is bilateral, the saw-cuts, one or more +in number, are placed on each side of the toe-clip. + +_(d) Broué's_.--This is one of the forms of so-called 'slipper' shoes (see +Fig. 77). We have already indicated that the shape of the bearing surface +of the ordinary shoe--by its 'seating' or sloping from outside to +inside--is sometimes a cause of contraction. In the 'slipper' of Broué +this bearing is reversed, and the slope is from inside to outside. In +the original form of this shoe the slope to the outside was continued +completely round the shoe. Experience taught that the strain this enforced +upon the junction of the wall with the sole was injurious, and that the +'reversed seating,' if we may so term it, was best confined to the hinder +portions of the shoe's branches. + +[Illustration: FIG. 76. This figure illustrates the principle of the +Hartmann expanding shoe. _a, a_, The clips to catch the inside of the bars; +_b, c_, saw-cuts.] + +The amount of slope should not be excessive. If it is, too rapid and too +forcible an expansion takes place, and pain and severe lameness results. +Dollar gives the requisite degree of incline by saying that the outer +margin of the bearing surface of the shoe should be from 1/12 to 1/8 inch +lower than the inner. + +In the case of the Broué slipper, it is the animal's own weight that brings +about the widening of the heels, the slope or outward incline of the +slipper simply causing the inferior edge of the wall at the heels to spread +itself outwards instead of sliding inwards on the bearing surface of the +shoe. + +[Illustration: FIG. 77.--THE SLIPPER SHOE OF BROUÉ.] + +_(e) Einsiedel's_.--Like the 'slipper' of Broué, the Einsiedel shoe depends +for its effects upon the slope of the bearing surface. + +It differs from the Broué in being provided with a 'bar-clip.' This, in +addition to gripping the bars like the bar-clips of other expanding +shoes, also assists, under the body-weight, in expanding the heels by the +pronounced slope given to its upper surface. The expanding force exerted +by the body-weight falls thus, through the medium of the bar-clip, clip, +_partly_ upon the bars, instead of, as in the Broué, solely upon the wall. +We say _partly_ advisedly, for, in addition to the slope upon the outer +side of the bar-clips, the bearing surface of the heels of the shoe is +_slightly_ sloped outwards also. The good office served by the bar-clip is +the lessening of any tendency to strain upon the white line. + +[Illustration: FIG. 78.--THE SLIPPER AND BAR-CLIP SHOE OF EINSIEDEL.] + +Those we have described by no means exhaust the number of expansion shoes +that have been devised. There are numerous others, many of which are +composed of three-hinged portions, the two hindermost of which are +gradually separated by a toothed arrangement of their inner margins and +a travelling bar, the disadvantage of which is that it is liable to work +loose. In the majority of this class of shoe the hinges are placed far +forward, one on each side of the toe. They there become exposed to +excessive wear. In fact, against the bulk of this form of shoe it may +be urged that they cannot be worn by the animal at work, that they are +expensive, difficult to make, and easily put out of order. + +3. _By Operations on the Horn of the Wall_. + +_(a) Thinning the Wall in the Region of the Quarters_.--This is best +done by means of an ordinary farrier's rasp. The thinning should lessen +gradually from the heel for 2-1/2 to 3 inches in a forward direction. That +portion of the wall next to the coronary border, about 1/2 inch in breadth, +should not be touched. At this point the thinning should commence, should +be at its greatest, and lessen gradually downwards until at the inferior +margin of the wall the normal thickness of horn is left. The animal is then +shod with a bar shoe and the hoof bound with a bandage soaked in a mixture +of tar and grease, in order to keep the thinned portion of the wall from +cracking. In this condition the animal may remain at light labour. + +When possible, however, it is better to combine the thinning process thus +described with turning out to grass. In this case the ordinary shoe is +first removed, and the foot poulticed for twenty-four hours to render +the horn soft. The foot is then prepared by slightly lowering the +heels--leaving the frog untouched--and thinning the quarters in exactly the +manner described above. + +After this is done, the animal is shod with an ordinary tip, a sharp +cantharides blister applied to the coronet, and then turned out in a damp +pasture. In this case the object of the tip is to throw the weight on +to the heels and quarters. The thinned horn yields to the pressure thus +applied, and a hoof with heels of a wider pattern commences to grow down +from the coronet. Two to three months' rest is necessary before the animal +can again he put to work.[A] + +[Footnote A: This is the treatment strongly advocated by A.A. Holcombe, +D.V.S., Inspector, Bureau of Animal Industry, U.S.A.] + +_(b) Thinning the Wall in the Region of the Toe_.--This is done with +the idea that the tendency of the heels to expand under pressure of the +body-weight is helped by the thinned portion at the toe allowing the heels +to more readily open behind. Seeing that in the case of toe sand-crack the +converse is argued--that contraction of the heels readily takes place and +forces the sand-crack wider open--it is doubtful whether this method is of +any utility in treating contracted heels. + +_(c) Grooving the Wall Vertically or Horizontally, and Shoeing with a Bar +Shoe_.--Marking the wall with a series of grooves, each running in a more +or less vertical direction, was suggested to English veterinarians by +Smith's operation for side-bones. + +The manner of making the grooves, and the instruments necessary, will be +found fully described in Section C of Chapter X. + +That the method is followed by satisfactory results the undermentioned case +will show: + +'A mare, which I have had in my possession since she was a foal, has always +had contracted feet, which were also unnaturally small.... Lately the mare +has been going very "short," and at length her action was quite crippled. +At times she was decidedly lame on the off fore-foot. At no time have I +been able to detect any sign of structural disease. I thereupon concluded +that the lameness was due to mechanical pressure on the sensitive +structures, and I determined to try the effects of the above treatment. As +this was my first experience of the process, I was careful to carry it out +in all its details, as described by Professor Smith. After the bar shoes +had been put on, the mare was very lame. I allowed her two days' rest, then +commenced regular walking exercise, and she daily improved. After fourteen +days there was no lameness, but still short action. I thereupon gave the +mare another week's walking exercise, at the expiration of which I drove +her a short turn of five miles, which she did quite well, and free from +lameness. For three months I kept the saw-cuts open to the coronet, and +continued the bar shoes, keeping the mare at exercise, and giving her +occasionally a drive. She never liked the bar shoes, and I was glad when I +could discontinue them, which I did in the fourth month. When shod with the +usual shoes the complete success of the treatment was shown. I have now had +her going with the ordinary shoes for the past two or three months, and the +improvement in the shape of the feet is very marked; there is no lameness; +the mare is free in movement, fast, and spirited, whereas previously she +was quite the reverse, and almost unfit to drive.'[A] + +[Footnote A: W.S. Adams, M.R.C.V.S., _Veterinary Journal_, vol. xxx., p. +19.] + +This method, though but recently introduced to the English veterinary +surgeon, is by no means new. According to Zundel, it was recently made +known on the Continent by Weber, but was previously known and mentioned by +Lagueriniere, Brognier, and Hurtrel d'Arboval. + +When the grooving is in a horizontal direction, a single incision is +sufficient. This is made 3/4 inch below the coronary margin of the wall, +and parallel with it, extending from the point of the heel for 2 or 3 +inches in a forward direction. As in the previous method, a bar shoe is +applied, and the animal daily exercised. Thus separated from the fixed +and contracted portion of the wall below, the more elastic coronet under +pressure of the body-weight commences to bulge. The bulging is of such +an extent as to cause the new growing hoof from the top to considerably +overhang the contracted portion below, and cure of the condition results +from the newly-expanded wall above growing down in a normal direction. + +This consideration of contracted heels may be concluded by drawing +attention to the advisability of always maintaining the horn of the wall in +as soft and supple a condition as is natural by the application of suitable +hoof dressings. + +A useful one for the purpose is that made with lard, to which has been +added a small quantity of wax or turpentine. + +Especially should a dressing like this be used when the hoof is inclined +to be hard and brittle, and where tendency to contraction has already been +noticed. + +The application of a hoof ointment is also particularly indicated where the +foot is much exposed to dampness, where the animal is compelled to stand +for long periods upon a dry bedding, or where the bedding is of a substance +calculated to have a deleterious effect upon the horn. + +This, in conjunction with correct shoeing, will probably serve to avoid the +necessity for more drastic measures at a later time. + +_(b)_ LOCAL OR CORONARY CONTRACTION. + +_Definition_.--Contraction at the heels, confined to the horn immediately +succeeding that occupied by the coronary cushion. Really, the condition is +but a somewhat arbitrary subdivision of contracted hoof, as we have just +described it in general. For that reason we shall give it but very brief +mention. + +_Symptoms_.--In this case the horn of the heels, instead of running down +in a straight line from the coronary margin to the bearing surface of the +wall, presents a more or less distinct concavity (See Fig. 79, _a_, _a_). + +As is the case with contraction considered as a whole, this deformity may +affect one or both heels; and during its first appearance, which is after +the first few shoeings, the animal may go distinctly lame. + +_Causes_.--Coronary contraction may occur in hoofs of normal shape +immediately shoeing is commenced, and frog pressure with the ground +removed. It is far more likely to ensue, however, if the hoof is flat, +with the heels low, and the wall sloping. And with those predisposing +circumstances it is that the horse goes lame, and not with the hoof of +normal shape. + +Seeing, then, that this condition is largely dependent upon the shape of +the foot, we may, to some extent, regard it as hereditary. Seeing further, +however, that it only appears when shoeing is commenced, we may in a +greater degree also regard it as acquired. The lesson, therefore, that this +and other forms of contraction should teach us is the carefulness with +which the shoeing should be superintended in a large stud, or in any case +where the animal is of more than ordinary value. + +[Illustration: FIG. 79.--HOOF WITH LOCAL OR CORONARY CONTRACTION (AS +INDICATED AT THE POINTS _a, a_).] + +The explanation of the restricted nature of this form of contraction +is simple enough. We have only to refer to the lessons taught by the +experiments of Lungwitz, described in Chapter III., and the condition +almost explains itself. We remember that, briefly, the coronary margin of +the wall resembles a closed elastic ring, which yields and expands to +local pressure, no matter how slight. We remember also that removal of the +counter-pressure of the frog with the ground tended to contraction of the +wall's solar edge when weight was applied. Connect these two facts with +the experience that this form of contraction more often than not occurs in +hoofs with sloping heels, and we arrive at the following: + +1. The excessive slope of the heels tends to throw a more than usual part +of the body-weight upon the posterior portion of the coronary margin of +the wall, with a consequent expansion of that part of the coronary margin +implicated. + +2. That the shoeing, in removing the counter-pressure of the frog with the +ground, is at the same time tending to bring about contraction of the lower +portions of the wall at the heels and quarters. + +3. That this tendency to contraction will at first appear in the thinner +portion of the area of wall named--namely, in that immediately below the +bulging coronary margin. + +We thus get the appearance depicted in Fig. 79--a contraction _(a, a)_ of +the heels in the horn below the coronary margin, with the coronary margin +itself bulging above, and a hoof of apparently normal width below. + +We say 'apparently' with a purpose, for, as actual measurements will show, +the wall near the solar edge is really contracting, for reasons which we +have just described connected with shoeing. Its 'appearance' of normal +width is accounted for thus: The contraction at _a, a_ is caused by the +dragging inwards of the coronary cushion brought about by the sinking +downwards of the plantar cushion, with which body it will be remembered the +coronary cushion is continuous. With the constant dragging in and down +of the coronary cushion there is given, to the horn-secreting papillæ, +studding both the lower third of its outer face and its lowermost surface, +a distinct 'cant' outwards. Below the lowermost limit of the coronary +cushion, then, by reason of the cant outwards of the coronary papillæ +in the situations mentioned, the horn of the wall takes a more outward +direction than normal, a fact which lessens in effect the contraction as a +whole really going on. It is interesting, too, to note that by this outward +cant of the wall below, and the bulging of the coronary margin above it, +the contraction (_a, a_) is heightened in effect, and caused to appear +greater than really it is. + +From what we have said it follows that contraction of the heels, excepting +the extreme coronary margin, is existent generally, and not confined solely +to _a, a_. + +We have, then, in this condition, as we indicated at the commencement, +but a phase in the evolution of ordinary contracted heels, for, with the +progress of the contraction already existing at _a, a_, and below those +points, it is only fair to assume that with it falling in of the at present +bulging coronary margin must sooner or later occur, that, though expanded +when compared with the wall below it, it will be really contracted as +compared with what it was once in that same foot. + +We may therefore conclude this section by remarking that factors tending to +contraction of the heels in general are equally potent in the causation of +contracted coronet alone. + +_Treatment_.--Exactly that described for contracted heels. Bearing in mind +that contracted coronary margin is but the onset of contracted heels, and +that its first exciting cause is that of removal of the ground-pressure +upon the frog, the most careful attention must be paid to the shoeing. The +use of bar shoes, ordinary frog pads, or heelless shoes and bar pads, are +especially indicated, together with abundant exercise. By these means the +normal movements of expansion will be brought into play, and the condition +quickly remedied. + + +C. FLAT-FOOT. + +_Definition_.--By this term is indicated a condition of the foot where the +natural concavity of the sole is absent. + +_Symptoms_.--In the flat-foot the inferior edge of the wall, the sole, +and the frog, all lie more or less in the same plane. It is a condition +observed far more frequently in fore than in hind limbs, and is seen in +connection with low heels, more or less obliquity of the wall, and a +tendency to contraction. The action of the animal with flat feet is heavy, +a result partly of the build of the foot, and partly of the tenderness that +soon comes on through the liability of the sole to constant bruising. + +[Illustration: FIG. 80. This figure represents the lower surface of a +typical flat-foot. It illustrates, too, the commencement of a condition we +referred to in Section B of this chapter--namely, the compression of the +frog by the ingrowing heels (b) and bars (a).] + +_Causes_.--Flat-foot is undoubtedly a congenital defect, and is seen +commonly in horses of a heavy, lymphatic type, and especially in those +bred and reared on low, marshy lands. It is thus a common condition of the +fore-feet of the Lincolnshire shire. + +As might be expected, a foot of this description is far more prone to +suffer from the effects of shoeing than is the foot of normal shape, and +regarded in this light shoeing may be looked upon as, if not an actual +cause, certainly a means of aggravating the condition. Directly the +shoe--or at any rate the ordinary shoe--is applied, mischief commences. The +frog is raised from the ground, and the whole of the weight thrown on to +the wall. The heels, already weak and inclined to turn in, are unable to +bear the strain. They _turn in_, and contraction commences. This 'turning +in' of the heels is favoured by the undue obliquity of the wall. At the +same time, the sole being archless, a certain amount of elasticity is +lost. The weight is thrown more on to the heels, and the os pedis slightly +descends, rendering the flatness of the sole even more marked than before. +With the loss of elasticity of the sole concussion makes itself more felt. +The animal is easily lamed, bruised sole becomes frequent, and corns sooner +or later make their appearance. + +_Treatment_.--Flat-foot is incurable. All that can be done is to pay +careful attention to the shoeing, and so prevent the condition from being +aggravated. In trimming the foot the sole should not be touched; the frog, +too, should be left alone, and the wall pared only so far as regards broken +and jagged pieces. + +The most suitable shoe is one _moderately_ seated. If the seating is +excessive, and bearing allowed only on the wall, there is a tendency for +the wall to be pushed outwards, and for the sole to drop still further. On +the other hand, if the seating is insufficient, or the web of the shoe too +wide, and too great a bearing thus given to the sole, then we get, first, +an undue pressure upon the last-named portion of the foot a bruise, and, +finally, lameness. The correct bearing should take in the whole of the wall +and the whole of the white line, and should _just impinge_ upon the sole. +Above all, the heels of the shoe should be of full length, otherwise, if +the shoe is worn just a little too long, its heels are carried under the +sole of the foot, and by pressure there produce a corn. + +If, with these precautions in shoeing flat-foot, tenderness still persists, +a sole of leather or gutta-percha must be used with the shoe. + + +D. PUMICED-FOOT, DROPPED SOLE, OR CONVEX SOLE. + +_Definition_.--This term is applied to the foot when the shape of the sole +is comparable to the bottom of a saucer. When least marked it is really an +aggravated form of flat-foot. + +_Symptoms_.--In pumiced-foot the sole projects beyond the level of the +wall. The obliquity of the latter is more marked than in the previous +condition, and progression, to a large extent, takes place upon the heels. +In addition to its deformity, the horn is greatly altered in quality, and, +as the name 'pumice' indicates, is more or less porous in appearance, +bulging, and brittle. + +_Causes_.--As a general rule, it may be taken that pumiced-foot is a sequel +of previous disease, although in its least pronounced form it may occur as +the result of accidental or other causes, such as those described in the +causation of flat-foot. + +Occurring in its most marked form, there is no gainsaying the fact that +pumiced-foot is a sequel of either acute or subacute laminitis. As we shall +see when we come to study that disease, the dropping of the sole is brought +about by distinct and easily-understood morbid processes affecting the +sensitive structures. Briefly, these morbid processes in laminitis may be +described thus: The accumulated inflammatory exudate, and in some cases +pus, weakens and destroys the union between the sensitive and insensitive +laminæ. This separation, for reasons afterwards to be explained, is +greatest in the region of the toe. The os pedis, loosened from its intimate +attachment with the horny box, is dropped upon the sole, and the sole, +unable to bear the weight, commences to bulge below. + +The altered character of the horn is accounted for by the inflammatory +changes in the sensitive laminæ and the papillæ of the keratogenous +membrane generally, for it follows as a matter of course that these +tissues, themselves in a diseased condition, must naturally produce a horn +of a greatly altered and inferior quality. + +When following the _subacute_ form of laminitis, the changes characterizing +pumiced-foot are slow in making their appearance. The animal at first goes +short, and the lameness thus indicated gradually becomes more severe, until +the animal is no longer able to work. The feet become hot and dry, the +hoof loses its circular form, and the growth of horn at the heels becomes +excessive. At this stage the appearance of bulging at the sole begins to +make itself seen. Later, the outer surface of the wall becomes 'ringed' or +'ribbed,' the rings being somewhat closely approximated in the region of +the toe, and the distance between them gradually widening towards the +heels. The wall too, especially in the region of the toe, instead of +running in a straight line from the coronary margin to the shoe, becomes +concave. It is this change, together with the appearance of the rings, that +indicates the loosening of the attachment of the os pedis to the wall, and +its afterwards backward and downward direction (see Fig. 124). + +[Illustration: FIG. 81.--HOOF WITH THE RIBS OR RINGS CAUSED BY CHRONIC +LAMINITIS.] + +As a sequel of _acute_ laminitis, these changes make their appearance with +more or less suddenness, and are generally complicated in that they owe +their occurrence to the formation of pus within the horny box. + +_Treatment_.--Pumiced-foot is always a serious condition. The animal is +useless for work upon hard roads or town pavings, and is of only limited +utility for slow work upon soft lands. The more serious form, that +following acute laminitis, and complicated by the presence of pus, we may +regard as beyond hope of treatment. + +With the more simple form of the condition, we may do much to render +greater the animal's usefulness. The same principles as were applied to the +shoeing of flat feet will have to be observed here. Trimming or paring +of any kind, save 'straightening up' of the wall, must be severely +discountenanced. A broad-webbed shoe, one that will give a certain amount +of cover to the sole, is indicated. As in the treatment of flat-foot, +however, direct pressure upon the sole must be avoided, and the shoe +'seated.' The 'seating,' however, should not commence from the absolute +outer margin of the shoe's upper surface. A _flat_ bearing should be given +to the wall and the white line, and the seating commenced at the sole. + +We have already remarked on the increased growth of horn at the heels. It +is in this position, then, that will be found the greatest bearing surface +for the shoe, and it is wise, in this case, to have the heels of the shoe +kept flat. In other words, the 'seating' is not to be continued to the +hindermost portion of the branches of the shoe. By this means there may be +obtained at each heel a good solid bearing of from 2 to 3 inches, which +would otherwise be lost. + +Where the accompanying condition of the horn is bad enough to indicate it, +a leather sole should be used, beneath which has been packed a compress of +tow and grease, rendered more or less antiseptic by being mixed with tar. + +Where the sole is exceedingly thin, and inclined to be easily wounded, and +where the hoof, by its brittleness, has become chipped and ragged at the +lower margin of the wall, it may perhaps be more advantageous to use, in +place of the compress of tow, the _huflederkitt_ of Rotten. This is a +leather-like, dark brown paste. When warmed in hot water, or by itself, it +becomes soft and plastic, and may readily be pressed to the lower surface +of the foot, so as to fill in all little cracks and irregularities, and +furnish a complete covering to the sole and frog, and to the bearing +surface of the wall. When cold it hardens, without losing the shape given +to it, into a hard, leather-like substance. + +Treated in this way, the animal with pumiced feet may yet be capable of +earning his living at light labour or upon a farm. + + +E. 'RINGED' OR 'RIBBED' HOOF. + +_Definition_.--A condition of the hoof in which the wall is marked by a +series of well-defined ridges in the horn, each ridge running parallel with +the coronary margin. They are known commonly as 'grass rings,' and may be +easily distinguished from the more grave condition we have alluded to as +following laminitis, by the mere fact that they do not, as do the laminitic +rings, approximate each other in the region of the toe, but that they run +round the foot, as we have already said, _parallel with each other_. + +[Illustration: FIG. 82.--HOOF SHOWING THE RINGS IN THE HORN BROUGHT ABOUT +BY PHYSIOLOGICAL CAUSES.] + +_Causes_.--This condition is purely a physiological, and not a pathological +one, and the words of its more common name, 'grass rings,' sufficiently +indicate one of the most common causes. Anything tending to an alternate +increase and decrease in the secretion of horn from the coronet will bring +it about. Thus, in an animal at grass, with, according to the weather +conditions, an alternate moistness and dryness of the pasture, with its +consequent influence on the horn secretion, these rings nearly always +appear. The effects of repeated blisters to the coronet make themselves +apparent in the same way, and testify to the efficacy of blisters in this +region in any case where an increased growth of horn is deemed necessary. +From this it is clear that the condition depends primarily upon the +amount and condition of the blood supplied to the coronary cushion. Thus, +fluctuations in temperature during a long-continued fever, or the effects +of alternate heat and cold, or of healthy exercise alternated with +comparative idleness, will each rib the foot in much the same manner. + +_Treatment_.--The condition is so simple that we may almost regard it +as normal. Consequently, treatment of any kind is superfluous. Where +constitutional disturbance is exerting an influence upon either the quality +or quantity of the blood directed to the part, then, of course, attention +must be paid to the disease from which it is arising. + + +F. THE HOOF WITH BAD HORN. + +(_a_) THE BRITTLE HOOF. + +_Definition_.--As the name indicates, we have in this condition an +abnormally dry state of the horn. + +_Symptoms_.--These are obvious. The horn is hard, and when cut by the +farrier's tools gives the impression of being baked hard and stony, the +natural polish of the external layer is wanting, and there is present, +usually, a tendency to contracted heels. With the dryness is a liability to +fracture, especially at points where the shoe is attached by the nails. +As a consequence, the shoes are easily cast, leading to splits in the +direction of the horn fibres. These run dangerously near the sensitive +structures, giving rise in many cases to lameness. Even where pronounced +lameness is absent the action becomes short and 'groggy,' and the utmost +care is required in the shoeing to keep the animal at work. + +_Causes_.--To a very great extent the condition is hereditary, and is +observed frequently in animals of the short, 'cobby' type. In ponies +bred in the Welsh and New Forest droves the condition is not uncommon, +especially in the smaller animals. Animals who have had their feet much +in water--as, for instance, those bred and reared on marshy soils--and +afterwards transferred to the constant dryness of stable bedding, are also +particularly liable to this condition. It is noticed, too, following the +excessive use of unsuitable hoof-dressings, more especially in cases where +coat after coat of the dressing is applied without occasionally removing +the previous applications. + +_Treatment_.--As a prophylactic, a good hoof-dressing is indicated. It +should not consist solely of grease, but should have mixed with it either +wax, turpentine, or tar. + +Above all, careful shoeing should be insisted on, and the owner of an +animal with feet such as these will be well advised if he is recommended to +have the shoeing superintended by one well competent to direct it rightly. +The foot should be trimmed but lightly, always remembering that in a foot +of this description the horn, in addition to being brittle, is generally +abnormally thin. Jagged or partly broken pieces should be removed, and the +bearing surface rendered as level as possible. The foot should be carefully +examined before punching the nail-holes in the shoe, and the nail-holes +afterwards placed so as to come opposite the soundest portions of horn. The +nails themselves should be as thin as is consistent with durability, and +should be driven as high up as possible. + +On the least sign of undue wear the shoes should be removed, never, as is +too often done, allowing them to remain on so long that a portion breaks +away. If, with the laudable idea of not interfering with the horn more than +is possible, this is practised, the portion of the shoe breaking off is +bound to tear away with it more or less of the brittle horn to which it is +attached. + +Where the breaks in the horn are so large as to prevent a level bearing for +the shoe being obtained, the interstices should be filled up with one or +other of the preparations made for this purpose. One of the most suitable +is that discovered by M. Defay. By its means sand-cracks or other fractures +of the horn may be durably cemented up. + +'Even pieces of iron may be securely joined together by its means. The only +precaution for its successful application is the careful removal of all +grease by spirits of sal-ammoniac, sulphide of carbon, or ether. M. Defay +makes no secret of its composition, which is as follows: Take 1 part of +coarsely-powdered gum-ammoniac, and 2 parts of gutta-percha, in pieces the +size of a hazel-nut. Put them in a tin-lined vessel over a slow fire, and +stir constantly until thoroughly mixed. Before the thick, resinous mass +gets cold mould it into sticks like sealing-wax. The cement will keep +for years, and when required for use it is only necessary to cut off a +sufficient quantity, and remelt it immediately before application. We have +frequently used this cement for the repair of seriously broken hoofs. It is +so tenacious that it will retain the nails by which the shoe is attached +without tearing away from the hoof.'[A] + +[Footnote A: _Veterinary Journal_, vol. iii., p.71.] + +Failing this, the bearing surface may be made level, and fractures repaired +by using the _huflederkitt_ described in the treatment of pumiced sole. + +(_b_) THE SPONGY HOOF. + +_Definition_.--This is the opposite condition to the one we have just +described, and is characterized by the soft and non-resistant qualities of +the horn. + +_Symptoms_.--Spongy hoof is quite common in animals that have large, flat, +and spreading feet--in fact, the two appear to run very much together. It +is a common defect in animals reared in marshy districts, and of a heavy, +lymphatic type. The Lincolnshire Shire, for instance, has often feet +of this description, and, the causative factors being in this case +long-continued, render the feet extremely predisposed to canker. The horn +is distinctly soft to the knife, and has an appearance more or less greasy. +Animals with spongy feet are unfit for long journeys on hard roads. When +compelled to travel thus, the feet become hot and tender, and lameness +results. A mild form of laminitis, extending over a period of three or +four days, often follows on this enforced travelling on a hard road, more +especially in cases where the animal is 'heavy topped,' and the usual +food of a highly stimulating nature. In fact, it has been the author's +experience to meet with this condition several times in the case of shire +stallions doing a long walk daily upon hard roads, with the weather hot and +dry. + +_Treatment_.--When a horse with spongy feet is shod for the first time, +care must be taken to avoid excessive paring of the sole, for already the +natural wear of the foot has been sufficient to keep the soft horn in a +state of thinness. For the same reason hot fitting of the shoe must not +be indulged in for too long a time. That common malpractice of the forge, +'opening up the heels,' must, in this case, be especially guarded against, +or the excessive paring of the frog and partial removal of the bars that +this operation consists in will lay the foot open to risk of contraction. +To begin with, the heels are naturally weak, and, once the bars are +removed, there is nothing to prevent them rapidly caving in towards the +frog. Even when carefully shod, a foot of this class is readily prone to +contract directly the animal is brought into the stable, and the horn +commences to dry to excess. An ordinary light shoe should be used, and the +nails should be light and thin. They should be driven carefully home, and +the 'clinching' made as tight and secure as possible. + + +G. CLUB-FOOT. + +_Definition_.--Under this name we indicate all cases in which the horn +of the wall become straightened from above to below. It will, therefore, +include all conformations varying from the so-called 'upright hoof,' in +which the toe forms an angle of more than 60 degrees with the ground, to +the badly 'clubbed' foot, in which the horn at the toe forms a right angle +with the ground, or is even directed obliquely backwards and downwards, so +that the coronary margin overhangs the solar edge of the wall. + +[Illustration: FIG. 83.--THE CLUB-FOOT.] + +_Symptoms_.--Even in its least pronounced form the condition is apparent at +a glance, the alteration in the angle formed by the hoof with the ground +striking the eye at once, and the heels, as compared with the toe, +appearing much too high. When the condition is slight, the wall of the toe +is about twice as high as that of the heels, while in the most marked form +the toe and the heels may in height be nearly equal (see Fig. 83). When +congenital, but little interference with the action is noticed. Such +animals, by reason of their 'stiltiness,' are unfit for the saddle, but at +ordinary work will perform their duties equally well with the animal of +normal-shaped feet. When acquired as the result of overwork, of contracted +tendons, or other causes, however, the gait becomes stumbling and +uncertain. The body-weight is transferred from the heels to the anterior +parts of the foot, and the shoe shows undue signs of wear at the toe. + +_Causes_.--Upright hoof is undoubtedly hereditary, and is even seen as a +natural conformation in the feet of asses and mules. When hereditary in the +horse, however, it is certainly a defect, and is associated commonly with +an upright limb, and a short, upright pastern (see Fig. 83). + +Among other causes, we may enumerate sprains or wounds of the flexor +tendons, or any disease of the limbs for a long time preventing extension +of the fetlock-joint, such as sprains or injuries of the posterior +ligaments of the limb, splints or ringbones so placed as to interfere with +the movements of the flexor tendons, or, in the hind-limb, spavin, keeping +for some months the fetlock in a state of flexion. In the very young animal +the condition may be induced by an improper paring of the foot--cutting +away too much at the toe, and allowing the heels to remain. + +_Treatment_.--When the condition is congenital, no treatment at all is +indicated. It might, in fact, be said that interference would tend rather +to minimize than enhance the animal's usefulness; for, in this case, the +club-shaped feet are in all probability due to faulty conformation above. +In other words, the upright hoof is in this instance but a natural result +of the animal's build, with which useful interference is impossible. + +Where the upright hoof is a consequence of excessive paring of the toe, +or insufficient removal of the heels, the condition may be remedied by +directing attention to those particulars, and preventing their continuance. +At the same time, a greater obliquity of the limb axis may be given by the +use of a suitable shoe. The shoe indicated is a short one, with thin heels +and a thick toe. In some cases the abnormality may be remedied by the use +of a tip. Whatever method is adopted, care must be taken not to attempt +too positive a change in the direction of the limb at one operation. The +process must be gradual. + +In cases where the abnormality has been brought about by wounds to the +flexor tendons, the alteration in the direction of the limb is often so +great as to produce 'knuckling over' of the fetlock. This, to a very great +extent, may be remedied by the use of a shoe with calkins and an extended +toe-piece (see Fig. 84). + +[Illustration: FIG. 84.--THE SHOE WITH EXTENDED TOE-PIECE AND HIGH +CALKINS.] + +With this shoe a certain amount of forced exercise is advisable, and at +intervals of about two weeks the calkins should be somewhat lowered, until +the heels are brought as close to the ground as is possible. In giving +directions for this shoe to be made the veterinary surgeon must, when +referring to the length of the toe-piece, be guided entirely by the +condition of the case. Ordinarily, a suitable length is from 3 to 4 inches. +It is necessary also to warn the owner that, by reason of the length +projecting, the shoe is liable to be torn off. + +Should the 'knuckling over' have become complicated by bony deposits round +the seat of the original injury, then a favourable modification of the +condition is not so likely to result. + +The benefit to be derived from the shoe with an extended toe-piece in a +case of excessive knuckling is admirably shown in a brief report of a case, +under the title of 'Hooked Foot,' in vol. xiv. of the _Veterinary Record_, +p. 716: + +'An eighteen months' old filly showed a deformity of the third phalanx, +resulting in her walking with the front face of the hoof on the ground. The +flexors were apparently all right, and the bending back seemed to be due to +contraction of the ligaments of the joint and the sheath of the perforans. + +'On the ground of absence of contraction of the flexors, or atrophy and +paralysis of the extensors, the surgeon considered the lesion curable by +simple orthopædic measures. By means of an elongated toe-piece to the +shoe and calkins, which were shortened every fifteen days, the filly was +completely cured in seventy days.' + + +H. THE CROOKED FOOT. + +(_a_) THE FOOT WITH UNEQUAL SIDES. + +_Definition_.--The foot thus affected has one side of the wall higher than +the other. + +_Symptoms_.--This deformity is the better recognised when the foot on the +floor is viewed from behind. In addition to the difference between the +height of the inner and outer heel is seen at once a deviation in the +normal direction of the horn. That of the higher side is distinctly more +upright than that of the lower, and runs from above downwards and inwards +towards the axis of the foot, while the horn of the lower side maintains +its normal direction of downwards and outwards. + +From what we have said before on contracted foot, this bending in of +the wall of the upright side will at once be recognised as a form of +contraction. It is, in fact, contraction confined to one-half of the foot +only, and, as a result, the upright side of the crooked foot is prone to +the troubles arising from that condition. Corns are frequent, and atrophy +of that half of the frog on the affected side supervenes. With the +inflammatory changes accompanying these conditions we find the horn of the +affected side deteriorating in quality. It becomes dry and brittle, and +extremely liable to sand-crack. At the same time, thrush of the contracted +frog begins to make its appearance. + +_Causes_.--More often than not this condition is a result of the +conformation of the limb. According as the build above inclines the animal +to 'turned in' or 'turned out' toes, so shall we have feet with a wall +crooked inwards or crooked outwards; and it may be mentioned here that the +evil results inflicted on the foot by ill-shaped limbs above will make +themselves the more readily noticed when the animal comes to be shod for +any length of time. So long as a natural wear of the foot is allowed, +so long does it accommodate itself to the form of limb above. So soon, +however, as the shoe is applied, and a more or less equal (and in this case +harmful) wear by that means insisted on, so soon does this abnormal change +in the height and direction of the horn fibres begin to make itself seen. + +While arising in the majority of instances from faulty conformation of the +limb, crooked feet may also be brought about by bad shoeing, or by unequal +paring of the foot, and, in a few cases, from unequal wear of the foot in a +state of nature. + +_Treatment_.--Although it may be taken as a rule that lowering of the +higher wall, even if persisted in at every shoeing, will do nothing towards +remedying the primary cause (viz., the evil conformation of the limb), yet +it will serve to keep the condition within reasonable limits. In this case, +while removing so much of the wall as is deemed necessary, care must be +taken to leave uncut the sole and the bar. Leaving these intact gives us +two natural and very potent protections against the contraction already +mentioned as impending. + +Where, by reason of the thinness of the horn or other causes, sufficient +paring to equalize the tread cannot be practised, then the same end may be +arrived at by the use of special shoes. That branch of the shoe applied to +the half of the foot with the lower wall should be thickened from above +downwards. Or, on the same branch, may be turned up a calkin of sufficient +height for the purpose. Of the two methods the first is preferable. + +In any case, whether depending upon paring, or upon the use of a special +shoe, the animal should be sent to the forge quite often, for it is only by +a well-directed, and therefore constant, application of the principles here +laid down that improvement may be brought about. + +When marked contraction of one-half of the foot is present, it will be +best treated with the expanding shoe of Hartmann, already described in the +section of this chapter dealing with contracted heels (see Fig. 76). + +(_b_) THE CURVED HOOF. + +_Definition_.--The hoof with the wall of one side convex, and that of the +opposite side concave. Fig. 85, showing the foot in section from side to +side, gives an exact idea of this malformation. + +_Causes_.--As was the case with the condition previously described, this +abnormality finds its primary cause in an unequal distribution of weight +due to vice of conformation in the limb above, causing one side of the +hoof to be higher than the other. As a result of this, the wall that is +inordinately increasing in height commences to bulge outwardly (Fig. 85, +_a_), while the opposite (Fig. 85, _b_) becomes concave. + +The same state of affairs may be occasioned in the forge by leaving one +side of the foot too high, and subjecting the other to excessive paring for +several consecutive shoeings. + +_Treatment_.--In the main this condition may be regarded as a long-standing +and aggravated form of the foot with unequal sides. We may say at once, +therefore, that it is not so easily remedied as that simpler defect; that, +although identical principles will be followed in its treatment, cure must +be a matter of some considerable time. + +[Illustration: FIG. 85.--SECTION THROUGH A CROOKED FOOT. _a_, The higher +and convex side of the wall; _b_, the lower and concave side of the wall] + +Again, we must look to successive parings of the wall of the higher side to +bring about a gradual return to the normal. At the same time, the tendency +to contraction of that side is counteracted by shoeing wide, and, if +necessary, giving to the upper surface of that branch of the shoe what we +have termed elsewhere a 'reversed seating'--viz., an incline of its upper +surface from within outwards. + + + +CHAPTER VII + +DISEASES ARISING FROM FAULTY CONFORMATION + + +A. SAND-CRACK. + +_Definition_.--A solution of continuity of the horn of the foot, occurring +usually in the wall, and following the direction of the horn fibres. + +_Classification_.--It is usual to classify sand-cracks according to-- + +_(a) Their Position_.--_Toe-crack_ when occurring in the middle line of the +horn of the toe, and _quarter-crack_ when occurring in the horn of the +quarters. + +Sand-crack of the frog and sand-crack of the sole may also each be met +with. They are, however, of rare occurrence, and are seldom serious enough +to merit special attention. + +The toe-crack is met with more often in the hind-foot than in the fore, +while the quarter-crack more often than not makes its appearance in the +fore-foot, and is there, as a rule, confined to the inner side. The reasons +for these positions being so affected we shall deal with when treating of +the causes of sand-crack in general. It is interesting to note that the +portions of wall known as inside and outside toe are seldom affected. + +_(b) Their Length_.--_Complete_ when they extend from the coronary margin +of the wall to its wearing edge; _Incomplete_ when not so extensive. + +_(c) Their Severity_.--_Simple_ when they occur in the horn only, and do +not implicate the sensitive structures beneath; _Complicated_ when +deep enough to allow of laceration and subsequent inflammation of +the keratogenous membrane. Such complications may vary from a simple +inflammation set up by laceration and irritation of the sensitive +structures by particles of dirt and grit that have gained entrance through +the crack, to other and more serious changes in the shape of the formation +of pus, hæmorrhage from the laminal vessels, caries of the os pedis, or the +development of a tumour-like growth of horn on the inner surface of the +wall known as a keraphyllocele. + +_(d) Their Duration_.--_Recent_ when newly formed; _old_ when of long +standing. + +_(e) Their Starting-point_.--This last distinction we make ourselves, +and, referring to cracks of the wall, term them _high_ when commencing from +the coronary margin, _low_ when starting from the bearing surface. + +_Causes_.--We have already classified sand-crack as a disease arising from +faulty conformation. Thus, in just so far as a predisposing build of body +may be handed down from parent to offspring, we may regard sand-crack as +hereditary. If we do so, however, we must afterwards make up our minds +to sharply distinguish between the sand-crack plainly brought about by +accidental cause, and that occurring as a result of hereditary evil +conformation. + +With regard to the latter, we need hardly say that feet with abnormally +brittle horn are extremely liable. But with this, as with many other +affections of the feet, we shall find it necessary to consider several +causes acting in cooperation. In this case, for instance, given the brittle +horn, it becomes necessary to further look for exciting causes of its +fracture. + +We will take conformation first. In the animal with turned-out toes a more +than fair share of the body-weight is imposed on the horn of the inner +quarter. Here, then, three causes exert their influence together: The horn +is brittle; the wall of the inner quarter is thinner than that of the +outer; additional weight is imposed upon it. Fracture results. + +Take, again, the vice of contracted heels. Here, in the first place, we +have a variety of causes tending to bring about the contraction. With the +contraction, and its consequent pressure upon the sensitive structures +in the region of the quarters and the frog, has arisen a low type of +inflammation. The horn of the part has become dry and brittle. The exciting +cause of its fracture is found in an excessive day's work upon a hard, dry +road, with, perhaps, a suddenly-imposed improper distribution of weight, +due to treading upon a loose stone, or a succession of such evil transfers +of weight due to travelling upon a road that is rough in its whole extent. + +In their turn, too, such defects of the feet as we have mentioned in the +last chapter--as, for example, the foot with the pumiced horn, the foot +with abnormally upright heels, or that which is upright on one side only, +or crooked--each offers a condition which is predisposing to the formation +of a sand-crack. In each case it wants but the uneven distribution of +the body-weight, which, as a matter of fact, some of these conditions +themselves give, to bring about a fracture. + +Apart from the predisposition conferred by conformation, must be remembered +the simpler predisposing causes leading to brittleness of the hoof. We +refer to the after-effects of poulticing, the moving from pasture to +stable, the emigration from a damp to a dry climate, or the alternate +changes from damp to dry in a temperate region. Each may have a +deteriorating influence upon the horn, rendering it liable to the condition +we are describing. Excessive dampness alone, especially when the animal is +called upon to labour at the drawing of heavy loads upon a rough road, is +not infrequently a cause. In this case the wet, together with the constant +friction of the sharp materials of which the road is made, serves to +destroy the varnish-like periople. The wet gains access to the inner +structures of the wall, the agglutination of the horn fibres is weakened, +and fissures begin to appear. + +Other causes of sand-crack are purely accidental. An animal at fast work +over-reaches. The secretion of horn at the injured coronet is interfered +with, a diminished supply at an isolated spot being the result. From this +point grows down a fissure in the wall. + +An injury of the same character may also be sustained in various other +ways--treads from other animals when working in pairs, accidental wounding +with the stable-fork, blows of any kind, or a self-inflicted tread with the +calkin of an opposite foot--each with the same result. + +So far as causation is concerned, toe-crack stands in a class almost by +itself. It is met with nearly always in a heavy animal in the hind-foot, +and is directly attributable to the force exerted in starting a heavy load. + +Unskilful shoeing also plays a part in the causation of sand-crack. Removal +of the periople by excessive rasping of the wall is most certainly a +predisposing cause. Cracks, or their starting-points, may also be caused by +using too wide a shoe, or by the use of nails too large in the shank. Also, +they may arise from unskilful fitting of the toe-clip, especially in the +hind-foot of a heavy animal. It must be admitted, however, that the part +shoeing plays in the causation of sand-crack is not a large one; far more +depends upon the state of the horn and the animal's conformation than upon +the exciting cause. + +So far, our observations on the causes of sand-crack have referred to that +form occurring in the wall. Sand-crack of the sole or frog we have already +said is but seldom met with, and then it is always in connection with some +exceptionally deteriorated quality of the horn, as in the case of badly +pumiced feet, or occurs as a result of direct injury. Extensive slit-like +cuts in this region, when deep enough to lacerate the keratogenous +membrane, are sometimes followed by the growth of a fissure in the horn, +and what might almost be termed a permanent sand-crack results. Such cuts +may be occasioned by sharp flints, broken glass, or other sharp objects +picked up on the road, or may result from the animal treading on the +toe-clip of a partially cast shoe. + +_Symptoms_.--In every case the fissure, or evidence of its commencement, +is a diagnostic symptom. It is well to remember, however, that this may +be easily overlooked, especially when the crack is one commencing at the +coronary margin. The reason is this: Sand-cracks in this position often +commence in the wall proper, and not in the periople. They may, in fact, be +first observed as a fine separation of the horn fibres immediately +beneath the perioplic covering. A crack of this description may even show +hæmorrhage, and have been in existence for some time, without the periople +itself showing any lesion whatever. Thus, unless lameness is present, or a +more than specially keen search is directed to the parts in question, the +sand-crack goes undiscovered, until of greater dimensions. + +Further, the fissure may be hidden, either accidentally or of set purpose. +It may be covered by the hair, filled in and covered over with mud, or +intentionally concealed by being 'stopped' with an artificial horn, with +wax, or with gutta-percha, or, as is more common, be hidden by the lavish +application of a greasy hoof-dressing. + +In this latter connection it is well to warn the veterinary surgeon, +especially the beginner, when examining for soundness, to be keenly +critical before passing an animal who is presented with feet smothered with +tar and grease or any other dressing. More especially should this warning +be heeded when examining any of the heavier breeds of animal with an +abundance of hair about the coronet. + +Referring again to the search for the crack, it is well to know that with +toe-crack the fissure is the more readily seen when the foot is lifted from +the ground. With quarter-crack, on the other hand, the fissure is wider, +and consequently the easier detected with the foot bearing weight. + +Although commencing in the insidious manner we have described, the lesion +is not thus often seen by the veterinary surgeon. Usually, the animal with +sand-crack is brought for his inspection when lameness has arisen from it. +In this case the cause for the lameness will reveal itself in the crack, +which is now too large to escape observation. The coronet is hot and tender +to the touch, and a sensation of warmth is sometimes conveyed to the hand +by the horn of the surrounding parts of the wall. It is hardly necessary to +say that, with accompanying conditions such as these, the sand-crack is a +_deep_ one. + +Where the lameness is but slight, we may attribute it almost solely to the +pain occasioned by the mere wounding of the keratogenous membrane, and to +no very extensive inflammatory changes therein. By some authorities this +is said to be due to the pinching of the sensitive structures between +the edges of the fissure in the horny covering. In our opinion, however, +pinching does not occur unless inflammatory exudation into the sensitive +structures adjoining the crack has led to sufficient swelling to cause them +to protrude. In other words, the movements of the horny box, communicating +themselves to the structures beneath, and so occasioning movement in the +wounded keratogenous membrane, are quite sufficient to give rise to the +lameness without actual pinching of the structures implicated. + +The severity of the lameness will vary with the rapidity of the gait, and +with the character of the road upon which the animal is made to travel. For +instance, many animals in which the lameness is imperceptible at a walk +become 'dead' lame at a fast trot. It is sufficiently explained when +one remembers the greater movements of expansion and contraction of the +posterior parts of the wall brought about by the increase in the rate of +progression. The same animal, too, will go distinctly more lame upon a hard +than upon a soft surface. + +In like manner the lameness from toe-crack also varies in degree with the +rate of progression and the character of the travelling, though not to +such a noticeable extent as in the lameness from quarter-crack. A greater +variation may in this case be brought about by moving the animal on +ascending and descending ground. Descending an incline, with a more than +ordinary share of the body-weight thus thrown upon the heels, the lameness +is most marked. The reason would appear to be that the greater expansion +of the wall of the heels thus brought about leads to a proportionate +contraction of the wall at the toe, especially at the edges of the crack, +thus causing undue pressure upon the exact spot of the wound in the +sensitive structures. Ascending--the weight in this case transferred from +the posterior to the anterior portion of the foot--the expansion of +the heels becomes a contraction, with a corresponding lessening of the +contraction at the toe and a distinct decrease in the lameness. + +In the case of a deep but recent crack there is always more or less +hæmorrhage. This favours risk of infection of the lesion with pus-forming +organisms, and so leads to a more or less pronounced lameness, a degree of +swelling, heat and tenderness in the coronet above, and a certain amount of +surgical fever. + +The acute symptoms subdued, but the fissure still remaining, gives us the +crack we have classified as 'old.' This may in every case be distinguished +from a more recent lesion by the amount of thickening of the overhanging +coronet, and the presence of an increased quantity of sub-coronary horn in +the region immediately about the crack. The previous inflammatory changes +in the adjoining sensitive structures have here led to an increased +secretion of horn, and a greater or less deposition of inflammatory +connective tissue in the wounded coronary cushion. + +Sand-crack of the toe always follows the direction of the horn fibres. That +of the quarter, however, may on occasion run a course that is somewhat +zigzag, first following the direction of the horn fibres for a short +distance, then travelling in a horizontal direction, and finally continuing +its course again in a line with the horn fibres, commonly at a point +posterior to that at which it commenced. + +In a quarter-crack that is old, and when contraction of the heels exists +(which in this case it usually does), then will often be found overlapping +of the edges of the crack. The expansion of the wall brought about when the +body-weight is on the heels, cannot, by reason of the break in it, continue +itself anterior to the crack. As a consequence, repeated expansion of the +wall posterior to the crack, with the portions anterior to it in a state +of enforced quiescence, leads in time to the posterior edge of the crack +coming to lie over that of the anterior. + +_Complications_.--The first complication likely to arise in a case of +sand-crack is that attending simple laceration of the sensitive structures +in a _deep_ lesion. With the laceration all the phenomena of a repairing +inflammation make their appearance. As a result, there is more or less heat +according to the degree of inflammatory hyperæmia, swelling according to +the amount of inflammatory exudate, and pain according to the amount of +pressure the two foregoing bring to bear on the nerves in the inflamed +area. + +A second and more serious complication is the greater inflammation set up +by the introduction into the crack of foreign substances. Small portions of +gravel and flint, both by the irritation set up by their friction and by +the infection they carry in with the dirt surrounding them, are responsible +for the mischief. + +When, from direct communication with the blood-stream, due to extensive +hæmorrhage, bacteria from the outside gain entrance, this simple +inflammation is further complicated by the formation of pus, or a limited +gangrene of the keratogenous membrane. + +In cases of great severity the gangrene of the keratogenous membrane +spreads until the deeper structures are involved. We then get a necrosis +(in the case of toe-crack) of the extensor pedis, and sometimes caries of +the os pedis. + +In like manner the necrotic changes occurring under these circumstances may +invade the deeper structures in the region of quarter-crack. As a result of +this, we may have the starting-point of suppurating corn, or necrosis of +the lateral cartilage--in other words, cartilaginous quittor. + +Commonly accompanying quarter-crack is the condition of contracted heels +and atrophied frog. Sometimes described as a complication of sand-crack, it +appears to us more rational to rather regard the sand-crack as a result or +complication of the vice of contraction. + +The overlapping of the edges of the crack before referred to occasionally +gives rise to the condition known as false quittor. A probe or a director +passed beneath the overhanging ledge of horn reveals sometimes a fissure of +1 inch or considerably more in depth, and quittor is diagnosed. A careful +paring away of the overhanging horn, however, reveals the true state of +affairs, and exposes to view the original cause of the mischief--a simple +fissure in the wall. + +A serious complication--one fortunately met with but rarely--is that of +keraphyllocele. This is a tumour-like growth of horn, varying in size from +the thickness of an ordinary quill pen to that of one's middle finger, +growing down from the coronary cushion, and attached to the inner side of +the wall of the hoof. With this lameness is always present, and more or +less deformity of the hoof results. This condition will be found described +at greater length in Chapter IX. + +_Prognosis_.--In the case of sand-crack this should always be guarded. It +may be taken as a general rule that cracks commencing from the coronary +margin are more troublesome to deal with than those originating below. The +reason is not far to seek. They here affect the wall just where the bevel +in it for the accommodation of the coronary cushion has rendered it +weakest. Not only is it weakest, but being more resilient than the portions +below it, it suffers more from the alternate movements of expansion and +contraction of the foot than does the horn below. + +Although in many cases a cure of the existing crack may be easily +accomplished, regard should be paid to the possibility of its recurrence, +either in the same position or elsewhere. Really, in offering an opinion +as to the future usefulness of an animal so affected, a greater attention +should be directed to the animal's conformation than to the crack itself. +Where the vice of conformation giving rise to it (as, for example, +contracted heels or upright hoof) gives hope of being remedied, then +naturally it may be safely said that the liability to sand-crack goes with +it. + +A like favourable prognosis may be given in the case of cracks occasioned +by purely accidental causes. + +Ordinarily, however, cracks once commenced tend rather to increase than +decrease in size and severity. From being superficial and incomplete, they +become complete and deep, with every unfavourable circumstance that an +increase in size and depth brings with it. + +This much, however, may be promised to the owner. A simple crack, even +though originating from the coronary margin, is, in the vast majority of +cases, curable. Under a rational treatment its increase in size may be +prevented, and a sound wall caused to grow down from the coronet. + +_Treatment_.--The principles governing the treatment of sand-crack are +simple enough in themselves, if not always followed by success. + +1. _Preventive_. + +This, as a rule, does not suggest itself until a crack of greater or less +extent has made its appearance. Then, simultaneously with the treatment +proper of the lesion, preventive measures should be adopted, to aid both in +the healing of the fissure already present, and to ward off the occurrence +of others that might be likely to form. The hoof, if abnormally brittle, +should be regularly dressed with a suitable ointment (one containing +glycerine for preference), and its horn kept as nearly as possible in +a normal condition. When the condition of the horn predisposing to its +fracture is brought about by excessive wet, then the appropriate preventive +measures to be adopted suggest themselves. + +With regard to the lesion itself, we may term 'preventive treatment' all +those measures having for their object the prevention of increase in the +size of the crack. They are as follows: + +_(a) Blistering the Coronet_.--In a simple case, where the crack is +superficial and close under the coronary margin of the wall, a sharp +cantharides blister to the coronet immediately above it will have the +desired effect. An increased secretion of horn is brought about, and by +this simple means the crack prevented from becoming longer. Very often this +is all that is necessary. In fact, we may say here that, no matter what +other treatment is adopted, the simultaneous application of a blister to +the coronet is always beneficial. To derive full advantages therefrom, +the blistering should be repeated several times at intervals of about a +fortnight. + +_(b) Clamping the Crack_.--When the services of a skilled smith are at +hand, one of the readiest methods of performing this is to draw the edges +of the crack together with an ordinary horse-nail. + +On each side of the crack a small horizontal furrow is burned or cut into +the wall, leaving the horn for about 1/4 inch on each side of the crack +intact. This provides a groove for the ends of the clamping-nail to rest +in, and brings them flush with the outer surface of the wall. The nail is +then driven carefully home through the crack, and the pointed end grasped +by the farrier's pincers. The edges of the crack are then drawn tightly +together, and the nail firmly clenched. + +[Illustration: FIG. 86.--THE SAND-CRACK FIRING-IRON.] + +'The horse-nails are prepared in the ordinary way as for driving, with the +exception that each is pointed on the reverse side, to prevent puncturing +the sensitive structures. Before being used the nails are put in a vice, +and the head hammered to form a shoulder, to prevent their being driven too +far into the wall, and breaking out the hold.'[A] + +[Footnote A: _Veterinarian_, vol. xlviii., p. 100.] + +Before driving the nail some operators burn or bore a hole for it. Opinion +seems to differ as to whether this is at all necessary. + +A method of clamping which, on account of its simplicity, has become +greatly popular, is that of Vachette. For this operation is needed the +outfit depicted in Figs. 86 and 87. + +[Illustration: FIG. 87.--THE SAND-CRACK FORCEPS AND CLAMP.] + +With the special firing-iron (Fig. 86) an indentation, sufficiently large +to admit the points of the clamp (Fig. 87), is made on each side of the +crack. The clamp is then adjusted, and pressed home tight by means of the +sand-crack forceps (Fig. 87). According to the length of the crack, one, +two, or three clamps may be necessary. Another useful clamp, though far +more complicated in its structure, is that of Professor McGill (Fig. 88). + +[Illustration: FIG. 88.--MCGILL's SAND-CRACK CLAMP.] + +'The object of this invention is to arrange on a spindle, which is +screw-threaded at one end with a right-hand thread and at the other with a +left-hand thread, two clips or clamps, free to travel on the thread, there +being a nut between the two which can be turned by a spanner. The clips +are placed on the hoof, one on each side of the sand-crack, the hoof being +prepared to receive the instrument by filing a groove or notch for the +clamps to fit into, and by turning the nut on the screw the clamps +are brought towards each other, and the crack thus prevented from +spreading.'[A] + +[Footnote A: _Veterinarian_, vol. lxi., p. 141.] + +Still a further useful clamp is that of Koster. This is considerably +broader than the clamp of Vachette, and its gripping edges are provided +with teeth (see Fig. 89). + +As with the clamp of Vachette so with this, a groove is burned into the +wall on each side of the crack for the accommodation of the jaws of the +instrument, and the clamp itself pressed home by means of a special pair of +forceps. This form of clamp holds well, and has the advantage of securing a +wider area of horn than that of Vachette or McGill. + +[Illustration: FIG. 89.--KOSTER'S SAND-CRACK CLAMP.] + +Clamping by any method should be advised or undertaken only under certain +conditions. The horn should be moderately strong, and the wall should be +thick. This practically restricts the use of the clamp to cracks of the +toe, and it is there, as a fact, they are found of most benefit. While +burning the grooves for the clamp, and while tightening the clamp itself, +the animal's foot should be on the ground and bearing weight at the heels, +thus insuring the greatest possible approximation of the edges of the +crack. + +With all methods of clamping an untoward result is sometimes the formation +of a fresh crack at the point of insertion of the clamps. + +(c) _By the Use of Thin Metal Plates_.--These are of use when the horn of +the wall is too thin to allow of clamping, and are therefore of especial +use in cracks of the quarters. The plates are made so as to cover the +greater part of the length of the lesion, and are fastened to the wall +by two or more screws on either side of the crack. It is an advantage to +slightly let the plate into the wall by means of fitting it hot. In a +complicated crack the plate serves the further useful purpose of holding in +position antiseptic pledgets, and so keeping the lesion free from dirt and +grit. + +_(d) By Various Methods of bandaging the whole Circumference of the +Wall_.--In our opinion this method of attempting to secure immobility of +the crack, and so prevent its extension, is not often followed by success. +The main objection to the method is that it subjects the whole of the wall +to the same pressure, and does not restrict the operation to the point at +which it is required. As in the case of the metal plate, however, this +method has the advantage that antiseptic dressings may be kept in position +in the case of a complicated crack. + +[Illustration: FIG. 90.--SAND-CRACK BELT.] + +The binding of the wall may be accomplished in two ways. The simpler of the +two is to merely apply the sand-crack belt depicted in Fig. 90. Beneath +this should be applied a compress of tar and tow or other material, and the +whole tightened up and kept in position by means of the buckle and strap. +This method of binding admits of after-tightening should it unfortunately +work loose. + +The older method of binding the wall, and one now often practised by the +smith, is to use a quantity of so-called 'tar-band' or other stout cord. +With this the foot is neatly bound after the manner of a cricket-bat +handle, and all movement of the crack apparently restricted. There is +always a tendency, however, for such a dressing to work loose, and in the +case of a complicated crack it has the disadvantage of permanently hiding +from view the changes taking place in the discharge from the fissure. + +_(e) By wedging the Crack_.--This is the exact opposite of clamping. +Whereas in clamping we obtain immobility of the crack by keeping it fixed +in the position of greatest approximation of its edges, in wedging, the +crack is rendered free from movement by maintaining it in that position +where its edges are most widely separated. In this case the edges of the +crack are pared smooth, the cavity thoroughly cleansed, and a wedge of hard +wood firmly driven in so as to fit exactly the fissure. + +On the face of it it appears that this procedure would really tend to force +open and so lengthen the crack, especially at its coronary extremity. What +one should really remember, however, is that the crack _is not made wider_ +than before, but that it is simply maintained in a position occurring with +every contraction of the heels of the foot, when it is normally at +its widest. Movement of the edges is thereby stopped, the immediately +surrounding structures are rested, and a new growth of horn, free from +crack, induced to grow down from the coronet. + +This method of treatment only serves to emphasize the fact that, with a +sand-crack once formed, it is the constant movement of the parts that tends +most to keep it in existence, and not any particularly marked exertion of +force. + +Some practitioners, with the wedge, apply also a clamp, thus assuring +additional firmness and solidity to that portion of the wall under +treatment. + +The method of wedging is undoubtedly successful, if neatly performed. + +_(f) By Surgical Shoeing_.--A partial rest is given to the affected parts +by easing the bearing of the shoe at the point required. This may be done +either by removal of part of the wall at the spot indicated, or by thinning +the web of the shoe in the same position. The former is the method usually +practised. Cessation of movement given in this way is, as we have already +said, only partial; for, while the effects of pressure and concussion from +below are minimized, the crack is still able to suffer from the movements +of expansion and contraction of the foot. Still, as an auxiliary to other +treatments, 'easing' of the wall under the affected part should always be +practised. + +[Illustration: FIG. 91.---THE BEARING 'EASED' BY REMOVAL OF THE WALL.] + +[Illustration: FIG. 92.--THE BEARING 'EASED' BY THINNING THE WEB OF THE +SHOE.] + +Figs. 91 and 92 show respectively the manner of 'easing' by removal of +the wall, and by thinning the web of the shoe. In this connection it is +necessary to point out that on no account should 'springing' of the heels +of the shoe be allowed. Fig. 93 illustrates the ill-practice. + +In this case, when the entire weight is thrown on to the heels, the portion +of wall posterior to the crack is bound to participate unduly in the +downward movement, and so tend to widening of the crack at its highest +point. + +[Illustration: FIG. 93.--THE BEARING 'EASED' BY 'SPRINGING' THE HEEL OF THE +SHOE.] + +We have already referred to the matter of 'clips.' In no case, whether the +crack be at the toe or in the quarters, should a clip be placed immediately +below it. If the crack is at the toe, the usual clip should be dispensed +with, and a clip at each side made to take its place. At the same time care +should be taken to avoid throwing the weight far forward. For that reason +a shoe with calkins or with very high heels should be removed, and a shoe +with an ordinary flat web substituted. + +In the case of quarter-crack, where the constant movement of the parts +under expansion and contraction of the foot makes itself most felt, it is +wise to apply a shoe with clips fitting moderately tight against the +inside of the bars. By this means movement will to a very large extent be +curtailed. + +Where a marked tendency to contraction is found, as is often the case with +quarter-crack, then the shoe with the clips may be rendered more marked in +its operation by giving to the outer face of each clip--that face applied +to the bar--a slope from above downwards and outwards. In other words, a +slipper shoe should be applied and the contraction given equally as much +attention as the sand-crack itself. + +Where the crack is situated far back in the quarter, and easing of the +bearing cannot be accomplished without tending to spring the heels, then +the most suitable shoe is a bar shoe. With it the bearing may, of course, +be eased in exactly the position required, and the heels still allowed +to take their fair share in bearing the body-weight, and thus assist in +closing the crack. The bar shoe, if properly fitted, gives us also a +bearing on the frog, and aids greatly in counteracting contraction. + +2. _Curative_. + +_(a) The Application of Dressings to the Lesion_.--In the case of a recent +crack, deep, and attended with hæmorrhage, the foot should be thoroughly +cleansed. Where possible, a constant flow of cold water from a hose-pipe +should be allowed to run over the foot. By this means the inflammatory +symptoms will be held in check and pain prevented. Later the shoe may be +eased at the required place, and a blister applied to the coronet. This, +with rest, will sometimes prove all that is needed. + +Should a crack be of old standing, and complicated by the presence of pus, +a course of hot poulticing will often prove of benefit. The poultice should +be medicated with any reliable disinfectant, and should be renewed, or at +any rate reheated, two or three times daily. The crack itself should be +thoroughly cleaned after the removal of each poultice, and a concentrated +antiseptic solution--such as Tuson's spts. hydrarg. perchlor., carbolic +acid, and water, (1 in 10) or liquor zinci chlor.--poured into it. On +discontinuing the poulticing, the strength of the antiseptic solutions may +be decreased, the parts rested by correct shoeing, and a blister applied to +the coronet as before. + +If these measures alone should prove insufficient, then the surgeon will +either fall back on those we have just related, or proceed to methods next +to be described. + +_(b) Immobilizing the Crack by Means of grooving the Wall_.--To our +minds, this is as ready and withal as successful a method of dealing with +sand-crack as has yet been devised. It may be done in a variety of ways: +(1) By two grooves arranged about the crack in the form of a V, as Fig. 94; +(2) by a perpendicular groove on either side of the crack, about 1 inch in +distance from it, and parallel with the horn fibres, as Fig. 95; (3) by a +single horizontal groove at the extreme upper limit of the crack; (4) by +drawing two horizontal grooves, one at its upper and one at its lower end +(see Fig. 96). + +[Illustration: FIG. 94, FIG. 95, FIG. 96. In Figs. 94, 95, and 96 the thick +black lines illustrate the positions of the various grooves made with the +firing-iron for the purpose of immobilizing a quarter sand-crack.] + +The points to be observed in carrying out this line of treatment are simple +enough. In all cases see that the crack is rendered as clean as possible +by the use of suitable dressings, and if an excess of horn is present +immediately around it, as in the case of a long-standing and complicated +lesion, have it thinned down by rasping. + +All that is then needed is one or two moderately sharp, flat firing-irons. +The groove is then burned into the horn in the positions indicated, and +that portion of the wall containing the sand-crack thus prevented from +participating in the movements of the foot. For our own part, we consider +the V-shaped incision, or either of the horizontal methods of grooving, +preferable to lines running in the direction of the horn fibres. With the +latter there is certainly a greater tendency to the formation of new cracks +than with either of those we advocate. The V-shaped incision we consider +most suitable of all, for the reason that by its means a greater degree of +immobility is conferred upon the necessary portion of the wall. + +Whichever method is adopted, care should be taken to carry the grooves deep +enough into the horn, taking them down as near as possible to the sensitive +structures. At the same time, especial care should be exercised in not +carrying them too deep at their extreme upper limit, or in that case the +liability to the formation of fresh cracks in those positions will be +greatly increased. + +After grooving, a sharp blister should be applied to the coronet every +three or four weeks, and the animal, if free from lameness, put to work. + +_(c) By stripping away a V-shaped Portion of the Wall around the +Crack_.--This method is only indicated when the crack is greatly +complicated by the presence of pus, or by the growth of adventitious horn +on the inner surface of the wall. A radical cure is thus obtained, but the +animal for a longer time incapacitated from work. + +The operation is best performed by first grooving a line to connect the +points _a_ and _c_ (Fig. 97). This should run immediately under the +coronary margin of the wall, and should stop short of injuring the coronary +cushion beneath. Grooves forming the sides _ab_ and _bc_ of the triangular +piece of horn are next made, and the horn contained within the lines _ab, +bc_, and _ca_, carefully removed. The grooves are the easiest made by a +cautious use of the firing-iron. The greater thickness of the horn may +thus be penetrated, and the grooves afterwards carried to their full and +requisite depth by the use of the drawing-knife. + +With the removal of the horn the diseased structures are exposed to view. +All such should be removed by a free use of the scalpel, and a suitable +dressing afterwards applied. A necessary factor in the treatment is the +employment of pledgets of antiseptic tow. With these the exposed tissues +are covered, and the successive turns of a bandage run tightly over +them, so as to exert a moderate degree of pressure. When hæmorrhage has +accompanied the operation, this dressing should be removed on the following +day, the wound dressed, and the pledgets of tow and the bandage renewed. +Any after-dressing need only then be practised at intervals of a week. +Repair after this operation is rapid, and takes place both from the exposed +podophyllus membrane and from the coronary cushion. + +[Illustration: FIG. 97. The dotted lines outline the V-shaped portion of +wall to be removed in the treatment of complicated toe-crack.] + +[Illustration: Fig. 98. The dotted lines indicate the portion of wall to be +removed in the complete operation for complicated toe-crack.] + +_(d) By stripping the Wall from the Coronary Margin to its wearing Edge on +Either Side of the Crack_.--This is merely a more extensive application +of the method just described, and is only indicated in a _complete_ and +_complicated_ crack that has refused to yield to other modes of treatment +(see Fig. 98). + +As in the previous case, a groove is run from _a_ to _c_. The grooves _ab_ +and _de_ are then continued to the lowermost edge of the wall, and the +whole of the wall within these points removed. To facilitate removal, +the white line should be grooved between the points _b_ and _d_. +After-treatment is exactly the same as that just referred to. + + +B. CORNS. + +_Definition_.--In veterinary surgery the term 'corn' is used to indicate +the changes following upon a bruise to that portion of the sensitive sole +between the wall and the bar. Usually they occur in the fore-feet, and are +there found more often in the inner than in the outer heel. + +The changes are those depending upon the amount of hæmorrhage and the +accompanying inflammatory phenomena occasioned by the injury. + +Thus, with the hæmorrhage we get ecchymosis, and consequent red staining +of the surrounding structures. As is the case with extravasations of blood +elsewhere, the hæmoglobin of the escaped corpuscles later undergoes a +series of changes, giving rise to a succession of brown, blue, greenish and +yellowish coloration. + +With the inflammation thereby set up we get swelling of the surrounding +bloodvessels, pain from the compression of the swollen structures within +the non-yielding hoof, and moistness as a result of the inflammatory +exudate. + +In a severe case the inflammation is complicated by the presence of pus. + +_Classification_.--Putting on one side the classification of Lafosse +_(natural_ and _accidental_), as perhaps wanting in correctness, seeing +that all are accidental, and disregarding the suggested divisions of Zundel +_(corn_ of the _sole_ and _corn_ of the _wall_) as serving no practical +use, we believe, with Girard, that it is better to classify corns according +to the changes just described. + +Following his system, we shall recognise three forms: (1) _Dry_, (2) +_moist_, (3) _suppurating_. + +The _dry_ corn is one in which the injury has fortunately been unattended +with excessive inflammatory changes, and where nothing but the coloration +imparted to the horn by the extravasated blood remains to indicate what has +happened. + +The _moist_ corn is that in which a great amount of inflammatory exudate is +the most prominent symptom. It indicates an injury of comparatively recent +infliction. + +The _suppurating_ corn, as the name indicates, is a corn in which the +inflammatory changes are complicated by the presence of pus. + +_Causes_.--The causes of corns we may consider under two headings--namely, +_predisposing_ and _exciting_. + +_Predisposing Causes_.--By the heading of this chapter we have already +intimated that corns are due to faulty conformation of the foot. It is, +therefore, merely a description of such shapes of foot as favour their +formation that will need mention here. + +The wide, flat foot, with low heels, may be first considered. Here the +posterior portions of the sole, those portions between the wall and the +bars, fall very largely in the same plane as the wearing surface of the +bars and the wall. As a consequence, these portions of the sole are more +prone to receive injury from stones and rough roads and from the pressure +of the shoe. + +The low heels, too, favour a more than due proportion of the body-weight +being thrown on to the posterior parts of the foot. Two evils, both +inclining to the production of corn, result from this. In the first +place, the sensitive structures of the posterior portions of the foot are +subjected to undue pressure from above; secondly, the posterior half of +the foot, by reason of the extra weight thrown upon it, is exposed also to +greater effects of concussion than normally it should meet. Added to this +we find that the abnormally flat condition of the sole has resulted in +a great loss of resiliency. With undue pressure above, and a loss of +resiliency and added effects of concussion below, the sensitive structures +included between the opposing pedal-bone and the horny sole are bound +to suffer more or less bruising each time the foot comes to the ground, +especially if the animal is moved at a rapid pace. + +Writing here of the effects of pressure and concussion affords a fitting +occasion to mention the fact that corns occurring in feet affected with +side-bones are always worse than in feet with normal elastic cartilages. +The explanation of this is simple, for there can be no doubt that the +loss of resiliency in the diseased cartilage is only another aid to undue +pressure and concussion. The sensitive structures are pinched between +unyielding bone above and practically unyielding horn below. + +Feet with high and contracted heels are also predisposed to corn. The +contraction in this case interferes with the downward movements of the os +pedis during progression, while in a state of rest there is a more or +less constant pressure upon the sensitive structures, due to the correct +downward displacement of the pedal-bone being opposed by the amount of +contraction present. In the contracted foot, too, the nutrition of the +vessels supplying the secretory apparatus of the horn is largely interfered +with. The horn loses its natural elasticity, fails to respond to the normal +movements of the parts within, and aids in the compression and laceration +of the sensitive structures. + +Weak feet, with horn too thin to withstand the expansive movements +continually going on--in other words, feet with weak, spreading heels--are +also prone to suffer from corns. In this case the flatness induced by the +spreading, and the insufficient protection afforded by the thin horn, +both combine to lay the sole open to the effects of concussion and direct +injury. + +Brittle feet--feet with horn of undue dryness, by reason of the contraction +thus brought about--are, again, particularly subject to corn. + +So also with long feet. Whether occurring as a natural deformity, or as the +result of insufficient paring, bruises of the sole in feet thus shaped are +common. The reason for this will be better understood when we come to deal +with the shoeing. + +Other and minor predisposing causes are those mainly referring to an +unnatural dryness of the hoof when animals reared in the country are put +to work in large towns. We here really get several predisposing causes +combining. A sudden change is made from a more or less moist condition +underfoot to one excessively dry. The character of the travelling is wholly +altered from occasional work upon soft lands to continual labour upon +hard-paved roads. The horn is often exposed to the vicious influences +of unsuitable litter, the application of unsuitable dressings, and the +deleterious effects of the street mud of our cities. All these play their +part in determining a condition of the horn, rendering it open to receive +the effects of the more exciting causes which we shall next consider. + +_Exciting Causes_.--Than the shoeing, no more frequent and exciting cause +of corn exists. Whatever the predisposing influences may be, it is the +shoeing that in nearly every case completes the list, and finally inflicts +the injury. + +The evils in this connection we shall consider under two headings--viz., +(1) the manner in which the foot is pared; (2) the make and fitting of the +shoe. + +First among the faulty preparations of the foot comes that of excessive +thinning of the sole, especially in the regions subject to corn. The +farrier addicted to this is not as a rule content to confine his operations +to the sole alone. In addition, the frog and the bars also suffer from the +too lavish use of his knife. His main object is doubtless that of giving +a broad and open appearance to the foot. It follows from this that his +operations are confined more to the posterior than the anterior parts of +the foot, and that the toe is therefore left too long. This gives us a +combination of causes leading to pressure and bruises upon the sensitive +structures at the seat of corn. + +By this unequal paring of the toe and the heels greater weight is thrown +upon the posterior half of the foot. What then happens to the structures +thinned as we have described is this: the pared frog, lessened in volume, +does not meet the ground. It therefore fails to expand laterally with +weight, and cannot assist, as normally it should, in aiding the heels +generally in their movements of expansion. The weakened bars and the +thinned sole, meeting with no opposition from the frog, give downwards and +inwards with the body-weight at the precise moment these movements should +be directed mainly outwards. As a further result of non-resistance on the +part of the frog, this time in a lateral direction, the bars, the sole, and +the wall at the heels all contract at the exact time they should expand. +The end result must mean abnormal pressure and bruising of the sensitive +structures in that particular region. Naturally, also, the excessive +thinning of the horn renders direct injury to the sole from stones or other +objects in the road far more probable. + +For this one reason alone--the manner in which it favours the production of +corn--too great a condemnation cannot be placed upon excessive paring of +the sole, the bars, and the frog. + +When corns are already present, as they may be from other causes, the same +remarks will again apply to excessive paring. It is the custom with many +smiths to carefully pare down the discoloured horn in every case of corn +they meet with, and at the same time to again weaken the bars and even part +of the wall at the heels, with the laudable idea of relieving pressure on +the part diseased. After what has gone before, we need hardly say that +their well-meant efforts have a precisely opposite effect to the one they +intend. + +The fitting of the shoe is, perhaps, to a greater extent responsible for +the causation of corn than is the paring we have just described. + +A few of the evils connected with the shoe may, however, be justly +described as unavoidable. We _must_ shoe; we cannot shoe and leave a normal +foot! + +A shoe excessively seated, especially from the last nail-hole backwards, +may be regarded as dangerous. In this case, with every application of the +body-weight, there is given to the foot a tendency to contract, especially +at its lower margin. Result: undue pressure upon the tissues around and the +production of corn. + +On the other hand, varying with the form of foot, the seating may be +insufficient. In the case of flat-foot, or dropped sole, for instance, +insufficient seating will lead to undue pressure of the web of the shoe +upon the sole, and in that way bring about bruising of the sensitive sole +beneath. + +Shoes with heels or calks too high, by destroying the counter-pressure of +the frog with the ground, serve to bring about a series of changes we have +described under contraction, and again result in pinching and bruising of +the sensitive structures. + +The opposite excess--a shoe thick at the toe and thin at the heels--is +blamed by Zundel for causing a like injury. In our opinion, the reason this +author gives--namely, that the throwing of greater weight upon the heels +leads to bruising of the sensitive structures--can only correctly apply to +a _wrongly-applied_ shoe of this type, and not to the shoe itself. True, a +shoe with a thick toe and thinned heels will throw an undue proportion of +the body-weight upon the heels if the foot is not properly prepared for +it. A wise man, however, will most certainly so cut down the toe for the +reception of this shoe that, with the shoe in position, there will still be +maintained a tread that is normal. To our minds harm is far more likely to +arise from a shoe of this class through the thinned iron heels of the shoe +becoming attenuated under wear to the point of bending, and so inflicting +an injury upon the adjoining sole. + +Similarly, this last remark with regard to the thinning of the heels of the +shoe will apply to a shoe with too broad a web. As the thinning of the shoe +proceeds with wear, the inner portion of the thinned branch is bent up on +to the sole, and again inflicts the injury. + +The matter of bearing is also of importance when considering the causation +of corn. In a previous chapter we have already described the correct +bearing as that which includes the whole of the lower margin of the wall +and the white line, and just impinges on the sole. Any marked deviation +from that will, if long continued, be followed by injury to the foot. + +With the bearing surface of the shoe too narrow--in contact with the +wall solely, or perhaps only a portion of it--it is evident that a large +proportion of the foot that should properly bear weight is thrown out of +action. A heavy strain is imposed on the white line, and undue descent of +the sole and contraction of the heels brought about. Again the result of +this is compression and bruising of the tissues around the seat of corn. + +With its bearing surface too wide, the shoe immediately exerts direct +pressure upon the sole with every movement of the animal. The sole normally +is not made to receive this, and harm is bound to result. + +Among other ill-fitting shoes we may mention the one with branches too +short, and the one with the extremities of the branches too pointed. In +the first case, as wear of the shoe proceeds, the thinned end is far more +likely to turn in under the seat of corn than is a shoe with branches +of ordinarily correct length. It is evident in the second case that the +pointed branch, when thinned, is a more dangerous agent than the branch +which is nearer the square at its end. + +The matter contained in the first half of the foregoing paragraph explains +in a large measure the rarity of corns in the hind-feet. Here there is +nothing to prevent a shoe with branches of full length being used. The +correct bearing is thus maintained, even with a shoe excessively thinned +with wear, and the liability to injury from it decreased. An exception is +to be found in the case of a feather-edged shoe, such as is used to prevent +cutting or brushing. The thinning by wear from above to below of the branch +already purposely thinned from side to side leads to the formation of a +thin and narrow piece of iron admirably calculated to bend over and injure +the sole. + +Even with a shoe of correct length, with a flat-bearing surface at the +heels, and other conditions favourable to correct application, evil may +still result from the shoe itself being made too narrow. As a result +of this, the branch of _each_ side is set too far under the foot, with +consequent injury to the sole. This is, of course, sheer carelessness +on the part of the smith. When practised, however, it is not easy of +detection, as in all cases the foot is rasped down to cover what has been +done. In other words, the foot is made to fit the shoe and not the shoe the +foot. + +Recognising this close fitting of the shoe as a cause, we are able to +explain in some measure how it is that corns should occur with greater +frequency in the inner than in the outer heel. There is no doubt that the +inner branch of the shoe is nearly always fitted closer than is the outer. +In the fore-foot it is also often shorter. Take these two evils and add +to them the fact that the inner heel is called upon to bear more of the +body-weight than is the outer, and the frequency of corns in the inner heel +will no longer be wondered at. + +Indirectly, the shoe may still be a cause of corn by reason of the +irritation set up by gravel and small pieces of flint becoming firmly fixed +between the sole and the web of the shoe. In nearly every case of this +description the part to be injured is the white line. + +Corns may also result from the animal picking up a stone. The stone becomes +firmly wedged in between the inner border of the branch of the shoe and the +bar or the frog. With every step the animal takes it becomes wedged more +tightly into position. Projecting below the level of the lower surface of +the shoe, it imparts the concussion it thus obtains directly to the sole. A +bruise--and a bad bruise--is the result. + +Finally, it cannot be denied that the work the horse is put to is largely +responsible for the causation of corn. In country animals corns are +comparatively rare, while in animals in town, almost constantly upon hard +paving, they are common. This seems to point strongly to the fact that +concussion through constant work upon unyielding roads is a great factor in +their production. + +_Symptoms_.--Unless the discoloration of the horn is accidentally +discovered by the smith, the simple, dry corn may go undetected. The +disturbance excited by it is so small, and the pain occasioned so slight, +that the patient may offer no indication of its existence. + +Ordinarily, however, the first symptom is that of pain. The animal goes +feelingly with one or both feet, in some cases even showing decided +lameness. The lameness, however, is in no way diagnostic, and the lesion +itself must be discovered before an exact opinion can be pronounced. + +As an aside, it is well to observe in this connection that a negative +opinion as to the existence of corn should never be given unless the +superficial layers of horn have first been removed with the knife. + +When standing at rest the animal exhibits signs more or less common to all +foot lamenesses. He 'points' the foot--in other words, the limb is slightly +advanced, the fetlock partly flexed, and the heels from off the ground. +When both feet are affected they are pointed alternately, and the animal +often manifests his uneasiness by repeated pawing movements, and by +scraping his bedding behind him. + +Should the injury run on to suppuration, the lameness becomes most +acute. The pawing movements become more pronounced, and there is evident +disinclination on the part of the animal to place the foot squarely on the +ground. One is then led to manipulate the foot. The hoof is hot to the +touch. Percussion causes the animal to flinch, and to flinch particularly +when that portion of the wall adjoining the corn is struck. Finally, +exploration with the knife reveals the serious extent to which the injury +has developed. In a neglected case of this description it is even possible +to detect the presence of pus by the amount of swelling and fluctuating +condition of the coronet. The suppurative process has advanced in the +direction of least resistance, and is on the point of breaking through the +tissues immediately above the horn. + +Lameness due to corn is oftentimes intermittent. With a simple corn, dry or +moist, this intermission is largely dependent on the degree of dryness of +the hoof or the road, and also on the character of the road surface. With a +neglected, suppurating corn, on the other hand, variation in the degree +of lameness, in addition to depending on circumstances such as these, +is dependent to a larger extent upon the changes occurring with the +suppuration. In this case the time of greatest lameness is immediately +before the pus gains outlet. Immediately after its exit at the coronet the +animal will go almost sound. Soundness continues so long as the opening at +the coronet remains clear. The tendency, however, is for the opening thus +made to quickly close again. Pus again accumulates, lameness arises as +before, and disappears again with the second discharge of the contents of +the sinus now formed. + +_Pathological Anatomy_.--When dealing with their classification we gave in +outline the main pathological changes to be met with in corns. It now only +remains to give the same matter in slightly greater detail. + +_In dry corn_ the changes we meet with are those accompanying blood +extravasation. From excessive compression of the parts, or from the effects +of direct injury, a portion of the sensitive sole has become lacerated. +The escaping blood stains the surrounding soft tissues after the manner +of blood extravasation elsewhere. If the escape of blood is sufficiently +large, the horn fibres in the immediate vicinity also are stained. It is +this stain in the horn that is the direct evidence of the injury, and is +itself popularly known as the corn. It may vary in size from quite a small +spot to a broad patch as large as half a crown, while its colour may be a +uniform red, or a mottled red and white. The microscopic changes in this +connection are illustrated in Fig. 99. + +[Illustration: FIG. 99.--HORIZONTAL SECTION OF A CORN. The section cut at +about the base of the papillæ of the sensitive sole. _a_, papillæ, with +horn-cells surrounding them; _b_, interpapillary or intertubular horn; +_c_, hollow spaces in the intertubular material filled with blood; _d_, a +papilla and its surrounding horn-cells filled with blood.] + +Ordinarily, this ecchymosis of the horny sole is due to injury of the +sensitive sole _immediately beneath_ it. It may, however, proceed from +injury to the vessels of the laminæ either of the bars or of the wall. In +this case the ecchymosis of the horny sole may be explained by the fact +that the escaped blood tends to _gravitate_ to that position. + +When the corn is of long standing, or is due to _repeated_ injuries on the +same spot, the horn adjacent to the lesion becomes hard and dry, and often +abnormally brittle, simply on account of the inflammatory changes thus kept +in continuation. This is often seen when attempts are made to _pare out_ +the corn with the knife. + +Should the injury be seated in the sensitive laminæ, then the brittle +nature of the horn secreted by the injured tissues makes itself apparent by +the appearance of cracks in the wall of the quarter. Why this should occur +will be readily understood by a reference to Fig. 100. + +[Illustration: FIG. 100.--INNER SURFACE OF THE WALL OF THE QUARTER, SHOWING +CHANGES IN THE HORNY LAMINÆ BROUGHT ABOUT BY CHRONIC CORN.] + +It will here be seen that the injury to the keratogenous membrane has led +to great interference with the secretion of horn from the sensitive laminæ. +As a result, the regularly leaf-like arrangement of the horny laminæ has +been largely broken up. Certain of the laminæ are altogether wanting, +while others are broken in their length and rendered incomplete. With this +condition there is always more or less contraction of the quarter. + +Microscopic examination of the structures involved in such a case reveals +the fact that with the contraction is an alteration in the normal direction +of the horny and sensitive laminæ. + +They become bent backward, and, instead of the regular and normal +arrangement depicted in Fig. 32, show the distorted appearance given in +Fig. 101. + +From the appearances and characters of the blood-stain in the horny sole +we are able to deduce evidence relative to the duration and nature of the +injury. + +[ILLUSTRATION: FIG. 101.--PERPENDICULAR SECTION OF THE WALL OF A CONTRACTED +QUARTER IN A CASE OF CHRONIC CORN. Both the sensitive and horny laminæ +are bent backwards, and hæmorrhages have taken place at the base of the +sensitive laminæ.] + +When, for instance, the stain is not to be found in the superficial layers +of the sole, but is only discoverable by deep paring, then the injury is a +recent one. + +Where the stain _is_ met with in the superficial layers of horn, and is +quickly pared out, then the injury has been inflicted some time before, and +has not been repeated. When, as is sometimes the case, layers of horn that +are stained are found alternated with layers that are healthy, then we have +evidence that the cause of the corn, whatever it may be, is not in constant +operation. + +Similar indication of the age of the injury is also afforded by the colour +of the lesion. + +A stain that is deep red is proof that the injury is comparatively recent. + +A distinct yellow or greenish tinge, on the other hand, is evidence that +the injury is an old one. + +_In the Moist Corn_ we have, in addition to the blood extravasation, the +outpouring of the inflammatory exudate. In the most superficial layer of +the horn this may not be noticeable. As one cuts deeper into the sole with +the knife, however, it will be found that the lower layers of horn are +more or less infiltrated with the discharge. This gives to the horn a soft +consistence, a yellow appearance, and a touch that is moist to the fingers. + +With the accompanying inflammation the cells in the neighbourhood of the +injury are enfeebled and their normal functions interfered with. We may +thus expect a corresponding interference with the growth of horn. This is +exactly what happens, and as one cuts deeper still into the horn a point is +finally reached when a well-marked cavity is encountered. A pale yellow +and usually watery exudate fills it. This cavity points out the exact spot +where the force of the injury has been greatest, where death of certain +cells of the keratogenous membrane has resulted, and where the natural +formation of horn has for a time been suspended. + +_In the Suppurating Corn_, as in moist corn, we have pathological changes +due to the tissue reaction to the injury, _plus_ the addition of pus +organisms. Confined within the horny box we have a discharge that, by +reason of the living and constantly multiplying elements it contains--the +pus organisms--is always increasing in bulk. This must be at the expense +of the softer structures of the foot. Accordingly, as the formation of pus +increases, we get pressure upon and final gangrene of the sensitive sole +and of the sensitive laminæ of the bars and the wall. With no outlet below, +the pus formation increases until finally it finds its way out of the hoof +by emerging at the coronet. + +This in some instances it may do by confining its necrotic influences +solely to the sensitive laminæ of the wall, in which case, if a dependent +orifice is quickly made at the sole, the injury to the laminæ is soon +repaired by the healthy tissue remaining. + +In other cases, however, the necrosis has spread deeper. Caries of the +os pedis, of the lateral ligaments of the pedal-joint, or of the lateral +cartilages, is a result. When this occurs the exuding discharge from the +coronet becomes thinner and more putrescent, and its feel, when rubbed +between the fingers, sometimes gritty with minute fragments of broken-up +bone. Here, unless operative measures prevent it, necrosis soon spreads +deeper still. The deeper portions of the os pedis become affected. The +capsular ligament of the joint is penetrated by the suppurative process, +and a condition of septic arthritis results. The cavity of the joint +becomes more or less tensely distended, according to the amount of drainage +present, which in this case is almost nil, with matter in a state of +putrescence. As a consequence, the surrounding ligaments become softened +and yield, and the articular surfaces displaced. The articular cartilages +also suffer, become necrotic in patches, and frequently wholly destroyed. +The end result is one of anchylosis of the joint and permanent lameness. + +_Prognosis_.--With the ordinary dry corn a return to the normal may nearly +always be looked for. Similarly, with moist corn, and even with careful +treatment of the suppurating variety, the same favourable termination may +be looked for and promised. + +What cannot so safely be assured is that a relapse will not occur. In other +words, the extent of the injury, no matter how serious, does not often +offer anything that cannot be overcome by Nature and careful surgery; but +the conformation of the animal does. A vicious predisposing conformation +once there is there always, and although the injury resulting from it may +easily give way to correct treatment, the same injury is bound to re-occur +when the animal is again put to work. + +Although with care suppurating corn, like other cases of suppuration +within the hoof, may yield to treatment, the owner of the animal should, +nevertheless, be warned that the condition is a serious one, especially +should the joint become affected. It may so happen, as sometimes in fact it +does, that the animal may die as a result of the infective fever so set up. +From no surface in the body can absorption take place quicker than from the +synovial membrane of a joint. So soon, therefore, as this membrane comes in +contact with septic material, so soon does a severe septic fever make its +appearance. The septic matter has gained the blood-stream, and the patient +succumbs to septic poisoning. + +Apart from death occurring naturally, the changes taking place in the joint +in the shape of bony growths or of actual anchylosis may be so severe as to +render the animal useless, and slaughter may have to be advised. + +_Treatment_.--We have already said that by far the most active cause in +the production of corn is the shoe. It follows from this that it is to the +shoeing we must largely look for a successful means of their prevention, +and that the treatment of corn in its most simple form is really a matter +for the smith, and not for the veterinary surgeon. + +The faults in connection with the shoeing we have mentioned fully when +treating of the _causes_ of corn. From those we learn that a shoe with a +flat-bearing surface, or one moderately seated but flat at the heels, is +the correct shoe for nearly all feet. The heels of the shoe should not be +too high, should not be too short, and should be wide enough apart from +each other to insure the wall of the foot obtaining a fair share of the +bearing. Finally, even with the present method of shoeing, whenever it is +possible to allow the frog to come to the ground, it should be encouraged +to do so, and excessive paring either of the latter organ or of the bars or +the sole should be strictly discountenanced. Where the sole is thin, or the +frog wasted, use a leather sole or a rubber pad. With these precautions, +corns may be prevented from occuring even in a foot with a predisposing +conformation. + +When corn is present, the first treatment usually adopted is that of +'paring it out.' This is advocated by Percival and by many other writers. +We cannot say, however, that we agree with it--at any rate, not in the case +of simple dry corn. + +'Paring it out,' and by that we mean thinning down the sole until close on +the sensitive structures, can only be advised in the case of suppurating +corn, or in cases where doubt exists as to whether pus is present or not. +In the latter case paring becomes necessary as an exploratory means to +diagnosis. + +When it appears fairly certain, even in the case of a moist corn, that pus +does not exist, then paring is to be discountenanced, for the reason that +it only tends to weakening of the parts and to assist largely in the corn's +recurrence. + +Those who advocate it do so for the reason that it relieves pressure on the +injured parts. + +That it does so directly from below cannot be denied; but that it also +favours contraction and compression from side to side is equally certain. + +A moderate paring may, however, be indulged in, say, to about one-half +the estimated thickness of the sole. Softening of the horn and consequent +lessening of pressure may then be brought about by the use of oil, oil and +glycerine, tincture of creasote, or by poulticing. + +In the case of a moist corn the paring should be stopped immediately the +true nature of the injury has made itself apparent. Warm poultices or hot +baths should then be used in order to soften the surrounding parts, lessen +the pressure, and ease the pain. After a day or two day's poulticing, +should pain still continue with any symptom of severity, the formation +of pus may be expected, and it is then time for the paring to be carried +further, until the question 'pus or no pus?' is definitely settled. + +Should the moisture be due simply to the presence of the inflammatory +exudate, then poulticing alone will have the desired effect, and the +pain will be lessened. With the decrease in pain the poulticing may be +discontinued, and the horn over the seat of the injury dressed with some +antiseptic and hardening solution. Sulphate of zinc, a mixture of sulphate +of zinc and lead acetate, sulphate of copper, or the mixture known as +Villate's solution,[A] may either of them be used. Suitably shod, and with +a leather sole for preference, the animal may then again be put to work. + +[Footnote A: The composition of the escharotic liquid bearing his name was +published by M. Villate in 1829 as under: + + Subacetate of lead liquid ... ... ... 128 grammes. + Sulphate of zinc [=a=a] ... ... ... 64 grammes. + Sulphate of copper, [=a=a] ... ... ... 64 grammes. + Acetic acid ... ... ... ... 1/2 litre. + +Dissolve the salts in the acid, add little by little the subacetate of +lead, and well shake the mixture.] + +When dealing with suppurating corn, then, a considerable paring away of the +horn of the sole becomes a matter of necessity. The freest possible exit +should be given to the pus, and this even when an opening has already +occurred at the coronet. Unless this is done, and done promptly, the +putrescent matter still contained within the hoof will make further inroads +upon the soft structures therein, and later upon the ligaments, and even +bone itself. + +Having given drainage to the lesion by the dependent orifice in the sole, +poulticing should again be resorted to and maintained for at least three +or four days. The poulticing may then be discontinued, and the openings in +the sole injected with a weak solution of Tuson's spts. hydrarg. perchlor., +a 1 in 20 solution of carbolic acid, a solution of copper sulphate, with +Villate's solution, or with any other combined antiseptic and astringent. +The success of the treatment is soon seen in the cessation of pain and in +the decreased amount of discharge from the opening in the sole. + +Should pain unfortunately continue, the discharge remain, and a state of +fever reveal itself, then it may be understood that the suppurative process +has not been checked, that a portion of necrosed ligament, cartilage, +or bone still remains, which, surrounded as it is by pus organisms and +putrefactive germs, is sufficient to excite a constant irritation and +maintain the internal structures in a state of infection. In other words, +we have what is known as a quittor. + +This will call for deeper operation. The horn of the wall must be removed, +and the diseased structures, whether gangrenous keratogenous membrane, +necrosed ligament, or carious bone, carefully excised or curetted. This +will be better understood by a reference to the chapter on Quittor, where +the means for carrying out the necessary operative measures will be found +described in detail. + +_Surgical Shoeing for Corn_.--In the case of an ordinary dry corn, where +the injury has been definitely ascertained to be accidental, no alteration +in the shoeing will be necessary. Where, however, the corn is attended with +a more than ordinary degree of inflammation, or where for some reason or +other excessive paring has been practised, then it will become needful +to shoe with a special shoe. The object to be attained is the removal of +pressure from that portion of the wall next to the seat of corn. + +The most simple shoe for effecting this is the ordinary three-quarter shoe. +The only way in which this differs from the ordinary shoe is that about an +inch and a half of that branch of the shoe adjoining the corn is cut off +(Fig. 102). If at the same time contraction of the heels exists, then, +perhaps, a better shoe is that known as the three-quarter bar (Fig. 103). + +Or, if preferred, a complete bar shoe such as that described for sand-crack +may be used, and the upper portion of the web in contact with the foot at +the seat of corn thinned out so as to avoid pressure on the wall at this +point. With this shoe we shall at the same time supply a certain amount +of pressure to the frog, and aid in the healthy development of the part +indirectly involved in the disease. + +The same pressure may also be given to the frog, and protection afforded +the sole, by the use of a leather sole, or rubber pad on leather, as +described when dealing with contracted feet. + +A further method of relieving pressure on this portion of the wall, without +removing the wall itself (a practice which should never be advised) is to +make certain alterations in the web of the shoe. This may be done in one of +two ways. + +[Illustration: FIG. 102.--THREE-QUARTER SHOE.] + +[Illustration: FIG. 103.--THREE-QUARTER BAR SHOE.] + +In the first, that portion of the bearing surface of the heel of the shoe +is 'dropped' about 1/8 inch from the plane of the remainder, so that the +shoe at this position does not come into contact with the foot at all (see +Fig. 104). + +In the second case the shoe is what is termed 'set' at the heel. Here it is +the plane of the _wearing_ surface of the shoe that is altered. The hinder +portion of the required heel is thinned so that its lower surface does not +come into contact with the ground. By this means the wall is freed from +concussion and pressure. At the same time the upper surface of the shoe is +in contact with the wall of the foot (see Fig. 105). + +This 'setting' of the shoe is preferable to the method first described. It +affords a greater protection to the foot, and does not allow of fragments +of stone and flint getting in between the foot and the shoe, and so giving +rise to further mischief. + +The 'set' portion should be fitted full and long. It is obvious, too, that +the animal should not be allowed to carry the shoe too long; otherwise, as +the other portion of the shoe wears down to the level of the 'set' heel, +pressure on the tender part of the foot will again result. + +[Illustration: FIG. 104.--SHOE WITH A 'DROPPED' HEEL.] + +[Illustration: FIG. 105.--SHOE WITH A 'SET' HEEL.] + +In applying surgical shoes for corn of long standing, it must be remembered +that the protection so afforded must be continued for some time. It is not +sufficient to see the lesion itself disappear. In addition to that there +is also, in the majority of cases, a certain amount of contraction to be +overcome. This can only be done by continuing the use of a leather sole +or some form of frog or bar-pad as recommended for the relief of that +condition. + + +C. CHRONIC BRUISED SOLE. + +A similar condition to that of corn may be met with in other positions on +the sole. It is described by Rogerson as sand-crack of the sole[A], and is +invariably met with around that portion of the sole in contact with the +shoe. + +[Footnote A: _Veterinarian_, vol. lxiii., p. 51.] + +The animal is lame, and the shoe is removed in order to ascertain the +cause. Nothing at first is noticeable except that the animal flinches when +pressure is applied to the spot with the pincers, or the sole is tapped +with the hammer. + +On removing the sole with the knife, however, a distinct black mark is +discovered, which, when followed up by careful paring, is often found to +have pus at the bottom. + +In this case the injury has resulted, as we have already intimated +elsewhere, from causing the animal to wear for too long a time a shoe with +too broad a web or insufficiently seated. Or it may have originated with +the irritation set up by foreign and hard substances between the web of the +shoe and the foot. + +In his description of this condition Mr. Rogerson draws attention to the +fact that the pus found should not be wrongly attributed to accidental +pricking of the foot. He says: + +'Considering that the cracks or splits are always found in the immediate +vicinity of the nail-holes, a certain amount of discretionary skill is +required in order that the lameness may be attributed to its proper cause. +This is an instance in which the presence of the veterinary surgeon +is imperative, in order to prevent undue blame being attached to the +shoeing-smith. Misconception in these cases might very easily arise when +parties concerned are disposed to accept an unskilled opinion, sometimes +resulting in danger to the proprietor of the forge, not only of losing a +shoeing contract, but also of being involved in other ways which would +probably prove even more disastrous. + +'Horses that stand on sawdust or moss litter are sometimes found with +extensive discoloration of the horny sole in front of the frog. Their +bedding material collects in the shoe as snow does, and forms a mass, which +keeps a continued and uneven pressure upon the sole. A sound foot is not +injuriously affected, but a very thin sole is, and so also is a sole which +has been bruised by a picked up stone. Even a slight bruise becomes serious +if pressure is allowed to remain active over the injured part. Lameness +increases, serous fluid is effused between the horn and sensitive part, or +even hæmorrhage may take place.'[A] + +[Footnote A: Hunting, _Veterinary Record_, vol. xiv., p. 593.] + +_The Treatment of Chronic Bruised Sole_ offers no special difficulty. +Removal of the cause (in nearly every case incorrect bearing of the shoe) +is the first consideration. That done, the lesion may be searched for and +treated in the ordinary manner as described for corn. When pus is present +it must, of course, be given exit, and an antiseptic solution applied to +the wound. Should the sensitive structures be laid bare when allowing the +pus to escape, then the wound so made should afterwards be protected with a +leather sole and antiseptic stopping. + + + +CHAPTER VIII + +WOUNDS OF THE KERATOGENOUS MEMBRANE + + +A. NAIL-BOUND--BIND OR TIGHT-NAILING. + +_Definition_.--By the term 'nail-bound' is indicated that accident +occurring in the forge in which the nail of the shoe is driven too near the +sensitive structures. Although involving no actual wound, it is important +to consider the condition under the heading of this chapter, in order that +it may be distinguished from the graver accident of a 'prick.' + +_Causes_.--Very largely the whole matter of causation turns on the correct +fitting of the shoe. The points especially to be noticed in this connection +are (1) the position of the nail-holes in the web of the shoe, (2) the +'pitch' of the nail-holes. + +Regarding the position of the nails, it goes without saying that the first +consideration when 'holing' the shoe should be to punch the holes opposite +to sound horn. This remark applies especially to shelly and brittle feet, +the type of feet in which tight-nailing most often occurs. The next +consideration in this connection is that of punching the holes so that the +nail emerges from the upper surface of the web at exactly its correct point +of entrance on the bearing surface of the foot. This should be on the white +line immediately where it joins the wall. From this position any marked +deviation inwards ('fine-nailing,' as it is termed) is bound to give to the +nail a direction dangerously near the sensitive structures. + +The 'pitch' of the nail-holes should be such that the nail is guided more +or less nearly to follow the line of inclination of the wall. Accordingly, +the nail-holes at the toe should be 'pitched' distinctly inwards, the +inward pitch lessening as the quarters are reached, until the hindermost +nail-hole or two is pitched in a direction that is almost perpendicular. + +Too great an inward inclination of the nail will, however, give rise to a +bind. + +It is probable that 'tight-nailing' results more often from fine punching +of the shoe than from any fault in the pitch of the hole. Inattention to +either detail, however, is apt to bring the mischief about. + +Even with a correctly fitted shoe, and with a normal foot, tight-nailing +may occur as a result of sheer carelessness on the part of the smith. + +_Symptoms_.--Possibly the animal returns from the forge sound. It is on +the following day, as a rule, that evidence of the injury is given by the +animal coming out from the stable lame. In a well-marked case the foot +is warmer to the hand than its fellow, and percussion over the wall will +sometimes reveal the particular nail that is the cause of the trouble. +Should the shoe be removed, then the fact that the hole the nail has made +is far too close to the sole often points out at once the seat of the +mischief. + +_Treatment_. As to whether or not the shoe should be removed is very much a +matter for careful discretion on the part of the veterinary surgeon. Where +the foot is shelly and brittle even a good smith sometimes finds himself +unable to firmly attach the shoe without verging closely on causing the +condition we are now describing. The author has known cases where animals +with feet of this description have almost invariably returned from the +forge, or rather been found the next day, with a suspicion of tenderness. +After the lapse of a day or two this has quite often disappeared, and +nothing in the meantime been done with the foot. Seeing, therefore, that +removal and refitting of the shoe is in this case attended with risk of +breaking away portions of the brittle horn, and so rendering the foot in an +even worse condition than it was before, it is policy to decline to have +the shoes removed unless worse symptoms make their appearance. + +In coming to this decision the veterinary surgeon must be guided by noting +in the wall the points of exit of the nails. Should the nail adjoining the +position already pronounced to be tender have come out at a higher point +than the others, it may be assumed that at a lower position in its course +through the horn it has gone near the sensitive structures without actually +penetrating the horny box, and that in the course of a day or two the +sensitive structures involved will accommodate themselves to the pressure +thus inflicted. + +If, on the other hand, symptoms of tight-nailing show themselves in an +animal with good sound feet, then there is no objection to be raised +against having the shoe at once removed. Should the offending nail be +definitely detected, then the shoe may again be put on, and that particular +nail omitted from the set. + + +B. PUNCTURED FOOT. + +(_Pricked Foot_--_Nail-tread_--_Gathered Nail_.) + +_Definition_.--Under this heading we propose describing wounds of the +foot occurring in the sole or in the frog, and penetrating the sensitive +structures beneath. + +_Causes_.--These we shall consider under two headings: + +1. Wounds resulting from the animal himself 'picking-up' or 'treading' on +the offending object. + +2. Cases of pricking in the forge. + +Those occurring under the first heading are, of course, purely accidental. +In the majority of cases, the object picked up is a nail; but similar +injury may result from the animal treading on sharp pieces of wood or +iron, on pieces of umbrella wire, on pointed pieces of bones, broken-off +stable-fork points, sharp pieces of flint, etc. The same accident may also +occur in the forge as a result of the animal treading on the stumps of +nails, from treading on an upturned shoe with the stumps of nails _in +situ_, or from treading on an upturned toe-clip. It may also occur from an +accidental prick with the stable-fork when 'bedding up,' or from casting +part of a shoe when on the road and treading on the nails, in this case +left sometimes partly in and partly out of the horn. + +'Serious wounds of this description are also met with in animals engaged in +carting timber from plantations in which brushwood has recently been cut +down. This is, of course, from treading on the stake-like points that are +left close to the ground. Hunters also meet with the same class of injury +when passing through plantations or over hedge banks, where the hedge has +just been laid low or cut down. + +'Agricultural horses also meet with severe wounds of this class from +treading on an upturned harrow.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv., +p. 2.] + +It has been remarked how strange it is that nails should so readily +penetrate the comparatively hard covering of the foot. The matter, however, +admits of explanation. One knows from common observation how easy it is to +tilt a nail with its point upwards by exerting a pressure in a more or less +slanting direction upon its head. This is exactly the form of pressure that +is no doubt put upon the nail if the animal treads upon it when moving at +any pace out of a walk. The foot in its movement forward tilts the nail +up, and almost simultaneously puts weight upon it. The great weight of the +animal is then quite sufficient to account for its ready penetration. + +In purely country districts cases of punctured foot are of far less +frequent occurrence than in large towns. In the latter, animals labouring +in yards where a quantity of packing is done, or engaged in carting +refuse containing such objects as we have mentioned, or broken pieces of +earthenware or glass bottles, meet with it constantly. + +For the manner of causation of those wounds to the foot occurring in +the forge the reader may be referred to the matter under the heading of +'nail-bound.' As in that case so in this the nail may be wrongly directed +by improper fitting of the shoe, by the 'pitch' of the hole, or by the +position of the hole. The nails may also be wrongly directed as a result of +faulty pointing, or by meeting with the stump of a nail that has carelessly +been allowed to remain in the substance of the horn. + +Often pricking is a result of carelessness engendered by a rush of work. +Often it is almost unavoidable on account of the character of the foot that +is brought to be shod. Feet with thin horn, especially a thin sole, feet +with horn shelly and brittle, each in their way are difficult to shoe. + +Sometimes pricking is purely accidental, as in the case of a 'split' nail. +The nail as it is driven splits at its point, and continues to split down +its centre, one half emerging at the correct spot on the wall, the other +half bending inwards, and penetrating the sensitive structures. + +_Common Situations of the Wound_.--In a case of picked-up nail the common +seat of puncture is about the point of the frog, either in one of the +lateral lacunæ, in the median lacuna, or the apex of the frog itself. In +comparison with this puncture of the sole is rare. + +Prick sustained at the hands of the smith may, of course, run in either of +the following directions: (1) Directly into the position where the horny +and sensitive laminæ interleave; (2) between the sensitive laminæ and the +os pedis; (3) into the os pedis itself; (4) the nail may bend excessively +immediately after entering the horn, and so pass either between the horny +and sensitive sole; or (5) between the sensitive sole and the bone. + +_Classification_.--Punctured wounds of the foot may be classified as +follows: + +_Simple or superficial_ when penetrating no structure of great importance. +For instance, a prick that penetrates to the sensitive sole and is not +driven with sufficient force to seriously injure the os pedis we may regard +as simple. In the same manner a prick to the frog that, although deep, is +mainly concerned with penetrating the plantar cushion may also be classed +as simple. + +_Deep or penetrating_ when driven with sufficient force or in such a +direction as to injure structures whose penetration is calculated to give +rise either to serious constitutional disturbance or to permanent lameness. +In this category we may place injuries to the terminal portion of the +perforans, puncture of the navicular bursa, fracture of the navicular bone +and penetration of the pedal articulation, and splintering of the os pedis. + +_Symptoms and Diagnosis_.--While discussing the symptoms and diagnosis, we +will still continue to consider our subject under the two headings of (1) +accidental 'gathering' of some foreign body, and (2) pricks inflicted in +the forge. + +In a few cases belonging to the former class the veterinary surgeon is +fortunate in obtaining a direct history of the injury. The driver has seen +the animal go suddenly lame, and has examined the foot for the cause. +Either the nail has been found embedded in the horn, or the puncture it has +made detected, and the matter has been reported. The foot is then explored +and the full extent of the injury ascertained. + +In many cases, however, it so happens that no evidence of the infliction of +the injury is forthcoming. The momentary lameness occurring at the time of +the prick is unreported at the time by the attendant, and the horse for +a time goes sound. It is not until the changes set up by the subsequent +inflammatory phenomena make their appearance, and lameness results, that +attention is called to the foot. When this happens there has, as a rule, +been time for pus to form around the seat of puncture--a matter of about +forty-eight hours. + +The horse is now brought out for the veterinary surgeon's examination, +going distinctly lame. If the case is well marked there may then be noted +by the man of experience many little signs pointing to the foot as the seat +of the lameness. These, though well enough known to the practitioner, are +nevertheless difficult to describe. It is, in fact, hard to say exactly in +what they really consist, appearing to be as much a matter of intuition as +of actual observation. + +There is a peculiar 'feeling' characteristic in the gait. The affected foot +is put forward fearlessly enough, but is not nearly so rapidly put to the +ground. When at rest the foot is almost immediately pointed, and the pain +at intervals manifested by pawing movements. It is this extreme liberty of +the rest of the limb, as evinced during the pawing movements, that really +strikes one. Shoulder, elbow, knee, and fetlock are all easily and +painlessly flexed and extended. There is nothing wrong with them; it must +be the foot. The short manipulation necessary to test the lameness--viz., +the walk and slow trot--is sufficient to raise the animal's pulse and +quicken the breathing. + +All this is enough, and more than enough, to lead the veterinary surgeon +to examine the foot. It is hot to the touch, and at the coronet tender to +pressure, possibly in a neglected case fluctuating at the heel. Pain is +evinced by the animal withdrawing his foot when percussion takes place over +the affected spot. In a bad case one gentle tap is all that is needed. The +animal at once snatches away his foot, holds it high from the ground, and +makes pawing movements in the air. At that moment, too, his countenance is +highly expressive of the pain he is suffering. Again the foot is explored, +the injury found, and the pus liberated. + +Regarding the manner of exploration of the foot we will take first that +case in which the veterinary surgeon is called in early, and in which pus +has not yet had time to form. Sometimes the merest cleaning up of the +inferior surface of the foot then reveals a distinct stab either in the +sole or the frog. + +If the accident be recent only a little blood will be found, either liquid, +or coagulated about the wound. Later there exudes from the stab a flow of +yellow, serous fluid. The opening thus found should be carefully probed, +and its depth and situation noted. + +At other times the prick is not so readily apparent. The nail or other +object has penetrated and afterwards withdrawn itself. The natural +elasticity of the horn, especially that of the frog, causes it to contract +upon the puncture, and to largely obliterate the hole made. What, +therefore, may look to be but a simple injury to the horn alone may +in reality be the only evidence of a stab complicating the sensitive +structures. It thus behoves the veterinary surgeon to follow up and +carefully cut out any unnatural-looking mark in the horn, more especially +if the horn is discoloured, or if blood is extravasated into its fibres, or +there is moisture exuding from the part. + +In some cases of this description the knife in the act of paring comes into +contact with the cause of the trouble. Sometimes this is a nail, sometimes +a sharp and small piece of flint, so deeply penetrated as to have become +quite buried. When met with in this manner, however, the foreign body is +more often than not a splinter of wood deeply embedded in the cleft of the +frog or in the frog itself. + +The fact that multiple punctures may occur should here be remembered, and +the remainder of the inferior surface of the foot thinly pared. + +On withdrawal of the foreign object blood may immediately follow. Should +the former have been fixed in position for some time, however, pus is +nearly always found at the bottom of the wound. As a rule, its removal is +comparatively easy, but one case recalls itself to the author's mind in +which the extraction was a matter of considerable difficulty. The offending +object was a large, flat-headed nail, some 2 inches long. This was driven +fast into the os pedis, and necessitated the employment of a pair of +pincers and the exertion of some amount of force to move it from its +position. + +In this connection it must be remembered that the penetrating object +sometimes breaks off after entering the foot. The fact that this +occasionally happens only serves to give point to the advice we have +previously rendered--that every stab should be carefully probed, and its +exact condition and depth ascertained. + +In those cases where percussion has led to the positive opinion that pus +really exists, then the exploration must be most searching. There may, or +may not, be a suspicious-looking mark to work on. In the latter case, the +veterinary surgeon must not be content with confining his paring operations +to one spot. The sole should be carefully thinned all round, and the +thinning cautiously proceeded with until either small, pin-point +hæmorrhages denote that healthy sensitive structures have been reached, or +a sudden flow of pus indicates that the injury has been definitely located. + +While the symptoms remain much about the same, the diagnosis of pricks +received in the forge, as compared with those occurring in the natural +manner, is easy. The animal starts to the forge quite sound, and returns, +perhaps, with a slight limp. The slight limp in two days' time becomes a +decided lameness, and no doubt remains as to what has occurred. The mere +fact of the lameness arising immediately after a visit to the forge should +be sufficient in the majority of cases to lead one to a correct diagnosis. + +Where the opinion has been formed that a prick has been received, then the +shoe should be removed. + +This operation should always be superintended by the veterinary surgeon +himself. After the removal of the clinches, the nails should be drawn one +at a time with the pincers, and carefully examined. Often the offending +nail may thus be picked out by observing upon it blood-stains, or the +moisture from inflammatory exudate or from pus. Further inflammation will +also be gathered by occasionally meeting with a nail that has split. + +At this stage, too, the veterinary surgeon should have noticed whether or +not the smith has previously sent the animal home with what is known as a +'draw back.' He has discovered, immediately after he has done it, that he +has pricked the animal. He has then withdrawn the nail, and either sent the +animal back with that nail altogether missing from the set in the shoe, or +with the hole filled up with a stump. + +The shoe once off, the holes made by the nails in the horn should be +minutely examined for the presence of hæmorrhage, inflammatory fluid, or +pus exuding from them, and also for evidence of their correct placing in +the foot. Should fluid matter issue from any one of them, or should it be +deemed that one has approached too near the inner margin of the white +line, more especially if tenderness exists around it, that hole should be +followed up with a 'searcher' or small drawing-knife until diagnosis is +certain. + +_Complications_.--Before proceeding to discuss the complications that may +arise in the case of pricked foot, we may call to mind that the anatomy of +the parts teaches us that the most serious position in which a punctured +wound can occur is at the centre of the foot. Here the plantar aponeurosis, +the navicular bursa, the navicular bone itself, or the pedal articulation +may be injured. + +Anterior to this position the most serious mischief that can ordinarily +result is stabbing of the os pedis. + +Posterior to the position we have named, the only structure to be injured +is the plantar cushion. + +Anatomically, then, the inferior surface of the foot may be divided into +three zones, as follows: + +_A. Anterior_, extending from the toe to the point of the frog. + +_B. Middle_, extending from the point of the frog to the commencement of +its median lacuna. + +_C. Posterior_, including everything posterior to the middle zone. + +This division of the inferior surface of the foot into zones will be +somewhat of a guide also when describing the complications next to follow: + +_(a) Suppuration_.--This is the common complication of most wounds of the +foot. When detected, it calls for immediate surgical interference in the +shape of removal of the horn of the sole or the frog, as the case may be. +This we shall consider further under the treatment. + +_(b) Separation of the Horny Frog_.--This is a sequel to pus formation in +the sensitive structures immediately beneath it, and the condition makes +itself apparent by a line of separation between the horn and the skin of +the heel of the injured side. + +_(c) Wounding of the Plantar Aponeurosis_.--This occurs when a +moderately-deep penetration of the horn of the middle zone has taken place. +It is always most painful, especially when complicated by necrosis. The +heel is then persistently elevated, and lameness is extreme, in some cases +so severe as to cause the leg to be carried altogether. + +In favourable cases the necrosed piece of tendon is sloughed off by the +process of suppuration, and escapes with the discharges from the wound. +There is then an abatement in the symptoms, and recovery is rapid. + +Commonly, however, on account of the non-vascularity of the structure of +the tendon, the necrotic spot in it tends to spread. The wound is thus led +to become fistulous in character, and the pus forming within it prevented +from escaping from the original opening. As a result, lameness and fever +persist. There is a gradual increase in the severity of the symptoms, and +later fistulous openings appear in the hollow of the heel. + +_(d) Puncture of the Navicular Bursa_.--This results from a prick in +exactly the same position as that last described, and means that the +penetrating object has gone deeper, It may be distinguished from puncture +of the plantar aponeurosis alone by the fact that there is an excessive +discharge of synovia from the wound. This, as it escapes, is at first clear +and straw-coloured. Later it becomes cloudy and flaked with pus, and shows +a tendency to coagulate in yellowish clots. + +Pain and accompanying fever is most marked, much more so than when the +plantar aponeurosis alone is injured. + +Should the original wound be insufficiently enlarged, or should its opening +become occluded by the solid matters of the discharge, then this condition, +like the last, ends in the formation of fistulous openings in the heel. +These make their appearance as hot, painful, and fluctuating swellings in +that position. Later they break, discharge their contents, and leave a +fistulous track behind. + +_(e) Fracture of the Navicular Bone_.--Penetration of the substance of +the navicular bone, _without_ its fracture, adds nothing to the symptoms we +have described under puncture of the bursa. That the bone has been reached +by the penetrating object may be detected by probing. This, however, +must be performed with care, especially if a flow of synovia is absent. +Otherwise, the wound, as yet, perhaps, superficial enough to avoid +penetrating even the bursa, is made a penetrating one by the probe itself. + +Fracture of the navicular bone is fortunately rare. + +_(f) Penetration of the Pedal Articulation and Arthritis_.--This we shall +consider in greater detail in Chapter XII. It is sufficient here to state +that the condition may be suspected when a hot and painful swelling of the +whole coronet makes its appearance. There is at the same time a diffused +oedema of the fetlock and the region of the cannon, sometimes extending +upwards to the whole of the limb. + +Of all the complications to be met with in punctured foot this is the one +most to be dreaded. The intense pain and the high fever render the animal +weak and thin in the extreme. The appetite becomes impaired, sometimes +altogether lost, and the patient in many cases appears to die from sheer +exhaustion. Added to this is always the extreme probability of the wound +becoming purulent, and later the dread of general septic infection of the +blood-stream ensuing, and death resulting from that. Even with the happier +ending of resolution, anchylosis of the joint and incurable lameness is +more often than not left behind. (See Suppurative or Purulent Arthritis, +Chapter XII.) + +_(g) Ostitis and Caries of the Os Pedis_.--Injuries to the os pedis are +met with in the anterior zone of the foot. Evidence that the bone has been +injured is not usually forthcoming until after the lapse of some days. +One is led to suspect it by the fact that there is no indication of the +suppurative process extending further upwards, coupled with the facts that +great pain, high fever, and extreme lameness persist, and that there is a +continuous discharge from the wound of a copious blood-stained and foetid +pus. Used now, the probe reveals the fact that the bone is bared, and +conveys to the hand that is holding it a sensation of crumbling fragility. + +_(h) Wounding of the Lateral Cartilage and Quittor_.--This occurs as the +result of a deep stab in the posterior zone. Ordinarily, wounds in this +position are unattended with serious consequences, and the prick has to be +a deep and a severe one before the cartilage is reached. What then happens +is that a spot of necrosis is formed round the seat of puncture in the +cartilage. This, unless met with surgical interference, is sufficient +to maintain the wound in a septic condition; it takes on a fistulous +character, and a quittor is formed. (See Chapter X.) + +_(i) Septic Infection of the Limb_.--This we have already once or twice +referred to. It simply means that the septic matters from the wound have +gained the lymphatics, and finally the blood-vessels of the limb, and set +up local lesions elsewhere than in the foot. Although dismissed here with +these few words, the condition is a most serious one. Usually, it has +resulted from penetration of the pedal articulation and septic infection of +the joint. In the vast majority of these cases slaughter is both humane and +economical. + +_Prognosis_.--The first consideration in giving a prognosis in punctured +foot should be the position of the wound. When occurring in the middle +zone, the surgeon's statements should be most guarded, and the dangers +attending a wound in that particular position fully explained to the owner. +A wound in the anterior position is, as we have said, far less serious, and +one in the posterior region of the foot even less serious still. + +Whenever possible, the nail or other object causing the prick should be +examined. Much of the prognosis may be based upon the estimated depth of +the wound, and this, in many cases, it is far safer to calculate from the +length of the offending body than from the use of the probe. We need hardly +say that in the middle zone the deeper the prick, the more serious the +case, and the less favourable the prognosis. As in succession the sensitive +sole, the plantar aponeurosis, the navicular bursa, the navicular bone, or +the pedal articulation is injured, so with each step deeper of the prick is +the severity of the case increased. + +The shape of the penetrating object may also be considered. One excessively +blunt, and calculated to bruise and crush the tissues, will inflict a more +serious wound than one of equal length that is pointed and sharp. + +The conformation of the foot should also be regarded. Wounds in well-shaped +feet are less serious than in feet with soles that are flat or convex, or +in which the horn is pumiced or otherwise deteriorated in quality. + +Although unaffecting the prognosis so far as the actual termination of the +case is concerned, it may be mentioned that punctured foot is far more +serious in a nag than in a heavy draught animal. With an equal degree of +lameness resulting in each case, the former will be well-nigh useless, but +the latter still capable of performing much of his usual labour. + +The temperament and condition of the patient will also in many cases +largely influence the prognosis. An animal of excitable and nervous +disposition is far more likely to succumb to the effects of pain and +exhaustion than the horse of a more lymphatic type. In the case of a +patient suffering from a prick to a hind-foot while heavily pregnant, the +attempted forecast of the termination should be cautious. More especially +does this apply to the case of a heavy cart-mare. Ordinarily, the +heavier the breed, the greater the tendency to lymphatic swelling of the +hind-limbs. With pregnancy this tendency is enormously increased, and it is +no uncommon thing to find a cart-mare in this condition, with legs, as the +owner terms it, 'as thick as gate-posts.' A prick to the foot, with the +lymphatics of the limb in this state, is extremely likely to end in septic +infection of the leg, for there appears to be no doubt but that invasion of +the lymphatics with septic matter is favoured by a sluggish stream. Also, +in the case of a patient in the advanced stages of pregnancy, it must be +remembered that, no matter how great may be the need, one is debarred, for +obvious reasons, from using the slings. + +_Treatment_.--_In a simple_ case--and by 'simple' here we mean the case +in which the injury is discovered early, and pus has not yet commenced to +form--our first duties are to give the wound free drainage, and to maintain +it in an aseptic condition. The first of these objects is to be arrived at +by paring down the horn in a funnel-shaped fashion over the seat of the +prick. It is, perhaps, even better to thin the horn down to the sensitive +structures for some little distance round the injury. By this latter method +pressure from inflammatory exudate is lessened, and the after-formation of +pus, if unfortunate enough to occur, the more readily detected, and the +less likely to spread upwards. The matter of asepsis may then be attended +to. + +When the puncture is sufficiently large to admit of it, the antiseptic +dressing is best applied by means of the probe. This instrument is thinly +wrapped with tow, or other absorbent material, so as to form a small swab. +Dipped in a suitable solution (as, for example, Zinc Chloride, Spts. +Hydrarg. Perchlor., Carbolic Acid, or any other that suggests itself), the +swab is inserted into the prick, and the wound conveniently mopped clean. +A further portion of the medicated tow is then pushed partially into the +wound, and allowed to remain in position. The foot is subsequently wrapped +in a clean bag, and kept free from dirt. This dressing should be repeated +twice daily. + +If the prick is in a dangerous position, and deep enough to occasion alarm, +our precautions to prevent the formation of septic matters within it may be +more elaborate. The thinning of the horn and the swabbing of the wound +may, as before, be proceeded with. In addition, the whole foot may then be +immersed for some hours daily in a cold bath, which bath should be strongly +impregnated with one or other of the following salts: Iron Sulphate, Zinc +Sulphate, Copper Sulphate, Aluminium Sulphate, Lead Acetate, or Sodium +Chloride--better still, a mixture of the various sulphates here mentioned. +If preferred, one of the more commonly accepted antiseptics--such as +Carbolic Acid, Lysol, Boracic Acid, or Perchloride of Mercury--may be +substituted. + +By the cold of the bath inflammatory phenomena are held in check, while its +added antiseptic prevents the formation of septic discharges. The lameness +gradually diminishes, and resolution is rapid. In this way deep and +serious, wounds are sometimes easily and successfully treated. + +_When suppuration has occurred_--and this, by-the-by, is by far the most +frequent condition in which we find punctured foot--treatment must be +prompt and decided. Careful search must at once be made by thinning down +the sole, and carefully trimming the frog. On no account should the +veterinary attendant rest content with 'digging' in one place, and upon +that basing a negative opinion as to the existence of pus. The paring +should be carried on, until either pus or hæmorrhage shows itself, in at +least three positions--namely, at the most anterior portion of the sole, +and in the sole at each side of the frog. In addition to this, the frog +itself should be minutely examined for evidence of puncture, or for leaking +of pus at the spot where the horn of the heels joins the skin. + +In many of our cases, however, this careful search is not so necessary. +The accompanying symptoms are so decided as to leave no doubt as to the +condition of the case. In such instances paring may often be commenced over +the exact position of suppuration as previously ascertained by percussion. + +When met with, the track formed by the suppurative process should be +followed up in whichever direction it has spread. This will often +necessitate the removal of the greater part, if not the whole, of the horny +sole. + +Having given vent to the pus, and opened up the cavity made by its +formation, the foot should be placed in a hot poultice or, preferably, in a +hot antiseptic bath.[A] + +[Footnote A: At the time of writing this, a certain amount of discussion is +going on in our veterinary journals as to whether a hot or a cold bath is +the one indicated. It is urged against the application of heat that it +favours organismal growth and reproduction, and tends rather to induce the +spread of the suppurative process than to overcome it. Those who hold this +opinion urge in support of it that cold applications are inimical to the +life of the pus organism. At the same time, it must be remembered that in +just so far as cold inhibits the growth of the invading germ, so in just +the same degree does it adversely influence the functions of the tissues +that are to fight against it. To our minds the question thus set up must +always remain more or less a moot-point, and while we fully agree that cold +undoubtedly checks the growth of septic material, we just as fully believe +that warmth serves to place the healthy surrounding structures in a far +better condition to maintain a vigorous phagocytosis against it. We +thus continue to advise a hot antiseptic poultice, or, better still, a +bath.--THE AUTHOR.] + +At the end of the third or fourth day the poultice or the bath may be +discontinued, and the opening in the sole dressed with any suitable +astringent and antiseptic. + +The most serious complication arising from this method of treatment is +one of excessive granulation of the sensitive sole. This we find to be +successfully held in check by a daily application of undiluted Spts. +Hydrarg. Perchlor. (Tuson). Should the granulations become very exuberant, +then the knife must be called to our aid, and the wound so made afterwards +dressed with an astringent. + +When the suppuration has under-run the horny frog there should be no +hesitation in at once removing all the horn that is visibly separated from +the sensitive structures beneath. + +_When the os pedis is splintered and carious_, a portion of the sole round +the wound is removed, and the bone exposed. The diseased portion is scraped +away either with a curette or with the point of the drawing-knife. In this +case the only after-treatment called for is the application of suitable +antiseptic dressings. + +_When necrosis of the plantar aponeurosis has occurred_. We have already +pointed out the tendency there is in this case for the wound to maintain a +fistulous character, and lead to the formation of abscesses in the hollow +of the heel. With a wound in this position, as with a wound in any other, +the only method of avoiding this termination consists in removing all that +is visibly diseased, whether it be soft structures, bone, ligament, or +tendon, and giving the wound free drainage. + +This can only be done by removing the horny sole and frog, and cutting +boldly down upon the structures beneath. The operation is known as +resection of the plantar aponeurosis, or the complete operation for +gathered nail. + +Practised for some years on the Continent, this operation, on account of +its gravity, has been avoided by English veterinarians. From reported +cases, however, it appears often to be followed by success. + +That there is a large element of risk in the operation is quite evident, if +only from the two facts mentioned beneath: + +1. That the close attachment of the plantar aponeurosis to the navicular +bursa, and the nearness of both to the pedal articulation, render +penetration of a synovial sac or a joint cavity extremely likely. + +2. That there is always great difficulty in maintaining strict asepsis of +the foot, more especially if it is a hind one. + +On the other hand, it may be argued that equal risk to the patient is run +in allowing him to remain with a disease (and that disease a progressive +one) of the structures so closely antiguous to the navicular bursa and the +pedal articulation. + +If only for that reason we give the operation brief mention here. + +The animal is prepared in the usual way for the operating bed; the foot +soaked for a day or two previously in a strong antiseptic solution, the +patient cast and chloroformed, and the operation proceeded with. + +[Illustration: FIG. 106.--'CURETTE,' OR VOLKMANN'S SPOON.] + +An Esmarch's bandage should be first applied, and a tourniquet afterwards +placed higher up on the limb. The foot is then secured as described in an +earlier chapter, and the whole of the horny structures of the lower surface +of the foot (the sole, the frog, and the bars) pared until quite near the +sensitive structures, or, if under-run with pus, stripped off entirely. An +incision is then made in each lateral lacuna of the frog, the two meeting +at the frog's point. Each incision thus made should be carried deep enough +to cut through the substance of the plantar cushion. A tape is then passed +through the point of the frog, tied in a loop, and given to an assistant to +draw backwards. The plantar cushion itself is then incised in a direction +from before backwards, and pulled on by the assistant, so as to expose the +plantar aponeurosis. + +Should this be found at all necrotic, it may be taken that purulent +inflammation of the navicular bursa and of the navicular bone itself +exists. The operator must then proceed to resection of the tendon in order +to treat the deeper structures thus affected. At its point of insertion +into the semilunar crest the tendon is severed and afterwards reflected. +This exposes the inferior face of the navicular bone. Instead of the +glistening and clear appearance it ordinarily presents, its glenoid +cartilage is found to be showing hæmorrhagic or even purulent spots of +necrosis. The terminal portion of the tendon must then be excised. + +To effect this a clean transverse incision is made at the extreme upper +border of the navicular bone. Here we are in close contact with the pedal +articulation, and great care is necessary in making this last incision, in +order that the synovial sac may not be penetrated. + +All structures showing spots of necrosis should now be carefully removed, +either with the knife or with the curette. The knives most suitable for the +last stages of this operation are those depicted in Fig. 45 (_c_, _d_, and +_e_). The curette, or Volkmann's spoon, we show in Fig. 106. + +[Illustration: FIG. 107.--RESECTION OF TERMINAL PORTION OF THE PERFORANS. +The horny sole and the horny frog stripped from off the sensitive +structures. _a_, The plantar cushion; _b, b_, the plantar aponeurosis, or +terminal portion of perforans; _c_, the navicular bone; _d_, interosseous +ligaments of the pedal articulation; _e, e_, semilunar crest of the os +pedis; _f_, inferior surface of os pedis; _g, g_, the sensitive laminæ of +the bars; _h, h_, bearing surface of the wall; _i, i_, the sensitive sole; +_k_, the sensitive frog.] + +When at all diseased the glenoidal surface of the navicular bone should be +curetted, even to the extent of the removal of the whole of the cartilage. +A healthy, granulating surface is thus insured. + +The above figure from Gutenacker's 'Hufkrankheiten' explains shortly the +position of the operation wound and the structures involved, rendering +further description unnecessary here. + +The operation ended, the dressing follows. Upon this depends very largely +the ultimate recovery of the patient, for it is only by careful attention +and suitable dressings that effectual repair of the injured structures may +be brought about. + +A light shoe is first tacked on to the foot, and those portions of the +horny sole that have been allowed to remain dressed with Venice turpentine, +tar, or other thickly-adherent antiseptic. + +The exposed soft tissues are then dressed with pledgets of tow[A] soaked +in alcohol and carbolic acid. This dressing must be allowed to remain in +position, and is kept there by means of a bandage, or the shoe with plates +(Fig. 55) and a bandage over it. No pressure is needed; consequently, the +pledgets of tow must not be too thick. + +[Footnote A: When using tow in the form of a pad, it is well to remember +that many small balls of the material rolled lightly in the palm of the +hand and afterwards massed together are far better than one large pad of +the tow taken without this preparation. The irregularities of the wound are +better fitted, and the whole dressing easier remains _in situ_ (H.C.R.).] + +In the after-dressing of the wound careful attention must be paid to the +granulating surface. Where tending to become too vigorous in growth it +should be held in check by suitable caustic dressings. At the same time it +must be remembered that the granulating process of repair is always more +rapid upon the plantar cushion and fleshy sole than upon the bone, or upon +tendinous or cartilaginous structures. As a result of this we have a wound +showing various aspects of cicatrization. Healthy granulation may be +profuse in one spot, while in another it may be checked either by a flow +of synovia from the still open bursa, or by fragments of bone or of tendon +still acting as foreign bodies in the wound. These latter may be readily +detected by their standing out as dark and uncovered spots in the healthy +granulation around, and should be at once removed. + +The time that an operation wound of this description takes to heal--and +that without complication--is from one to two or three months. Continuation +of pain and intensity of lameness are not to be taken as indications of +failure. The reparative inflammation in the synovial membrane is quite +sufficient to induce pain severe enough to prevent the animal from placing +his foot to the ground for some weeks, even though the progress of the +case, all unknown, may be all that is desired. So long as a great amount of +pain is absent, and so long as appetite remains and swellings in the hollow +of the heel fail to make their appearance, so long may the progress of the +case be deemed satisfactory. + +_Recorded Case of the Treatment_.--A cart-horse, aged six years, was sent +to the Alfort School by a veterinary surgeon for having picked up a nail +in the hind-foot. Professor Cadiot, judging the necessity for the complete +operation, performed it on January 14, and spared the plantar cushion +as much as possible. In consequence of the plantar aponeurosis being +extensively necrosed, it was advisable to scrape the navicular bone and +a part of the semilunar crest. The wound having been washed with a 1 per +cent. solution of perchloride of mercury, it was dusted with iodoform +and packed with gauze, and covered with a cotton-wool dressing, kept in +position by means of a suitable shoe. + +On January 16 there was no snatching up of the limb when the horse was made +to put weight upon it; he ate his food well, and his condition improved +every day. On January 21 the dressing was removed; the wound appeared pinky +and granular, and there was no suppuration. The clot remaining from the +hæmorrhage after the operation was removed, the wound was irrigated with a +hot solution of sublimate, and then dusted with iodoform and covered with a +dressing of iodoform gauze and absorbent wool. At this date the horse could +stand on the injured limb. On January 31 a second dressing was made, and +the animal almost walked sound. On February 7 the wound had almost closed +up, save in its central part, where there was a small cavity, and the +lameness had disappeared. On February 15 the wound had completely healed, +and its borders were covered by a layer of thin horn. As the animal was +sound it was sent to work. + +The author directs attention to the rapidity with which a large and +complete wound cicatrizes after the operation for gathered nail.[A] + +[Footnote A: _Veterinary Record_, vol. XV., p. 226 (Jourdan).] + +_In the case of Penetrated Navicular Bursa_, unaccompanied by the formation +of any large quantity of pus, and uncomplicated by necrosis of the +aponeurosis, our aim must be to maintain the wound in that happy condition. +This is doubtless best done by keeping the foot continually in a cold bath, +rendered strongly antiseptic by the addition of sulphate of copper and +perchloride of mercury. Should there be intervals when the bath must be +neglected, the foot in the meantime must be kept clean by antiseptic +packing and bandaging, and a clean bag over all. This treatment should be +continued so long as the character of the discharge denotes that synovia is +running. If, in spite of our precautions, the discharge becomes purulent, +then the track made by the penetrating object should be syringed twice +daily with a 1 in 1,000 solution of perchloride of mercury. + +During the treatment it will be wise to shoe the animal with a high-heeled +shoe. We do not know as yet the full extent of the injury. The navicular +bone may be tending to caries; or necrosis of the plantar aponeurosis, all +unknown, gradually becoming pronounced. This calls for a relief of tension +on the perforans, and is only to be brought about by the high-heeled shoe. + +The result of the inflammatory changes in the tendon, aided possibly by +the use of the high-heeled shoe, is to afterwards bring about contraction. +Where this has occurred, and the animal walks continuously on his toe, the +shoe with the projecting toe-piece (Fig. 84) must be applied. When the +continual use of the toe-piece appears inadvisable, the shoe devised by +Colonel Nunn may be used in its stead (see Fig. 108). + +The toe-piece is screwed into the toe of the shoe when the horse is about +to be exercised, and forms a powerful point of leverage with which to +stretch the contracted tendon, and the shoe, being thin at the heels, +admits of this. The advantage of this form of toe-piece over the ordinary +form of fixed toe-lever is that it can be removed when the horse is in the +stable; while the curved point diminishes the danger of the horse hurting +itself--a danger always present if it is on a hind-foot. (See also +Treatment of Purulent Arthritis in Chapter XII.) + +[Illustration: FIG. 108.--COLONEL NUNN'S SHOE WITH DETACHABLE TOE +EXTENSION.] + +_Should a Sinuous Wound remain in the region of the Lateral Cartilage_, +it should be explored, and its depth and likely number of branches +ascertained. Should this exploration denote that the cartilage itself is +diseased, or that the wound is not able to be sufficiently drained from +the sole, then we know that we have on our hands a case of quittor. The +treatment necessary in such a case will be found described in Chapter X. + +_When the Complication of Purulent Arthritis has arisen_, the surgeon has +to admit to himself, reluctantly no doubt, that the case is often beyond +hope of aid from him. Nothing can be done save to order continuous +antiseptic baths and antiseptic irrigation of the wounds with a quittor +syringe, and to attend to the general health and condition of the patient. +At the best it is but a sorry look-out both for the veterinary attendant +and the owner of the animal. Even with resolution incurable lameness +results, and the animal is afterwards more or less a walking exhibition of +the limitations of surgery, while the owner, unless the animal is valuable +for the purpose of breeding, finds himself encumbered with a life that is +practically useless. (See Treatment of Purulent Arthritis, Chapter XII.) + +_In the case of Lameness Persisting after the healing of all appreciable +lesions_, then neurectomy is followed by good results. The animal, +apparently recovered, is for a long time useless. Lameness persists for +several months, as if the nail had at the moment of its penetration caused +lesions, which doubtless it sometimes does, similar to those of navicular +disease. Examination of the foot in this case reveals no lesion, and the +pain has evidently a deep origin. The lameness caused by it is subject to +variation. Frequently it becomes lessened during rest, and increased by +hard work, while sometimes it is very much more pronounced at starting than +after exercise. + +It is here that neurectomy is called for. The operation does nothing to +impede the work of healing going on, and allows free movement of the foot +and pastern to take place. At the same time suffering and emaciation cease, +and the animal is rendered workable.[A] + +[Footnote A: _Veterinary Record_, vol. ii., p. 371.] + + +C. CORONITIS (SIMPLE). + +TREAD, OVERREACH, ETC. + +1. _Acute_. + +_Definition_.--Under the heading of simple coronitis in its acute form we +intend to describe those inflammatory conditions of the skin and underlying +structures of the coronet occurring without specific cause. Specific +coronitis will be found described in Chapter IX. + +_Causes_.--This condition is almost invariably set up by an injury--either +a bruise or an actual wound--to the coronet. By far the most common among +such injuries are those inflicted by the animal himself by means of the +shoes. + +That known as 'tread' is caused by the shoe on the opposite foot, and may +happen in a variety of ways. More often than not it is met with in the feet +of heavy draught animals, and is there caused by the calkin, either when +being violently backed or suddenly turned round. It may also occur in +horses with itchy legs, as a result of the animal rubbing the leg with the +shoe of the opposite limb. The irritation in this case is nearly always +due to parasitic infection (_Symbiotes equi_), and becomes sometimes so +unbearable as to render the animal unmindful of the injury he may be +inflicting so long as he experiences the relief obtained by the rubbing. + +Self-inflicted tread is also sometimes met with when horses are worked +abreast at plough. The animal in the furrow, with one foot sometimes in and +sometimes out of the hollow, is caused to make a false step, and so brings +the injury about. + +Animals worked in pairs are further liable to receive a tread from the foot +of their companion. This is commonly seen in heavy animals at agricultural +labour in fields, where the walking is uneven, and abrupt turning constant. +It is not uncommon either in animals at work in vans in town, and is +occasionally met with in the feet of carriage-horses. + +'Overreach' is the term used to indicate the injury inflicted on the +coronary portion of the heel of the fore-foot by the shoe of the hind. +Ordinarily, overreach occurs when the animal is at a gallop, and is thus +met with in its severest form in hunters and steeplechasers. It can only +occur when the fore-foot is raised from the ground and the hind-foot of the +same side reached right forward. When the feet separate the injury takes +place. In its movement backwards the inner border of the shoe of the +hind-foot catches the coronet of the fore, and tears it backwards with it. +Quite frequently a portion of the skin is removed entirely, but often it +hangs as a triangular flap. The flap in such a case is always attached by +its hindermost edge, and indicates plainly enough that the direction of the +blow that cut it must have been from before backwards. + +Although ordinarily inflicted at the gallop, the same injury may, +nevertheless, be caused by allowing a fast trotter, and one with extreme +freedom of action behind, to push forward at the utmost limit of his pace. +The outside heel is the one most subject to the injury. + +While the common form of injury to the coronet is, as we have described, +that occasioned by the animal's own shoe, or that of a companion, it is +evident that the foot is also open to similar injuries from quite outside +sources. Falls of the shafts when unyoking animals from a heavy cart, blows +or wounds from the stable fork, wounds resulting from the foot becoming +fixed in a gate or a fence, either may equally well set up the mischief. + +Apart from severe injury, a particularly troublesome form of coronitis may +arise from the condition of the roads. We refer to the conditions attendant +on a thaw after snow. The animal is called upon to labour in, or perhaps +stand for long periods in, a mixture of snow and water, or snow and mud. +That this must have a prejudicial effect upon the structure of the coronet +is plain. The circulation of the part, already predisposed to sluggishness +by reason of its distance from the heart, is farther impeded by the +action of the cold. Small abrasions of the skin, so small as to scarce +be noticeable, are in this case freely open to infection with the septic +matter the mud contains. Necrosis and consequent sloughing of the skin +is bound to follow, and an extensive ulcerous wound, or a spreading +suppuration of the coronary cushion is the result. + +_Symptoms_.--We will take first the case in which no actual wound is +observable. Here the first indication of the trouble is the appearance +of an inflammatory swelling, confined usually to one side, but extending +sometimes to the whole of the coronet. Always the part is hot and tender, +and with it the patient is lame--so much so, in many cases, as to be unable +to put the foot to the ground, the toe alone being used. + +In a mild case, uncomplicated by septic infection, these symptoms rapidly +subside, and resolution occurs. + +Always, however, the presence of septic infection must be suspected and +looked for. When this has occurred, the inflammatory swelling becomes +larger and more diffuse, and the animal fevered. This is then followed by +a slough of the injured part. A portion of the skin first becomes gray, or +even black, in appearance, and around it oozes an inflammatory exudate, or +even pus. The skin immediately adjoining the spot of necrosis is swollen +and hyperaæmic, and extremely painful and sensitive. Later, the necrosed +portion becomes cast off, and an open wound remains. This as a rule marks +the turning-point in the case. The pain and other symptoms rapidly abate, +and the wound, with proper attention, is not more than ordinarily difficult +to treat. + +In the case of an actual wound the symptoms are probably less severe. The +injury is, in this instance, the sooner detected, and remedial measures put +into operation. In this manner the formation of septic material is often +checked, and nothing but the treatment of a simple wound demands attention. + +There are, however, complications. + +_Complications--(a) Diffuse Purulent Inflammation of the Sub-coronary +Tissue_.--This condition is brought about by the spread into the loose +tissue of the coronary cushion of the septic material introduced by the +tread. The whole coronet in this instance becomes excessively swollen, hot, +and painful, and the dangerous nature of the complication is evident enough +when the structure and situation of the parts involved is considered. The +amount of tendinous and ligamentous material in the neighbourhood offers +a strong predisposition to necrosis, and the necrosis, with its attendant +formation of pus, offers a further danger when the close proximity of +the pedal articulation and the unyielding character of the horny box is +considered with it. + +The pus formed in this condition may remain confined to the coronet and +break through the skin as an ordinary abscess, or it may, before so doing, +burrow beneath the wall, and invade the sensitive laminæ. In this case, +whenever portions of the secreting layer of the keratogenous membrane are +destroyed, or perhaps only temporarily prevented from fulfilling their +horn-producing functions, then corresponding cavities in the horn are the +result (see Fig. 109). + +_(b) Purulent Arthritis_.--Only too readily the pus so formed tends to +penetration of the articulation and the causation of an incurable arthritis +(see Chapter XII.). + +[Illustration: FIG. 109.--MESIAL SECTION OF A HOOF ILLUSTRATING THE +CONDITIONS FOLLOWING UPON CORONITIS. _a_, Cavity in the horn of the +wall; _b_, enlargement of the coronet and the horn of the wall following +subcoronary suppuration; _c_, cavity in the wall following purulent +inflammation of the sensitive laminæ; _d_, hollow in the horn of the sole +consequent upon suppuration of the sensitive sole.] + +_(c) Necrosis of the Extensor Pedis_.--This may arise either as a result +of spreading purulent infection of the coronary cushion, or as a result +of direct injury immediately over it. The close relation of the terminal +portion of this tendon with the pedal articulation, and the incomplete +protection from outside injuries here afforded to the joint by the horny +box, sufficiently points out the gravity of the condition. + +_(d) Penetration of the Articulation_.--This also may be a result either +of the inroads made by pus, or of an actual wound. When occurring from the +latter, it is seen more often than not in the hind-foot, being there caused +by the calkin of the opposite foot. Where a wound in this position is +characterized by an excessive flow of synovia, the condition should be +suspected, and, if the wound be large enough, the little finger should be +introduced in order to ascertain. Needless to say, the injury is a grave +one. + +_(e) Sand-crack_.--Sand-crack is likely to result from tread when an injury +is inflicted in the region of the quarter by a severe overreach. Treads, +too, especially with the calkin of the hind-shoe, are especially apt to end +in this way. In this latter instance the sand-crack usually has its origin +in a nasty jagged tear at the top of the wall of the toe. + +_(f) Quittor_.--In one respect any suppurating wound at the coronet may be +deemed a quittor. By indicating quittor as a complication of coronitis, +however, we denote the more serious form of this disease, in which the +wound has taken on a sinuous character, and conducted pus to invasion of +the lateral cartilage. It is one of the worst complications we are likely +to meet with in this condition, and will be found fully described in +Chapter X. + +_(g) False Quarter_.--This complication of coronitis occurs when the injury +or after-effect of the formation of pus has been severe enough to destroy +outright a comparatively large portion of the papillary layer of the +coronary cushion. To this condition we devote Section D of this chapter. + +_Prognosis_.--In giving a prognosis in a case of coronitis, attention +should be paid to the manner in which the condition originated, and the +extent, when present, of the wound. + +When the inflammatory swelling has arisen from bruising alone, without +actual division of the skin, when the weather is that of winter, and the +swelling showing a marked tendency to spread, then the prognosis must be +guarded. As we have seen, this state of affairs is probably ushering in +a condition of spreading suppuration of the coronary cushion, and +considerable gangrene and sloughing of the skin. We have here no intimation +as yet of how far the suppurative process may run, nor what important +structures it may involve. Consequently, the guarded prognosis we have +mentioned is imperative. + +Where an actual wound is to be seen, and where advice is sought early, +then a more favourable opinion may be advanced. In this case antiseptic +measures, commenced early and persisted in, may prevent the rise of further +mischief. + +It goes without saying that, should there arise any other of the +complications we have mentioned (viz., Arthritis, Necrosis of the Extensor +Pedis, Sand-crack, Quittor, and False Quarter), the fact should be pointed +out to the owner, and the prognosis regulated thereby. + +_Treatment--Preventive_.--Seeing that at any rate the majority of cases of +coronitis result from injuries inflicted by the shoes, we may look at once +to that particular for a means of prevention. + +Take first the case of 'treads'. There is no doubt that they are most +common in animals shod with heavy shoes and with high and sharp calkins. +This suggests at once that a preventive is to be found in substituting a +calkin that is low and square. + +Where the injury is an overreach, and where, on account of the animal's +pace and manner of gait it is in risk of being constantly inflicted, the +shoeing should be seen to at once. + +We have already pointed out that it is the inner border of the lower +surface of the toe of the hind-shoe which, in the act of being drawn +backwards, inflicts the injury. (See Fig. 110). + +In this case prevention may be brought about either by shoeing with a shoe +whose ground surface is wholly concave, or by bevelling off the sharp +border (see Fig. 110, _a_, p. 236). When the tendency to overreach is not +excessive, prevention may in many cases be effected by simply placing the +shoe of the hind-foot a trifle further backwards than would ordinarily be +correct, thus allowing the horn of the toe to project beyond the shoe. This +at the same time does away with the annoyance of 'forging' or 'clacking,' +which, as a rule, accompanies this condition. + +While recognising the value of shoeing in these cases, we must not forget +that a great deal may be brought about by careful horsemanship. The animal +should be held together and kept well up to the bit, but should _not_ be +allowed to push forward at the top of his pace. With many animals of fast +pace and free action overreach is more an indiscretion of youth than any +defect in action or conformation, and his powers should therefore be +husbanded by the driver until the animal has settled down into a convenient +and steady manner of going. + +[Illustration: FIG. 110.--UNDER SURFACE OF THE TOE OF A HIND-SHOE. _a_, +Marks the portion of the inner margin that inflicts overreach.] + +[Illustration: FIG. 111.--THE INNER MARGIN OF THE INFERIOR SURFACE OF THE +HIND-SHOE BEVELLED TO PREVENT OVERREACH.] + +_Curative_.--Although in some cases it is so small as to go undetected, +we may take it that in all cases of coronitis there is a wound, with +consequent danger of septic infection of the surrounding parts. Therefore, +after attention to the shoeing and removal of the cause, the first +indication in the treatment will be to render the parts aseptic. This is +best done by removing the hair from the coronet and soaking the whole foot +in a cold antiseptic solution. After removal from the bath, the coronet +may be dressed with a moderately strong solution of carbolic acid or +perchloride of mercury. When the injury is slight and recent, such is +sufficient to effect resolution. + +When marked swelling persists, however, and the increase in heat and +tenderness denotes the formation of pus, recovery is not so easily +obtained. In this case the application of hot poultices or hot baths is +called for. By these means suppuration is promoted and induced to early +break through in the most favourable position--namely, the softened skin of +the coronet. The pus so escaping is always more or less blood-stained, and +contains both large and small pieces of broken down and decomposed tissue. +After discharge of the pus, the cavity remaining should be mopped out with +an antiseptic solution, and a pledget of antiseptic tow or other material +left in position. All that is then needed is constant dressing in a +suitable manner. We prefer in this instance washing some three or four +times a day with hot water until a perfectly clean wound is obtained, and, +after the washing, painting the raw surface with a strong solution (1 in +200, or 1 in 100) of perchloride of mercury. + +When the abscess we have described as forming is extremely large, or where +it is more than ordinarily slow in 'pointing,' the likelihood of its having +burrowed for some distance below the upper margin of the wall must be +suspected. Here it is sometimes wise to thin the wall with the rasp +immediately below the point of greatest swelling of the coronet. This will +serve to lessen pressure on the sensitive structures beneath. + +Immediately the abscess contents have found exit at the coronet, the cavity +formerly occupied by the pus should be explored. If to any extent it is +found then to have 'pocketed' beneath the upper border of the wall, a +counter-opening should be made where the horn of the wall has been thinned +with the rasp. + +When it so happens, either from extensive bruising or from the action of +excessive cold, that we have or suspect the condition of sloughing, then +the first indication is to aid the live tissues to throw off the necrosed +portion. In spite of what is sometimes urged to the contrary, a hot +poultice is, perhaps, the best means of bringing this about. Directly the +necrosed piece is shed, a wound remains which, so far as treatment is +concerned, may be regarded exactly as that left by the formation of pus. +Hot water applications, some three or four times daily, will serve both to +cleanse the wound and also to maintain vitality in the tissues immediately +surrounding it. After each washing, the use of a strong antiseptic solution +to the wound is again beneficial. + +In the case of an actual wound, whether, as in overreach, affecting the +coronet alone or involving destruction of part of the wall, or, as in the +case of toe-tread, penetrating the pedal articulation, the treatment to be +followed is simple enough, in theory, if not always easy to carry out. It +consists solely in maintaining a rigid asepsis of the parts until healing +is well advanced or complete. The whole foot, including the coronet, should +first be thoroughly washed in warm water. At the same time there should be +used some agent that will tend to remove the natural grease of the parts. +In this manner cleansing will be rendered more thorough, and penetration of +the antiseptic solution to be afterwards applied made the more certain. +The most ready way of effecting this is to use the ordinary stable +'water'-brush, and plenty of a freely-lathering soap. + +This done, the foot should be rinsed in cold water, and afterwards +constantly soaked in a cold antiseptic bath. Where it is inconvenient or +impossible to have the constant bathing carried out, a dry antiseptic +dressing may be tried in its stead. In this case the foot should first be +thoroughly washed and dressed as before. Afterwards an antiseptic powder in +the shape of a mixture of iodoform 1 part, boracic acid 10 parts, should +be freely dusted on the wound, a pledget of carbolized tow or cotton-wool +placed over it, and the whole maintained in position with a bandage +previously soaked in a 1 in 500 solution of perchloride of mercury. Once +on, this dressing should be allowed to remain until healing is complete. +Should the animal manifest pain, however, by constantly pawing, or should +swelling and heat of the parts be suspected, the bandage should be removed, +and the condition of the wound ascertained. + +An excellent example of the value of this method of treatment is that given +below: + +'I call to mind a valuable hunter in my practice a few seasons since, who, +whilst hunting, we suppose, struck himself in the way we suggest. He not +only removed the superior portion of the inner heel, but tore about 3 +inches of the hoof from the top nearly to the bottom. This was clapped back +by the owner, tied with a handkerchief, and the horse removed home. When +the handkerchief was removed, I confess I did not think the horse looked at +all like hunting again. The heel was fairly pulled down, the portion of the +hoof that was hanging to it I could easily have wrenched off. The parts +were fomented, however, with warm water which was slightly carbolized. I +then removed a great portion of the heel and the lateral cartilage, which +was split; placed the portion of hoof again on the laminæ, smothered the +wound with iodoform pulv., covered it with cotton-wool packing, and all +the boracic acid I could get it to hold. A piece of linen bandage was +then tightly wrapped a few times round, and the lot enclosed in a +plaster-of-Paris bandage. I did not undo it for a fortnight, when, to +my great pleasure, the heel and hoof presented a highly satisfactory +appearance. I did it up in much the same way for another ten days, then put +the sand-crack clamps into the hoof and fixed it to the sound part. The +hoof remained in position while the new horn grew from the top, and the +horse hunted again the same season.'[A] + +[Footnote A: _Veterinary Record_, vol. ix., p. 501 (Bower).] + +_Sequels_.--Either of the complications we have mentioned--as, for +instance, Arthritis, Sand-crack, or Quittor--may persist and remain as +sequels to the case. In addition to these, there may be left behind +a cavity in the horn of the wall (see Fig. 109), or a loss of the +horn-substance of the wall proper, as that depicted in Fig. 112, or +described under the heading of False Quarter. + +[Illustration: Fig. 112.--HOOF WITH A CAVITY IN THE SUBSTANCE OF THE WALL +FOLLOWING UPON 'TREAD' TO THE CORONET.] + +The treatment of Arthritis, Sand-crack, Quittor, False Quarter, and +Seedy-toe, will be found in the chapters devoted to their consideration. + +2. _Chronic_. + +_Definition_.--Coronitis in which, owing to the persistence of the cause, +inflammatory phenomena continue, resulting in the growth of large fibrous +tumours about the coronet. + +_Causes_.--In many cases it is possible, of course, that abnormal large +growths in this position may have an origin similar to that of neoplasms +elsewhere--that is to say, an origin as yet undiscovered. There is no +doubt, however, that the majority of the huge enlargements about the +coronet have their starting-point in one or other of the diseases to +which the foot is liable, in which the cause remains, and a low type of +inflammation persists. + +In chronic and neglected suppurating corn, in untreated quittor, and in +long-standing complicated sand-crack, for instance, we have conditions in +which pus and other septic matters find ready entrance into the subcoronary +tissues. Should either of these be neglected, or should the pus formation +from the onset take on a slow but gradually spreading form (in other words, +should either of these cases run a chronic rather than an acute course) +then, with the persistence of the inflammatory phenomena so caused, is +bound to result a steady and increasing growth of inflammatory fibrous +connective tissue. This, as it grows, becomes in its turn penetrated by the +ever-invading pus, and, under the stimulus thus caused, itself throws out +new tissue. And so, constantly excited, the tumour-like mass tends to +steady increase in size, until enlargements are formed which one may +sometimes truly term enormous. + +_Symptoms_.--The appearance of the growth is, of course, immediately +evident. Usually these swellings are slow in forming, so that the size +of the enlargement depends entirely upon its age. We may thus meet with +growths of this description, varying in weight from 4 or 5 pounds to +the almost incredible size of 33-1/2 pounds. In the majority of cases a +discharging sore is to be found upon it--in some cases several. Explored, +these sores reveal their true nature. Their lip-like openings, and the +ready manner in which they may be searched by the probe, show them to be +sinuses. + +In a few cases, however, the outer surface of these tumours is intact. When +this is the case, it is possible that the growth is a true fibroma--that is +to say, a non-inflammatory new growth of fibrous connective tissue. On the +other hand, it may have resulted from one or other of the causes we have +enumerated, and its exact diagnosis have been impossible until operative +measures had been proceeded with. In this case, small and encysted foci of +inspissated pus scattered more or less throughout the growth indicate its +true nature. + +Pain as a rule is absent, and, unless the growth, on account of its size, +interferes with progress, the animal walks perfectly sound. Here the +patient may, without offending the dictates of humanity, be put to slow +work. + +_Treatment_.--In very many cases, possibly on account of the decreased +circulation and vitality of the parts, these growths occur in aged animals. +Here treatment is not economic, and may for that reason be put out of the +question. Further, the growths are more common in heavy cart animals of a +lymphatic type than in those of a lighter breed. Couple this with the fact +that the tumour is often unattended with pain, and we see that the animal +is still able to perform his accustomed labour. Here, again, treatment is +contra-indicated. + +For still another reason surgical treatment, which is the only treatment +likely to be of benefit, must not be undertaken rashly. A large and open +wound is bound to be left behind. So large is it in many cases that the +complete covering of the exposed surface with epidermal growths from the +circumference cannot possibly be looked for. There is then left a large and +horny-looking scar, which is an even worse eyesore than was the original +enlargement. + +When the patient is a young and otherwise valuable animal, however, and +when the case, judged either by the size of the swelling or its outside +appearance, promises a fair measure of success, operative measures may be +determined on. + +In this case the author's practice has been, after casting the animal, to +apply a tourniquet to the limb and proceed to excision. A lozenge-shaped +incision, extending to near but not quite the circumference of the +swelling, should be made with a large knife right through the skin and +deeply into the growth. The whole is then removed, proceeding in an +excavating manner under the thickened skin at the margin. Hæmorrhage, +though proceeding from several apparently large vessels in the structure of +the tumour, and oozing generally over the whole of the outer surface, +is rarely profuse enough to interfere with the operation, and is easily +controlled by cold water douches and the application of the artery forceps +to one or more of the larger vessels. The operation completed, the larger +bleeding-points should be secured by exerting torsion with the artery +forceps, and the surface oozing stayed by frequent dashing with cold water. + +When the hæmorrhage has sufficiently ceased, an ordinary flat firing-iron +should be passed over the whole of the cut surface, and an effectual eschar +formed. + +Following this, and _before removing the tourniquet_, the wound should be +filled with pledgets of carbolized tow, and the whole tightly secured by a +stout and broad linen bandage of not less than 6 yards in length. + +_Reported Case_.--'The patient, a middle-aged cart mare, had a pair of +fore-feet the like of which I never saw. As the result of long-standing and +imperfectly-treated quittor all over the seat of side-bone on the outer +side of each fore-foot, beginning pretty far forward, and extending to the +heel on the inner side, filling up the hollow and reaching nearly to the +fetlock, was a big, bulging, hard, calloused enlargement or tumour standing +out 3 or 4 inches all round, covered with thick horny skin and stubby hair, +and having on its surface the small openings of several sinuses leading +deeply down to the ossified and diseased cartilage underneath. And yet +with all this diseased undergrowth the mare, strangely enough, walked and +trotted sound. I was told that this mare had been troubled with suppurating +corns and quittor, that many unsuccessful attempts had been made at cure, +but that, getting worse instead of better, these tumours had formed. + +'After casting and anæsthetizing, a strong rubber tourniquet was placed +above the knee and the operation commenced. With a surgeon's amputating +knife all the big fibrous mass which I could safely remove was cut and +sliced off, and the coronet and pastern reduced as nearly as possible to +its natural dimensions. The diseased cartilage, or side-bone, gave some +trouble, a considerable portion having to be cut and scraped, and the sinus +in it gouged out; but its complete removal did not appear to be called for. + +'There was little if any hæmorrhage until release of the tourniquet, when +the whole broad surface became deluged with blood, three or four small +arteries spurting and veins flowing in all directions, so much so that I +was glad to reafix the clasp, and with the firing-iron seal up the vessels, +searing gently all over the surface. + +[Illustration: FIG. 113.--CHRONIC CORONITIS FOLLOWING 'TREAD.'] + +'A good dusting with antiseptic powder, a thick pad of carbolized wool, and +two long calico bandages wound tightly round, completed the work. + +'The other, the near-leg, was then dealt with in the same way. + +'The mass removed weighed a little over 9-1/2 pounds--5 pounds from the +off-foot and 4-1/2 pounds from the near. Its structure was fibrous tissue, +almost as firm and hard as cartilage, and with no appearance of malignancy. + +'The after-treatment consisted simply of fresh dry dressings--copper, +sulphate, zinc sulphate, and calamine, equal parts--applied every third +or fourth day, after first bathing the feet in a shallow tub of warm +antiseptic water. + +'At the end of eight or ten weeks a fairly presentable appearance existed. +The greater part of what had been raw surface was covered with healthy +skin, and the remainder had become dry and horny.'[A] + +[Footnote A: _Veterinary Record_, vol. xiv., p. 201 (C. Cunningham, +M.R.C.V.S.).] + +A further form of chronic coronitis is that shown in Fig. 113. + +This condition is commonly the result of a severe and jagged tread with +the calkin, and takes the form of an ulcerous and excessively granulating +wound. As time goes on the granulations become hard and horny-looking, and +their fibrous tissue as hard and unyielding as tendon or cartilage. + +These if treated in the early stages with repeated dressings of caustic, +or, if very exuberant, the use of the knife, usually yield to treatment. If +neglected until the condition depicted in the figure is arrived at, then +treatment, as a rule, is of no avail. Neither is treatment of any use if +any great loss of the coronary cushion has occurred. + + +D. FALSE QUARTER. + +_Definition_.--False quarter is the term applied to that condition of the +horn of the quarter in which, owing to disease or injury of the coronet, +the wall is grown in a manner that is incomplete. + +_Symptoms_.--This condition of the foot appears as a gap or shallow +indentation, narrow or wide, in the thickness of the wall, with its length +in the direction of the horn fibres. By this we do not mean that the +sensitive laminæ are bared and exposed. Horn of a sort there is, and with +this the sensitive structures are covered. Running down the centre of the +incomplete horn is usually a narrow fissure marking the line of separation +in the papillary layer of the coronary cushion, which, as we shall later +see, is responsible for the malformation. + +On either side of the indentation, as if wishing to aid further than +ordinarily it should in bearing the body-weight, the horn takes on an +increased growth, and stands above the level of the horn surrounding it. It +may, as perhaps it really is, be regarded as a form of hypertrophy, brought +about by the increased work that the loss of substance in the region of the +false quarter puts upon it. + +So long as the sensitive structures are protected the animal remains sound. +Sometimes, however, from the effects of concussion or of the body-weight, a +fissure appears in the narrow veneer of horn that covers them. Into this, +which, of course, is but a form of sand-crack, gravel and dirt penetrate, +and so set up inflammatory changes in the keratogenous membrane. As a +result suppuration ensues, and the animal is lame. + +_Causes_.--False quarter may result from any disease of the foot that +involves destruction of a portion of the coronary cushion. As we may see +from a reference to Chapter III., it is from the papillæ of this body that +the horn tubules of the wall are secreted. Destruction of any portion of it +necessarily results in a corresponding loss of horn in that position. The +disease occasioning this more often than any other is perhaps quittor. It +may also result from suppurating corn, from a severe tread or overreach, or +from the effects of a slowly progressing suppurating coronitis. + +_Treatment_.--A radical treatment of false quarter is not to be found. Once +destruction of the secreting layer of the coronary cushion has occurred, +the appearance of the fissure in the wall will always have to be reckoned +with. A false quarter, therefore, not only renders the horse liable to +occasional lameness, but also renders weaker that side of the hoof in which +it occurs. + +The only method of treatment that can be practised, therefore, is that of +palliation. Seeing that the trouble the veterinary attendant will have to +deal with is loss of a portion of the weight-bearing surface, his attention +is immediately directed to the shoeing. As with sand-crack, so with false +quarter, the frog and the bars must be called upon to take more of the +body-weight than commonly they do with the ordinary shoe. The indication, +then, is a bar shoe. At the same time, the bearing of the wall on the shoe +on either side of the fissure should be eased by slightly paring it, and +the hypertrophied horn on the outer surface of the wall removed with the +rasp. + +In cases where penetration of the sensitive structures has occurred, +complicated with the formation of pus, the same treatment as for +complicated crack is to be followed. The foot should be poulticed for +several days with hot antiseptic dressings, and thorough cleansing of the +infected parted brought about. Afterwards strong solutions of suitable +antiseptics should be applied daily until such time as the horny covering +has renewed itself. This done and the bar shoe applied, the fissure may be +plugged with any effectual stopping. Either a mixture, such as Percival's, +of pitch 2 parts, tar 1 part, and resin 1 part, melted and mixed together, +or one of the artificial hoof-horns may either be used with advantage. + + +E. ACCIDENTAL TEARING OFF OF THE ENTIRE HOOF. + +_Causes_.--Seeing that this accident to, and consequent severe wounding of, +the keratogenous membrane nearly always occurs in but one way, it is worthy +of special mention. So far as we are able to ascertain, it is an accident +peculiar to horses continually engaged in shunting operations either in +pits or station-yards. At the moment the animal is released from the waggon +he has been pulling, and should turn to the right or the left in order +to allow it to pass him, the shoe either becomes wedged in between two +converging rails, or is trapped by the wheel of the waggon. Either the +approaching waggon with the added weight its impetus gives it then pushes +the animal suddenly away, leaving a part of his foot still fixed to the +rails, or the animal himself, feeling securely held, makes a sudden effort +to release himself, and draws his foot cleanly out of the imprisoned horny +box. + +The author calls to mind a case in which entire removal of the horn of +the foot of an ox occurred through the passing over it of the wheel of +a heavily-laden cart. It is therefore quite conceivable that the same +accident might occur to the horse. As a matter of fact, we find one case on +record where one-half of the horny box was thus removed.[A] + +[Footnote A: _Veterinary Record_, vol. xiii., p. 129.] + +So far as we are able to gather, it is more a result of imprisonment of the +shoe than of the foot. It appears, further, to be always a result of the +animal being newly shod, and the clinches firmly secured; so much so that +it would be probable, with imperfectly secured clinches, that the animal +would draw the hoof from the clinches and the shoe rather than the foot +from its horny covering. + +Therefore, as the author of one of the cases we shall afterwards relate +suggests, it should be proposed as a preventive that the shoe-nails of +animals regularly engaged in work on the metals should not be clinched in +the regulation manner, but should have their points merely screwed off, and +the nails afterwards rasped level with the wall. + +These cases are particularly interesting as illustrating the rapid manner +in which a new hoof is afterwards formed, and the way in which the exposed +sensitive laminæ take their share in adding to, though not forming the bulk +of, the horn of the wall. + +From the cases we are able to record it will be seen that this accident +need not be looked upon as fatal, nor the injury itself beyond hope of +repair. Dependent largely upon the temperament of the animal, the amount of +pain that is caused, and the way in which the animal bears it, recovery may +be looked for. Even from the very commencement of the accident, however, +the pain may be so acute and the animal so violent with it that slaughter +becomes necessary. + +_Treatment_.--This consists in applying an antiseptic and sedative dressing +to the injured parts (for example, Carbolized Oil and Tincture of Opium, +equal parts) and afterwards bandaging. + +From the only data we are able to work on, it appears that this dressing +should be repeated daily, the bandage being removed, each time, the +foot well bathed in warm water, and the dressing and bandage afterwards +replaced. On first sight, it would appear that once cleansed and bandaged +the dressings might be left _in situ_ for several days. Seeing, however, +that suppuration, if once set up, would add further to the intense pain the +animal is already suffering, and considering the always constant exposure +of the foot to infection, it is perhaps wise to persist in daily changing +of the dressings. + +At the same time, the general health of the animal should be attended to. +Suitable febrifuges should be administered, either in the shape of a +dose of physic, or salines and liq. ammonia. acetatis; and the pain, if +appearing unbearable, allayed by doses of choral and hypodermic injections +of morphia. + +_Recorded Cases_.--1. 'A short time ago I was called to see a horse which +had had his hoof torn off in a railway "point." When I arrived at the +stable the injury had been done two hours, and the horse had been led from +the railway to a loose-box nearly half-a-mile off. On going to this box I +was surprised and horrified to find the poor animal mad with pain, rolling +and dashing himself about. When on his back he would struggle and kick the +walls with the injured foot, as though unconscious of pain. Not one moment +was he still, and as I could see that the sensitive structures were much +damaged by his violence, I obtained a gun and put him out of his pain. + +'The accident happened in this way. The horse was employed in shunting +coal-waggons, and had just drawn four loaded trucks up to a point at which +they diverged to the left, and the horse, being unhooked, ought to have +turned to the right. Here, unfortunately, the near fore-foot became wedged +in between two converging railway plates, one of which formed a part of the +waggon-way, on which the trucks were running. The horse was a big animal, +and freshly shod with heavy shoes, on which a toe-piece and calkins were +used. The shoe was roughly but strongly nailed on with eight nails, the +clinches of which were all firm. This shoe was fitted wide at the heels, +and when the foot was fixed in the points (toe downwards) it protruded over +the face of the rail. When the trucks reached it they pressed it down, and, +the horse leaning forward, the hoof was drawn off like a glove. The hoof +was almost as clean inside as if taken off by maceration--only towards the +toe was a small portion of the coffin-bone and some torn laminæ left inside +the hoof. + +'As soon as possible after the accident, so I was told, the foot was bound +up with tow and a bandage; then a sack was cut up and placed over all, and +the horse slowly led to his loose-box. He "carried" the leg all the way, +limping along on the three sound ones. Almost immediately after reaching +the box he lay down, but only for a short time. The standing position was +not long maintained--profuse perspiration set in, and the alternations of +position became more rapid and violent, till plunging and rolling were +added to the other signs of excruciating pain. I was also told that the +groaning of the poor animal was almost constant, and at times so loud and +prolonged as to amount to a shriek. + +'I have no experience of a similar case, and I should not have supposed +that this accident would have caused such acute suffering and violent +symptoms. I think I have heard of such cases making a complete recovery; +but I feel sure that, in this case, I only anticipated death by, at most, a +few hours.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 127.] + +2. 'The case I am about to give you an account of, being one of rare +occurrence, I thought would not prove uninteresting to the members of the +Veterinary Medical Association. It is an instance of complete removal of +the hoof by mechanical force. + +'Our patient was a brown mare, five years old, the property of Messrs. +Crawshaw and Co., railway contractors on the Sheffield and Manchester line. + +'On June 20 the mare was, as usual, working on the line, drawing one of the +waggons for the removal of soil from one place to another, and, as was the +custom, the pace is generally increased at about the distance of from sixty +to eighty yards from where the unloading takes place, in order to add to +the velocity, so that the contents of the waggons might roll down so great +a precipice. It was at this increased action, when the mare was being +removed from the waggon, that she stepped between the ends of two iron +rails, sufficiently apart to admit the foot only, when one end of the rail +inserted itself between the sole and toe of the shoe, the other at the top +and in front of the crust. + +'The mare, finding herself fixed, endeavoured to disengage herself, and, in +doing so, got in front of the waggon, which, coming at a great pace, forced +her down into the pit, leaving behind the off fore-hoof, which was only +removed from its situation between the two rails by a large hammer, it +being so firmly wedged in. The shoe and hoof were bent in a very peculiar +manner, as the accompanying cuts will show, the inside heel being +completely raised from above the level of the frog, not one of the nails +being unclenched, or in the slightest degree having given way to so large +an amount of force imposed upon them, although the toe of the shoe was +raised from the sole by the rail being immediately under it (see Fig. 114). +The mare had been shod the day before, and, having a good sound foot, the +shoe was firmly put on. + +'Being a mile from home, she was with some difficulty made to travel that +distance. On her arrival, my preceptor, Mr. Taylor, was immediately sent +for, who found her, as I have before stated, with the off fore-foot +hoofless. + +'Proceeding to examine the foot, he ascertained that it had bled +considerably, which, however, was stopped by bandages to the foot and a +ligature round the coronet. The laminæ on one side and a small portion of +the sensitive sole, though not to any great extent, were lacerated. The +coffin-bone was not at all injured. The bleeding having nearly ceased, +she was put into slings, the foot carefully washed with warm water, and +immediately bound up with pledgets of tow saturated with the simple +tincture of myrrh and tincture of opium, of each equal parts. + +[Illustration: FIG. 114.--HOOF TORN FROM THE FOOT BY ACCIDENT.] + +'The dressing was ordered to be allowed to remain on all night, and on the +following morning to be removed. The foot was then bathed, as before, +in warm water, and the application of the tinctures repeated night and +morning. The medicine internally given was castor oil, with tinct. opium, +and this, in a diminished dose, was ordered the next morning. Blood was +also abstracted from the jugular vein, to the amount of 6 quarts, so as +to allay the inflammatory fever set up. The food consisted of bran and +linseed, with small portions of hay and water. The mare being in a highly +excited state, and suffering such severe pain, the opinion Mr. Taylor gave +was that, should she get over the first four days (which appeared quite +uncertain), he had no doubt of her ultimately getting well, and also that +she would have a perfect hoof formed. It was now left for the owners' +consideration, whether they thought the mare worth her keep till such took +place, the time mentioned by Mr. Taylor being four or five months. She was +seen again the fourth day after the accident, and was then found to be +perfectly tranquil and feeding well; her pulse, which at the first visit +could not be counted, was now not more than 65 beats in the minute. On +removing the dressings, the foot presented a very favourable appearance, +the treatment therefore varied only in the application of a linseed-meal +poultice over the former dressings of tinctures of opium and myrrh, +confining the whole in a soft leather boot. Diet as before, in addition to +which give a few oats. Should the bowels become constipated, repeat the +castor oil without the opium. + +'_June_ 28.--The animal was again seen, and appeared to be going on very +favourably. The poultices were directed to be discontinued, and the parts +dressed every other day with sol. sulph. cupri, as the granulations were +getting rather luxuriant. + +'_July_ 6.--To-day she was found to have gone on so well, having two days +before been removed from the slings, that it was thought justifiable to +turn her out, protecting the foot with a boot, and ordering the dressings +to be repeated. + +'_July_ 23.--She was seen by me in the field, where I had the boot removed, +and so much had she improved, that not less than 2 inches of crust, +proceeding from the coronary ring, had been formed, and the foot looked +remarkably healthy. + +'It will be seen that the accident occurred on June 20, a fortnight after +which time I observed the horny crust to be forming from the coronet, +and the insensitive laminæ at the same time, in which on every visit an +increase of growth was perceptible, and it soon attained a thickness +exceeding that of the other hoof, but which at the same time presented a +more upright appearance. It was not until three weeks after our first visit +that any formation of new sole or frog was to be seen. Of the two the sole +was the first, being secreted by the sensitive sole, the growth proceeding +from the heels. In like manner the insensitive frog was being produced by +the sensitive. + +[Illustration: FIG. 115.--HOOF TORN FROM THE FOOT BY ACCIDENT.] + +'During the last week in October the mare, having her foot protected with a +bar shoe plated at the bottom, and so formed as to open without necessity +of removing the shoe, in order to facilitate the applications of the +tinctures, was put to light work, which has since been gradually increased, +and she now performs her usual labour equal to any other horse. + +'The growth of the wall or crust and insensitive laminæ is not yet quite +complete, nor is the sole, there being wanting about an inch of the horny +substance of it, the entire completion of which I should rather doubt, as I +mentioned in my former communication that the sensitive laminæ and a small +portion of the sole were lacerated, and it is in these parts that the +imperfections exist. + +'The yet imperfectly-formed wall not admitting of the insertion of nails +all around it, the shoe is held on partly by nails and partly by a strap +attached to it bound round the coronet.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 182 (B. Cartledge).] + +3. 'This case is related by Mr. A. Rogerson, F.R.C.V.S. It occurred to an +animal regularly engaged in shunting, and happened through the corner of +the shoe becoming "trapped" between a line of metal and the wheel of +a truck. It is particularly interesting on account of the photograph +accompanying it, and which we here reproduce in Fig. 115. + +'The photograph shows plainly the manner in which the holding of the +"clinches" on the left side of the hoof has resulted in drawing it off +from the foot. Had these clinches, as Mr. Rogerson suggests, been left +unfastened, then the accident in all probability would not have occurred. +The animal was destroyed.'[A] + +[Footnote A: _Ibid_., vol. xiii., p. 2.] + + + +CHAPTER IX + +INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS + + +A. ACUTE. + +ACUTE LAMINITIS. + +_Definition_.--The term 'laminitis' is used to indicate a spontaneous and +diffuse inflammation of the whole of the sensitive structures of the foot, +more particularly the sensitive laminæ. Usually it occurs in the two front +feet, often in all four, and occasionally in the hind alone. + +_Causes_.--In dealing with the causes of laminitis, we will first dispose +of those coming under the heading of _traumatic_. Correctly speaking, +however, lesions of the laminæ thus occurring do not present the same +symptoms, nor run an identical course with the disease we now purpose +describing, and for which we would prefer to entirely reserve the term +'laminitis.' The fact, however, that traumatic causes are detailed in other +works on the same subject compels us to give them mention here. + +Strictly traumatic causes giving rise to a limited inflammation of the +sensitive laminæ are violent blows upon the foot, either purely accidental, +or self-inflicted by violent kicking. + +A similar limited laminitis is to be found in the conditions we have +described under 'Nail-bound and Punctured Foot.' It is met with also in +the injuries resulting from tread and overreach, and in the tissue-changes +accompanying corn. + +The tenderness following upon excessive hammering in the forge, or of too +long an application of the shoe in hot-fitting has also been described as +laminitis. + +With either of the conditions we have mentioned, it goes without saying +that there is either a simple congestion or an actual inflammation, +localized or general, of the laminæ of the injured foot. In neither case, +however, can the resulting mischief be closely compared with the lesions +attending an attack of laminitis proper, a disease which appears to have an +almost specific cause, and to run a course peculiarly its own. + +The specific cause we have indicated as existing can, in the present state +of our knowledge, be only vaguely described as a poisoned state of the +blood-stream. This, as clinical evidence teaches us, may result from a +variety of causes. + +Among these, by far the most common is that state of the circulation +induced by excessive feeding with too stimulating or too irritating a diet. +In any case, where the use of old oats as a staple diet is departed from, +and where the quantity and manner of using the substitute is left to the +discretion of careless or unskilled attendants, trouble is likely to ensue. +The food more prone, perhaps, than any other to bring about an attack is +wheat improperly prepared--that is, uncooked or unground. So much so is +this the case that one full meal of this provender to an animal unused to +it is sufficient to lead to a train of symptoms often ending fatally. + +Beans, peas, barley, rye, new maize, or even new oats, are all liable, if +carelessly used, to have the same effect. + +It is the laminitis following feeding on new oats that has caused us to +apply to the food the adjective 'irritating.' Here, more often than not, +the peristaltic action of the bowels is found to be abnormally in evidence, +and the excessive use of the diet is always accompanied by a more or less +fluid discharge of the intestinal contents. + +In addition to the foods we have mentioned, many others might be +enumerated, more especially the numerous 'made-up' feeding materials now +on the market. Many are composed of substances that may be regarded as +absolutely opposed to the correct feeding of a horse, and their use can +only be followed by this and other evil results. + +Another most fruitful cause of laminitis is a severe and continued +inflammatory condition of the system elsewhere. It is the laminitis known +to veterinary surgeons as 'metastatic,' and perhaps the two most notable +examples of it are the laminitis following a prolonged attack of pneumonia, +and the 'Parturient Laminitis' occurring as a concomitant of septic +metritis. + +Parturient laminitis it is that offers us the most striking illustration of +the truth that a poisoned state of the blood-stream is a sure factor in the +causation of an attack. From the direct evidence of our senses (namely, +manual exploration of the infected womb, and the stench of the exuding +discharge) we know that we have in the interior of the womb matter in a +state of putrescence. From the experience of previous post-mortems we +know, further, that the putrescent matter thus originating often gains the +blood-stream, and forms foci of septic lesions elsewhere--liver or lung. +When, therefore, during an attack of septic metritis a condition of +laminitis supervenes, we are justified in attributing it to the escape of +septic matter from the already infected uterus. + +In the same category of laminitis from metastasis may also be placed the +laminitis occurring as a result of an overdose of aloes. The enteritis thus +set up is often followed by laminitis, and that of a serious type. + +Prolonged and excessive work upon a hard road is also apt to induce an +attack. When this occurs it in many cases resolves itself into a case of +cruelty. (See reported case, No. 1, p. 279.) + +Laminitis from this cause was frequent among coach and carriage horses in +the pre-railroad period, and resulted from attempting to obtain from the +animal a faster pace and a greater number of miles than he was physically +capable of giving. + +In our day, however, it is more often a result of gross feeding, combined +with only that amount of work which the horse, if ordinarily fed, would +be easily able to perform. An excellent example of this is the laminitis +occurring in the Shire stallion when commencing his rounds of service in +the spring and early summer. At this season these animals are constantly +supplied with a more than sufficient supply of a highly stimulating and +nutritious diet. In this case the blood is already in that state in which +it is predisposed to the disease. Add to this the unwonted exercise--for +during all the winter the animals are idle--and congestion of the venous +apparatus of the extremities is not to be wondered at. + +Passing from these, the more common, we may consider other and less +frequent causes of the disease. Congestion of the laminal blood-vessels and +consequent laminitis occurs when animals are made to maintain a standing +position for prolonged periods, as, for instance, when making sea voyages. +A long and painful disease of one foot, necessitating the whole of the +weight being borne by the other, ends often in laminitis of the second +member. It may thus occur as a sequel to quittor, complicated sand-crack, +suppurating corn, and punctured wounds of the feet. + +Laminitis has also been known to occur as a result of septic infection of +the blood-stream consequent on the operation of castration. (See recorded +case, No. 2, p. 281.) + +A sudden lowering of the surface circulation at a time when the animal is +excessively perspiring is also said to favour an attack, as also is the +giving to drink of cold water to an animal just in from a long and tiring +journey. Also, according to Zundel, 'the influence of the season cannot be +denied, and it is during the summer months that laminitis is more frequent, +while it is rare in winter, as well as in the spring and autumn.' + +Further, laminitis has been described as occurring when the animal is at +grass, and when all causes--at any rate, active ones--have appeared to be +absent. (See reported case, No. 3, p. 282.) + +Regarding heredity, we may safely say that, as a cause of laminitis, it may +be almost totally disregarded. That a bad form of foot, either a flat-foot +or a foot with heels contracted, and already thus affected with a mild type +of inflammation, did not offer a certain predisposition, we should not like +to assert. There must, however, be an exciting cause--namely, a poisoned +condition of the blood-stream. This latter cannot, of course, be in any way +regarded as hereditary. + +In short, the dietetic cause is by far the most common, and, in prosecuting +inquiries as to the starting-point of an attack, the veterinarian's +attention should be directed in the main to that particular. + +_Symptoms_.--Laminitis is always ushered in by a set of symptoms indicative +of a high state of fever. The pulse is raised from the normal to as many as +80 or 90 a minute, muscular tremors are in evidence, the respirations are +short and hurried, and the temperature rises to 105°, 106°, or 107° F. The +visible mucous membranes are injected, that of the eye, in addition to the +hyperæmia, often tinged a dirty yellow. The mouth is dry and hot, the urine +scanty, and the bowels frequently torpid. As yet, however, the walk is +sound. + +Called in during this early stage, the veterinarian is often puzzled as +to the exact significance of the symptoms. Enteritis, lymphangitis, or +pneumonia he knows to be often heralded in the same manner. In this +connection, Zundel says: 'Laminitis, in most instances, is preceded by +certain general symptoms, such as are premonitory of the invasions of +ordinary inflammatory diseases, but of an uncertain significance.' + +So far we agree with him, but to what we have already said we would add +that, even in this early stage, there is an additional symptom, unmentioned +by Zundel, which often leads one to an exact diagnosis. The feet are in +turn lifted a short distance from the ground, and almost immediately +replaced. This movement ('paddling,' we may term it) is constant, the +animal appearing to obtain ease in no one position for more than a few +moments at a time. + +Seen but a few hours later, when the swelling caused by the hyperæmia +and outpouring of the inflammatory exudate has led to compression of the +sensitive structures within the horny box, the symptoms presented admit of +no misreading, save by the most casual and careless observer. The patient +now stands as though fixed to the ground. The pulse is hard and frequent, +the respirations tremendously increased in number, the body wet with a +patchy perspiration, and the countenance indicative of the most acute +suffering. Only with difficulty, and often only at the instigation of the +whip, can the animal be induced to move. This he does by throwing his +weight, so far as he is able, on to the heels of the feet affected, and +putting the feet slowly forward in a shuffling and feeling manner. The feet +themselves give to the hand a sensation of abnormal heat, percussion upon +them with the hammer is followed by painful attempts at withdrawal, while +any effort we may make to remove one foot from the ground is useless, so +great an aversion does the animal show to placing a greater weight upon the +opposite foot. + +According as the front-feet alone, the hind-feet alone, or all four feet +are affected, the symptoms will vary. + +With all four feet diseased, the animal stands with the two front-feet +extended in front of him, while the hind-limbs are at the same time propped +as far beneath him as is possible. The horse is, in fact, standing upon the +extreme hindermost portions of the feet. + +Why the animal should thus distribute his weight is easily explained. +Standing in the normal position, the body-weight is borne by the sensitive +laminæ, the sole, of course, sharing in the burden, but the laminæ taking +by far the greater part of the pressure thus exerted. With the vessels of +the laminæ gorged with blood, and the laminal connective tissue infiltrated +with a profuse inflammatory exudate, the most excruciating pain is bound +to result by reason of the compression of the diseased tissues within the +non-yielding structures. In some little measure the suffering animal may +afford himself relief by partly removing pressure from the fore-parts of +the hoof. When placing the body-weight behind, the pressure, instead of +falling upon the highly sensitive laminæ, is directed to the follicular and +fatty tissues of the plantar cushion: from there, with only a small portion +of the sensitive sole intervening, to the horny frog, and from thence to +the ground. + +The same distribution of weight also places the foot in a position of +greatest expansion, thus, by giving greater room to the diseased parts, +again affording relief of pressure on the inflamed lamina, while it at the +same time relieves of weight the foremost portions of the sensitive sole. + +With the fore-feet alone attacked, the animal affects exactly the same +position of standing as that just described. The fore-feet are again +extended, and the hind propped far beneath him. The fore extended, in order +to obtain the relief occasioned by standing on the heels; the hind in this +case carried forward in order to take a greater share of the body-weight, +and thus relieve the congested members in front. + +With the hind only attacked, then the fore and the hind feet are more +closely approximated than in the normal position. The reason, of course, +is that the hind-feet are carried forward in order to be placed upon the +heels, while the fore are taken backwards to relieve the hind of the +body-weight. + +In like manner the movements of the animal will vary with the feet +affected. With only the front-feet diseased the animal is, comparatively +speaking, comfortable. The hind-feet take the weight, and the animal stands +for long periods together, resting alternately first one fore-foot and then +the other, moving often in a circle of which his body is the radius, and +his hind-limbs the centre. If urged to move forward, then immediately his +countenance and movements manifest the pain to which he is put. Only with +reluctance does he cause the fore-feet to take weight. They are shuffled +forward quickly one after the other, so that weight may not be placed +upon them for one instant longer than is necessary, and the hind-limbs +immediately brought again with two short, awkward movements beneath the +body. Progress thus takes place in a succession of movements 'half hobble,' +'half jump.' + +Painful though this may appear, progress is still more difficult when the +hind-feet alone are diseased. Afraid that, in placing his fore-members +freely forward, he will add to the pain in his hind, the walk takes place +in a series of extremely short steps, with the feet more or less closely +approximated. The gait is thus rendered extremely awkward, and Zundel, by +saying that 'the animal appears as if treading on sharp needles,' most +fitly describes it. + +Movement with all four feet affected, though less awkward in appearance, +is doubtless more painful than in either of the other conditions. Here +the animal can hardly be induced to shift his position at all. Only by +flogging, and that severe, can he be made to go forward. When so induced to +move, the agonizing pain to which the patient is subjected may be gathered +by noting his countenance and manner of progression. + +With each movement forward, muscular tremors affect the limbs; each step +is short, jerky, and convulsive; the respirations and pulse are almost +immediately greatly quickened, and the lower lip is hung pendulous, and +moved almost unconsciously up and down with a flapping noise against the +upper. A patchy perspiration breaks out about the body and quarters, and +the tail is outstretched and quivering. At the same time the lines of the +face become drawn, the commissures of the lips pulled upwards, the eyes +staring and haggard, the eyelids puckered, the nostrils extended, and +the whole expression indicative of the intense and agonizing pain of the +disease. + +One can perhaps better give one's client some vague idea of the patient's +suffering by likening the pain to the throbbing sensation of a festered +finger-nail. Tell him that each hoof of the horse is similarly, or, if +anything, more delicately, constructed, that in each foot the same process +of 'festering' is going on, and that upon them the animal has perforce to +stand. + +As one might expect, the position of greatest ease is the decumbent. +Strange to say, though, in many cases of laminitis the animal persists in +maintaining a standing posture. Once down, however, one has sometimes the +greatest difficulty in persuading him again to rise. The lying position is +so long maintained that bedsores begin to make their appearance, and the +animal rapidly loses flesh, not only by reason of the fever and the pain, +but by giving to rest the time he should normally give to feeding. + +Difficulty in rising is greatest when all four feet are affected; is +_nearly_ as great when the hind-limbs only are in trouble, but is least +when the disease exists alone in the two fore-feet. + +THE COURSE OF THE DISEASE AND ITS PATHOLOGICAL ANATOMY.--As with +most inflammations of any severity, so with this we may consider the +pathological changes taking place in the foot under three headings: (a) +The period of Congestion; (b) the period of Exudation; (c) the period of +Suppuration. + +(a) _Congestion_.--In the early stages of laminitis there is a state of +engorgement of the vessels of the keratogenous apparatus generally, but +more particularly the laminal portion of it. With the hoof removed at this +stage the sensitive laminæ are found to be swollen, dark red in colour, and +affording a distinct feeling of increased thickness when pressed between +the fingers, Incised, there escapes from the cut surface a large flow of +dark venous-looking blood. At this stage hæmorrhages of the laminal vessels +occur. The escaping blood infiltrates the surrounding connective tissue, +and in many cases destroys the union between the horny and sensitive +laminæ. This change is most noticeable in the region of the toe and the +commencement of the quarters, the os pedis appearing as though pushed +backwards by the escaping fluid collected between the wall and the bone. In +severe cases, fortunately but rarely seen, the blood so escaping continues +to infiltrate, and separate the tissues until it is seen to be freely +oozing at the region of the coronet. (See reported case, No. 1, p. 279.) + +(b) _Exudation_.--The period of exudation marks the outpouring of the +inflammatory fluid. This, even more than the hæmorrhages attending the +stage of congestion, tends to destroy the intimacy between the sensitive +and the horny laminæ, leading finally to their complete separation at +the region of the toe. Fig. 116 illustrates this state of affairs after +laminitis has existed for a week. The sensitive and horny laminæ are here +shown to be distinctly separated from each other, a well-marked cavity +existing between them, which cavity is greatest in extent at the toe of the +os pedis. With the sensitive structures thus detached from the wall, it is +evident that very much that formerly held the os pedis in normal position +has been destroyed. What then happens is that the whole of the body-weight +is placed upon the sole. Never intended to bear the strain thus imposed, +it naturally sinks. With the sinking is a corresponding 'dropping' of the +pedal bone--in fact, of the whole of the bony column. Seeing that the +structures _above_ the hoof are still normally adherent to the bones, it +follows that they must, as the os pedis sinks, be carried with it. As a +consequence we get a marked depression at the coronet (see Fig. 117, _a_), +which depression may be often noticed after the second or third week of a +severe attack of the disease. + +[Illustration: FIG. 116.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +EIGHT DAYS' STANDING. The separation between the sensitive structures and +the hoof is indicated by a dark line. The cavity is filled with exudate. It +will be noted that as yet there is little change in the position of the os +pedis.] + +Here, again, though to a greater extent than that caused by the hæmorrhage +alone, the os pedis appears to be pushed backwards, the space at the toe +between the bone and the horny box being closely filled with the yellow, +slightly blood-stained exudate. This condition is well depicted in Fig. +117. + +[Illustration: FIG. 117.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +FOURTEEN DAYS' STANDING. _a_, The depression at the coronet caused by the +dropping of the bony column within the horny-box: _b_, a portion of the +sensitive sole pushed downwards and forwards by the descending os pedis.] + +With the descent of the os pedis we get in many cases a penetration of the +horny sole (see Fig. 117), leading always to serious displacement of the +sensitive sole (see Fig. 117, _b_), and often to caries of the exposed +bone. + +The backward displacement of the os pedis may be accounted for in two ways. +Firstly, the greater vascularity of the membrane covering its front leads +to a greater outpouring of inflammatory fluid in that particular position. +Here, therefore, loss of adhesion with the wall is greatest, while into the +cavity so formed is poured a large quantity of a fluid that is practically +incompressible. The os pedis _must_ be pushed backwards. Secondly, the +manner in which the animal distributes his weight--namely, upon the +heels--is calculated to aid in the bone's backward movement, for with his +feet in this position tension upon the extensor pedis is relaxed, while +that upon the flexor perforans is greatly increased. + +(c) _Suppuration_.--Should the animal survive the pain and exhausting calls +made upon his system by the accompanying fever of the foregoing conditions, +the case ends either in resolution or suppuration. When suppuration occurs +it is found, as a rule, at the sole, leading to almost entire separation of +the sensitive and horny structures. The pain, if possible, is even worse +than in either of the foregoing stages, and relief for the suffering +patient is only obtainable by the natural exit of the pus at the coronet, +or by giving it escape with the knife at the sole. As a rule, suppuration +in laminitis is rare, and then only occurs when the disease has been of +some several days' duration. It has been the author's experience, however, +to meet with it in a case but three days' old. This particular animal had +laminitis restricted to the hind-feet. The condition was diagnosed and pus +liberated at the sole of one foot during the third day of the lameness. The +animal was cast on the fourth day, and pus obtained from the sole of the +opposite foot. + +_Complications_.--In a moderate case, carefully treated, laminitis +terminates at the end of three or four days in resolution. The general +symptoms of fever gradually subside, the appetite returns, and the walk +becomes easier. Cases thus terminating fortunately leave behind them no +change of serious importance, either in the sensitive tissues or in the +horny envelope. Should resolution, however, be longer delayed, then the +case, although eventually terminating successfully so far as soundness in +gait is concerned, leaves more or less evidence behind in the shape of +rings about the wall and alterations in the build of the sole. + +When the happy ending of rapid resolution is denied us, then, in addition +to the condition we have described as suppuration, we may meet with one or +other of the following complications: + +_(a) Metastatic Pneumonia_.--This complication is not uncommon, and, +when occurring, more often than not ends fatally. It may be accounted for +indirectly by the greater work the lungs are called upon to perform in +carrying out the increased number of respirations occasioned by the general +fever and pain, and directly by the poisonous materials circulating in the +blood-stream. + +_(b) Metastatic Colic_.--This may be either a subacute obstruction of the +bowel or an enteritis accompanied by an offensive purge. + +A striking case of the former is related in the _Veterinary Journal_ (vol. +xvi., p. 180) by H. Thompson, of Aspatria. Here no evacuation of the bowels +occurred for three days, and the pains of laminitis were added to by the +usual pains of intestinal obstruction. + +The colic of enteritis is in some cases caused by the nature of the food, +giving rise to laminitis. In our opinion, however, it is more often +occasioned by the drastic action of the aloes nearly always resorted to in +the treatment of the disorder. As does the pneumonia, the enteritis thus +brought about nearly always has a fatal termination. + +_(c) Gangrene of the Structures within the Hoof_.--This complication is +the one most to be dreaded. It occurs as a result of the great pressure +exerted by an excessive exudation, and doubtless affects first the laminæ +and softer structures. Once commenced, however, it rapidly extends to death +of the other structures (ligament, tendon, and even bone), and gives a +fatal ending to the case. + +That gangrene of the tissues ("mortification" as our older writers called +it) has occurred is soon made evident to the veterinarian by the symptoms +shown by the patient. The agonizingly acute pains suddenly subside, the +feet are placed firmly and squarely to the ground, and the animal walks +with ease. Perhaps but the night before the patient is seen racked with +excruciating pain; the morning sees the astounding change of apparent +absolute recovery. Too well, however, the eye of the experienced veterinary +surgeon sees that such is not the case. Even before proceeding to take a +record of the other symptoms, he knows that it is but the commencement of +the end. Methodically, however, he notes the other conditions. The pulse +he finds small and imperceptible, save at the radial. The thermometer +registers a subnormal temperature, the extremities are cold, and cold +sweats bedew the body. To the same experienced eye the countenance of the +animal is almost suggestive of what has occurred. The drawn and haggard +expression, to which we have previously referred, becomes more marked, and +the angles of the lips are drawn back in what has been described by some +writers as a 'sardonic' grin. + +We can best express what the whole look of the animal's countenance +indicates to us by saying that it gives us the impression that the animal +himself knows that some serious change, and a change fatally inimical to +his chances of life, has taken place in his feet. + +It may be that in some odd cases, although it has not yet been our lot to +meet with them, gangrene may terminate in the casting off of one or more +hoofs. Needless to say, there can still be but one termination to the case. + +_(d) Periostitis and Ostitis_.--This complication is referred to by other +writers under the term of 'Peditis.' It signifies, of course, that the +periosteum and the bone have become invaded by the inflammatory process. +It is our opinion that these two conditions, even including an actual +arthritis, always exist, even in an attack of laminitis that ends +favourably. We do not claim, however, to be able to relate any means, save +that of post-mortem examination, by which it may be singled out from the +other changes occurring in the foot. The high fever and pain occasioned by +the inroads of the inflammation into the other sensitive structures serves +to effectually mask whatever evidence of it we might otherwise obtain. +It may be sometimes only small in degree, but we feel confident that +inflammation, at any rate of the _outer_ layer of the periosteum, is in +laminitis constant even, we repeat, in a mild case. + +[Illustration: FIG. 118.--SHOWING CHANGES IN THE OS PEDIS WITH LAMINITIS OF +LONG STANDING, (_a_, Viewed from the front; _b_, viewed from the side.) +The porous condition of the bone, which is here shown, is a result of a +rarefying or rarefactive ostitis. This specimen also illustrated (what the +photograph cannot show) an accompanying condition of condensation of bone, +or osteoplastic ostitis. (For a fuller description of the changes occurring +in these forms of ostitis, see Chapter XI.)] + +When the case is a serious one we have ample evidence to show that ostitis +exists, and exists in a severe form. The bones become vastly altered in +shape, a process of absorption leads to the formation of large, irregular +cavities within their substance, and what of the bone is left is rendered +hard and ivory-like (condensed) near what was the original centre, while +the edges and other portions show often a tendency to become brittle and +porous. + +Fig. 118 illustrates the effects of a severe ostitis in pedal bones removed +from hoofs with laminitis of several weeks' standing. + +_(e) Chronic Laminitis_.--The most common complication--or, perhaps, +rather we should term it 'sequel'--to acute laminitis is the chronic form +of the disease. For this condition we have reserved a separate section of +our work. It will be found described in Section B 1 of this chapter. + +_Diagnosis and Prognosis_.--One is almost tempted to state that the +diagnosis of laminitis offers no difficulty. In the very early stages, +however, it may, as we have already indicated, be mistaken for the oncoming +of Enteritis, Lymphangitis, or even Pneumonia. The paddling of the feet +may help us. If this is absent, however, nothing but a most careful +examination, or, if necessary, the withholding of our opinion until the +following visit will prevent a blunder being made. + +Even when well established, laminitis has been mistaken for paralysis, +for tetanus, for rheumatic affections of the loins, or even for some +undiscovered affection of the muscles of the arms and chest. This latter is +no doubt suggested to the uninitiated by the reluctance the animal shows to +move the muscles _apparently_ of that region, and led the older writers to +give to the disease its name of 'Chest-founder.' It is only fair to add, +however, that these blunders in diagnosis are nearly always committed by +persons without a veterinary training. + +Thus warned, the veterinary surgeon of average ability should have no +difficulty in establishing a distinction between the diseases we have +enumerated as likely to be confounded with it, and the one this chapter is +describing. + +The prognosis in laminitis should, in our opinion, always be guarded. No +advice given in a work of this description can be of any real use, for +every case must be judged entirely on its merits. The severity of +the symptoms, the cause of the attack, the complications, and the +idiosyncrasies of the patient, have all to be taken into account. These the +veterinarian must be left to judge for himself. + +_Treatment_.--The treatment of acute laminitis in its early stage must be +based upon the fact that we have to deal with a congested state of the +circulatory apparatus of the whole of the keratogenous membrane. This fact +was well enough known to the older veterinarians. It is not surprising, +therefore, to learn that jugular phlebotomy was at once resorted to as the +readiest means of relieving the overcharged vessels of their blood. As a +matter of fact, bleeding from the jugular is still advocated by modern +authorities. We cannot say, however, that we unhesitatingly recommend it. +Mechanically, of course, the removal of a large quantity of blood is +bound to result in a lowering of the pressure in the vessels. The effect, +however, is but transient. Blood removed in this way is again quickly +returned to the vessels so far as its fluid matter is concerned, and the +pressure, removed for a time, is again as great as before. With the +other and more vital constituents of the blood-stream--namely, the +corpuscles--restoration is not so rapid. We have, in fact, a weakened state +of the system, in which it is probable it will not so successfully combat +the adverse conditions the disease may induce. + +With these prefatory remarks, we may advise bleeding under certain +conditions. The quantity removed must be moderate (7 to 8 pints), and the +pulse and other conditions must show no signs of weakness or collapse. + +Local bleeding, either from the toe or the coronet, is also advised. In +the former situation the sole is thinned down until a sufficient flow +is obtained, while at the coronet scarification is the method adopted. +Bleeding locally, however, is far less effectual than the jugular +operation. Neither must it be forgotten that wounds in these situations, +more particularly at the toe, are extremely liable, especially with +the existing poisoned state of the blood-current, to take on a septic +character. What might possibly have remained a comparatively simple +inflammation is induced by the operation itself to terminate in the more +complicated and serious condition of suppuration. + +Other means of combating the congested state of the membrane are +principally those of local applications. With many veterinary surgeons warm +poulticing is still largely advocated and practised. We do not believe in +it. Warmth, as a means of removing local congestion, can only be successful +when applied _widely_ round the congested area, and so dilating surrounding +bloodvessels and lymphatics. Applied to the congested area itself, and to +that alone, it is almost worse than useless. + +With the foot, both around and below it, a surrounding area is denied us. +The only vessels we are able to dilate with the warmth, and so enable them +to carry off the fluid from the congested foot, are those in the +limb above. That poulticing cannot be successfully there applied is +self-evident. Apart from that, it is an open question whether poultices may +not do actual harm in inducing suppuration in cases where, probably, it +would not otherwise occur. + +For these reasons we hold to the opinion that when a local application is +determined on it should be a cold one. Various methods of applying cold are +in vogue. Cold swabs are perhaps most in favour. They must, however, be +_kept_ cold. When a suitable water-course, pond, or other expanse of +shallow water is at hand, then the animal may be kept standing therein, or +preferably walked about in it. When suitable apparatus is obtainable, a +constant stream over each foot from a rubber hosepipe is most beneficial. + +Astringent baths, containing solutions of alum, of copper sulphate, of iron +sulphate, or of common salt, or composed of a mixture of two or more of the +salts mentioned, may also be used with advantage. In addition to the fact +that such solutions are for a time below the temperature of simple water, +we have the advantage that they have also a more or less antiseptic +property. + +While on the subject of the relief of the congestion, we must not forget +to mention a treatment which we ourselves have practised with considerable +success--namely, that of forced exercise. It appears to have been first +brought into prominence by Mr. Broad, of Bath, and the two terms 'Forced +Exercise and Rocker Shoes' and 'Broad's Treatment' have come to be +synonymous. + +The Broad shoe is a shoe with a web of quite twice the thickness of the +animal's ordinary shoe, and has this web gradually thinned from the toe +backwards until at the heels the shoe is at its thinnest (see Fig. 119). + +The excessive thickness of the shoe serves two purposes. It allows of the +requisite amount of slope being given to the web, and so enables the animal +readily to throw himself back on to his heels, a position in which, as we +have already indicated, he obtains the greatest ease. It also minimizes to +some extent the effects of concussion. + +[Illustration: FIG. 119.--SEATED ROCKER BAR SHOE (BROAD'S) FOR TREATMENT OF +LAMINITIS.] + +With forced exercise, as practised by Mr. Broad, this shoe is first +applied, and the animal afterwards made to walk upon soft ground, or even +upon the roadway, for a half an hour to an hour and a half three times a +day. + +For our own part, we consider the shoe to be almost if not quite +superfluous, so far as its influence upon the progress of the disease is +concerned. We therefore dispense with it, and have the animal exercised in +his ordinary shoes. To do this, the patient has sometimes to be severely +flogged into taking the first few steps. After that progress gradually +becomes easier. + +It has been said to be cruel. In so far as we knowingly, and of set +purpose, occasion the animal pain, cruel it undoubtedly is; but it is +cruelty with an aim that is truly benevolent, and the object of our +benevolence is the animal upon whom the cruelty is practised. + +One word of advice is needed. The forced exercise must be commenced early. +In the later stages, when the stage of congestion has passed from that +to the acuter stages of the inflammation and the outpouring of the +inflammatory exudate, then forced exercise cannot be safely commenced. The +loss of adhesion between the pedal bone and the horny box, which we know to +be then existent, negatives its advisability. + +By many it is advised to always remove the shoes. From what we have already +said, it will be seen that this is not our practice. But one argument +in favour of so doing appears to us to carry weight, and that is that +'dropping' of the sole is probably prevented from becoming so marked. That +condition, however, is entirely dependent upon the changes occurring within +the horny box. It is bound to occur with the animal shod or unshod, and +to reach a stage when only contact with the ground prevents its further +descent. The complication then sometimes following--namely, penetration of +the sole by the bone, is not prevented by having the shoes removed. It may, +in fact, be thus rendered more likely. + +Internal treatment consists in the exhibition of suitable febrifuges and +the administration of a dose of aloes. + +With regard to the wisdom of the latter proceeding, opinion seems to be +divided. Personally, we hold an open mind concerning it. This much is +certain: in many cases of laminitis--those cases which have their origin +in overfeeding with an irritating food--there is already a strong +predisposition to enteritis. The administration of aloes in this case +is extremely apt to induce a fatal super-purgation. Aloes is, again, +contra-indicated when the laminitis is a result of excessively long +journeys, and the patient is already greatly exhausted. Neither can it be +advocated in the laminitis occurring as a sequel to septic metritis or to +pneumonia. + +On the other hand, when the disease has occurred as a result of long +standing in the stable and an overloaded condition of the bowels, or where +one full meal of some constipating food, such as whole wheat, pea or bean +meal, wheat or barley meal, has occasioned the attack, then a dose of aloes +at the commencement of the treatment is productive of good. + +Suitable febrifuges are found in potassium nitrate, potassium chlorate, +sodium sulphate, or magnesium sulphate, either of which or a mixture of two +or more of them, the animal will readily take in his drinking-water. + +The administration of sedatives is also indicated. In this connection +aconite will be found most useful. More especially in the early stages of +the disease, when pain is excessive and the temperature high, will its +good effects be noticed. This also the animal will often take in his +drinking-water. We have been in the habit of so prescribing the B.P. +tincture in 1/2-dram doses three times daily. By its use the temperature is +rapidly lowered, the pulse reduced in number and in fulness, and the pain +in some instances perceptibly diminished. With others hypodermic injections +of morphia and atropine have given equally satisfactory results. + +Needless to say, good nursing is a _sine quâ non_. During the first +stages of the fever a light and easily digested diet should be +allowed--bran-mashes, roots and grass when obtainable, and a carefully +regulated supply of water. The animal should be warmly clothed and the box +well ventilated, even to the opening of the doors and windows. Only in this +way is pneumonia as a sequel sometimes prevented. The patient's comfort +should be attended to in providing him with a suitable bed. Anything in +the shape of long litter should be avoided. When nothing else is at hand, +litter that has already been broken and shortened by previous use is best. +With this the box floor should be thickly covered, and matting of the +material prevented by constant turning. A good bed for the horse with +laminitis is peat-moss mixed with short straw. This, without being +dragged into irregular heaps, remains springy and elastic with but little +attention. Better than all, however, especially with good weather, is an +open crewyard. Here the animal has an abundance of fresh air, has a bed +that is always soft, and has plenty of room in which to get up and down +with some degree of ease. + +Leaving the dietetic and medicinal, we may consider other treatments of +laminitis that come more particularly under the heading of operative. + +The first matter that here demands our attention is that of allowing the +exudate to escape at the sole. If after the expiration of three or four +days pain and other symptoms of distress continue, then it may be judged +that the inflammatory exudate has made its appearance. Operative measures +allowing of its escape, though not giving absolute ease, do undoubtedly +relieve the more marked expressions of suffering, and should be at once +determined on. To do this completely it is necessary to cast the animal. +The sole is then thinned at the toe with the drawing-knife until the +sensitive structures are reached. A flow of yellow and sometimes +blood-stained discharge is immediately obtained, and the sole itself found +to be underrun to a considerable extent. An opening sufficiently large to +admit of free drainage (about the size of a half a crown-piece) is made, +the wounds antiseptically dressed, and the hobbles removed. + +If showing an inclination to do so, the animal should then be allowed +to remain and rest. In one instance in which we so operated (a case of +laminitis in the hind-feet alone), the relief given was at once manifested. +For three days previously the animal had remained standing in agonizing +pain. On the fourth he was cast, and the discharge--partly inflammatory +exudate, and partly a sanious foetid pus--liberated. The hobbles were +removed, and the animal allowed to remain down while our attention was +drawn to another case. This attended to, we walked back to the field +where, our first patient was lying. His breathing, but a short time before +distressedly short and catching, was now so slow and deeply regular that +for one brief moment the thought flashed across our mind that he was dead. +He was in a _profound_ sleep. + +Other operators sometimes give the exudate escape while making the grooves +in what is now known as 'Smith's Operation.' + +In this operation the hoof is so grooved as to allow of its expansion, so +relieving the pressure on the sensitive structures within it. Incidentally, +the inflammatory exudate is given exit. + +[Illustration: FIG. 120.--DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE +GROOVES MADE IN THE TREATMENT OF LAMINITIS.] + +The animal is cast, the shoes removed, and three vertical grooves made +in the wall. The first is cut down the centre of toe, extending from the +coronet to the ground surface. The second is made to the right of this, and +the third to the left, each following the direction of the horn fibres, and +each distant about 2 inches from the first (see 1, 2, and 3, Fig. 120). + +Each of the grooves must run completely from the coronary margin to the +ground surface, and each should be carried through the substance of the +horn until the horny laminæ are reached. This done, the underneath surface +of the foot is grooved at the white line (see curved groove 4, Fig. 121) +in such a manner as to entirely isolate the two pieces of horn _a_ and _b_ +from the remainder of the hoof. + +Expansion of the horny box is thus brought about, while at the same time +the semicircular groove at the toe is made deep enough to allow of the +escape of the exudate. + +If thought wise by the operator, the two pieces of horn _a_ and _b_ may be +isolated, and the exudate given exit by making the fourth groove in the +position of the dotted lines in Fig. 120--that is to say, at the lowermost +portion of the sensitive structures. By this means the sole will be left +intact. + +[Illustration: FIG. 121.--LOWER SURFACE OF FOOT SHOWING POSITION OF THE +GROOVES MADE IN THE TREATMENT OF LAMINITIS.] + +Fuller instruction for making the grooves and the instruments required will +be found described in Section C of Chapter X. + +The animal should be afterwards shod, and the bearing on the portions +_a_ and _b_ of the wall removed. Almost immediate relief is afforded the +patient. + +_Recorded Cases_.--1. 'On the evening of September 28 last, I was called +rather hurriedly to attend a posting-horse which had just arrived from a +twenty-one miles' journey, and was said to be "very ill." I lost no time in +proceeding to the spot, and found my patient "very ill" indeed. No need for +long consideration as to diagnosis; the symptoms showed at once that I had +an uncommonly severe case of acute founder before me. On examination I +found the pulse was 120, the respirations 100, and the thermometer 106° F. +The poor brute could not move, the fore-legs were well out before, and the +hind-legs thrown back behind; in fact, he was, as one might say, propping +himself up with his four legs! + +'On examining his feet, I discovered what I had never either seen or heard +of before--namely, _blood freely oozing out_ at the coronet of all four +feet; if anything, the hind-feet were the worst, and, showing that this +bloody discharge at coronets had commenced during progression and before +he was stabled, the inside of the thighs were all shotted over with blood, +which had been thrown up by his feet while he was trotting or walking. He +was completely soaked all over with perspiration. + +'My prognosis could not well be otherwise than unsatisfactory. I resolved, +however, to do all I could to relieve the poor suffering brute. As a matter +of course, jugular phlebotomy was utterly impracticable; so, to relieve the +pressure in the feet, I had him (after, with extreme difficulty, removing +the shoes) bled, or rather opened, at all four toes, and hot poultices +applied. On opening the off-side toe, in both hind and fore feet, I found +an escape of very dark-coloured blood, with a great many bubbles of gas, +thus showing that the destructive process was fairly established in the +two bony extremities mentioned. The near fore and near hind feet showed no +signs of gas-bubbles on being opened at the toe. + +'I gave a laxative in combination with a diffusible stimulant, and ordered +doses of aconite and potassium iodide; I also applied strong sinapisms to +each side, immediately behind the shoulders. After three hours I found my +patient rather easier; respiration about 90, and temperature 104°; willing +to take a little water, and even attempted to take some hay. Ordered +continued applications of hot water to the poultices at feet, and +clothed him up for the night. Next morning there was little improvement; +respirations over 80, and temperature 103.5°. Continue same treatment. +Second morning, horse apparently easier; temperature 102.5°, but very +difficult respiration; laxative had operated during the night; ordered +diffusible stimulants. About two hours and a half after my last visit, the +horse turned round in his stall and dropped down dead! + +'_History of the Horse_.--He belonged to an extensive horse-hiring +establishment; was purchased a short time before for £60--a long price for +a post-horse--had recently suffered and been off work from some "severe +cold"; was taken out, and did forty-seven miles of a journey the day +_before_ I saw him; on forenoon of the day on which he was attacked he did +two or three short turns, and then twenty-one miles of a journey in the +afternoon, during which he became so ill as scarcely to be able to conclude +the twenty-one miles; this was the last turn he was to do. He was a grand +stepper, and no doubt was pushed a little during this final journey, as +the driver intended, after a short rest, to finish off with the twenty-six +miles between this and home. With the short turns on the second forenoon, +this would have been over 100 miles in less than two days, with a horse +just out of a _severe cold_.'[A] + +[Footnote A: _Veterinary Journal_, vol. xvii., p. 314 (A.E. Macgillivray).] + +2. 'Whilst attending a patient on a farm on September 5 last my attention +was called to a cart-horse, five years of age, that had been castrated in +the standing position by a travelling castrator about ten days previously. + +'I found the animal presenting the following symptoms: Head down, blowing +hard, very dull, and disinclined to move, temperature 105° F., hard, rapid, +slightly irregular pulse, membranes injected, appetite lost; scrotum, +sheath, and penis tremendously swollen, castration wounds unhealthy, and +exuding a thin, reddish-brown discharge of a most foetid odour. + +'The next day well-marked symptoms of laminitis were present. I finally +ceased attending him about the middle of October, and at the end of that +month he was turned out for the winter.'[A] + +[Footnote A: _Veterinary Record_, vol. xiv., p. 649 (Charles A. Powell).] + +3. 'On July 8 an interesting case of laminitis came under my notice. The +subject was a mare, eight years old, which had been running on the common +here for some months, and was taken up on the night of July 2 by a boy, +who did not observe anything amiss with her. The following morning, on the +owner going to the stable, he found the animal in great pain, and at once +sent for me. I discovered her to be suffering from laminitis, and saw her +again in the evening, when she was much worse. The attack proved to be a +most severe one. + +'The owner informed me that she had not been allowed any corn for two +months, and that she had no distance to travel on the road from the common. + +'Though on such a poor pasture, the mare was very fat; she had never been +unwell before this attack. + +'This is the first case I have seen of laminitis occurring when the animal +was on grass.'[A] + +[Footnote A: _Veterinary Journal_, vol. ix., p. 176 (W. Stanley Carless).] + + +B. CHRONIC. + +1. CHRONIC LAMINITIS. + +_Definition_.--A low and persisting type of inflammation of the sensitive +structures of the foot, characterized by changes in the form of the hoof, +and incurable pathological alterations within it. + +_Causes_.--Chronic laminitis more often than not is a sequel to the acute +form we have just described. With an attack of acute laminitis that defies +treatment, and does not end in resolution in from ten days to a fortnight, +then the chronic form may be expected. + +The brittle horn, convex sole, and other changes we have described under +Pumiced Foot may, however, be regarded as a chronic laminitis, and this +condition, as we have already indicated in Chapter VI., may run a course +slow and insidious from the onset. + +_Symptoms_.--When the disease arises without previous acute symptoms, the +first thing noticeable is an alteration in the gait. The animal begins to +go feelingly, especially when first moved out from the stable. Our opinion +is asked as to the cause of the lameness, and an inspection is made. With +the changes in the form of the hoof as yet wanting, we have nothing to +guide us, and other causes for the lameness suggest themselves, probably +corns. Evidence of these is not forthcoming, and we in all probability +withhold our opinion until a later visit. On the second or a subsequent +call we are perhaps lucky enough to find our patient down. Diagnosis is +then rendered easier. Made to rise, the animal stands in the attitude we +have described as indicative of laminitis. We have him walked and trotted +out. The symptoms of tenderness disappear, and the animal soon goes fairly +sound. He is, in fact, workable--that is, by anyone who is careless as to +the comfort of his beast. + +When following an acute attack, we have the most marked symptoms of pain +and distress, somewhat abating after the second or third week. The walk, +however, is still painful, and, for a short time after rising from the +ground, even difficult. + +In short, in both cases we have the horse going on his heels, with a walk +that is painful, and with symptoms of pain that are most apparent when +moved on after a rest. + +Later, the changes in the form of the hoof begin to appear. It seems to +have lost its elasticity, and is seen to be dry and chippy, and to have +become denuded of its varnish-like outer covering. + +In addition, it is of largely altered shape. The toe, by reason of the +animal walking on his heels, and by reason of an increased growth of horn, +becomes elevated, so that the front of the wall, instead of forming an +obtuse angle with the ground, comes to run very nearly horizontal with +it. The horn of the heels, as compared with that of the toe, takes on an +increased growth. The same thing we have already indicated as happening at +the toe, though in lesser degree. Taken together, this increased growth of +horn at the toe and at the heels has the result of lengthening the diameter +of the foot from before backwards, the transverse diameter remaining more +or less normal. The hoof thus loses its circular build, and comes to +approach nearer an elongated oval. + +[FIG. 122.--FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS.] + +At this stage, too, the pathological 'ribbing' of the hoof is observable. +The outer surface of the wall becomes marked with a series of ridges +encircling the hoof from heel to heel (see Fig. 81, which illustrates a +moderate deformity of the hoof occurring after laminitis). In the badly +laminitic hoof, however, this deformity is largely increased, until in some +cases the shapeless mass can hardly be likened to a foot at all (see Fig. +122). + +The inferior or solar surface of the foot also offers certain changes for +our consideration. The first thing that strikes one is the convexity of the +sole. This, as we have already pointed out, is due to descent of the os +pedis, and the highest point of the convex portion is that immediately in +front of the apex of the frog. Here the horn is sometimes found to be quite +yielding to the finger, is excessively thin, and is more or less granular +and inclined to break up under manipulation. As a consequence, any rough +use of the drawing-knife, or an accidental wounding with sharp flints or +stones, leads to exposure of the sensitive structures and local gangrene. + +With the horn of the sole thus deteriorated by reason of excessive and +continued pressure upon the parts secreting it, it is not surprising to +find that, in many cases, actual penetration of it with the os pedis +occurs. It is the anterior portion of the inferior margin of the bone that +makes its appearance, and shows itself as a small semicircular white or +dark gray line on the sole. + +[Illustration: FIG. 123.--SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS, +SHOWING ITS ABNORMAL OVAL SHAPE FROM BEFORE BACKWARDS, AND THE EXCESS OF +HORN GROWING FROM THE WHITE LINE IN THE REGION OF THE TOE.] + +Exposure of the bone is soon followed by its necrosis, in which case the +wound takes on an ulcerating character. From it there is a discharge of +pus, black in colour and offensive in smell, and, protruding from the +opening, are excessive granulations of the remains of the sensitive sole. + +The 'white line,' so apparent when a normal foot is cleaned with the knife, +can no longer be sharply distinguished from the surrounding horn, while in +some cases the horn composing it takes on an abnormal growth at the toe +(see Fig. 123). This adds still further to the abnormal lengthening of the +antero-posterior diameter of the foot already mentioned. + +In other cases horn in this position is altogether wanting, and in its +place is a well-defined cavity, into which the blade of a knife can be +readily passed. This cavity is bounded in front by the original wall of the +hoof, and is here lined by a degenerated and hypertrophied growth of the +horny laminæ. Posteriorly the cavity is bounded by the front of the os +pedis, and is lined by a thin growth of horn secreted by the keratogenous +membrane covering the bone. Superiorly the cavity is quite narrow, +and extends to near the lower surface of the coronary cushion, while +inferiorly, at its open portion, it is often 1/2 inch to 1 inch wide. +Laterally it extends on each side of the toe to the commencement of the +quarters. + +[Illustration: FIG. 124.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +THREE WEEKS' STANDING. On the anterior face of the cavity, in front of +the os pedis, are thickened horny laminæ. Due to the sinking of the bony +column, the os pedis has perforated the horny sole.] + +Exploration with a director, or with the blade of a scalpel, removes from +the opening a dry detritus. This is composed of the solid constituents +of the escaped blood, the dried remains of the inflammatory exudate, and +broken-down fragments of cheesy-looking horn. The size to which the cavity +may sometimes extend is illustrated in Fig. 124. The thickened horny laminæ +forming the anterior boundary of the cavity are here depicted, together +with commencing perforation of the horny sole by the os pedis. It is this +cavity which, when opened at the bottom and discharging its mealy-looking +contents, is known as seedy-toe, for a further description of which see p. +293. + +The lameness occurring with chronic laminitis does not always persist. As +time goes on the sensitive structures accommodate themselves to the altered +form and conditions of the horny box. In certain situations--namely, where +pressure is greatest--the softer structures become atrophied, and sometimes +even wholly destroyed; while in other positions the changes in form of the +hoof tend to increase in size of its interior, with a consequent diminution +of pressure upon, and increased growth of the structures within it. + +_Pathological Anatomy_.--In detailing the changes to be observed in chronic +laminitis, we take up the description where we left it when dealing with +the pathological anatomy of the acute form. The alterations to be met +with are best observed by taking a foot so diseased and making of it two +sections--one longitudinal, from before backwards; the other horizontal, +and in such a position as to cut the os pedis through at its centre. + +These sections will expose to view the cavity formed by the pouring out of +the exudate, and its full extent may be noticed by examining the sections +alternately. Taking the horizontal section first, it will be seen that +the hollow space extends wholly round the toe, and as far back as the +commencement of the quarters. In the latter position one is able to observe +laminæ still in their normal positions and condition. At the toe, however, +the horny and secretive laminæ are widely separated, and the space between +them filled with a yellow, semi-solid material, the remains of the +inflammatory exudate and new horn secreted by the keratogenous membrane. +The laminæ, both horny and sensitive, are greatly enlarged. This is a +hypertrophy, resulting from the continued effects of the inflammation, and +leads in time to the formation of laminæ quite three or four times their +normal size. It is this hypertrophy of the laminæ and the pressure of the +exudate that causes the bulging and increased growth of the horn at the toe +(see Fig. 125), and contributes towards the oval formation of the foot we +have mentioned before. + +[Illustration: FIG. 125.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +SEVERAL YEARS' DURATION.] + +In the longitudinal section the first thing noticeable is the change +in position of the bones, more especially in that of the os pedis. The +circumstances we have mentioned before--pressure of the exudate upon it in +front and tension of the perforans on it behind--have caused it to assume +a more upright position than is normal, so much so that in a bad case the +front of the bone becomes quite vertical. This vicious direction the other +bones of the digit follow (see Fig. 125). + +Consequent upon the displacement of the bone, the plantar cushion, by +reason of the continued pressure thus put upon it, becomes atrophied, while +its hinder half is, as it were, squeezed into taking up a position +more posterior and higher in the digit than normally it should. The +horn-secreting papillæ covering its inferior face thus become directed +backwards sooner than downwards, in which way we account in some measure +for the noticeable increase of horn at the heels. + +_Treatment_.--Chronic laminitis is incurable. Treatment must therefore be +directed towards the palliation of such conditions as are present, with +the object of rendering the the animal better able to perform work. When +perforation of the sole has occurred, with the attendant formation of pus +and necrosis of the os pedis, it is doubtful whether treatment of any kind +is advisable. There are on record cases of this description, where careful +curetting of the exposed and necrotic portions and the after application of +antiseptic dressings, held in position by a plate shoe or a leather sole, +has been followed by good results, and the animal restored for a time to +labour. In our opinion, however, early slaughter is the most economical +course to adopt, and certainly the wisest advice to give to the ordinary +client. + +When perforation of the sole is absent, and when serious alteration in the +shape of the horny box has not occurred, then the most simple treatment is +to put the animal straight away to slow work, with the feet protected by +suitable shoes. + +Here, again, the most useful shoe is the Rocker Bar (Fig. 119). The broad +web and deep seating gives ample protection to the convex sole, and with +the ease in distributing his weight that this shoe affords the animal is +able to perform slow work on soft lands with some degree of comfort. + +Should the growth of the horn at the toe and at the heels be unduly +excessive, then our attention may be directed towards reducing it to some +approach to the normal. This is accomplished by removing with the rasp and +the knife those portions indicated by the dotted lines in Fig. 127. Here it +will be seen that the bulk of the horn removed is that protruding at +the toe. After this the animal should again be suitably shod. In this +connection it should be noted that the fact of the animal walking largely +on the heels tends to a forward displacement of the shoe. This must be +prevented by providing each heel of the shoe with a clip, after the manner +shown in Fig. 128; or, in the case of a bar shoe, supplying it with a clip +at the centre of the bar. + +[Illustration: FIG. 126.--DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN +AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS.] + +[Illustration: FIG. 127.--THE SAME FOOT AS IN FIG. 126. The dotted lines +show the excess of horn removed preparatory to shoeing.] + +Among other treatments to be noted we may mention one or two to be found +chiefly in Continental works on this subject. + +The method of Gross consists in thinning down with a rasp about 1-1/2 +inches of the horn of the wall immediately below the coronet, the thinned +portion extending from heel to heel. The groove made is filled with +basilicon ointment,[A] and the coronet stimulated with a cantharides +ointment, In this way there is induced to grow from the coronet a new wall +of nearly normal dimensions. + +[Footnote A: Basilicon ointment is made by heating together resin 8 parts, +beeswax 8 parts, olive oil 8 parts, and lard 6 parts. Allow to cool without +stirring.] + +By other operators (Bayer, Imminger, Meyer, and Gunther) this treatment +has been modified by enlarging upon it and removing the whole of the +adventitious horn. + +[Illustration: FIG. 128.--THE SHOE WITH HEEL-CLIP.] + +This is done by means of the drawing-knife and the rasp, the ugly-looking +pumiced foot being carefully cut and trimmed until, so far as outward +appearances are concerned, it is perfectly normal. This done, the whole +foot is treated with a suitable hoof ointment, and a shoe applied that +affords protection to the sole without imposing pressure upon it. The +shoe indicated is either an ordinary shoe with an unusually broad and +well-seated web, or the seated Rocker Bar of Broad. With either it is well +to additionally protect the sole by means of a leather or rubber pad and +tar stopping, or by using the Huflederkitt described on p. 148. In every +case the nails must be kept well back in order to avoid the weakened and +degenerated horn at the toe, and to take advantage of the greater growth of +horn at the heels. + +The wisdom of thus removing the whole of the adventitious horn may be +questioned. Although a foot of a nearly normal shape is obtained, it must +be remembered that the grave alterations within it are unchanged, and +that in certain positions the operation must have carried us nearer the +sensitive structures than is advisable. + +All other treatments failing, the operation of neurectomy has been advised. +This we do not think wise. One would imagine that, with degenerative +processes already going on in the foot, the tendency to gelatinous +degeneration, always to be looked for in neurectomy, would be increased. +This, as a matter of fact, is the case, and is borne out by the statements +of those who have tried this method of treatment. In many cases the +lameness even is not got rid of. Even where it is, the operation is +afterwards followed by a great tendency to stumble, by sloughing of the +hoof, or by a marked increase in the adventitious horn, and a consequent +greater deformity of the foot. + +Sooner than risk neurectomy, it seems to us wiser to give a trial to the +operation advocated by M.G. Joly, namely, that of ligaturing one of the +digital arteries on each affected foot. This operation is performed in the +same position as is the higher operation of plantar neurectomy, and may be +either internal or external. The vessel is exposed, and a double ligature, +preferably of silk, placed on it. The artery is then divided between +the two ligatures. The immediate effect of the operation is to cause +a considerable diminution in the arterial pressure, and so lessen the +intensity of the ostitis in the os pedis. Its consequences are not so +serious as those of neurectomy, and it decongests tissues which neurectomy +congests. + +In cases related by M. Joly this operation, practised both in conjunction +with removal of the excess of horn and without it, has resulted in a marked +improvement in the gait, the animal going to work one month after the +treatment, and remaining sound for some time afterwards. + +2. SEEDY-TOE. + +_Definition_.--A defect in the horn of the wall, usually at the toe, but +occurring elsewhere, resulting in loss of its substance in either its +internal or external layers (see Figs. 129, 130, and 131). + +_Causes_.--The most common factor in the causation of this defect is +undoubtedly disease of the sensitive laminæ. We have, in fact, just given +an excellent example of the formation of a seedy-toe in the sections of +this chapter devoted to laminitis (see pp. 265 and 286). The cavity here +formed by the outpouring of the inflammatory exudate and the separation of +the sensitive and horny laminæ persists. It becomes filled with the +dried remains of the exudate and perverted secretions from the horny and +sensitive laminæ (see p. 287). As yet, however, the cavity is closed below, +and its existence only surmised. Later, with successive visits to the +forge, the layer of solar horn forming its floor is cut away, and the +cavity exposed to view. Its mealy-looking contents are removed, and the +case reported by the smith. + +Although occurring in this way with an acute attack of laminitis, it must +be remembered that seedy-toe may arise without previous noticeable cause. +The first intimation the owner has is a report from the forge that +seedy-toe is in existence. To refer to cases so arising a probable cause is +far from easy. At one time it was believed to be due to parasitic infection +of the horn. Others have blamed the pressure of the toe-clip, excessive +hammering of the wall, or pressure from nails too large or driven too +close. Others, again, say that seedy-toe may result from a prick in the +forge, from hot-fitting of the shoe, from standing on a dry and sandy soil, +or from the use of high calkins on the front shoes. In these cases--cases +with an insidious onset--we are inclined to the opinion that the disease +of the horn commences from below, and that the sensitive laminæ become +implicated later. Holding this view, one must account for the commencing +disease of the horn by giving, as causes, firstly, those factors (as, +for instance, alternate excessive dampness and dryness) leading to +disintegration of the horn tubules; secondly, the penetrating into and +between the degenerated tubules of parasitic matter from the ground; and, +thirdly, the final breaking up of the horn, and spread of the lesion under +the invasion thus started. + +[Illustration: FIG. 129.--DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE +(INTERNAL). 1, The horn of the wall; 2, the horn of the sole; 3, the cavity +of the seedy-toe; 4, the os pedis; 5, the keratogenous membrane.] + +_Symptoms_.--Lameness sometimes attends seedy-toe, and sometimes does not. +This is an important point to be carried in mind by the veterinary surgeon +who is accustomed in his practice to have many animals pass through his +hands for examination as to soundness. An animal with advanced seedy-toe--a +condition constituting serious unsoundness--may walk and trot absolutely +sound, and may give no indication, either in the shape of the wall or the +condition of the sole, that anything abnormal is in existence. Later, +however, after the veterinary surgeon has passed him, the purchaser lodges +the complaint that the horse has a bad seedy-toe, which, so he is told, +must have been there for some time. In this case, culpable though he may +appear, there is every excuse for the veterinary surgeon. + +Once the cavity is opened at the toe in the neighbourhood of the white +line, then diagnosis is easy. A blunt piece of wood, the farrier's knife, +or a director may be easily passed into it, sometimes as far up as +the coronary cushion (see Fig. 129). Issuing from the opening is seen +occasionally a little inspissated pus; more often, however, the dry, +mealy-looking detritus to which we have before referred. This form of the +disease we may term 'Internal Seedy-Toe.' for, plainly enough, it has had +its origin in chronic inflammatory changes in the keratogenous membrane. + +[Illustration: FIG. 130.--EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR +BORDER OF THE WALL.] + +[Illustration: FIG. 131.--EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR +FACE OF THE WALL.] + +Disease of the horn and loss of its substance may, however, also commence +from without. A report on this condition, under the title of 'External +Seedy-Toe,' is to be found in vol. xxix. of the _Veterinary Journal_, from +which we borrow Figs. 130 and 131. + +In Fig. 130 it will be seen that the disease commences at the plantar +surface of the toe, and extends upwards and inwards. The same condition +may also appear anywhere between the coronet and the ground, gradually +extending into the substance of the wall, as shown in Fig. 131. According +to the writer, Colonel Nunn, the progress of the disease in this latter +case appears to be faster in a downward than in an upward direction. This, +however, is more apparent than real, as the rate of growth of the horn +downwards detracts from the progress of the disease upwards, although it +spreads over the horn at the same rate. + +Before concluding the symptoms, we may again allude to the fact that, +although usually occurring at the toe, the same condition may be met with +in other positions--namely, at either of the quarters. In appearance and in +other respects it is identical with that occurring at the toe. + +When the animal is lame and the existence of seedy-toe is surmised, or when +the cause of the lameness is altogether obscure, a little information may +perhaps be gathered from noting the wear of the shoe. If the animal has +been going lame for any length of time as a result of disease in the +sensitive laminæ, then the shoe will be greatly thinned at the heels, and +the toe but little worn. + +_Treatment_.--As with diseased structures elsewhere, the most rational +treatment, when possible, is that of excision. The entire portion of the +wall forming the anterior boundary of the cavity is thinned down with +the rasp and afterwards removed with the knife, wholly exposing the +hypertrophied, but usually soft layer of horn covering the sensitive +structures. These hypertrophied portions are also removed, and every +particle of the dust-like detritus cleaned away. After-treatment consists +in dressing the parts with a good hoof ointment, protecting them, if +necessary, with a pad of tow and a stout bandage. It may be that the +removal of a large portion of the wall may for some time throw the animal +out of work. Acting on Colonel Fred Smith's suggestion, this may be avoided +by having made a thin plate of sheet-iron, slightly larger in circumference +than the portion of horn removed, and shaped to follow the contour of the +foot. This made, it is sunk flush with the wall by hot-fitting it, and kept +in position by several small steel screws fixed into the sound horn, just +as in the treatment for sand-crack (see p. 174). This will serve the +useful purpose of maintaining in position any dressing that may be thought +necessary, of acting as a support to the horn left on each side of the +portion removed, and of keeping the exposed structures free from dirt and +grit. + +Practical points to be remembered in fitting plates of this description +to the feet are: The plate must never quite reach the shoe, or it will +participate in the concussion of progression, and so loosen the screws that +hold it in place. For the same reason, that portion of the sole adjoining +the piece of horn removed must have its bearing on the shoe relieved. The +screws holding the plate should be oiled to prevent rusting, and should +take an oblique direction in order to obtain as great a hold as possible on +the wall. + +When excision is deemed unwise or unnecessary, treatment should be directed +towards maintaining the cavity in a state of asepsis. To this end it +should be thoroughly cleaned of its contents, and afterwards dressed with +medicated tow. The ordinary tar and grease stopping is as suitable as any. +This, together with the tow, is tightly plugged into the opening and kept +in position by a wide-webbed shoe. Instead of the tar stopping and the tow, +there may be used with advantage the artificial hoof-horn of Defay (see p. +152). Before using this the cavity should again be thoroughly cleaned out, +and should in addition be mopped out with ether. The latter injunction is +important, as unless the grease is thus first removed, the composition will +fail to adhere to the horn. With the cavity thus cleaned and prepared, the +artificial horn, melted ready to hand, is poured into it and allowed to +set. + +In every case, no matter what else the treatment, the bearing of the horn +adjacent to the lesion should be removed from the shoe. + +Whether practising the method of plugging the cavity or that of excision of +the wall external to it, attempts to quickly obtain a new growth of horn +from the coronet should be made. To further that, frequent stimulant +applications should be used. Ointment of Biniodide of Mercury 1 in 8, of +Cantharides 1 in 8, or the ordinary Oil of Cantharides, either will serve. + +3. KERAPHYLLOCELE. + +_Definition_.--By this term is indicated an enlargement forming on the +inner surface of the wall. In shape and extent these enlargements vary. +Usually they are rounded and extend from the coronary cushion to the sole, +sometimes only as thick as an ordinary goose-quill, at other times reaching +the size of one's finger. Often they are irregular in formation and +flattened from side to side. + +[Illustration: FIG. 132.--A PORTION OF THE HORN OF THE WALL AT THE TOE +REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.] + +_Causes_.--Keraphyllocele is very often a sequel to the changes occurring +at the toe in laminitis. Probably, however, the most common cause is an +injury upon, or a crack through, the wall. It may thus occur from excessive +hammering of the foot, from violent kicking against a wall or the stable +fittings, and from the injury to the coronet known as 'tread.' It may also +occur as a sequel to complicated sand-crack, and to chronic corn. + +That fissures in the wall are undoubtedly a cause has been placed on record +by the late Professor Walley, who noticed the appearance of these horny +growths following upon the operation of grooving the wall.[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iii, +p. 170.] + +This gentleman had a large Clydesdale horse under his care for a bad +sand-crack in front of the near hind-foot, and, as the lameness +was extreme, he adopted his usual method of treatment--viz., rest, +fomentations, poulticing, and the making of the V-shaped section through +the wall, and subsequently the application of an appropriate bar shoe +to the foot, and repeated blisters to the coronet. In a short time the +lameness passed off, and the horse was put to work. A few days later the +animal met with an accident, and was killed. + +On examining a section of the hoof it was found that a vertical horny ridge +corresponding to the external fissure had been formed on the internal +surface of the wall, and that a well-marked cicatrix extended upwards +through the structure of the hoof at the part forming the cutigeral groove; +furthermore, _a similar ingrowth had been taking place in the line of the +oblique incisions made for the relief of the sand-crack_. + +This case has an important bearing on the operation of grooving the wall, +which operation we have several times in this work advocated for the relief +of other diseases. It teaches us that the incisions should not be carried +so completely through the horn as to interfere with and irritate the +sensitive laminæ, and so set up the chronic inflammatory condition leading +to hypertrophy of the horn. + +From the position on the os pedis of the indentation made in it by the +keraphyllocele (see Fig. 133) it has been argued that pressure of the +toe-clip is a cause of the new growth. This, we should say, cannot be a +very strong factor in the causation, for, while we admit that the continual +pressure of the clip, and the heavy hammering that sometimes fits it into +position, is likely to set up a chronic inflammatory condition of the +sensitive laminæ in that region, we must still point out that the rarity +of keraphyllocele, as compared with the fact that clips are on every shoe, +does not allow of the argument carrying any great weight. + +_Symptoms_.--Except under certain conditions this defect is difficult +of detection. As a rule, lameness is not produced by it. In making that +statement we are led largely by the conclusion arrived at by Professor +Walley. This observer noted the fact that ingrowths of horn such as we are +describing nearly always take place in false quarter, or after a sand-crack +has been repaired, and that they commonly occur after the operation of +grooving the wall in the manner we have just shown. + +Now, we know that quite often under these circumstances the horse goes +perfectly sound. Thus, while we know that in all probability keraphyllocele +is in existence, we have ocular demonstration that the animal is quite +unaffected by it. + +In some cases, however, lameness is present. During the early stages of +the growth's formation it is but slight, increasing as the keraphyllocele +enlarges. Should this be the case, other symptoms present themselves. +The coronet is hot, and tender to the touch, sometimes even perceptibly +swollen, and percussion over the wail is met with flinching on the part +of the animal. In other cases one is led to suspect the condition by +the prominence of the horn of the wall of the toe. This is distinctly +ridge-like from the coronet to the ground, while on either side of it the +quarters appear to have sunk to less than their normal dimensions. We +believe this to be an illusion, as a ridge of any size at the toe readily +gives one the impression of atrophy behind it, without this latter +condition being actually present. + +Should this ridge-like formation and the accompanying symptoms of pain and +lameness occur after repair of a sand-crack, then keraphyllocele may, with +tolerable certainty, be diagnosed. When these outward signs are wanting, +however, and the true nature of our case is a matter of mere conjecture, a +positive diagnosis may still be made at a later stage--that is, when the +abnormal growth of horn reaches the sole. In this case either there is +met with when paring the sole a small portion of horn, circular in form, +distinctly harder than normal, and indenting in a semicircular fashion the +front of the white line at the toe, or solution of continuity between the +tumour and the edge of the sole and the os pedis takes place, and the +lameness resulting from the ingress of dirt and grit thus allowed draws +attention to the case. + +_Pathological Anatomy_.--With the sensitive structures removed from the +hoof by maceration or other means, these growths are at once apparent. They +may occur in any position, but are usually seen at the toe, and they may +extend from the coronary cushion to the sole, or they may occupy only +the lower or the upper half of the wall. In places the tumour (or 'horny +pillar' as the Germans term it) is roughened by offshoots from it, and does +not always exhibit the smooth surface depicted in Fig. 132. Commonly, the +horn composing the new growth is hard and dense. Sometimes, however, it is +soft to the knife, and is then found to be itself fistulous in character, +a distinct cavity running up its centre, from which issues a black and +offensive pus. + +In a few cases the sensitive laminæ in the immediate neighbourhood are +found to be enlarged, but in the majority of cases atrophy is the condition +to be observed. Not only are the sensitive structures found to be shrunken +and absorbed, but the atrophy and absorption extends even to the bone +itself (see Fig. 133). This latter is a result of the continued pressure of +the horny growth, in a well-marked case ending in a sharply-defined groove +in the os pedis in which the keraphyllocele rests. The fact that the softer +structures, and even the bone, thus accommodate themselves to the altered +conditions is, no doubt, the reason that lameness in many of these cases is +absent. + +_Treatment_.--It is doubtful whether anything satisfactory can be +recommended. When we have suspected this condition ourselves, it has been +our practice to groove the hoof on either side of the toe, after the manner +illustrated in Fig. 120, and, at the same time, point-firing the coronet +and applying a smart cantharides blister. Certainly, after this operation, +lameness has often disappeared--whether, however, as a result of the +treatment adopted or by reason of the structures within accommodating +themselves to the condition, we would not care to say. + +[Illustration: FIG. 133.--OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY +ATROPHY AND ABSORPTION INDUCED BY PRESSURE OF A KERAPHYLLOCELE.] + +Other writers advocate the removal of that portion of the wall to which the +tumour is attached, after the manner described on p. 182, and illustrated +in Fig. 98. This, however, should be a last resource, and should be adopted +only when weighty reasons, such as excessive and otherwise incurable +lameness, appear to demand it. + +4. KERATOMA. + +In our nomenclature the terms 'Keratoma' and 'Keraphyllocele' are both used +to indicate the condition we have just described. There are some, however, +who reserve the term 'Keratoma' for horny tumours occurring only on the +sole, and for that reason we draw special attention to the word here. +Keratoma may thus be used to describe what we have called keraphyllocele +directly that growth makes its appearance at the sole, and is there able +to be cut with the knife. Similar hard and condensed growths may, however, +make their appearance on the sole in other positions quite removed from the +white line, plainly being secreted by the villous tissue of the sensitive +sole, and having no connection whatever with the sensitive laminæ. +They appear as circular patches, varying in size from a shilling to a +two-shilling piece. Compared with the surrounding horn, they stand out +white and glistening, while in structure they are dense and hard, and +offer a certain amount of resistance to the knife. They are of quite minor +importance, and, beyond keeping them well pared down, need no attention. +Keratoma probably offers us the best analogy we have to corn of the human +subject. + +5. THRUSH. + +_Definition_.--A disease of the frog characterized by a discharge from it +of a black and offensive pus, and accompanied by more or less wasting of +the organ. + +_Causes_.--The primary cause of this affection is doubtless the infection +of the horn, and later the sensitive structures, with matter from the +ground. Those factors, therefore, leading to deterioration of the horn, and +so exposing it to infection, may be considered here. Such will be changes +from excessive dampness to dryness, or _vice versâ_; work upon hard and +stony roads; prolonged standing in the accumulated wet and filth of +insanitary stables, or long standing upon a bedding which, although dry, is +of unsuitable material. + +In this latter connection may be mentioned the harm resulting from the use +of certain varieties of moss litter. This we find pointed out by J. Roalfe +Cox, F.R.C.V.S.[A] Tenderness in the foot was first noticed, and, on +examination, the horn of the sole and of the frog was found to be +peculiarly softened. It afforded a yielding sensation to the finger, not +unlike that which is imparted by indiarubber, and on cutting the altered +horn it was almost as easily sliced as cheese-rind. The outer surface +being in this way slightly pared off, the deeper substance of the horn was +discoloured by a pinkish stain. The horn of the frog was in many instances +found detaching from the vascular surface, which was very disposed to take +on a diseased action, somewhat allied to canker, and became extremely +difficult to treat. + +[Footnote A: _Veterinary Journal_, vol. xvi., p. 243.] + +Conditions such as these, although not constituting the disease itself, +certainly lay the frog open to infection, especially if afterwards the +animal is called upon to work in the mud of the streets of a large town, or +to stand in a badly drained and damp stable. + +A further cause of thrush is to be found in the condition of the frog, +brought about by contraction of the heels (see p. 118). We have already +seen that one of the most prominent factors in the causation of contraction +is the removal of the frog from the ground by shoeing, with its consequent +diminution in size and deterioration in quality of horn. This leads to +fissures in the horny covering, and favours infection of the sensitive +structures beneath. Thrush is, in fact, nearly always present in the later +stages of contracted foot. + +By some thrush is believed to be but the commencement of canker. With this, +however, we do not hold. We believe both to be due to specific causes as +yet undiscovered, but that the cause of thrush is not the one operating in +canker. In arriving at this conclusion we are guided by clinical evidence. +The two conditions are quite dissimilar, even in appearance, and, while +one is readily amenable to treatment, the other is just as obstinately +resistant. + +_Symptoms_.--The symptoms of thrush are always very evident. Probably the +first thing that draws one's attention to it is the stench of the puriform +discharge. The foot is then picked up and the characteristic putrescent +matter found to be accumulated in the median, and often in the lateral, +lacunæ. The organ is wasted and fissured, the horn in the depths of the +lacunæ softened and easily detachable, and portions of the sensitive frog +often laid bare. + +With a bad thrush lameness is present, the frog itself is tender to +pressure, and often there is considerable heat and tenderness of the heels +and the coronet immediately above. More especially is this noticeable after +a journey. + +It is, perhaps, more common in the hind-feet than in the fore, and more +often met with in heavy draught animals than in nags. The hind-feet are, of +course, more open to infection by reason of their being constantly called +upon to stand in the animal discharges in the rear of stable standings, +while it is a well-known fact that heavy animals have their stables kept +far less clean, and their feet less assiduously cared for, than do animals +of a lighter type. + +In a nag-horse with thrush of both fore-feet lameness becomes sometimes +very great. The gait when first moved out from the stable is feeling +and suggestive of corns, while progress on a road with loose stones is +sometimes positively dangerous to the driver. + +_Treatment_.--When this condition has arisen, as it often does, from want +of counter-pressure of the frog with the ground, this pressure must be +restored after the manner described when dealing with the treatment of +contracted foot (see p. 125) either by the use of tip or bar shoes, or by +suitable pads and stopping. + +So far as direct treatment of the lesion itself is concerned, the first +step is to carefully trim away all diseased horn and freely open up the +lacunæ in which the discharge has accumulated. Good results are then often +arrived at by poulticing, afterwards followed up by suitable antiseptic +dressings. With us a favourite one is the Sol. Hydrarg. Perchlor. of Tuson, +used without dilution. Others use a dry dressing, and dust with Calomel, +with a mixture of Sulphate of Copper, Sulphate of Zinc and Alum, or with +Subacetate of Copper and Tannin. + +With restoration, so far as is possible, of the frog functions, and with +careful dressing, a cure is nearly always obtained. + +6. CANKER. + +_Definition_.--Under this unscientific, yet expressive term, is indicated a +chronic diseased condition of the keratogenous membrane, commencing always +at the frog, and slowly extending to the sole and wall, characterized by a +loss of normal function of the horn secreting cells, and the discharge of a +serous exudate in the place of normal horn. + +_Causes_.--The exact cause of canker has still to be discovered. Therefore, +before expressing an opinion as to what the _probable_ cause may be, we may +state here that such opinion can only be based upon clinical observation. +Such being the case, we are almost duty bound to give the views of older +authors before those of more modern writers. + +From the mass of material ready to hand we may select the following as +serving our purpose. + +The earliest opinion appears to have been that canker, as the name +indicates, was of a cancerous or cancroid nature. This was also believed by +Hurtrel D'Arboval, who looked upon canker as carcinoma of the recticular +structure of the foot. The same theory we find enunciated in the +_Veterinary Journal_ so late as 1890. Although the word 'cancer' or +'carcinoma' is not there used, the author employs the terms 'Papilloma' and +'Epithelioma' with the evident intention of expressing his belief in the +malignant nature of the disease. + +Another early opinion was that the disease was a _spreading ulcer_, +gradually extending and changing the tissues which it invaded. + +A further early theory, and one which if not still believed in, has died a +hard death, is the constitutional theory. This was believed in by nearly +all the older writers, and is mentioned so late as 1872 by the late +Professor Williams. In his 'Principles and Practice of Veterinary Surgery,' +he says: 'Canker is a constitutional disease due to a cachexia or habit +of body, grossness of constitution, and lymphatic temperament.' This, we +believe, is credited to-day by some, and yet, quite 100 years before the +date of the 1872 edition of Williams's work--in 1756, to be exact--we find +a veterinary writer when talking of grease (a disease, by-the-by, very +closely allied to canker) exclaiming against this habit of referring +everything which we do not rightly understand to some ill-humour of the +body. The wisdom his words contain justifies us in giving them mention +here. 'It is a very foolish and absurd Notion,' he says, 'to imagine a +Horse full of Humours when he happens to be troubled with the Grease. But +such Shallow Reasoning will always abound while Peoples' Judgments are +always superficial. Therefore, to convince such unthinking Folks, let them +take a thick Stick and beat a Horse soundly upon his Legs so that they +bruise them in several Places, after which they will swell, I dare say, +and yet be in no danger of Greasing. Now, pray, what were these offending +Humours doing before the Bruises given by the Stick?' + +At the present day it is safe to assert that neither the ulcerative, the +cancerous, nor the constitutional theory is believed in widely, and, among +the mass of contrary opinions as to the cause of this disease, we may find +that even quite early many of the older writers had discarded them. + +Quoting from Zundel, we may say that Dupuy in 1827 considered canker as +a hypertrophy of the fibres of the hoof, admitting at the same time that +these fibres were softened by an altered secretion; while Mercier in 1841 +stated that canker was nothing more than a chronic inflammation of the +reticular tissue of the foot, characterized by diseased secretions of this +apparatus. + +Saving that they make no mention of a likely specific cause, these last two +statements express all that we believe to-day. As early as 1851, however, +the existence of a specific cause was hinted at by Blaine in his +'Veterinary Art.' We find him here describing canker as a _fungoid_ +excrescence, exuding a thin and offensive discharge, which _inoculates_ the +soft parts within its reach, particularly the sensitive frog and sole, and +destroys their connections with the horny covering. + +The use of the word 'fungoid,' and particularly that of 'inoculate,' is +suggestive enough, and is evidence sufficient that either Blaine or his +editor recognised, simply through clinical observation, the working of a +special cause. + +Four years later, Bouley is found holding the opinion that canker was +closely allied to tetter, thus recognising for it a local specific cause. +The same observer also pointed out that the secretion of the keratogenous +membrane instead of being suspended was greatly increased, taking care to +explain, as did Dupuy, that the products of the secretion were perverted +and had lost their normal ability to become transformed into compact horn. + +In 1864 this slowly growing recognition of a specific cause received +further impetus from the statements of Megnier. This observer claimed to +have discovered in the cankerous secretions the existence of a vegetable +parasite (namely, a cryptogam, as in favus), which he termed the +keraphyton, or parasitic plant of the horn. + +Modern research, though failing to substitute anything more definite, has +not confirmed this. The exact and exciting cause of canker is therefore +still an open question, and a matter for research. We may, however, sum the +matter up by briefly discussing the causes, so far as clinical observation +teaches us. This we shall do under two headings--namely, _Predisposing_ and +_Exciting_. + +_Predisposing Causes_.--Starting with the assumption that the disease is +due to local infection, we may relate as predisposing causes anything +having a prejudicial effect upon the horn, disintegrating it, and so laying +the tissues beneath open to attack. The most prominent in this connection +is certainly a continued dampness of the material on which the animal +has to stand. Particularly is this the case when the material is also +excessively foul and dirty, contaminated with the animal discharges, and +presumably swarming with the lower forms of animal and plant life. We +shall therefore find bad cases of canker in stables where the "sets" are +irregular, or where no paving at all is attempted, where the drainage +is defective, and where darkness and want of proper ventilation favours +organismal growth. The fact that with modern drainage and a general +hygienic improvement in stabling, canker has to a large extent died out, +supports this contention. + +Again, as with thrush, anything removing the counter-pressure of the frog +with the ground and throwing that organ out of play, may be looked upon +as a predisposing cause. The atrophy of the frog thus occurring, the +deterioration in the quality of its horn and the fissures in its surface +lay it specially open to infection. That one of the principal factors in +the treatment of canker is a restoration of ground-pressure to the frog and +the sole is sufficient proof of this. + +Further, it is well to note that, although playing no part in the actual +causation, certain constitutional conditions may in some measure predispose +the foot to attack. Clinical observation teaches us that animals of a +lymphatic nature, with thick skins and an abundance of hair, with flat feet +and thick, fleshy frogs, are far more liable to attack than are animals +with reverse points. + +_Exciting Causes_. Those who give this subject careful consideration cannot +fail to arrive at the conclusion that canker is most certainly due to local +infection with a specific poison, and that poison a germicidal one from the +ground. The symptoms arising may be due to the action of a single germ, or +to two or more germs acting in conjunction. As to whether the parasitic +invasion is single or multiple we cannot feel certain, but that it _is_ +parasitic we feel absolutely assured. + +It is simply the light that bacteriological advance has made during the +last two decades that enables us to make the statement with such feelings +of assurance. We arrive at our conclusions by reasoning from analogy. +Here we have a disease always exhibiting the same symptoms, more or less +peculiar to one class of animal, always with a similar characteristic +appearance and smell, always obstinately refractory to treatment, showing +always a tendency to spread to the other feet of the same animal, and often +to the feet of other animals _near enough to become_ infected, and always +cured--when cured it is--by a treatment which may be summed up in two words +as 'rigid antisepsis.' Other diseases, with points in common with this, +have been directly proved to be due to a specific cause. Common regard for +logic compels us to admit the same for canker. + +[Illustration: FIG. 134.--A FOOT, THE SUBJECT OF CANKER, SHOWING +DESTRUCTION OF THE HORNY FROG, AND A FUNGOID-LOOKING HYPERTROPHY OF THE +TISSUES BENEATH.] + +_Symptoms and Pathological Anatomy_.--The symptoms of canker are seldom +noticeable at the commencement of an attack. The disease is slow in its +progress; for some time confines its ravages to the sub-horny tissues +unseen, and is quite unattended with pain. It is not observed, therefore, +until considerable damage has been done, and the disease is far advanced. +What is usually first seen is a peculiar softening and raising of the horn +of the frog. The infective material has set up a chronic inflammation of +the keratogenous membrane, leading to abnormal secretion, and, in place of +the horny cells it should normally secrete, is thrown out an abundance of a +serous fluid. + +This upraised and softened horn once thrown off is not again renewed, and +the whole of the sensitive frog and perhaps a portion of the sensitive sole +is left uncovered. In place of the normal horn, however, is often found a +hypertrophy of the elements of the keratogenous membrane leading to huge +fungoid-looking growths with a papillomatous aspect, damp in appearance and +offensive in smell, and readily bleeding when injured (see Fig. 131). + +The horn immediately surrounding the lesion is loose and non-adherent to +the sensitive structures. This indicates, of course, that the disease has +spread further beneath the horny covering than is at first sight apparent. +Portions of this loose horn removed reveal beneath it a caseous foetid +matter, easily removed by scraping (the perverted secretion of the +keratogenous membrane). When this is carefully scraped away, the sensitive +structures appear to be covered with a thin, smooth membrane, gray in +colour and almost transparent, while beneath it may be seen the red +appearance of normal sensitive structures. + +If the horn surrounding the lesion is not touched with the knife, but +little is seen of the extent of the disease, for that removed by natural +means is often very small in quantity. To all intents and purposes the +disease appears to be confined to the frog. This appearance is misleading, +especially if the disease has been in existence for some time, for it +may have easily spread to the whole of the sole, and even to the greater +portions of the laminæ secreting the wall. + +It is, in fact, not until the pressure exerted by the normal horn +is removed by its breaking away that the vascular structures of the +keratogenous membrane begin to swell, and the perverted secretions to +enlarge in size. Once the pressure is removed, however, this quickly +comes about, and the characteristic fungoid growths rapidly make their +appearance. + +This tendency to spread is highly indicative of canker. The serous matter +exuding from the diseased keratogenous membrane appears, in fact, to be +highly infective. Once its flow is commenced, it slowly, but surely, +invades the sensitive structures near it, appearing, as Elaine has put it, +to 'inoculate' them. What is really the case, of course, is not that the +discharge itself is infective, but that it is contaminated with infective +material. + +The fungoid-looking growths to which we have before referred are, in +reality, nothing more than the villi of the sensitive frog and sole greatly +hypertrophied and irregular in shape. At times the hypertrophy is as a huge +and compact enlargement occupying the position of the frog. Sometimes, +however, it occurs as numerous elongated and twisted fibrous bundles, +separated from each other by deep clefts, and the clefts filled with the +offensive cankerous discharge (see Fig. 134). + +[Illustration: FIG. 135.--LOWER ASPECT OF CANKERED FOOT, SHOWING +DESTRUCTION OF WALL.] + +At a very advanced stage canker leads to destruction of much of the horny +sole and frog; or even parts of the wall may become separated from the +tissues beneath, and break away from the foot (see Fig. 135). At other +times the disease brings about a deformity of the whole of the foot. Its +longitudinal and transverse diameters become enormously increased, and the +whole foot apparently flattened from above to below (see Fig. 136). This +indicates that not only has the horny sole been entirely destroyed, but +that the destructive process has also extended to the greater part of the +lower half of the wall, with a consequent hypertrophy of exposed soft +structures, and a sinking of the bony column, similar to that which occurs +in laminitis, but not so pronounced. + +[Illustration: FIG. 136.--FOOT WITH ADVANCED CANKER.] + +A further aspect of the badly-cankered foot is to be found in an apparently +enormous increase in the length of the wall. This we have seen protruding +for quite 5 inches beyond the plane of the sole. It simply indicates that, +in order to keep the animal at work, the smith has at every shoeing spared +the wall, so that the diseased structures might be kept from contact with +the ground. + +As we have said before, pain and other symptoms of distress are quite +absent. Animals affected with canker for a long time maintain their +condition, feed well, and are quite capable of performing work under +ordinary conditions. + +_Differential Diagnosis and Prognosis_.--Perhaps the only disease with +which canker may be confounded is thrush. They should, however, be easily +distinguishable. The discharge from thrush is not so profuse, and is +thicker and darker in colour, while the loosening of the horn is almost +entirely absent. Furthermore, thrush shows no tendency to spread, and, even +when left untreated, may remain confined to the frog for months, and even +years. Canker, on the other hand, is slowly progressive, and soon shows the +characteristic fungoid excresences, which growths are in thrush never seen. +A further point of difference is discovered when treatment is commenced. +Canker is found to be refractory to a point that is absolutely +disheartening, while thrush, with careful attention, is soon got under +hand, and a permanent cure effected. + +The prognosis must be guarded. By many canker has been said to be +incurable. This, however, has been clearly shown to be wrong. When the +animal is young, and treatment may reasonably be judged to be economical, +then a favourable prognosis may be indulged in, provided the veterinary +surgeon intends to put into that treatment a more than ordinary amount of +individual care and attendance. Even then, however, he will have to be very +largely guided by the condition of his case. He should see that it is +not too far advanced, and that a great deformity of the hoof, or actual +exploration, does not indicate disease of the greater part of the wall. + +_Treatment_.--From what has gone before, it will be seen that the +eradication of canker is no easy task, that it is, in fact, a most +difficult matter, and one not to be lightly undertaken. At the risk of +recapitulating what we have said before, we may mention here the two points +which the veterinarian must bear in mind. (1) That there is no actual +disease or alteration in structure of the deep layers of the keratogenous +apparatus. It is only the superficial, or horn-secreting, layer that +concerns us. (2) That the disease of this superficial layer is infection +with a material that may reasonably be presumed to be infective. + +Put thus, treatment of canker would at first sight appear to be easy. One +would imagine that a simple and long-continued soaking of the entire foot +in a strong enough antiseptic would be all that was needed. Clinical +observation, however, shows that this is not so, and for this there must be +reasons. + +The reasons are these: (1) Between us and the diseased layer upon which our +attention must be directed is often a layer of normal horn, effectually +protecting the tissues beneath from any dressing which we might consider +beneficial. (2) Anything applied with the object of destroying septic +material, but strong enough, or caustic enough, to injure the membrane upon +which we are working, only makes the case worse. The superficial layer of +the keratogenous membrane in which we have judged the disease to exist is, +after all, but a delicate structure. When attacked by the application of +too potent a drug its horn-secreting layer is easily destroyed, and thus, +although we may succeed in establishing asepsis, we cannot expect at the +point of injury a growth of horn. In its place we are confronted with large +outgrowths of inflammatory fibrous tissue. (3) Shedding of the diseased +horn and removal of the pressure exerted by the hoof faces us with +hypertrophy of the exposed villi. The difficulty of meeting this with an +adequate and evenly-distributed pressure is well enough known, and we find +in that a further reason that the treatment of canker is superlatively +difficult. (4) The material on which the animal has to stand is a distinct +bar to the maintaining of a strict asepsis. + +When we have said this, it is easy to understand that canker is not to be +successfully met with any so-called specific--that it makes but little +difference what the application may be so long as it is antiseptic, and is +used by a man thoroughly conversant with the difficulties he has to contend +with, and with his mind firmly set upon surmounting them. + +With this point established, we will not devote more of our space to a +consideration of the various dressings that have at different times been +highly advocated in the treatment of the disease. It is interesting, +however, to note that intensely irritating and caustic applications have +been greatly in favour. Nitric acid, sulphuric acid (either alone or its +action reduced by the addition of alcohol, oil, or turpentine), arsenic, +butter of antimony, creasote, chromic acid, carbolic acid, arsenite of +soda, and the actual cautery, have all been used. + +Without dwelling further on that, we may say at once that a correct +treatment consists in (1) the removal of all horn overlying infected +portions of the keratogenous membrane, (2) the application of an antiseptic +not too powerfully caustic in its action, (3) frequent changes of the +dressings in order to insure a maintenance of antisepsis, and (4) the +application of an adequate pressure to the exposed soft structures. Thus +combated, canker is curable. + +The man who, at the expense of much time and trouble, has demonstrated the +truth of these axioms is Mr. Malcolm, of Birmingham. The determination with +which he clung to his point that canker was, with correct treatment, in +every case curable, was some years ago provocative of much discussion in +veterinary circles. That he was successful in proving his contention is +more to our point here. It is his method of treatment, therefore, that we +shall give, and this we shall do by liberal extracts from Mr. Malcolm's own +writings. + +'On the first occasion of operating upon and dressing the cankered foot, +it is usually necessary to cast the horse, and this may have to be done +at intervals for a second or even third time; but in most cases once is +sufficient, subsequent dressing being usually accomplished without much +difficulty, frequently even without the aid of a twitch. After the horse +has been secured, the drawing-knife is first employed; and if the frog +alone is affected, it is unnecessary even to pare the sole, the removal of +all frog horn not intimately adherent to its secreting surface being all +that is required. But if both sole and frog be involved, the whole of the +sound horn should be first thinned until it springs under the thumb, +and then, using a sharp knife, every particle of diseased horn must be +carefully removed from both sole and frog, a process much more easily, and +with far greater certainty, secured by the previous thinning of the horn. + +'The removal of diseased horn should always commence at the most dependent +part of the foot, so that any hæmorrhage produced may be below the parts +still to be operated on, a matter of considerable moment for effective +treatment. But with due care there will be little hæmorrhage, as, except in +the initial stage, there is no real union between the diseased horn and the +diseased vascular secreting surface. + +'After all apparently diseased horn has been removed by the knife, any +still remaining should be at once destroyed by the actual cautery, by +which it can be identified. All the diseased secreting surface should be +_carefully scraped with a thin hot iron_,[A] fungoid growths excised and +cauterized, and, indeed, every particle of cankered tissue should, if +possible, be eradicated. In securing this more reliance can be placed on +the actual cautery than on any other, whether liquid or solid: it is more +under control in application, more decisive in effect, and its results can +be anticipated with a far greater certainty. Moreover, its aid in diagnosis +is of immense value; applied to the thinned horn or secreting surface it +unmistakably demonstrates the presence or absence of canker. Healthy tissue +chars black; cankered tissue, on the contrary, bubbles up white under the +hot iron, and presents an appearance not unlike roasted cheese. + +'Although this test is certain for horn thinned to the quick, it is not to +be relied upon with thick horn, the outside of which may be practically +healthy and char black, while its underlying surface may be cankered. With +this exception the test is an infallible one, as by it the demarcation +between cankered and healthy tissue can be clearly traced, and as a result +we can with equal confidence radically _remove_[A] all cankered tissue, and +conserve all healthy. As the object of that abominably cruel and barbarous +operation of stripping the sole is the exposure of all canker, and as this +can be done with equal certainty with the aid of the hot iron, there can be +no necessity for performing it. The pain of cauterizing cankered tissue, +which is a necessary operation, is infinitesimal (canker largely destroying +sensation), compared with the pain produced in the totally unnecessary +process of tearing healthy horn from a highly sensitive tissue. + +[Footnote A: The words in italics are alterations in the original article +made by Mr. Malcolm in a private letter to the author (H.C.K.).] + +'Having by means of the knife and cautery removed every known particle of +disease, the next procedure is to pack the surface of the sole and frog +thus exposed with a _mild dressing, such as vaseline; but if the cankered +surface has not been efficiently, scraped, than there is required a more_ +[A] powerful astringent or caustic dressing, which may vary considerably +according to the individual fancy. A great favourite of mine consists of +equal parts of sulphates of copper, iron, and zinc, mixed with strong +carbolic acid, a very little vaseline being added to give the mass +cohesion. The dressing, covered by a pledget of tow, is held in position +by a shoe with an iron or leather sole, and the dressing and tow together +should be of sufficient bulk to produce slight pressure on the sole when +the nails of the shoe are drawn up. This insures contact between the +dressing and the exposed surface, as well as any benefit derivable from +pressure. + +[Footnote A: The words in italics are alterations in the original article +made by Mr. Malcolm in a private letter to the author (H.C.E.).] + +'The dressing of the foot and nailing of the shoe can usually be more +expeditiously performed when the horse is on his feet than when prone. If +only the frog, or the frog and a small part of the sole, be involved, the +horse should be kept at work, but if a large part or the whole of the sole +a few days' rest may be necessary; but as soon as the condition of the foot +will allow, work should be resumed, and it is simply marvellous how sound a +horse will walk while minus the greater part of his sole from canker. + +'On the second day following the shoe should be removed, and the foot +redressed. To effect this it is necessary to recast the horse. Commencing +at the edge of the sound horn, at the most dependent part of the foot, +all new horn, no matter what its condition, must be pared to the quick, +especial care being taken to effectually remove any lingering disease. Want +of success is frequently attributable to neglect of this precaution. +A small particle of canker remains undetected, forms a new centre of +infection, and just when success is anticipated, much to your chagrin you +have to deal with a fresh outbreak of canker, instead of a rapidly-healing +foot. Parenthetically, I may here remark that the amount of more or less +imperfect new horn produced by a cankered surface after an effective but +not too destructive cauterization is almost incredible, and one cannot fail +to be struck with the very active proliferation here compared with the +meagre production of new horn by the healthy surface. + +'After all disease has been excised, carefully clean the foot with waste, +thoroughly protect any raw surface resulting from overcauterization by some +mild agent, such as a saturated calomel ointment, reapply an astringent +dressing over the whole affected surface, and nail on the shoe. This method +of procedure should now be thoroughly carried out daily for a time, and +as it is proceeded with a successful issue soon becomes assured in nearly +every case. Where, in spite of these efforts, the disease still persists, +depend upon it the fault is with the operator, who has failed to eradicate +some centre of infection. Under these circumstances it may be necessary +to recast the patient, repare the foot, and by the aid of eye, knife, +and cautery, endeavour to find the cause, and having found it, which can +invariably be done, remove it. The usual treatment will then speedily +become successful. As the case proceeds dressing every other day will +soon be sufficient, then twice a week, and finally, once a week until +sufficiently cured. + +'During this healing process, and after the complete eradication of canker +it may be again repeated, no agent seems to have a more beneficial effect +than calomel, and for this purpose it is best used as a dry powder. Under +this dressing any remaining spot of canker is readily detected by the wet +condition of the calomel when the shoe is removed the next day. In dealing +with such a spot, a very good plan, after all apparently diseased tissue +has been excised, is to touch the cankered part with solid nitrate of +silver, or a feather dipped in one of the strong mineral acids, and +then reapply calomel over the surface. The result of this treatment is +frequently very gratifying. + +'In successful treatment the shoe must be removed each time--an adjustable +plate will not do, as no man can thoroughly pare and examine a foot with +the shoe on, and imperfect dressings are worse than useless. Indeed, it is +better not to pare or thin the horn at all, than to imperfectly pare, since +canker, if undestroyed, develops far more rapidly under thin horn than +under thick. + +'In conclusion, I would again urge the necessity, at the very first +operation, when the horse is down, of removing _every single particle_ of +the diseased tissue, either by excision or effectual cauterization, but at +the same time taking very great care to guard against the latter being +too destructive. The cautery should be laid aside as soon as the tissue +cauterized ceases to _burn white_. The moment at which the canker has +thus been eradicated without destroying sound tissue is indicated by +the appearance of healthy horn, by the intimate union of that with the +secreting surface, and by the healthy aspect of the exuded blood when +paring has been carried to the quick. + +'Should subjacent healthy structures be destroyed during the process, +that is shown by the production of a raw sore, or of a sore to which a +"sit-fast," coextensive to the injury, is firmly attached. This seriously +retards recovery. The secreting surface having been destroyed, no new horn +can be produced directly from the part, and a new secreting surface and new +horn have now to grow inwards from the surrounding undestroyed tissue, and +that is a slow process. At the same time, on the principle of choosing +the least of two evils, practical experience teaches that it is better to +produce a small sore or a "sit-fast" than to leave a part of the canker +undetected; but, on the other hand, it is better to leave a small part +of canker undetected, which can be recognised and removed at the next +examination, than to cause a large slough. The object of the skilful +surgeon is, naturally, to avoid both extremes; and if trouble be taken to +carry out the procedure described, there need be no fear of the result.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv., +p. 24.] + +Treated in this way, the horse with cankered feet may be usually kept at +work during the whole time that treatment is carried out, and a cure is +obtainable in periods varying from six weeks to six or even twelve months. + +The same essentials in treatment--namely, removal of diseased horn, +antiseptic dressings, and pressure--are insisted on by other writers. +Bermbach,[A] in 1888, treats canker as follows: The horse having been cast, +the undermined hoof-horn is removed with the knife, and the hypertrophied +sensitive structures, if necessary, reduced in the same manner. The chief +difficulty in removing the latter is experienced in the lateral lacunæ of +the frog, where it is most conveniently scraped away with a spoon or sharp +curette. Professors Hoffmann and Imminger also operate in the same way, +applying an Esmarch's hæmostatic bandage, and using the knife and curette +freely.[B] + +[Footnote A: _Ibid_., vol. ii., p. 68.] + +[Footnote B: _Veterinary Journal_, vol. xxxv., p. 433.] + +Hæmorrhage is afterwards arrested, and a dressing of perchloride of mercury +(a solution, 1/2 per cent., in equal parts of alcohol and water) applied. +The after-dressings succeeding best are those of _slightly_ caustic and +astringent agents, preferably in the form of a powder, and held in position +by carbol-jute pads and linen bandages applied with a certain amount of +pressure. + +The same author draws attention to the fact that caustic agents such as +nitrate of lead, chloride of zinc, etc., act too powerfully if the bleeding +has been arrested and the wound disinfected. They then form a thick crust, +under which profuse suppuration takes place. The same agents are likewise +contra-indicated when hæmorrhage is still present. In this latter case +they combine with the blood to form metallic albuminates, which lie as an +impenetrable layer on the surface of the wound, and so hinder the action of +drugs on the tissue below. + +During his after-treatment, Bermbach advocates removal of the dressings +every second day, all cheesy material to be scraped away with the knife, +and the sublimate lotion to be used again. He also insists on the animal +being kept standing in a _dry stable_,--nothing but a stone pavement kept +clean--and put to regular work in a plate shoe after the first or second +week. Cure of advanced cases is said to be obtainable in from four to six +weeks. + +As illustrative of the value of pressure in the treatment of canker, we may +also draw attention to a treatment advocated by Lieutenant Rose.[A] This +observer holds that adequate pressure is unobtainable by packing the foot, +and, to obtain it, removes the wall from heel to heel, much after the +manner of preparing the foot for the Charlier shoe, so that the _whole_ of +the weight is taken by the sole and the frog. Tar and tow is then lightly +applied, the foot placed in a boot, and the patient turned into a +loose-box. The dressing is repeated at intervals of four or five days until +the animal is cured. + +[Footnote A: _Veterinary Record_, vol. xi., p. 435.] + +Those who have followed this method of treatment have modified it by +actually shoeing the animal Charlier fashion, and keeping him at work, +attention, of course, being at the same time given to a proper antiseptic +dressing. + +_Reported Cases_.--1. (Malcolm's Treatment[A]). The subject was a five-year +old horse belonging to a client of Mr. Giver's, of Tamworth. The case was +an exceptionally bad one, for not only was the whole of the frog and sole +of the near hind-foot cankered, but the disease on the outside quarter +extended to within 1/2 inch of the coronet, and on the inside quarter to +within 2 inches of it. As the owner, a farmer, had not proper convenience +for Mr. Olver to treat the case, the latter asked me, while visiting him, +if I would care to undertake the treatment, saying at the time it would +be a very good test-case, as the disease was so far advanced. I readily +agreed, and, after the necessary arrangements, had the horse removed to +Birmingham on July 2. In this case it was found necessary to cast the +animal and cauterize the foot a second time before a healthy granulating +surface was secured; but after this the progress towards recovery was +uninterrupted, although necessarily slow, on account of the large amount of +new secreting surface which had to be formed. + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 48.] + +The horse was finally discharged, after inspection by Mr. Olver, absolutely +cured and free from canker, on January 7. + +The illustration (Fig. 135, p. 312) is from a photograph, and it gives a +somewhat imperfect representation of the state of the foot two months after +it came under my care. + +2. (Rose's Treatment.[A]) This was a bad case of canker, which had been for +two or three months treated in the ordinary manner, with but little sign +of ultimate success. Commenced in June and carried on until the end of +September, the ordinary treatment consisted in burning down the fungus +growth with the hot iron, and dressing with copper sulphate, zinc sulphate, +and boracic acid. The cauterization was repeated every five days. + +[Footnote A: _Veterinary Record_, vol. xi., p. 435.] + +The treatment of Lieutenant Rose was commenced at about the end of +September, at which date the disease extended from the toe on one side of +the foot right back to the heel, involving the sole, half of the frog, and +the bulb of the heel. One week after treatment the diseased surface was +drier, and granulations were more healthy. At the expiration of a fortnight +the new horn had commenced to grow from the wall, and also from the frog, +right round the diseased surface, the diseased part of the bulb of the heel +being divided from the sole by new horn. + +Three to four weeks later the diseased surface was gradually getting +smaller, while in about six weeks it was quite healed up, the last place to +heal being a strip outside the bar, between it and the wall, and a smaller +spot on the bulb of the heel. These healed up simultaneously, and left the +animal sound. + +3. (Treatment by Pressure, H. Leeney [A]). I was consulted in the early +part of last summer, before the dry weather had begun, as to a farm-horse +with canker in three feet. Her shoes were in the 'disgruntle' condition we +so often find on farms, that, to give her a level bearing until I should +call another day with a farrier to help me to pack the foot up in the +old-fashioned way, I had the remaining shoes pulled off. The case somehow +dropped out of my list, and I neglected to call, until asked one day to see +something else. + +[Footnote A: _Veterinary Records_, vol. xi., p. 447] + +I then found that, under a pressure of work, the animal had been used in +the shafts of a farm-cart on tolerably level ground, and when the dry +weather had already set in. There was a distinct improvement in all the +diseased feet, and as she was badly wanted I contented myself with rasping +off some broken crust, and supplied some caustic dressing for use at night. +Without shoes she worked continuously on the dry and hard meadow-land for +several weeks, and was practically cured in something less than three +months. My astringent or caustic lotion may have had something to do with +the cure of the deep-seated parts, but the bare recital of the case should +be sufficient to show that it is all a question of bearing, or nearly so. + +7. SPECIFIC CORONITIS. + +_Definition_.--In describing this condition under the above heading, we +are following the lead of Mr. Malcolm. We may define it as a chronic +inflammatory condition of the keratogenous membrane, usually confined to +that of the coronary cushion, the ergots and the chestnuts, but sometimes +extending to that of the frog and the sole, characterized by a malsecretion +of the affected membrane similar to that observed in canker. + +_Causes_.--The cause which we have indicated for canker--namely, a local +specific one, is in all probability the one operating here. Apparently +there is a variance of opinion as to whether the condition is actually +canker or not. We think, however, that the character of the secretion of +the affected membranes, the appearance of the growths, the manner in which +they react to the hot iron, the comparative absence of pain, and other +points of similarity, point to the fact that the two conditions are +actually identical. In other words, the cause is precisely the same, and +the only point of difference is the alteration in the point of attack. + +_Symptoms_.--Like canker, the disease is insidious in onset. In precisely +similar manner the horn, and in this case the skin of the coronet, is +underrun. Later there is the partial shedding and fissuring of the +undermined horn and the exuding of the characteristic discharge--in this +case not so watery as that of canker. The caseous material of canker is +also present, as is a disposition to hypertrophy of the exposed sensitive +structures. What horn is left becomes rough and irregularly fissured, and +has been likened by some observers to deeply-wrinkled bark of an old tree. +A peculiar characteristic of this condition is the state of the ergots and +chestnuts. Here the keratogenous membrane participates in the diseased +process, and their horn becomes dry and brittle, and readily splits into +small fibrous bundles very similar to the fibroid growth described in +canker. These excrescences are easily separated from the sensitive +structures beneath, and the exposed surface is seen to be more or less +moist, or even exhibiting a slight oozing of blood. + +Again, as in canker, the deeper layers of the sensitive structures appear +to be normal, the horn-secreting layers being the only ones affected. +According to Malcolm, the disease is in its nature equally as inveterate as +canker, but it is easier to treat, on account of its more exposed position. + +_Treatment_.--This is exactly that as described for canker. + +[Illustration: FIG. 137.--SPECIFIC CORONITIS OF ALL FOUR FEET.] + +[Illustration: FIG. 138.--OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS.] + +_Recorded Case_.--The subject of this case was a young black cart gelding. +The disease is reported as having begun as thrush, and then extended to the +coronet. When I saw him he had been in a similar condition to that depicted +in Fig. 137 for, it was said, two or three months, the driver of the horse +meanwhile endeavouring to effect a cure by some potent drug of his own. The +animal was in good condition, but walked with difficulty owing to the pain. +The coronary bands were swollen to two or three times their natural size, +and this caused the hair immediately above to curl upwards. Just below the +coronary bands there was a line of separation between them and the wall. +They themselves were covered with the cheesy substance typical of canker, +and they bled on friction. Down the wall of the off fore-foot some blood +had trickled, which may be seen in Fig. 138. The frogs of all four feet +bulged backwards, and were badly affected. The soles were covered with +normal horn, but I did not resort to paring to see if they were affected. +One very curious feature about the case was the fact that all the +callosities (ergots and chestnuts) seemed to participate in the morbid +process, and they, too, were covered with a thin layer of soft cheesy horn. +The animal used to bite at his coronets and also the callosities above the +knees and hocks until they bled, which they did quite easily. The owner +would not go to the expense of having him treated, so he was destroyed.[A] + +[Footnote A: Henry Taylor, _Veterinary Record_, vol. xvii., p. 311.] + + + +CHAPTER X + +DISEASES OF THE LATERAL CARTILAGES + + +A. WOUNDS OF THE CARTILAGES. + +To a consideration of this we shall devote but little space. It is +sufficient to say that any wound in the region of the coronet should always +be given the most careful attention. More particularly should this be so +when it is ascertained that the wound has involved one of the lateral +cartilages. Wounds of non-vascular bodies such as these are always slow to +heal, and, by reason of their slowness, invite septic infection. In many +cases, in fact, it happens that they do not heal at all. Instead, the +injured part becomes necrotic, is unable to cast itself off, and remains as +a centre of infection in the depths of the wound, thus constituting what is +known as a quittor. + +Apart from this, it will be remembered that the internal face of the +cartilage is in intimate contact with the pedal articulation, especially +anteriorly. Wounds in this situation are, therefore, likely to penetrate +the joint, giving us as a complication of the injury the conditions of +synovitis and arthritis. + +Immediately a wound is inflicted in this position, attempts should be made +to insure thorough asepsis of the part. When possible, by far the better +way of accomplishing this will be to wholly immerse the foot in a tub of +cold antiseptic solution, and keep it there for an hour three times daily. +During the time the foot is out of the solution the wound should be +protected with a pad of carbolized tow or other suitable dressing, and +wrapped in a linen bandage or clean bag. If unable to use the bath, then +antiseptic solutions of more than moderate strength should be freely +applied to the wound and the adjacent parts, a carbolized or other +antiseptic pad placed over it, and the bandage adjusted as before. Repeated +injuries to the cartilages, even if not attended with an actual wound, +are apt to bring about their ossification and end in the formation of +side-bones. + + +B. QUITTOR. + +_Definition_.--A fistulous wound of the foot, usually opening at the +coronet, and variously complicated according to the structures invaded by +its contained pus. For the reason that quittor is in every-day veterinary +nomenclature _usually_ associated with necrosis or other abnormal condition +of the lateral cartilage, we include its description in this chapter. + +_Classification_.--It has been customary with Continental authors to +classify quittor according to the extent and position of the diseased +process. There were thus distinguished: + +_(a)_ The _Simple_ or _Cutaneous Quittor_, in which had occurred nothing +more than necrosis of a portion of the coronary skin and the structures +immediately underlying it--that is, the superficial portion of the coronary +cushion. + +_(b)_ The _Tendinous Quittor_, in which not only the immediately +subcutaneous tissues were attacked, but also portions of tendon and of +ligament. + +_(c)_ The _Sub-horny Quittor_, in which the diseased process had invaded +the deeper portions of the coronary cushion, and continued a downward +course until the laminal tissue below the upper margin of the wall was +involved, or any other case, no matter what the starting-point, in which +pus existed within the horny box and was discharging itself by a fistulous +opening. + +_(d)_ The _Cartilaginous Quittor_, in which a portion of the lateral +cartilage had become attacked and rendered necrotic. + +We believe that--in this country, at any rate--the word 'quittor' is +usually held to indicate one or other of the two latter conditions, and +probably the last of these; and that the two first are held of small +account, or hardly of sufficient gravity to allow of the word 'quittor' +being applied to them. In fact, by defining quittor as a 'fistula,' or +little pipe, we have ourselves already indirectly restricted the use of the +word to the two latter conditions, for in those varieties known as Simple +or Cutaneous and Tendinous, the wound is generally broad and open, or, +at any rate, superficial, and can scarcely be strictly described as +'fistulous.' In the two latter, however, a true fistula exists. These, +however, have only one essential difference, and that consists simply in +the position of the lesion and the structures it has attacked. In the main +the symptoms will be the same, the disease in each case about equally +serious, and in each the same essentials of treatment will have to be +regarded. + +In our opinion, therefore, a lengthy classification serves no useful end, +and we think matters will be simplified by considering quittor under +two headings only--namely, 'Simple or Cutaneous' and 'Sub-horny,' and +discussing the other varieties as simply complications of either of these +two. + +1. SIMPLE OR CUTANEOUS QUITTOR. + +_Definition_.--This condition is simply a sloughing of a portion of the +skin of the coronet, together with a portion of the immediately underlying +soft structures. + +_Causes_.--This form of quittor has its origin more often than not in +contusions, punctures, or wounds of the region severe enough to cause death +of a small portion of the tissues. In this case the low vitality of the +parts does not allow of the dead portion being removed piecemeal by a +process of phagacytosis, as is usually the case with similar injuries +elsewhere. Instead, the tissues around, aided by a process of suppuration, +cast the offending portion off as a slough. It is the wound remaining after +the slough which we may really regard as a quittor. In this connection may +be considered as causes blows from falling shafts, self-inflicted treads, +or treads from other horses, overreach, etc. On the other hand, simple or +cutaneous quittor may occur without ascertainable cause. In this case we +can only explain its appearance, as we did that of simple coronitis (see p. +231), by attributing it to septic infection through a wound or a blow that +is able to inoculate the skin, yet which is insufficient to cause pain, or +in any other way attract the attendant's notice. Meanwhile, the spot of +infection thus started spreads, and the end result is an abscess in the +coronary region, again accompanied with necrosis and sloughing of more or +less skin and other tissue, which terminates by discharging its contents +and leaving behind a wound which again constitutes a cutaneous quittor. +Thus, as with simple coronitis, anything lowering the vitality of the +parts, and so favouring infection of the skin, may bring about a quittor. +Walking through much water in the winter months, through the dirt and mud +of our streets, through melting ice and snow, or through anything in the +nature of a chemical irritant, may be looked upon as a cause. + +_Symptoms_.--Whether commencing from an ascertainable injury, or beginning +at first unnoticed, cutaneous quittor is characterized sooner or later by +the appearance of an inflammatory swelling, usually confined to the seat of +injury. Heat and tenderness are present, and the animal is lame. + +Later the inflammatory swelling becomes more profuse, the animal is +fevered, and the symptoms of lameness increased. Poulticing is at this +stage perhaps resorted to. By its means the process of suppuration is +aided, and the swelling (at first tense and hard) either becomes gradually +softened, its contents discharged, and a simple abscess cavity left behind, +or the suppuration runs immediately round the necrosed structures, and +casts them off bodily as a slough. This latter condition is always +manifested, where the hair does not hide it, by the colour of the skin. At +first this is only red in colour--the angry red of an inflamed spot. As its +intention to slough away becomes evident, the red gradually gives way to a +gray, or even blue-black appearance, while from around it oozes a slight +discharge of pus, yellow in colour and non-offensive, or blood-stained and +dark in appearance, and foetid to the smell. + +Almost invariably these symptoms are added to by a more or less diffuse and +oedematous swelling of the lower portion of the limb, extending in some +cases to as high as the fetlock or the upper third of the cannon. + +With the casting off of the slough the phenomena of inflammation to a great +extent subside, the pain ceases, and the case under ordinary conditions +commences to mend. + +_Pathological Anatomy_.--In its early stages the condition of simple or +cutaneous quittor is really a condition of acute coronitis (see p. 229), +and consists in an inflammation of the subcutaneous tissue, and the more +superficial portions of the coronary cushion. The tissues implicated are +destroyed outright, become infiltrated with the inflammatory exudate and +escaped blood, and act as a source of irritation to the still living +tissues around. Under the irritation the latter, as we have said before, +cast the necrosed portion away by a process of sloughing. + +Always, however, it is found that the portion to be sloughed off, while +easily separated from the tissues adjacent to its sides, is closely +connected on its lowermost or deeper face with the structures below, and +cannot be torn away without hæmorrhage and the causing of acute pain. + +_Prognosis_.--With wounds about the feet our forecast should always be +guarded. Even with this, the most simple form of quittor, no decided +opinion should be given until the progress of the case warrants one in +reasonably assuming that complications are absent. Once this point is +decided, a favourable prognosis may be given. + +_Complications_.--With cutaneous quittor various complications may arise, +according to the extent of the invasion of the septic matter. Necrosis of +tendon, of ligament, or of cartilage, caries of the bone, or a condition of +synovitis and arthritis may be met with. As these complications are equally +common to sub-horny quittor, we shall reserve their description until +dealing with that condition. _Treatment (Preventive)_.--Immediately after +the infliction of an injury in this position, more especially if it is such +as to lead one to judge that necrosis will follow to any large extent, the +patient should be rested. Ill effects may then be probably warded off by +having the foot immersed in a cold antiseptic solution, and afterwards +bound with an antiseptic pad and bandage. + +_Curative_.--When the condition has gone undiscovered until commencing +necrosis and suppuration are plainly discernible, then the wisest course we +can follow is to do all we can to hasten removal of the necrosed portion. + +This is best done by promoting the suppurative process by means of warmth +or stimulant applications. + +To this end hot poultices, or, better still, hot baths, should be resorted +to. Under their influence a greater supply of blood is directed to the +still healthy tissues enabling them to actively continue the inflammatory +processes necessary to the detaching of the portion necrosed, while, at +the same time, the pus organisms, stimulated by the heat, are stirred into +greater activity, and the readier accomplish their purpose of destroying +the adhesion still existing between the necrotic portion and the +surrounding living tissues. + +When prolonged poulticing or bathing cannot be practised, then the swelling +should be stimulated with a sharp cantharides blister, repeated, if the +case demands it, at intervals of a few days. + +Should the swelling show distinct signs of pointing, and an abscess is +plainly the condition to be dealt with, its contents should be liberated by +a free use of the knife. In this connection it is important to insist on +the fact that the opening should be made large enough. One bold incision +from the uppermost limit of the swelling down to the coronary margin of the +wall is usually sufficient. + +Even when pointing is not very evident, and suppuration is plainly more or +less diffuse, benefit may still be derived from the use of the knife. In +this case a deep scarification of the part is indicated. Three, four, or +more vertical incisions are made in the swelling, and from them obtained a +flow of blood mingled with a small quantity of pus from several different +centres. By this means sloughing of the diseased portion is quickly +obtained, and nothing but an ordinary open wound left for treatment. It +should be mentioned, however, that when sloughing can be in any way induced +to take place naturally it is better to allow this to take place. Even when +the necrosed portion is freely movable, and only adherent by its base, it +should not be forcibly removed, but left to the slower but more effectual +action of the tissue reactions. If torn forcibly away, we in all +probability leave in the bottom of the wound remnants of the dead tissue, +which, being small and consequently less productive of inflammatory +phenomena, are not so readily sloughed as the larger portion. These remain +as centres of infection, and prolong the case. + +Once a suitable slough has occurred, the after-treatment is simple. It +consists in dressing the wound with reliable antiseptics, and maintaining +the parts in a healthy condition until Nature completes the cure by +repairing the breach. Solutions of carbolic acid, of perchloride of +mercury, of zinc chloride, or of moderately strong solutions of copper +sulphate, are all of them useful (see also treatment of coronitis on p. +236). + +It is sometimes found that even with careful attention the wound left +by the removal of the slough shows a marked disinclination to heal. The +greater portion of the cavity becomes filled with granulation tissue, and +the epidermis gradually closes round until all is covered except a spot of +perhaps the size of half a crown or a crown piece. Here the regenerative +process stops, and the wound obstinately refuses to effectually close. + +In such cases we have derived excellent results with the actual cautery. +The animal is cast, the foot firmly secured by fastening it upon the cannon +of another limb, and the animal chloroformed. A practical point to be +remembered in this connection is that all necessary fixing of the limb is +easier performed if the chloroform is administered first. With the patient +thus secured we first of all ascertain by means of the probe whether or no +the non-healing of the wound is due to the presence of a fistula. Decided +in the negative, we take an ordinary flat firing-iron, and with it cut away +a portion of the skin immediately around the still open wound, carrying +our incisions deep enough to 'scoop' out a large portion of the new +inflammatory tissue beneath. With the loss of pressure from beneath, +occasioned by the removal of so much of the cicatricial tissue, the +epidermis the more readily closes over the wound. To a large extent also +this new growth of epidermis is helped by the renewal of the inflammatory +phenomena brought into being with the cauterization. + +2. SUB-HORNY QUITTOR. + +_Definition_.--A fistulous wound of the foot in which the lower and blind +end of the fistula is situated below the level of the coronary margin of +the wall. + +_Causes_.--These, again, will be practically the same as those mentioned +in the cause of cutaneous quittor--namely, bruises, punctures, wounds--in +fact, any injury upon the coronet severe enough to cause death of tissue +and a suppurating wound. We may thus expect sub-horny quittor to follow +upon treads, overreach, accidental injuries with the stable-fork, and kicks +from other animals. + +Sub-horny quittor may also arise without original injury at all to the +coronet. Either from a violent blow upon the hoof, or from the animal +himself kicking violently against a wall, death of a portion of the +sensitive structures takes place within the hoof, suppuration ensues, and +the formation of quittor commences. With the escape of the pus at the +coronet the quittor is fully formed. + +Any other diseased condition of the foot in which suppuration is present +may in like manner terminate in quittor. In complicated sand-crack, +suppurating corn, or in ordinary pricked foot quittor may be a sequel. In +these conditions the pus formation either goes unnoticed or is neglected, +and after seriously invading the sensitive structures within the hoof, +breaks out at the coronet. Again, too, as with the simpler form of quittor, +and as with coronitis, we may always regard as a predisposing cause the +action of excessive cold in promoting septic infection of the wound when +occurring at the coronet. + +_Symptoms and Diagnosis_.--Where the fistulous wound has had its +starting-point in an injury to the coronet diagnosis is, of course, easy. +The history of the case explains it. Nothing in this instance remains but +to probe the opening, and ascertain its direction, depth, and extent. + +An animal with the wound thus open at the coronet, and freely discharging +its contents, may, if no serious complications exist, walk tolerably sound. +It is only when put to the trot that symptoms of lameness are apparent. + +It may so happen, however, that we first see the case when the symptoms are +wholly those arising from a painful suppuration within the horny box. +This occurs when the original injury has taken place at a more dependent +position than the coronet. Either from violent blows upon the hoof, +puncture from below, from corn or from sand-crack, or any other causes we +have enumerated, suppuration is occurring deeply within the hoof, with as +yet no opening upon the coronet. + +Even when an opening has already occurred on the coronet, the same +condition of sub-horny suppuration may be met with in cases when the +opening of the fistula has by some means or other become occluded. +Granulation tissue, for instance, may have temporarily closed the mouth of +the fistula. The pus, instead of continuing its discharge thereat, is made +to burrow in other directions. + +In either of these cases pain is excessive, the animal walks on three legs, +the foot is painful to percussion, and grave constitutional disturbance +is noticeable. The presence of pus is immediately suspected, and, in the +absence of any indication of an opening having existed at the coronet, +searched for at the sole. It may or may not be found. If found it is given +exit, and the case ends as one of ordinary pricked foot, of suppurating +corn, or some other condition equally simple when compared with quittor. +In those cases where the pus is not discovered at the sole, one adopts the +expectant treatment of poulticing. This, if pus is present, is followed +by a painful swelling of the coronet. At one point there forms a hot and +tender enlargement, with the hairs on it standing straight up from the +skin, which latter is seen below red and inflamed in appearance. + +Later, the abscess--for abscess it is--discharges its contents, the opening +is explored, and we find that in extent it is not confined to the coronary +region, but that it is deep enough to constitute a true sub-horny quittor. + +This discharge of the abscess contents may take place at a well-defined +spot on the coronet, or it may ooze out at the junction of the wall +with the skin. In appearance the discharged pus varies. When the softer +structures only are attacked it is thick, and yellow or white in colour; +when bone is involved it is ichorous; and when attacking the horn itself +black or gray. It may or may not be extremely foetid, and often it is +mingled with blood. + +When evidence of a previous opening upon the coronet is plain, then it is +not considered wise to attempt a paring of the sole. Instead, poulticing +is at once resorted to, to induce the discharge of the pus through its +original channel. Once this has occurred a fistulous wound remains, which +is open for treatment upon one or other of the lines we shall afterwards +indicate. + +COMPLICATIONS--_(a) Necrosis of the Lateral Cartilage_.--This is the +so-called 'cartilaginous quittor' of other writers. In all probability it +is the condition generally understood when the word 'quittor' is used by +one practitioner to the other. Its tendency to keep the disease existing in +a chronic form renders it of grave importance, and for that reason we give +it first mention among the complications. + +It may occur as a sequel either of cutaneous or of sub-horny quittor, and +may result either from actual wounding and infection of the cartilage, or +from an attack on it of septic matter originating elsewhere. + +Unless there has been discovered a fistula, which on probing is seen to +lead direct to the position in which we know the cartilage to be, we +know of no precise means by which the existence of this condition may be +diagnosed. When free from other complications, the horse with his foot in +this state may travel fairly sound. This is so when the necrosis is situate +in the posterior half of the cartilage, in which case the irritation set up +by the disease is confined to the comparatively non-sensitive tissues of +the cartilage itself and the fibrous mass of the plantar cushion. When +attacking the anterior half of the cartilage, the close contiguity of the +joint renders the disease of a more serious nature. It is then that we have +acute pain, and with it extreme lameness, for in this position it is more +than likely that we have involved either the synovial membrane of the +articulation or the tops of the sensitive laminæ. It will be remembered +that here the synovial membrane protrudes as a small sac between the +antero- and postero-lateral ligaments of the joint. More or less easily +then it is bound to come into intimate contact with the septic matter +attending the necrosis of the cartilage, and so share in the inflammatory +processes, afterwards communicating them to the interior of the +articulation. + +With necrosis of the lateral cartilage is always swelling and thickening of +the skin and subcutaneous structures of the coronet. This is the greater +the longer the disease has been in existence. Upon the swelling is seen the +mouth of the fistula, or it may be the mouths of several, and from them all +a discharge of pus. + +The mouth of each fistula is generally filled with a mulberry-like +granulation tissue, standing above the level of the skin, and bleeding +easily if touched. The exuding pus is thin and pale gray in appearance, +gritty to the touch, and generally free from pronounced smell. At other +times its colour is reddened with contained blood, and floating in it are +tiny particles of a pale-green substance, which when picked up and rubbed +between the fingers are seen to be small fragments of the diseased +cartilage. + +Should the mouth of a fistula become occluded with the granulations filling +it, and the discharge prevented from escaping, it soon happens that we have +close to the fistula that has closed a tender fluctuating swelling. This +points and breaks, and pus is again discharged from another opening. In +this manner is accounted for the multiplicity of scars and fistulas seen on +the swelling of an old-standing quittor. + +The continued, inflammation thus kept in existence has the effect of +rendering the skin and subcutaneous tissues in the neighbourhood greatly +thickened and indurated. This in time leads to a tumour-like enlargement, +and causes the structures of the coronet to greatly overhang the hoof. At +the same time the constant inflammation has made its stimulant effects +noted in a great increase in the growth of the horn of the wall. + +Although more abundant, however, the quality of the horn is deteriorated. +The perioplic ring has become obliterated, and the varnish-like appearance +of the healthy wall destroyed. Cracks and fissures in its surface are +numerous, and sometimes deep enough to lead to exposure of the sensitive +structures beneath, complicating the quittor with a sand-crack of a +peculiarly objectionable type. + +_Pathological Anatomy of the Diseased Cartilage_.--The bulk of observers +appear to agree in the statement that in quittor the necrotic cartilage is +pea-green in colour, and recognise it by that characteristic. In size the +necrotic portion thus recognisable varies from the tiniest speck to a +portion the size of a horse-bean. Commonly, however, it is about as large +only as a pea. It is seen to be more or less detached from the rest of +the cartilage, to which it is adherent by one of its extremities only. In +general appearance we can best liken it to the split half of a green pea, +whilst others have compared it with the green sprouting of a seed. The +portions of cartilage nearest the necrotic piece are also slightly green in +colour, thus indicating that here also the diseased process has commenced. +This peculiar change of colour in the affected cartilage is of great +importance to the surgeon. It enables him when operating to distinguish +with some degree of certainty those portions of the cartilage which are +healthy and those which are not. + +_(b) Necrosis of Tendon and of Ligament_.--This complication of quittor +is, as we have said before, treated by other writers as a distinct form of +the disease, and described by them under the heading of Tendinous Quittor. + +This simply means, of course, that the diseased process has extended to +either of the flexor tendons, to the tendon of the extensor pedis, or, +perhaps, to the ligaments of the pedal articulation. + +Of the flexor tendons, the perforans is the one commonly attacked, by +reason, of course, of its more superficial position. At times, however, +especially when its aponeurotic expansion is diseased, the necrosis of the +perforans spreads until the aponeurosis is eaten through and the phalangeal +sheath penetrated. Septic materials gain entrance thereto, and commence to +multiply. In this way the flexor perforatus is invaded, and comes to share +in the diseased process. + +The extensor pedis is usually attacked by extension of the disease from a +necrotic cartilage, or results from the infliction of a severe tread in a +hind-foot. In this case the diseased structure has nothing between it and +the articulation, the synovial membrane in one position actually lining its +inner face. The result is that a condition of synovitis is easily set up, +and the case aggravated by that and by arthritis. + +With the flexor tendons attacked pain is always very great, and lameness is +excessive. This, however, is not sufficiently characteristic to enable us +to determine the precise seat of the necrotic changes. Later, however, a +tender but hard enlargement made its appearance in the hollow of the heel, +which enlargement, later still, became soft and fluctuating. At this stage +there is also considerable swelling along the whole course of the tendons, +as high up as the knee or the hock. The foot is carried forward with all +the phalangeal articulations flexed, and in many cases the limb is unable +to take weight at all. Manipulated after the manner of examining the +tendons for sprain, this swelling is found to be extremely painful. The +animal flinches from the hand, and shows every sign of acute suffering. +This condition may, in fact, be mistaken for sprain, and is only to be +distinguished from it by carefully noting the history of the case--first, +the appearance of the swelling in the hollow of the heel, and, secondly, +the _after_-swelling of the upper portions of the tendons. + +The formation of the abscess, the after-discharge of its contents, and the +final establishing of a fistula, are processes greatly prolonged in this +form of quittor. It will readily be understood why this should be so when +one remembers the depth at which the suppurative process is going on, the +thickness of the metacarpo-phalangeal sheath, and the resistant nature of +the material of which this latter is made, and which must be penetrated +before the condition becomes observable. + +After the opening of the abscess, which usually takes place in the hollow +of the heel, there is left the fistulous wound which obstinately refuses to +heal. Or it may be, again, that there are several of these fistulas, each +opening in the heel, and the mouth of each marked by a small, ulcer-like +projection. The discharge continually oozing from these keeps the heel +constantly wet with a thick purulent discharge, which is nearly always +blood-stained, and very often foetid. + +This constitutes what is known as tendinous quittor in its worst form, +for more often than not there is associated with it inflammation of +the navicular bursa, caries of the bones, or arthritis of the pedal +articulation. + +With the extensor pedis attacked matters are not quite so grave, in spite +of the fact that the articulation is closely situated thereto, for in this +case the more superficial position of the diseased structure allows both +of readier exit of the discharges and of easier removal of the necrosed +portion and after-treatment of the wound. + +_(c) Caries of the Bones_.--Portions of the os pedis, more especially of +its wings, and therefore usually occurring in conjunction with necrosed +cartilage, become carious in quittor. In many cases it is impossible to say +with certainty when this has occurred. In a few instances, however, the +exuding discharge gives evidence of what has happened. It is thin, but +extremely offensive, with the characteristic odour of decayed bone or +tooth, and with a feel that is gritty with contained particles of broken-up +bone. If, with a discharge of this nature present, the probe also conveys +to the fingers the sensation that bone is reached, then diagnosis may be +sure. + +_(d) Ossification of the Cartilage_.--This may take place in part or in +whole. It, of course, constitutes Side-bone, a fuller description of which +will be found in a later portion of this chapter. + +_(e) Penetration of the Articulation_.--This may occur either as a result +of the suppurative changes or as an accident in excision of the diseased +cartilage. Unless it is followed by a severe purulent arthritis, it is not +so grave a complication as at first sight it would appear. + +_(f) Synovitis and Arthritis (Purulent)_.--Should this complication arise, +the case is a most serious one. Beyond here mentioning the fact that it may +occur, we shall not dwell on it. Fuller consideration is given to it in +Chapter XII. + +_Treatment_.--The various treatments adopted for the cure of sub-horny +quittor offer the veterinary surgeon a large number to select from. We +will describe them in the order in which they are, perhaps, most commonly +practised. + +_Poultices and Hot Baths_.--As in cutaneous quittor, and as in coronitis, +when the pus formation is only suspected, and has not yet broken out at the +coronet or elsewhere, then the first indication in treatment is the use +of warm poultices or of hot baths. Their application is in most cases +productive of pointing at the coronet. + +Directly this appears it is a wise plan to thin the wall down with the rasp +immediately below the swelling. To some extent it relieves the pressure of +the inflammatory products within, and at the same time paves the way for +operative measures which may be necessary later on. + +With the breaking of the abscess and the discharging of its contents, we +may in some measure ascertain the condition we have to deal with. The probe +is used, and the abscess cavity explored. The size of the wound, its depth +below the upper margin of the wall, the structures involved, and other +information, may be thus obtained. + +At first, however, the nature of the wound, and the character of the +discharges, must largely guide us as to the treatment we adopt. In many +cases, even where the abscess cavity is far below the upper margin of the +wall, and is presumably in an unfit position to drain and heal, a a regular +application of an astringent and antiseptic dressing is sufficient to bring +about resolution. If, however, the discharge from the wound continues to be +liquid, and the wound itself at one spot refuses to heal, it may be judged +that a portion of necrotic tissue is situated under the wall, and affecting +the laminæ, the cartilage, or ligament, as the case may be. If this is so, +then operative measures must be determined on (see Removal of the Wall, p. +349). + +_Blisters_.--Instead of the poultice and hot baths, the pointing of the +abscess and the casting off of the slough may be brought about by the +application of a sharp cantharides blister. We have, in fact, seen many +cases where this treatment was adopted prior to the formation of a fistula, +and also in cases where one or more fistulous openings already existed, +where repeated blisters to the coronet have alone been sufficient to effect +a cure. + +We are bound to admit, however, that the treatments of poulticing and +blistering are only expectant--we might almost say empirical. At any rate, +we admit to ourselves that what we have advised and carried out is not in +itself curative, but only a means of assisting Nature to satisfactorily +work her own ends. Empirical or not, however, we believe that in every +case of quittor it is wise in practice to at first adopt some such simple +measure, for in nearly every instance where operative measures are +practised, the patient must be laid aside for at least several weeks, +whereas in this way he may be kept at work and a cure effected at the same +time. + +_The Actual Cautery_.--Largely of the same empirical nature, yet doing +something a little more calculated to destroy necrotic tissue and bring +about its sloughing is the use of the cautery, both actual and potential. + +The actual cautery may be beneficially employed for the relief of sub-horny +quittor in at least two ways. + +In the first place, it is often used--a blunt 'point-firing' iron being the +instrument--instead of the knife as a means of evacuating the contents of +the coronary abscess. Those who use it for this purpose are able to say +this in its favour: it brings about the opening of the abscess without the +unsightly hæmorrhage attending the use of the knife, and at the same time +just as effectually empties it. The opening made is not nearly so likely +to close prematurely--that is, before a proper course of treatment of the +wound has been carried out--and so leave necrotic tissue at its bottom. The +intense tissue reaction it sets up is productive of a large slough, cast +off by highly active inflammatory phenomena, which means that the remaining +wound is one in which no dead tissue is left, and which is more amenable to +treatment. + +We have also seen the actual cautery used in sub-horny quittor, where that +disease has reached a chronic fistulous stage, as a means of cauterizing +the whole length of the lining of each fistulous passage. + +At the present day this method is regarded as barbarous, and savouring +too largely of the methods and practice of the old empirics. There is no +denying the fact, however, that it is at times followed by a speedy and +complete cure of what has for months been an intractable and apparently +incurable quittor; and, honestly speaking, we ourselves can see nothing +very greatly against the operation in certain cases save its appearance. In +that it is certainly rough, and is not calculated to favourably impress the +more critical of our clientele. With the animal chloroformed, however, much +of what can really be urged against it disappears, and on farms and other +places where a skilled and competent dressing of an operation wound cannot +be looked for, it is sometimes wise to advise this method of treatment in +preference to more advanced methods of operating. So far as we can judge, +the after-effects are very little worse than those following other +operative measures, more especially when a suitable case has been chosen. + +This method of treatment is particularly applicable to cases of chronic +sub-horny quittor in the more posterior parts of the foot. Here, if one or +more fistulas exist, their openings are probed and the direction of the +sinuses determined. In all probability they are burrowing down along-side +the wall to the sole, where, for want of outlet, they are invading the +substance of the plantar cushion or the plantar aponeurosis. + +Should this preliminary probing demonstrate that neither of the fistulas +run dangerously near the joint, then the operation may be decided on. + +The animal is cast and chloroformed, the foot firmly fixed, and the horn of +the quarter rasped away quite thin. The sole of the same side is also pared +with the knife until the horn of both the quarter and the sole yields +easily to pressure of the thumb. All that is then needed is three or four +long, round, and pointed irons (about 1/4 to 3/8 inch in diameter) heated +to redness. These are inserted into the fistulas, and the false mucous coat +of these passages thus destroyed. When the iron, on being directed into the +fistulous opening at the coronet, is found to travel alongside the wall, +and to easily reach the sole, it should be made to go further still. The +sole is penetrated, and a dependent opening thus made for the escape of the +discharge that afterwards accumulates. + +What happens now, of course, is that an intense and acute inflammation +is set up along the whole track of the fistula, in which position the +inflammatory changes were heretofore chronic. The whole lining of the +fistula, and with it, we hope, all necrotic tissue, is cast as a slough, +leaving nothing but healthy tissue behind. This, with a suitable dressing, +heals and gives no further trouble. + +The after-treatment consists in the application of hot poultices. These +tend to greatly ease the pain, and at the same time to facilitate the +removal of the slough. The poulticing should be continued, therefore, until +the sloughing comes about, which happens, as a rule, at about the fifth or +seventh day. + +Immediately the slough is cast off, the poultices may be discontinued and +dressing of the wound carried out. This consists of injections of solutions +of zinc chloride 1 in 200, perchloride of mercury 1 in 1,000, carbolic acid +1 in 20, of Villate's solution, or of such other antiseptic as the surgeon +may think fit. The dependent orifice at the sole should be kept open for as +long as possible, being occasionally trimmed round with the drawing-knife, +and scooped out with a sharp-edged director. + +Directly a healthy and pink-looking granulation is observed along the +track of the iron, and the discharge therefrom takes on a thick and yellow +appearance, the strength of the antiseptic solutions should be gradually +diminished. This point, in fact, is of great importance in treating all +wounds of the foot. There is a great temptation, on account of the known +excessive liability of the parts to septic infection, to use an antiseptic +solution unduly strong. What must be remembered is that used _too_ strong +they themselves give rise to dead tissue, or to impermeable layers +consisting of compounds of the discharges with themselves, and so create +substances that prove a source of irritation and subsequent trouble. + +_The Potential Cautery_.--This is employed in the treatment of sub-horny +quittor, either in the solid form (in sticks, in lumps, or in the powder), +or in the liquid form, when it is injected with a quittor syringe. + +In the former method such drugs as perchloride of mercury in the lump, or +nitrate of silver, chloride of zinc, and caustic potash or soda in the +stick, are introduced into each of the sinuses present. This is done by +means of a director or a probe. + +A better method, however, when the dressing lends itself to the purpose, is +to use it in the form of a powder, wrapped in the form of small cubes +in extremely thin paper, such, for instance, as is used for rolling +cigarettes. It is then conveniently inserted into each fistula. Introduced +in this more finely divided form the drug is, perhaps, a little more active +in bringing about the desired result. + +This method of 'plugging,' although practised by many, we cannot recommend +in preference to the use of the hot iron or of liquid injections. Our +reasons are these: the action of the drug is a protracted one. Almost +immediately after its introduction into the fistula there is formed about +it an almost impermeable layer of a metallic albuminate, which effectively +prevents further rapid action of the caustic. In addition to thus +preventing further action of the dressing, this combination of the tissue +albumin with the metal of the salt, together with much necrotic tissue that +it has caused, is extremely hard to remove from the healthy tissues. This +we explain by pointing out that the action of the caustic, prolonged as +it is, sets up a tissue reaction which partakes largely of the type of a +chronic rather than an acute inflammation. With a chronic inflammation +there is sooner a tendency to the production of fibrous tissue (and thus +the firmer attachment of the necrosed portions) rather than an active +phagocytosis and the casting-off of a slough. Again, careful though we may +be with the probe, it is extremely difficult to be certain that we have +discovered the whole extent of any fistula. An equal difficulty, therefore, +exists in being certain that we have placed the caustic in the position +in which it is most wanted--namely, at the furthermost end of the fistula +where the necrotic tissue is to be found. + +When a caustic is used at all, it is far better to employ it in the liquid +form, when either of the drugs we have just mentioned may again be used. In +the first place, the liquid is far more likely to be brought into contact +with the diseased structures than is the solid salt. Also, its action may +be regulated by altering the strength of the solution, and the liability to +form impermeable albuminates thus diminished. + +Probably the best solution for use in this way is the old-fashioned +Villate's solution (see p. 199). + +This liquid should be injected at least every day, and, in a bad case, +even two or three times daily. Practical hints to be borne in mind when +attempting to cure quittor by means of injections are these: + +If the fistulas are numerous, the fluid should be injected into their +various orifices. + +In order to force the fluid to the bottom of each diseased track, it is +necessary, when injecting one opening, to firmly close all others. + +Several injections should be made at each time of injection. In other +words, we must not be content with just forcing fluid in. It must be forced +in, and again forced out by a further syringeful. The fistulous tracks +must, in fact, be washed in the liquid. + +The effect of the injection during the first eight or ten days is to render +suppuration more abundant and whiter. After two weeks of the treatment +sloughing of the inside of the sinuses occurs, and healing of the wound +commences. Signs that this is occurring are--slight hæmorrhage at the end +of each injection, and a gradually increasing difficulty in forcing in the +fluid. + +_The Making of Counter-openings to the Fistulas_.--Although Villate's +solution or any other caustic used in the manner we have described +often effects a cure, many practitioners insist on the fact that a +counter-opening to the fistula must also be made. + +The probe is used and the direction and depth of the fistula ascertained. +Through the wall is then made an opening at exactly opposite the lowest +point found by the probe, or through the sole if the probe should there +lead us. This opening is best made with a sharp-pointed iron, and may +afterwards be kept large enough by an occasional trimming with the knife. +Many of the older authors, and with them writers of the present day, +declare that unless this is done the ordinary injection is likely to fail +in a great many instances where it would otherwise have been successful. + +Where a counter-opening is thus made it is found that it very readily +closes with granulation tissue, and the purpose for which it was made +defeated. This may be avoided by the use of a seton. In preference to the +seton, however, we ourselves would advise that the opening be kept free by +the occasional use of a sharp-edged director or a fine scalpel. + +An interesting modification of the practice of making a counter-opening is +that related by Veterinary-Captain S.M. Smith.[A] In point of severity it +runs a middle course between the making of a simple counter-opening and +the removal of a wedge-shaped portion of the coronary band and the wall, a +method which we shall later describe. + +[Footnote A: _Veterinary Record_, vol ii., p. 157.] + +To perform this operation, the animal is cast and chloroformed. The foot is +fixed and the parts thoroughly cleansed. The horn of the wall is then sawed +through in a direct line from the coronary margin to the solar edge, the +saw-line running exactly over the seat of the sinus. + +A strong scalpel is now introduced at the coronary opening, with its +cutting-edge outwards, and is gradually passed down the opening made by the +saw. In this way the sinus is completely destroyed, and from end to end +converted into an open wound. The parts are then washed in a perchloride of +mercury solution, covered with a mixture of powdered iodoform and boracic +acid, over which a pledget of carbolized tow is placed, and then a bandage +over the whole. This dressing should be left on three or four days, after +which the injury should be treated as an ordinary wound. In conclusion, +the author says: 'I can safely recommend this line of treatment to any +practitioner having an obstinate case under treatment.' + +_Removal of the Wall and Excision of the Necrotic Tissue_.--This we +may term the radical operation for sub-horny quittor, for it is often +productive of a successful issue when all other means have failed. No +matter in what position the sinus is, whether at the extreme anterior +portion of the coronet, or whether in the region of the heels, it is to be +thoroughly opened up. To do this, the fistula is carefully explored with +the probe and a knowledge of its exact dimensions arrived at. This is +carefully noted, and the horn of the wall for some little distance around +it then rasped down quite thin. Immediately over the sinus, and for a short +distance on either side of it, the horn is stripped away to the sensitive +structures. The cavity of the fistula is then opened up with a scalpel, and +every particle of diseased tissue removed with this instrument and a pair +of forceps. After-dressing consists simply in the application of suitable +antiseptics. + +_When the Complication of Necrosed Tendon or Ligament exists_.--We may take +it as an axiom that wherever this exists, whether it is in the extensor +pedis, in the lateral ligaments of the joint, or in portions of the +flexors, all diseased structures should, where possible, be removed. This +is done either with a scalpel or with a curette. + +When septic matter has gained the sheath of the perforans, and the +formation of pus therein is indicated by inflammatory swellings in the +hollow of the heel, it is sometimes advisable to lay the sheath open for 1 +to 2 inches along the course of the tendons. This, if a fistula is present, +may be best done with a blunt-pointed bistoury, or with a cannulated +director and a scalpel. With the pus thus given exit, and an antiseptic +dressing regularly applied, the case sometimes ends in rapid resolution. +More often than not, however, it is found that the pus has been liberated +too late, and that it has gravitated in the sheath to the extent of +affecting the plantar aponeurosis. Or it may be, of course, that it was in +the plantar aponeurosis the disease commenced. Whichever may have been the +case, we have in the hollow of the heel one or more fistulous openings, or +an opening we have made ourselves, leading down to a necrosed portion of +the terminal expansion of the perforans. + +In such cases we ourselves have derived benefit from a regular flushing +of the sinuses with a 1 in 2,000 solution of perchloride of mercury, +introduced by means of a glass syringe, followed later by flushing in the +same manner with a 1 in 40 solution of carbolic acid, the hollow of the +heel meanwhile being kept clean with an antiseptic pad and bandage, or by +liberal applications of an antiseptic powder. + +The septic materials are in this way destroyed, and the wound heals without +further complication. We must admit, however, that the cure of the lesion +is generally at the expense of slight lameness, due, in all probability, +to inflammatory tissue adhesions between the flexor perforans and the +perforatus, and to a partial destruction of the synovial membrane of the +sheath. + +If, in spite of the antiseptic irrigations, the fistula persists, then +nothing remains but to resort to excision of the aponeurosis, as described +on p. 222. + +_When Necrosis of the Lateral Cartilage is present_.--In this case we may +at first try the ordinary treatments of poulticing; and blistering, of +antiseptic caustic injections, and of plugging. In some cases a cure is +effected. Should these fail, however, and we intend to see the finish of +our case, then operative measures must be determined on. This means cutting +down upon the diseased cartilage, and either removing the necrosed portion, +or excising the cartilage in its entirety. + +The latter method is seldom practised in this country. As it is the most +radical of the two, however, we shall describe it here first. + +_Extirpation of the Lateral Cartilage_.--The operation of extirpating the +lateral cartilage is by no means a new one, being introduced, according to +Zundel, by the senior Lafosse in 1754. It consisted in removing a portion +of the wall by grooving and stripping it, and of excising the exposed +cartilage by means of a sage-knife. + +As to what portion of, and how much of the horn of, the quarter should +first be removed, and as to what particular direction each groove should +take, opinion among the older writers varied considerably. This we know +now is not an important matter, and it is sufficient to say that the first +preliminary is a thinning down of the horn of the quarter with the rasp +over the position occupied by the cartilage. At the present time there are +two or three modifications of the operation as originally introduced. +In all, however, the preliminary steps are the same. We shall therefore +describe them collectively, as applying correctly to either of the three +methods of operating we are about to show. + +_Preparation of the Subject and Preliminary Steps in the Operation_.--On +the day previous to the operation the horn of the wall immediately over the +cartilage must be so thinned with a rasp as to yield readily to pressure +of the thumb in any position. It should be so thin as to only just avoid +wounding the sensitive structures below. + +The whole of the foot must then be thoroughly cleansed, and rendered as +nearly aseptic as possible. The use of warm water, soap, and a stiff brush +is the readiest means of removing the surface dirt. Afterwards the foot +should be soaked for some time in a reliable antiseptic solution, a 1 in +1,000 solution of perchloride of mercury being the most suitable. When +removed from the solution the foot must be packed round with wool or +tow impregnated with corrosive sublimate, and then bandaged, the whole +afterwards wrapped in a thick cloth, or protected with a boot. + +On the following day the animal is brought out and cast, and the foot +desired to be operated on firmly secured, after the manner described on p. +81. The bandages and sublimate pads are then removed, and the skin of +the coronet over the seat of operation shaved of hair. An Esmarch rubber +bandage is next run up the limb, and the tourniquet applied, thus rendering +the operation a nearly bloodless one. + +This done, the animal is chloroformed, and an antiseptic douche played over +the foot. + +So far, the steps in the operation are common to all methods. There are +now, however, three slightly differing modes of extirpating the cartilage, +which modes vary simply according to the structures severed by the knife. + +_First Method_.--This is the oldest method of the three, and consists in +making (1) a horizontal incision through the sensitive laminæ along the +lower border of the cartilage, and (2) a vertical incision through the skin +of the coronet, the coronary cushion, and a portion of the sensitive laminæ +(see Fig. 139). + +The flaps (Fig. 139, _a, a_) are now held back by tenaculæ, and the whole +of the cartilage, or only the necrosed portion, carefully excised by means +of right- and left-handed sage-knives. Fistulous openings in either of the +flaps _a, a_ must now be carefully curetted and dressed, and the flaps +allowed to fall into position. They are then sutured with carbolized gut, +and the wound finally dressed as to be described later (p. 357). + +[Illustration: FIG. 139.--EXCISION OF THE LATERAL CARTILAGE (OLD METHOD). +The wall covering the lateral cartilage first thinned and stripped off; the +two flaps (_a, a_) of skin and the coronary cushion made by the vertical +incision turned back. _a_, The operation flaps; _b_, the exposed cartilage; +_c_, the sensitive laminæ; _d_, the coronary cushion.] + +_Second Method (after Holler and Frick_[A]).--These operators deem it wise +to leave untouched the skin of the coronet and the coronary cushion. They +therefore make their first incision along the lower border of the coronary +cushion (see Fig. 140), afterwards exposing the lower half of the cartilage +by removing a half-moon-shaped portion of the thinned horn and underlying +sensitive laminæ (see Fig. 140, _b_). + +[Footnote A: Two cases of quittor successfully treated by this method are +reported by R. Paine, M.R.C.V.S., in the _Journal of Comparative Pathology +and Therapeutics_, vol. xv., p. 81.] + +[Illustration: FIG. 140.--EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER +AND FRICK.) _a_, The thinned horny wall covering the coronary cushion; _b_, +the lateral cartilage exposed by stripping off the thinned wall; _c_, the +sensitive laminæ.] + +This done, the external face of the cartilage is separated from the skin +of the coronet. To do this a double sage-knife is run flatwise between the +coronary cushion and the cartilage, with the convex surface of the blade +towards the skin. The knife is then passed backwards and forwards until the +necessary separation is accomplished. During these movements of the knife +a finger of the unoccupied hand should follow the knife, and guard the +coronary cushion against injury. + +Following this, the inner surface of the cartilage must be also separated +from the structures lying beneath it. To this end a sage-knife (right- or +left-handed, according as to whether the anterior or posterior portion of +the cartilage is to be first removed) is again passed into the incision. +With the cutting-edge of the knife forward, it is gradually reached round +and under the hindermost end of the cartilage, and theposterior half of +the cartilage separated from underlying structures, and at the same time +excised by one clean cut forwards. Using the second sage-knife in a similar +manner, the cutting-edge this time backwards, it is reached in front of the +cartilage, whose anterior half is then excised by a careful cut backwards. +Any small portions of cartilage remaining after this are sought for with +the finger, and carefully removed by means of a scalpel and a tenaculum. + +The fistulous opening or openings in the skin of the coronet should now be +thoroughly curetted, and the whole of the wound dressed as to be described +later. + +In removing the anterior half of the cartilage it is highly important to +remember the close contiguity to it of the synovial membrane of the +pedal articulation. This projects as a small sac between the antero- and +postero-lateral ligaments of the joint. Risks of injury to it may be +diminished by having the foot secured with a line, and pulled forward by an +assistant while the cut is being made. + +_Third Method (after Bayer)_.--This operator recommends that, after +stripping a half-moon-shaped piece of horn from the seat of operation, +instead of raising the skin of the coronet and the attached coronary +cushion in two flaps (as Fig. 139, a, a), that the cartilage be exposed +by raising up one flap only (Fig. 141, a), consisting of a portion of +the sensitive laminæ, the coronary cushion, and the skin and underlying +structures of the coronet. + +With the horse cast and the preliminary steps over, the thinned horn of +the quarter is incised in a semicircular fashion, and the half-moon-shaped +piece thus separated from its surroundings stripped off. At about 1/4 inch +from the incision in the horn, a second incision of similar shape is made +through the sensitive structures, which incision is also carried up into +the skin and structures of the coronet. This incision severs, from bottom +to the top, (1) the sensitive laminæ covering a portion of the pedal bone +and a portion of the lateral cartilage, (2) the coronary cushion, and (3) +the skin of the coronet and such structures as lie between it and the +cartilage. + +[Illustration: FIG. 141.--EXCISION OF THE LATERAL CARTILAGE. (AFTER +BAYER.) The horny wall is stripped off over the seat of operation. _a_, +Semicircular flap of sensitive laminæ, coronary cushion, and skin; _b_, the +lateral cartilage; _c_, the sensitive laminæ; _d_, the coronary cushion.] + +That this incision of the sensitive structures should be kept at 1/4 inch +from the one in the horn has a reason. It is that when this flap is again +placed into position (as later it will have to be) we have round its +circumference a rim of soft structures into which to place the sutures. And +in this connection it is well to advise the operator that the thinness of +the keratogenous membrane (the laminal portion of it) should warn him that +the portion of it to be turned up--namely, that forming the tip of the +flap--should be _scraped_ away quite close to the os pedis. Unless this is +done, there will not be a sufficient thickness left to afterwards bring +into position and suture. + +The half-moon-shaped piece of tissue incised is now carefully dissected +away from the external face of the cartilage, until it may be turned up as +a flap (see Fig. 141, _a_), and held from off the cartilage by a tenaculum. + +The exposed cartilage is now carefully removed by the aid of a sage-knife +and a stout pair of forceps, the same precaution of holding the foot well +forward being again taken in order to avoid wounding of the articular +capsule. + +At this stage in the operation considerable care is required. The operator +must remember that close beneath him, and more particularly in front, is +the pedal articulation. It is better, therefore, to excise the cartilage +piecemeal, and to do it carefully, than to attempt, at the risk of injury +to the joint, to make the operation 'showy.' + +During removal of the cartilage, the terminal branches of the digital +arteries are wounded, as also are the veins of the coronary plexus. Should +either of these stand out with extra prominence from the others, it should +be picked up with a pair of forceps, and ligatured with either carbolized +gut or silk. + +Attention should then be given to the flap of skin and coronary cushion. +Wherever a sinus has existed in it, it is to be carefully scraped, and all +dead portions of tissue removed. This done, the flap is allowed to fall +into position, and is there carefully sutured, not only at the skin of the +coronet, but along the whole circumference of the incision. + +_Dressing of the Wound and After-Treatment_.--The whole secret of the +success of this operation is in afterwards maintaining a strict asepsis +of the wound. Unless there is reasonable room for belief that this may be +done, the operation had far better not be advised, for if the wound is +afterwards suffered to get into a suppurating and dirty condition, the last +stage of the case may be worse than the first Synovitis and arthritis, with +certain anchylosis of the joint, and a probable loss of our patient, is +almost bound to follow. + +We cannot, therefore, too strongly insist upon the advice that the whole of +the preliminary antisepticising of the foot that we have described, and the +after maintaining of asepsis that we are now about to relate, _must_ be +methodically and thoroughly carried out. It is of even _more_ importance +than little details in the operation itself. + +In the first and second methods of operating, directly the actual operation +is over, the surface of the wound and both surfaces of the skin-flaps +should first be thoroughly douched with a 1 in 1,000 solution of +perchloride of mercury. Bayer prefers a 1 in 5 solution of iodoform in +ether. + +Next, either iodoform or chinosol in the powder should be dusted over the +whole surface, including again both inner and outer faces of the reverted +skin-flaps. This done the flaps are allowed to fall into position and +sutured there with carbolized silk or gut. + +Another liberal application of an antiseptic dressing follows this. +Iodoform, iodoform and boracic acid, or chinosol, is freely dusted over +the wound and for some distance around it. Bayer, however, again prefers a +dressing of the wound, and especially the moistening of the line of sutures +with the 1 in 5 solution of iodoform in ether. + +Over the wound is then placed a protective layer of gauze, impregnated +either with boric acid, with a mercuric salt, or with iodoform. + +Finally, numerous small and lightly-rolled balls of dry carbolized tow +are packed regularly over the whole of the operation wound, and the foot +bandaged. + +Practical points to be remembered in this after-dressing are: (1) The +balls[A] of tow should be numerous enough to exercise pressure upon the +sutured flap when the foot is finally bandaged. (2) The bandage should +be run on from the coronet downwards, in order to insure pressure being +exerted in the exact position over the sutured flap. (3) Bandages should +be used in abundance, commencing always from the coronet, and carefully +applied so as to exert an even and uniform pressure. (4) The bandages +should be of clean, unused linen. + +[Footnote A: Bayer recommends that the tow be rolled into cylindrical +tampons, each long enough to cross the wound. These are placed on the wound +in alternate horizontal and vertical layers, so that when rolled round by a +bandage they are pressed into an even and compact pad.] + +Once the bandages are adjusted, the hobbles may be removed, and the +tourniquet loosened. Directly the tourniquet is removed there is a steady +oozing of blood through the bandages, no matter how many we have put on. +This should occasion no alarm, as experience has taught that the careful +attention to antiseptic measures observed throughout the operation has the +effect of maintaining the lowermost dressings, those next to the wound, in +a state of asepsis. The bandaged foot should now be wrapped in a piece of +thick clean cloth or placed in a boot. + +If our antiseptic precautions have been thorough, the dressings and +bandages so adjusted may be allowed to remain without disturbance for from +eight to fourteen days. In this, however, the veterinary surgeon must be +largely guided by the symptoms of his patient. If, at the end of the +first three or four days, the animal maintains a vigorous appetite, if he +commences to place a little weight on the foot, and if the thermometer +gives no indication of a rise beyond the one or two degrees of ordinary +surgical fever, then the surgeon may know that things are proceeding +satisfactorily. Pawing movements with the foot, inability to place weight +upon it, loss of appetite, an increase in the number of respirations, and +a serious rise of temperature, denote the opposite state of affairs. The +wound is in all probability suppurating. The bandages and dressings should +therefore be removed, and the wound either redressed and bandaged, or +treated as an ordinary open wound. + +Ordinarily, however, if the operation has been properly performed, healing +takes place by first intention, and the wound when the bandages are removed +at the end of the first or second week appears clean and _dry_. + +Having assured ourselves that such is the case, we dress the foot in +exactly the same manner as before, save that so many bandages are not put +on. A similar dressing is repeated weekly until such time as the wound +shows sufficient growth of horn--quite a thin pellicle--to act as a +protective. It may then be left undressed, except for some simple hoof +dressing and a bandage. + +Complete healing of the wound takes from about four to eight weeks, at the +end of which time the animal can be again gradually put into work. The +labour, however, should be light, and quite three or four months should be +allowed to elapse before any attempt is made to put him to heavy work. + +Should the second method of operating have been the one adopted, then there +is one slight difference in the after-dressing that needs attention calling +to it. In this case we have more or less of a _hidden_ cavity left to deal +with rather than the broad and _open_ wound left in either of the other +methods. This cavity, left by the extirpation of the cartilage, must be +thoroughly dressed with iodoform or chinosol, or with Bayer's iodoform +in ether. The packing with carbolized tow and the bandaging may then be +proceeded with as before. + +In conclusion, we may say that the operation is one of some delicacy, and +needs a good surgeon for its successful performance. Furthermore, no one of +the antiseptic precautions we have advised can be omitted. It is, perhaps, +these two considerations (and in justice to the English surgeon we should +say most probably the latter of them) that have prevented this operation +from being generally adopted. + +That it is successful there is no gainsaying. Professor Bayer, of the +Vienna School, with whose name is associated the last of the three methods +of operating we have described, is enthusiastic in praise of the operation, +and says: 'The favourable results that I have got by this operation have +caused me wholly to abandon the medicinal treatment, and to prefer in all +cases the surgical operation as being the best means to the end.' + +_Partial Excision of the Lateral Cartilage_.--Discarding the somewhat +elaborate methods we have just described, there are English operators who +removed the necrosed portion only of the cartilage, and do so in what +appears at first sight a comparatively rough-and-ready manner. + +The apparent roughness is that they do not concern themselves with +conserving the coronary cushion, and hesitate but little in cutting +portions of it bodily away. One would imagine that in this case the quarter +of the side operated on would be always more or less bare of horn. Such, +however, is not the case. + +To perform this operation the animal is again cast and chloroformed. Some +operators, however, use the stocks and dispense with the anæsthetic. The +foot is first well cleaned with soap and water and a stiff brush, and the +hair of the coronet over the seat of operation shaved. Again, too, the horn +of the affected quarter is rasped until it yields easily to pressure of the +thumb, and the whole of the foot washed in an antiseptic solution. + +A probe is now inserted into the opening at the coronet, and the direction +of the fistula noted, after which the foot is firmly secured, and an +Esmarch bandage and tourniquet applied to the limb. + +This done, a triangular or wedge-shaped portion of skin, coronary cushion, +and thinned horn is removed with a strong sage-knife or scalpel. + +The base of the wedge-shaped portion removed contains the opening of the +fistula, and the apex of the wedge should reach to the bottom of the sinus +(see Fig. 142). + +After the horn is removed and the fistula followed up, it is sometimes +found that what we at first thought was its end, it may now be continued in +an altogether different direction. + +It is again followed up with the probe, and the horn and sensitive +structures excised until we are quite certain we have reached its furthest +extent. + +Attention should next be paid to the cartilage. Wherever spots of necrosis +are found, as indicated by the pea-green colour of the affected parts, they +must be _carefully_ excised. Care should be taken in so doing to carry the +line of excision some little distance around the visibly affected parts. +This is done that we may be quite certain nothing at all remains calculated +to give rise to further trouble. + +It goes without saying that, in addition to the necrosed cartilage, all +other diseased and necrotic tissues should also be removed. The os pedis is +occasionally found necrotic just where the cartilage joins it, or it may be +that a small portion of the sensitive laminæ, by reason of its _liver-red_ +or even gray coloration, gives evidence of death of the part. + +The former must be well curetted, and the latter cleaned carefully with a +scalpel and forceps. + +[Illustration: FIG. 142.--PARTIAL EXCISION OF THE LATERAL CARTILAGE BY +REMOVING A PORTION OF THE CORONARY CUSHION. The dotted lines show the +outline of the wedge-shaped portion of structures to be removed, including +skin, coronary cushion, horn, and sensitive laminæ. _a_, The opening of the +fistula.] + +The operation finished, the foot is again douched in an antiseptic +solution, the wound mopped dry with carbolized tow, dressed with either of +the dressings described on page 358, and finally bandaged. The dressing +should be changed every three days only, unless in the meanwhile pawing +movements and other symptoms of distress indicate their removal. + +The length of coronary cushion removed in this operation is from 1/4 to 1/2 +inch (we ourselves, however, have seen it more), and yet its loss seems to +occasion no serious after-trouble beyond a slight deformity of the parts +beneath. The sensitive structures become sufficiently covered with horn, +and the animal in nearly every case is returned to work, while in a great +many instances he may also trot perfectly sound. + +Simple though the operation may appear, and apparently rough in its method, +it is nevertheless successful in effecting a cure in cases where blisters, +plugging, injections, and other means have failed. + +Mr. W. Dacre, M.R.C.V.S.,[A] after reading an article on the operation +before the members of the Lancashire Veterinary Medical Association, says: +'My observations have not been based on a single case, and having had nine +of them, and all of them successful, I felt it to be my duty to bring this +subject before the Society.' + +[Footnote A: _Veterinary Record_, vol. v., p. 407.] + +Mr. T.W. Thompson, M.R.C.V.S.,[A] says: 'In a great number of cases I have +removed a 1/2 inch of the coronary band.... I have performed the operation +a great number of times, and have never seen a foot that has been damaged +by it.' + +[Footnote A: _Ibid_.] + +Professor Macqueen[A] says: 'I do not spare the coronary band or sensitive +laminæ when I find those parts diseased. I do not unnecessarily damage +those structures. At the same time, I am confident that excision of a piece +of the coronary band or removal of a few sensitive laminæ has not the +untoward consequences so much dreaded in former days.' + +[Footnote A: _Ibid_., p. 714.] + +Mr. John Davidson, M.E.C.V.S.,[A] says: 'The treatment described, if +carefully carried out and details attended to, will be found a success in +dealing with the majority of cases of quittor. If I may be permitted to say +so, without being considered boastful, I have yet to see the first case +that has resisted the treatment.' + +[Footnote A: _Ibid_., vol. xiv., p. 769.] + +Should our case of quittor be complicated by caries of the bone, this must, +where possible, be scraped or curetted until the whole of the diseased +portion is removed, and a healthy surface is left. After-dressing must then +be carried out as in other cases. + +The treatment of ossified cartilage will be found under treatment of +side-bones, and the methods of dealing with penetrated articulation and +purulent arthritis are treated of in Chapter XII. + +_Surgical Shoeing in Quittor_.--In the case of simple or cutaneous quittor, +no alteration in the shoeing is necessary. + +When the condition becomes sub-horny, however, and particularly when it is +situated in the region of the quarters, ease is afforded to the diseased +parts by removing the bearing of the shoe in that position. + +Should there be no dependent opening at the sole, then the best shoe for +the purpose is an ordinary bar shoe (Fig. 68), with the bearing eased under +the affected quarter. + +If, however, there is a dependent orifice, or one is expected, then it will +be necessary either to leave the animal unshod or to provide him with +a shoe that admits of dressing the lesion. In the latter case the most +suitable shoe will be found to be either a three-quarter shoe (Fig. 102) +or a three-quarter bar shoe (Fig. 103). Many operators, however, keep the +animal unshod. We must say ourselves that we consider a shoe useful after +either of the operations for removal of the cartilage, if only to assist in +maintaining the bandages and dressings in position. + +In this case a very useful shoe will be the three-quarter bar shoe. With a +little manipulation the bandages are easily run under the bar portion of +the shoe, and a few of their turns every now and again wrapped round the +bar in order to keep the whole firmly in position. + +In connection with tendinous quittor, when septic matter has gained the +sheath of the flexor tendons, there is, for a long time after healing of +the fistula, a marked tendency for the animal to go on his toe. To a large +extent we judge this to be due to slight adhesions between the two tendons +brought about by the growth of inflammatory fibrous tissue. In such cases +benefit is sometimes derived from the application of a shoe with an +extended toe-piece (see Figs. 84 and 108). + + +C. OSSIFICATION OF THE LATERAL CARTILAGES, OR SIDE-BONES. + +_Definition_.--An abnormal condition of the lateral cartilages, in which +the substance of the cartilage becomes gradually removed and bone formed in +its place. + +[Illustration: FIG. 143.--OSSIFIED LATERAL CARTILAGES (SIDE-BONES).] + +_Symptoms and Diagnosis_.--Side-bones are nearly always met with in heavy +draught animals, and are rarely seen in the feet of nags. They are, +moreover, nearly always confined to the fore-feet. In the ordinary way +little need be said concerning their characteristics, and the way in which +they may be detected. Neither need any concern be ordinarily manifested +with regard to the effect they may have on the animal's gait and future +usefulness. Seeing, however, that side-bone constitutes one of the +recognised hereditary diseases, and that at the various agricultural and +horse shows its existence or otherwise in a certain animal is a matter of +great importance, some little attention must be given to these two points. + +With a side-bone anywhere approaching full development, diagnosis is easy. +The thumb is pressed into the coronet over the seat of the cartilage, when, +in place of the elasticity we should normally meet with, we have the solid +resistance offered by bone. In some instances diagnosis is even easier +still. We refer to those cases in which the side-bone stands above the +level of the coronet with such prominence as to be readily _seen_ and +recognised without manipulation, and where its growth has caused distinct +enlargement and bulging of the wall of the affected quarter. It seems that +in such cases the bone-forming process does not end with simply depositing +bone in place of the removed cartilage, but that, after that is +accomplished, the bone still continues to be produced, as in the case of an +exostosis elsewhere. + +Although diagnosis in cases such as these is easy, it becomes a very +different matter when we are called upon to give an opinion in cases where +ossification of the cartilage is only just commencing. Whether the result +of our examination is to decide the sale or purchase of an animal, to +determine his fitness or otherwise to enter the show-ring, or to merely +advise a client as to whether or no a side-bone is in course of formation, +our position is equally difficult, and in either case our examination must +be searching. + +Perhaps the best advice we can give is to say that the whole of the +cartilage must be manipulated both with the foot _on_ and _off_ the ground. +What the reason may be we do not pretend to say, but it is a well-known +fact that in many instances the cartilage, with the foot bearing weight, +is so rigid as to at once convey the impression that ossification has +commenced or is even far advanced. And yet that same cartilage, with the +foot removed from the ground, is as pleasantly yielding to pressure of the +thumb as the most exacting of us could wish for. In any case, then, where +doubt exists, the foot should be lifted to the knee, and the cartilage +carefully examined with the foot in that position. If, then, at any spot +above the normal contour of the os pedis we meet with hardness or rigidity, +we are to look upon that foot with suspicion. Nevertheless, providing our +conscience is sufficiently elastic, the animal may be passed _sound_ so far +as the _existence_ of a side-bone is concerned. We know, however, that with +commencing rigidity we may ere long expect one, and if our opinion is asked +with regard to that particular, it must be admitted that with rigidity of +the cartilage once commenced it is usually not long afterwards before a +fully-developed side-bone makes its appearance. + +As is only to be expected, the first noticeable hardening of the cartilage +is to be found near the normal bone. We may thus look for it more +particularly in the lower portions of the cartilage. We think we may say, +too, that in the vast majority of cases the ossification of the cartilage +commences in its anterior half. It is thus brought about that often we +are called upon to examine and report on the condition when we have +_anteriorly_ a side-bone in course of formation, and _posteriorly_ a +perfectly normal cartilage. It is to the latter half of the cartilage that +dealers and others mainly, if not wholly, devote their attention. A horse +with the cartilage in this transition state will therefore pass muster, and +a nice little point of ethics has again to be decided by the veterinary +surgeon before giving his signature to a certificate of examination of an +animal in this condition. + +With regard to alteration in gait, we may say at once that side-bones in +heavy animals are not often the cause of lameness. In fact, where the foot +is well developed, when neither the foot as a whole nor the phalangeal +bones give evidence of disease, and where the pasterns are fairly oblique +and well formed, this alteration of the cartilages may be looked upon as of +no serious import at all. Neither is the side-bone due to blows or other +injuries likely to be productive of lameness--that is, always supposing, of +course, that the foot in other respects is of good shape. If lameness is +met with at all, then it is where we have a foot that is in other respects +unsound, with badly contracted heels and upright 'stumpy' hoof, or where +side-bones have occurred in a young animal, and have already reached a +large size before the horse is put to labour. In this latter case, the +added effects of concussion and the evil influences of shoeing are +sufficient to turn the scale. Directly the animal, previously sound, is +asked to work, lameness is the result. + +It follows, therefore, that side-bone in the feet of young animals is of +far more serious import than when occurring in older horses. In a nag +animal they constitute a positive unsoundness, and lameness in this case is +more often than not an accompanying symptom. + +_Causes_.--To commence with, we may remark that, although met with +sometimes in very early life, side-bones are seldom, if ever, congenital, +and that more often than not they may be looked for in animals of three +years old, or older, seldom earlier. They appear, in fact, only when the +animal is shod and commences work. + +This at once suggests two of the principal factors in their +causation--namely, concussion and loss of normal function. Directly the +horse is put to work he has for a great part of his time to travel upon +roadways--either macadamized roads or town sets--where everything is +calculated to bring concussion about. In addition to that he has the +lateral cartilage itself thrown largely out of action by shoeing. We +explained in Chapter III. (p. 66) that the chief function of the cartilage +was to take concussion received by the plantar cushion and direct the +greater part of it outwards and backwards. Now, with the animal shod, the +plantar cushion does not itself, as normally it should, receive concussion. +By the shoeing the frog is lifted from the ground, and the plantar cushion, +together with the cartilage, taken largely out of active work. In other +words, the normal outward and inward movements of the cartilage are +enormously reduced. + +It is fair, we think, to take it that the mere fact of the lateral +cartilage persisting _as_ cartilage is due in large measure to its constant +movement. Directly, therefore, it is placed in a state of comparative +idleness, then it commences to ossify, more particularly if there should at +the same time be a tendency to a low type of inflammation of the parts. + +Does this latter exist? We may safely say that it does. It is in this way: +The secondary effect of loss of ground-pressure upon the frog and plantar +cushion is to bring about contraction of the heels. With this we get +compression of the parts within, with a certain amount of irritation and +the exact low type of inflammatory phenomena calculated to assist in the +bone-forming process. + +The fact that concussion acts as a cause explains in great measure how it +is that side-bones are more frequent in cart animals than in nags, and also +why they should be more common in the fore-feet than in the hind. Taking, +in both animals, a rough calculation as to the weight of body carried +by feet of a certain size, we notice at once that the cart animal has +proportionately more weight to carry than has the nag. Concussion to the +foot is therefore greater. The greater part of the body-weight is borne by +the fore-limbs. Concussion is therefore greater to the fore-feet than to +the hind. + +This, however, does not explain altogether the comparative immunity of the +nag animal from this defect. He, too, must also be subject to the effects +of concussion, especially when his higher and faster action is taken into +account. To our minds there is only one explanation to be offered here. We +point at once to the years of constant and judicious breeding of the nag. +Compare that with the relatively few minutes that have been devoted to a +more careful selection of the cart animal, and we at once see a possible +explanation. That the explanation holds some amount of truth is borne out +by the fact that, since a greater attention has been paid to the selection +of our cart animals, side-bone has grown a great deal less common. + +Is side-bone hereditary? We can best answer that by saying that, some +several years ago, the Council of the Royal College of Veterinary Surgeons, +at the request of the Royal Commission on Horse Breeding, drew up a list of +those diseases 'which by heredity rendered stallions so affected unfit as +breeding sires,' and that in that list was included side-bone. + +Side-bones, therefore, are hereditary. We think, however, the statement +needs qualifying. It is in this way: side-bones occur only at a certain, +usually well-defined, time after birth, and we might say are _never_ +congenital. They occur only after the animal has been put to work, and are +more or less plainly due to mechanical causes--namely, the ill effects of +shoeing and concussion. The cause of their appearance, in short, is more +plainly extrinsic than intrinsic, and side-bone in the horse is, as +Professor McCall puts it, about as much due to heredity as is corn on the +human foot. + +Between these two opinions--that they are plainly hereditary, and that they +just as plainly are not--it is well to strike a middle course. They are, we +will say, hereditary in this way: So long as a cart animal is bred, to put +it vulgarly, 'top-heavy' (that is, with a body out of reasonable proportion +to the feet that have it to support), so long will the foot be subjected to +a greater concussion, and so long will side-bones in such animals commence +to make their appearance at about middle life. + +In addition to the causes we have now mentioned, side-bones are often +the result of other diseases of the foot. They thus occur as a sequel to +sub-horny quittor, to suppurating corn, to complicated quarter sand-crack, +or to the inflammation of the parts occasioned by a prick. They also arise +in many instances from the effect of a prick or injury to the coronet. +Among the latter we may mention treads from other animals, and treads +inflicted by the animal himself with the calkin of an opposite shoe, or the +repeated injury occasioned by the shafts being carelessly allowed to drop +on to the foot. In severe cases of laminitis, too, the cartilages are +nearly always affected. In this instance the inflammatory phenomena in the +os pedis no doubt give rise to an abnormal activity of bone-forming cells. +The cartilage is invaded, and the side-bone formed (see Fig. 118). + +_Treatment_.--In the ordinary way the 'treatment' of side-bone is a thing +but rarely mentioned. The explanation lies, of course, in the fact that +side-bones are so rarely the cause of lameness. When lameness does occur +with a side-bone, and we have reason to believe that the said side-bone +is the cause of the lameness, it is well before talking of treatment to +question ourselves thus: 'In what way does the side-bone cause lameness?' +The now generally-accepted answer to that query is the explanation put +forward several years ago by Colonel Fred Smith--namely, that the pain, and +therefore the lameness, was due to the compression of the sensitive laminæ +between the ossified and enlarged cartilage and the non-yielding and often +contracted wall of the quarters. That, in fact, constitutes the basis upon +which Smith's operation for side-bone (that of grooving the wall of the +quarters) is founded. + +Before describing the operation, however, we may say that we are now able +to understand that older operators who claimed success for other methods of +treatment, were to a very great extent justified in so doing. + +For instance, take the combined treatments of firing and blistering, and +the use of a bar shoe. Here the beneficial action of the cautery and the +blister may be largely problematical. The bar shoe, however, would be +almost certain to give good results. Frog-pressure with the ground would be +again restored, and the contraction of the heels removed. Pinching of the +sensitive structures would be diminished, and the lameness cured. + +Take, again, the treatment of 'unsoling.' It was barbarous, we know +barbarous, because unnecessary and easily avoidable. It was practised, +however, certainly very little more than two decades ago, and practised by +men of standing in the profession. Without dragging the case to light again +by mentioning the names of those concerned, we may mention that not +many years ago a highly respected member of the profession was, at the +instigation of the Royal Society for the Prevention of Cruelty to Animals, +prosecuted for practising unsoling for the relief of side-bone. Practically +only one other member of the profession was able to come forward and defend +the operation on the score of its utility. We see now, however, that--as +does Smith's operation--unsoling does permit of the greater expansion of +the heels. The contraction is done away with, the pressure on the sensitive +laminæ again diminished, and the lameness relieved. + +Not that we are attempting to defend the operation--far from it. We simply +mention it as interesting, and quote this and the use of the bar shoe (with +both of which methods older operators have claimed success) merely as +evidence that the operation of Smith is based on a logical foundation. + +When treatment is decided on, therefore, we may first advise blistering and +the use of a bar shoe. After that, should the lameness continue, and should +we still judge the side-bone to be the cause of it, the operation may be +advised. + +As we have said before, the operation consists in so grooving the wall as +to allow of the quarters widening sufficiently to relieve pressure on +the parts within. In one or two previous portions of this work we have +considered operations involving this procedure. Before detailing the +operation here, therefore, we will first describe the instruments +necessary, and the most satisfactory methods of incising the horn. + +To begin with, it must be remembered that all methods of hoof section have +for their object the after-expansion of the horny box, and that this can +only be brought about by making each groove complete from coronary margin +to solar edge of the wall, and carrying it, throughout its length, _deep +enough to reach the commencement of the sensitive structures_. + +To this end, therefore, the operator must bear in mind the comparative +thickness of the various parts of the wall, and must, in particular, +remember the relative thinness of that portion of horn forming the outer +boundary of the cutigeral groove, and accommodating the coronary cushion. + +For the making of the incisions there is the special saw devised for this +operation by Colonel F. Smith, A.V.D., and which we illustrate in Fig. 144. +With this the wall is sawn through _until the depth arrived at is equal to +what is indicated by a previous examination of the thickness of the crust +as viewed from the solar surface_. Here Colonel Smith says: 'I strongly +advise everyone to use a metal gauge (a thin piece of material) to +introduce into the incision made by the saw, and run it up and down to +ascertain whether the wall is properly divided throughout. The depth to +which this should be done we know from the previous measurements of our +gauge on the crust.' + +[Illustration: FIG. 144.--SMITH'S SIDE-BONE SAW (EARLY PATTERN).] + +Should the saw be of a pattern in which the set of its teeth makes only a +narrow incision,[A] it should, while operating, be kept well oiled, and +should be withdrawn every few seconds in order that the horn-dust lying in +its teeth may be examined. If this is getting slightly blood-stained, +we know, of course, that the sensitive structures are reached, and the +incision has been carried far enough. In so judging the depth of the +incision, however, care must be taken to see that the top of the coronary +cushion is not injured with the saw, for if this is done the blood +trickling into the depth of the incision will tinge the horn-dust, and give +the false impression that the incision is sufficiently deep. + +[Footnote A: That is Smith's older pattern. The newer pattern (Fig. 145) +has the teeth so set as to make an incision wide enough to be looked into. +In this case the depth arrived at is to be judged by the appearance of the +bottom of the incision.] + +If the operator has had no previous experience of the use of the saw in +this operation, he must also be careful to avoid placing too great a +pressure on the teeth of its lower third. This is done by keeping the hand +too greatly depressed. Again, this leads to wounding of the sensitive +structures (this time at the lower end of the incision), and again the +operator is confused by the blood thus allowed to run into the groove. + +The only portion of horn difficult to operate on is that immediately under +the coronet. This is best severed with a succession of downward movements, +and is easier performed with Smith's later pattern of side-bone saw (Fig. +145) in which the set of the foremost teeth is reversed. + +[Illustration: FIG. 145.--SMITH'S SIDE-BONE SAW (IMPROVED PATTERN).] + +In making these grooves we must say that we think the use of the special +saw may be dispensed with, and the incisions just as easily, or, at any +rate, just as successfully, made with the knife. Those who select to use +this instrument should choose a narrow-topped and sharp searcher, or a +modern shaped drawing-knife of suitable size, such as those depicted in +Fig. 46, _a_ and _b_, and they will find their work much easier if +they will make the first steps in the incisions with an ordinary flat +firing-iron. By the use of the latter instrument the grooves are made +conveniently open along their tops, and room left for nicely finishing the +more delicate manner of removing with the knife the softer horn near the +sensitive structures. + +Those whose leaning is towards the use of special instruments, but who, at +the same time, do not care to use the saw, will find their wants supplied +in the hoof plane (Smith's), Fig. 146, or the hoof chisel (Hodder's), Fig. +147. With the hoof plane the groove in the wall is made by a succession of +downward scraping movements, while with the chisel the cut in the wall is +made either from below upwards, or from above downwards, according as +the foot is held forward or backward--whichever, in fact, comes most +convenient. + +[Illustration: FIG. 146.--HOOF PLANE (SMITH'S).] + +When using the knife or the hoof plane it is not often that the sensitive +structures are injured. In all cases, however, no matter what the +instrument used, the metal gauge should be employed when the sensitive +structures have been touched, and the operation obscured by blood. + +[Illustration: FIG. 147.--HOOF CHISEL (HODDER'S).] + +Our instruments at hand, the operation may be proceeded with. The first +step is to ascertain the extent of the side-bone, and to determine the +position of the incisions. To do this the coronet is felt with the thumb, +and the anterior extremity of the side-bone noted. This is marked on the +horn with a piece of chalk, and a vertical line dropped from this position +to the inferior margin of the wall (Fig. 148,1). The line crosses the horn +fibres obliquely, and is purposely made in that direction in order that its +inferior end may be far enough back to avoid the last nail-hole. Should the +side-bone reach very far forwards, it may be wise to cause this line to +slant from before backwards (see dotted line _a_, Fig. 148). Unless this is +done, it is found that in some feet so much of the wall is isolated at the +bottom that insufficient is left to nail the shoe to. + +The next line to be made is the rear one. Its correct position is +ascertained by first noting the junction off the wall with the bar (see +groove 2, Fig. 149); and its inferior end must be just anterior to the +inflexion of the wall. This is done that we may avoid cutting the bar. The +position of the lower end of the rear line thus ascertained, it is run +upwards with the chalk in the direction of the horn fibres. + +[Illustration: FIG. 148.--DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES +IN THE WALL IN COLONEL SMITH'S OPERATION FOR SIDE-BONE. 1,2, and 3, mark +the grooves in the order in which they are made; the dotted line _a_ marks +the position taken by the anterior line when the side-bone, is one reaching +far forward, while the dotted lines _b_ and _c_ mark the position of the +additional grooves to be made if thought necessary.] + +The third line is made in such a position as to divide into two equal +portions the wall between lines 1 and 2. Here, however, some operators +prefer to make two, or even three, lines, adding those as at _b_ and +_c_, Fig. 148; and Smith himself says that a multiplicity of lines is an +advantage rather than not. + +In any case, having once determined the position of the lines, they should +be plainly marked out with chalk, and then viewed from a distance with +the foot on the ground, in order to judge of their regularity. If we are +satisfied with them, we then lightly mark them with the saw, with the hot +iron, or with the knife, whichever instrument we may be intending to use. + +Unless the details are methodically carried out as here described, it is +probable that more of the foot will be isolated than is necessary, and that +as a consequence very little is left to which to nail the shoe. + +[Illustration: FIG. 149.--DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES +MADE IN THE HOOF IN COLONEL SMITH'S OPERATION FOR SIDE-BONES. 1, 2, and 3, +show the grooves in the wall in the order in which they are made; 4 shows +the groove made at the junction of the sole with the wall.] + +The incisions are then made with the saw or the knife, with the foot +held in a convenient position by an assistant. That usually found most +comfortable for the first incision is with the foot held forwards and +placed on an assistant's thigh in the position adopted for 'clenching up' +when shoeing, while that for the rear incision is with the animal's knee +flexed, and the foot held well up to the elbow. In this, however, each +operator will suit himself. + +Should the preliminary steps in making the incisions be performed with the +iron, it will be easiest done with the foot on the ground. + +When the incisions through the wall are complete, our attention must be +given to the sole. A drawing-knife is here used, and a further incision +made over the white line so as to destroy the union of the sole with the +wall between incisions 1 and 2, and so completely isolate the portions of +wall included within the four grooves (see groove 4, Fig. 149). When this +is done it should be found that the portions of the isolated wall spring +readily to pressure of the thumb. + +The inferior or wearing margin of the isolated wall must now be so trimmed +that it takes no bearing on the ground when the opposite limb is held up by +an assistant and full weight placed upon the foot. + +For a day or two after the operation lameness is intense. This is to be +treated with hot poultices or hot baths, and and soon disappears. Three to +four days later a bar shoe is nailed on (taking care that the bearing of +the quarters is still eased), and the hot poultices still continued. Four +days later still walking exercise may be commenced, to be followed +shortly afterwards by trotting. At about the twelfth day some animals may +conveniently be put to work, while in other cases a fortnight, or even a +month, must elapse before this can be done. When put to work early, it is +wise to fill in the fissures made in the wall with hard soap, with wax, or +with a suitable hoof dressing, in order that irritation of the sensitive +structures with outside matter may be prevented. + +This operation is soon followed by remarkable changes in the shape of the +foot. At about the third week the coronet shows signs of bulging, and the +upper part of the wall operated on is often so protruding as to render the +foot wider here than at the ground surface. This is a sign that the case is +doing well. + +Should no improvement be noticed at the end of three weeks or a month, or +should the grooves become filled from the bottom (which they do remarkably +fast), then the incisions must be deepened, the exercise reduced, and the +fomentations or poulticing repeated. So treated, many cases of side-bone +lameness will be relieved, if not entirely cured, and, should the worst +happen, and no alteration in the lameness is noticeable, no harm will have +been done to the foot. In this connection, the originator of the treatment +says: 'I may assure those induced to doubt either their diagnosis or the +value of hoof section that no harm is done to the foot, even should the +operation be of no value. It may do much good; it cannot do harm. The +operation will never succeed until the inherent timidity of sawing or +cutting into the wall is overcome. The _incisions must be deep, and of the +same depth from the coronet to the ground_.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +iii., p. 313.] + +It is well to remark here that the operation of hoof section cannot be +expected to succeed in every case. The last man in the world to claim that +for it would be its originator. Failure to relieve the lameness may be +accounted for in a variety of ways. First, of course, will come errors in +diagnosis. No one of us is infallible, and the lameness we have judged as +resulting from side-bone may arise from another cause. There are, too, +complications to be reckoned with, the existence or absence of which cannot +always be definitely ascertained. Such are: Ringbone, especially that form +of ringbone known as 'low'; bony deposits on the pedal bone, either on its +laminal or plantar surface, or even changes in the navicular bursa. + + + +CHAPTER XI + +DISEASES OF THE BONES + + +A. PERIOSTITIS AND OSTITIS. + +We head this section, Periostitis _and_ Ostitis, for the reason that in +actual practice it is rare for one of these affections to occur without the +other. The periosteum and the bone are so intimately connected that it is +difficult to conceive of disease of the one failing to communicate itself +in some degree to the other. Pathologically, however, and for purposes of +description, it is more convenient to describe separately the abnormal +changes occurring in these two tissues. + +With the main phenomena of inflammation occurring elsewhere we presume +our readers are aware. Briefly we may put it, that under the action of an +irritant, either actual injury, chemical action, or septic infection, +the healthy tissues around react in order to effect repair of the parts +destroyed. Also that this reaction involves the distribution of a greater +blood-supply to the part, with an abundant migration of leucocytes, and +the outpouring of an inflammatory exudate, together with symptoms of heat, +pain, redness, and swelling of the affected area. And that in chronic +inflammations, owing to persistence of the cause, the process of repair +thus instituted does not stop at mere restoration of lost tissue, but +continues to the extent of forming an abnormal quantity of such tissue as +normally exists in the parts implicated. + +The process of inflammation in bone is essentially the same. It takes place +along the course of the bloodvessels, and is only modified in its attendant +phenomena by the structure of the parts involved. Swelling, for instance, +cannot take place in the centre of compact bone tissue. Otherwise, other +changes occur exactly as in inflammations of other structures. + +When the causal irritant has been excessively severe and the migration of +leucocytes abundant, actual formation of pus may occur, the bony tissue +being broken down and mingled with it, and an abscess cavity formed. In +milder cases, affected and necrotic tissue is removed by a process of +phagocytosis, and new tissue (this time osseous) formed in its place. + +In the periosteum we may take it roughly that inflammation runs a course +similar to that occurring in soft tissues elsewhere. There is but one +exception, and that, as we shall mention shortly, is connected with its +deeper layer. + +As we know, the periosteum consists of two layers, an outer fibrous and +an inner yellow elastic, and is extremely vascular. Numerous bloodvessels +ramify in it, and, with their attendant nerves, break up to enter the +numberless canals of the Haversian system. This extreme vascularity, of +course, favours abundant exudation. The exudate, however, is, as it were, +shut in by the dense fibrous layer of the membrane, and the result is that +in periostitis it collects between the membrane and the bone, causing +swelling and raising of the membrane, and giving rise to excruciating pain +from pressure upon the nerves. + +Should the periostitis be complicated by the formation of pus, then the +vessels entering and supplying the bone are, in the suppurative area, +destroyed. With their destruction it may happen that we get also death of +a portion of the osseous tissue. This, however, when the suppuration is +abundant, cannot commonly occur, as the bloodvessels within the bone--those +of the medulla--commence to supply blood to the affected part. In cases of +trouble with the bones of the foot, these last few remarks have a special +significance. Here we have three bones whose medullary cavity is extremely +small--almost nil, in fact--which explains in some measure how easy it is +when suppuration exists to get necrosis and exfoliation of, say, portions +of the os pedis. Necrosis and sloughing of the periosteum itself may also +happen, but as the extreme vascularity of the membrane is a fairly strong +safeguard against that it is of only rare occurrence. + +In connection with the deep layer of the periosteum, and forming part of +it, are found numerous bone-forming cells (_osteoblasts_). These, under +ordinary conditions, are relatively quiescent. Under the slightest +irritation or stimulation, however, their bone-forming functions are +stirred into abnormal activity, thus explaining how easy it is (especially +with bones so open to receive slight injuries as are those of the foot) to +get ossific deposits, the starting-point of which we are quite unable to +account for. + +With this brief introduction we will now describe such pathological changes +as occur in the separate structures, and which we are likely to encounter +in the various diseases of the foot. While so doing, we shall draw +attention to such diseases as we have previously described in which the +pathological conditions we are considering may be met with. + +1. PERIOSTITIS. + +This we shall consider under _(a)_ Simple Acute Periostitis, _(b)_ +Suppurative Periostitis, _(c)_ Osteoplastic Periostitis. + +_(a) Simple Acute Periostitis_.--This is the periostitis that follows on +the infliction of a slight injury to the membrane--an injury without an +actual wound and free from infective material. It is one, therefore, which +we always judge as existing in those cases where we have distinct evidence +or history of injury, but in which the injury has not been severe enough to +lead to fracture or to the infliction of an actual wound. + +Such cases may be those of lamenesses persisting after violent blows upon +the foot--cases where the animal has been kicking against the stable +fittings, or where the foot has been partially passed over by the wheel of +a waggon. It may be, too, that in a case of 'nail-bound' a great deal of +the pain and lameness is due to a simple periostitis caused by pressure of +the bulged inner-layer of horn upon the sensitive structures. + +Simple acute periostitis may also occur in cases where an actual wound is +in existence, but where such wound, fortunately, remains aseptic. We may +thus have this condition accompanying ordinary cases of pricked foot, of +treads in the anterior region of the coronet, and of accidental injuries of +other kinds. + +In simple acute periostitis the membrane is thicker and redder than normal, +and is easily stripped from the bone. As it is pulled off it is noticed +that there are numerous fibril-like processes hanging to its inner surface, +and which draw out from the substance of the bone. These are simply the +vessels (bloodvessels and nerves) which, loosened by the inflammatory +exudate, are readily detached and drawn from the Haversian canals into +which they normally run. In addition to its increased redness, the membrane +has a swollen and gelatinous appearance owing to its infiltration with the +inflammatory discharges. Simple acute periostitis may and often does end +in resolution. On the other hand, it may end in suppuration or may become +chronic. If the latter, then the osteoblasts of the innermost layer become +active, and abnormal deposits of bone are the result. + +_(b) Suppurative Periostitis_.--This condition simply indicates that +the inflammation is complicated by the presence of pus organisms. It is, +therefore, a common termination of the simple acute form attending the +infliction of a wound. The wound becomes contaminated, and the case of +simple periostitis is soon changed into the suppurative form. Once having +gained entrance to the wound, the pus increases in quantity, and slowly +runs between the membrane and the bone. This, however, it does not do to +any large extent, showing rather a tendency to penetrate the outer fibrous +layer and gain the outside of the membrane. + +Suppurative periostitis is met with in foot cases, commonly in connection +with punctured foot. It occurs, too, as a complication in suppurating corn, +in severe tread, in complicated sand-crack, as a result of the spread of +suppurative matter in acute coronitis, and in sub-horny quittor. + +In ordinary cases of suppurative periostitis the pus formed is yellow +in colour, creamy thick, and free from pronounced odour--the so-called +'laudable' pus of the older writers. It so happens in many cases of foot +trouble, however, that putrefactive organisms gain entrance side by side +with those of pus. In this case the characters of the discharge are +very different. It is distinctly more fluid, is of a pink or even light +chocolate colour, and extremely offensive. In these instances the pus +shows a marked tendency to spread, strips the periosteum from the bone, +perforates the outer layer of the membrane, and finally infiltrates the +surrounding tissues. + +This forms a near approach to what is known in human surgery as an +_infective_ periostitis, and in our subjects is nearly always met with in +cases of severe prick. Its rapidly spreading character makes it always +a dangerous condition, and a punctured foot exuding a discharge of this +nature should always be regarded as serious. The close contiguity of +the joint (it can never be _far_ distant in foot cases), the spreading +character of the disease, and the rapidity with which the horse succumbs to +arthritis, are all factors to be taken into consideration, and to lead to a +warning-note being struck when attending a case of such kind. + +A further instance of infective periostitis is that met with in acute +laminitis. The discharge obtained from the sole in these cases very often +bears the character we have just described, and when one considers the +thinness of the keratogenous membrane, one is bound to admit that changes +so grave occurring in it cannot fail to spread and infect the periosteum. + +_(c) Osteoplastic Periostitis_.--This is more particularly a chronic +process, and is, as the suffix '_plastic_' indicates, associated with +bone-forming changes in the membrane. It may occur as a consequence of +slight but continued irritation, often without ascertainable origin (see +Case 2, p. 392), or it may be the sequel of acute disease. + +In this form of periostitis the membrane is again swollen and more vascular +than in health, and is also easily separable from the bone. The exposed +bone is generally rough, in some cases even spicular, and the inner layer +of the removed membrane is rough and gritty to the touch--characters +imparted to it by numerous minute fragments of bone that have been torn +away with it from the more compact osseous tissue beneath. + +The results of an osteoplastic periostitis are frequently met with in the +bones of the foot, and are described by veterinary writers under +such headings as 'Pedal Exostoses,' 'Ossifying Ostitis,' and 'Pedal +Ossification' (see Figs. 152, 153, 154, and 155). In many of these cases +the disease is purely chronic, and the original cause nearly always +wanting. When the foot has been subjected to laminitis of some weeks' +duration, the same condition is also met with, being at the same time +associated with rarefactive osteoplastic ostitis, conditions which we +shall shortly describe. Cases we have examined have undoubtedly shown this +condition of osteoplastic periostitis, the rarefactive and osteoplastic +changes in the bone itself, met with in older cases, occurring no doubt +as a result of non-expansion of the horny box. So far as we are able to +ascertain, there is every reason to believe that in chronic laminitis the +accompanying periostitis leads to the formation of bone, and would, if it +were possible, lead to increase in the size of the os pedis. If proof were +wanted of this, it is only necessary to point out the increased growth at +points where resistance is nil--namely, along the upper margin of the bone +(see Fig. 118). However, increase in size elsewhere is prevented by the +resistance of the hoof, so that, as the bone-forming process progresses, as +it inevitably _must_ under the inflammatory changes going on, it is, as it +were, compensated for by rarefaction or bone-absorption changes occurring +simultaneously with it. + +2. OSTITIS. + +We shall next deal with the inflammatory changes occurring in the bones +themselves, and shall consider them under (_a_): Rarefying or Rarefactive +Ostitis, (_b_): Osteoplastic Ostitis, and (_c_): Caries and Necrosis. + +Inflammatory changes occurring in the medulla we may pass without +consideration, for in the bones of the foot the medullary cavity is so +small, and the changes taking place in it of such minor importance, that we +may do this without in any way seriously prejudicing our work. + +_(a) Rarefying or Rarefactive Ostitis_.--By this term is indicated an +inflammation of the bone attended by its absorption, the absorption being +due to the action of certain cells, termed _osteoclasts_. This condition +may be due to the pressure of tumours, may occur as the result of injury +when a piece of bone is stripped of periosteum, or may be the result of an +inflammation occurring in the periosteum elsewhere. + +A piece of bone undergoing rarefactive ostitis is redder than normal, and +the openings of the Haversian canals are distinctly increased in size. As a +result a greater number of them become visible. Their increase in size is +due to the inflammatory absorption of the bony tissue forming them, and in +the larger of them may be seen inflammatory granulation tissue surrounding +the bloodvessels. This enlargement of the Haversian canals is well seen +when the bone is macerated, the whole then giving the appearance of a piece +of very rough pumice-stone. + +This process of rarefaction or absorption of bone tissue may be confined +to quite a small portion, or it may be spread over the whole of the bone, +rendering it more porous than is normal, but stopping short of complete +destruction of the bone tissue (a condition which is sometimes known +as inflammatory osteoporosis (see Fig. 118)). In this latter case the +condition is a chronic one, and the bone tissue remaining often appears to +be strengthened by a compensatory process of condensation. For an example +of rarefactive ostitis as met with in cases of disease of the feet, +we refer the reader to laminitis (see Fig. 118). The osteoplastic or +condensing process that appears to exist simultaneously with it explains, +no doubt, how it is that bones so affected do not more commonly fracture. + +A further example of this process is illustrated in Fig. 133. The pressure +of a tumour (in this case a keraphyllocele) has led to rarefactive changes +in the bone, forming a neat indentation in the normal contour of the bone +which serves to accommodate the tumour. + +_(b) Osteoplastic Ostitis, Osteosclerosis, or Condensation of Bone_.--This, +too, is essentially a chronic process. It may occur as a result of, or, as +we have just shown, exist simultaneously with the condition of, diffuse +rarefactive ostitis. In this case there is a formation of new bone in the +connective tissue surrounding the vessels in the Haversian canals. As a +consequence the bone affected is greatly increased in density, and many +of the Haversian canals by this means obliterated. The end result is an +increase in size of the bones in such positions as the horny box admits of +it, and a peculiar ivory-like change in their consistence. + +For an example of this, we again refer the reader to the changes occurring +in chronic laminitis. + +_(c) Caries and Necrosis_.--_Caries_ is a word which appears to be used +with a considerable amount of looseness. In addition to the meaning implied +by necrosis (namely, 'death' of the part), caries is generally used to +indicate that there is also a condition of rottenness, decay, and stench. +It is particularly applied, in fact, when the death of the bone is slowly +progressive, and is due to the inroads made upon it by putrefactive or +septic matter. + +_Necrosis_ of bone may be the result of any injury, such as severe blows, +or pricks and stabs. In such cases it would appear that it is loss of a +portion of periosteum that is the starting-point. With death of a portion +of this membrane the vascular supply to a portion of the bone is cut off, +and necrosis ensues. It may also result from the extension of inflammatory +affections of the structures adjoining it, as, for instance, the spread of +the infective material in severe tread, or the encroaches made by pus in +cases of quittor, suppurating corn, or complicated sand-crack. + +When the necrosed portion of bone is small, and is free from infective +properties, it is quite possible that it may, as is the case with small +spots of necrosis in softer tissues, be removed by a process of absorption. +It must be remembered, however, that where the necrosis has occurred as a +result of septic invasion this cannot be looked for, for in every case such +reparative changes are worked solely by healthy tissue. If the tissues +around the necrosis are engaged in dealing with organismal invasion and +the poisonous products thus poured into their working area, their state of +health is so weakened that they are unable to successfully combat with the +two conditions simultaneously. As a consequence, the necrotic piece of bone +persists, and acts as a permanent source of irritation. + +It must be remembered, too, that if the dead portion of bone--even though +it be free from septic matter--is very large, that it may itself act as a +continual irritant, in which case it again persists, and cannot by natural +means be removed. + +In our cases necrosis of bone may be met with in punctured foot, in severe +cases of tread, in cases of complicated crack, and in suppurating corn. +It is met with, too, in navicular disease, in the extension of irritating +discharges in cases of quittor, and in cases of chronic laminitis where the +solar margin of the os pedis has penetrated the sole. In this latter case +the protruding portion of bone is quickly denuded of its periosteum. Its +blood-supply is destroyed, and necrosis follows. + +_Treatment_.--In simple cases of periostitis, those caused by a blow but +free from an actual wound, the most beneficial treatment is the continued +application of cold by means of a hose-pipe or by swabs. If by these means +we are successful in holding the inflammatory phenomena in check, any large +formation of new bone is prevented, and the case does well. + +When the case is complicated by a wound, then antiseptic measures, such as +those described in the treatment of punctured foot, will at the same time +have to be practised. + +It must be admitted, however, that in all but the most simple cases +ordinary treatment such as this is of very little use; for with only a +slight exostosis in almost any position in the foot, excessive lameness +presents itself and remains. In such cases nothing is left to us but the +operation of neurectomy. + +When the periostitis and ostitis is the result of a wound, and is +complicated by caries or necrosis of the bone, the diseased portion of +bone must in every case be laid bare and removed. It so happens that the +majority of cases of this kind occur in positions where the diseased bone +is easily got at. The lower margin of the os pedis or portions of the wings +are commonly the seat of such changes. We meet with the former in cases +of pricked foot, and with the latter in severe cases of tread, or as a +complication in suppurating corn or in quittor. In such cases the animal +must be cast and the foot secured. The wound is then followed up, the horn +if necessary removed, and the bone curetted with a Volkmann's spoon; or, if +showing itself as a sequestrum, removed with a scalpel and a strong pair +of forceps. Care must be taken that every particle of the diseased bone +is removed, and that no part of it is left to act as an after-source of +irritation. With removal of the diseased portion and a strict attention to +antisepsis healing soon takes place. + +_Reported Cases of Periostitis and Ostitis_.--1. 'Figs. 150 and 151 +represent the phalangeal bones of the off fore-leg of a thoroughbred horse +named Osman, who was well known as a hunt steeplechaser of considerable +merit in the Midland counties some twenty years ago. I may say that this +horse was under my observation pretty regularly during the whole of his +career, and up to the time of his death, from ruptured aorta, when eight +years old. My attention was called to him as a yearling by his owner, who +told me that he sometimes fancied the colt was lame. I went over to see +him, and found that he was unmistakably lame on the off fore-leg. Careful +examination showed no heat or enlargement anywhere. I advised rest and the +colt became pretty sound, though not quite so--in fact, he never did become +quite sound, and sometimes he was very lame indeed. + +[Illustration: FIG. 150.--EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR +BONES.] + +'Every imaginable sort of treatment was tried short of neurectomy, without +avail. The curious part of the case was that there never was much heat or +any apparent change of structure, nor was "pointing" a very noticeable +feature. The foot always remained a good-looking one. As the horse won a +good number of races he was of some value, and was seen by a good many +members of the profession, who were by no means unanimous as to the cause +of lameness. The favourite theory was that it was a sequence of "split +pastern." A post-mortem examination showed that there was no fracture. +There was no adherence of the tendon to the navicular bone nor any +ulceration. The morbid changes consisted entirely of osseous deposit as +shown in the photographs. The under surface of the navicular bone was much +enlarged and roughened by this bony deposit, which extended on to the os +pedis, causing complete anchylosis at each extremity of the navicular. The +lateral cartilages were healthy. The interesting points in connection with +the case are the insidious commencement of osseous disease, its extensive +development, and the entire absence of any external manifestation, through +its being confined entirely within the limits of the hoof. + +[Illustration: FIG. 151.--EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR +BONES.] + +'It should also be noted that the animal was able to undergo a severe +course of training for some years, and to gallop successfully over some of +the most trying courses in England. During the whole of this time he walked +and galloped apparently sound, but trotted always lame, and generally dead +lame.'[A] + +[Footnote A: W. E Litt, M.R.C.V.S., _Veterinary Record_, vol. viii., p. +527.] + +[Illustration: FIG. 152.--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +2. 'I herewith send you photographs of three cases of the above disease, +occurring in the internal surfaces of the wings of the os pedis. The photos +were kindly done for me by Dr. A. Lingard, Imperial Bacteriologist to +Government of India. It is a cause of many cases of obscure foot lameness +in India, and frequently accounts for the numerous entries on veterinary +medical history sheets under the heading "Contused Foot." + +'The course of the disease is as follows: The disease makes its appearance +very soon after arrival in India, the animal being admitted to hospital +suffering with undoubted foot lameness, generally slight. One is soon led +to suspect this disease by negative symptoms of other disease being in +existence. No coronary enlargement or flinching on pressure to the coronet, +no shrinkage or wiring in of the heels, neither is the characteristic +pointing of navicular present. In the early stages one has false hopes +of recovery by finding gradual improvement for a time by fomentation and +poultices, followed by irrigation and stimulants to the coronet, and +perhaps the animal is discharged from hospital, to be returned after a +few days worse than ever. The disease then becomes insidious and more +pronounced, the nodding of the head, even at a walk, more exaggerated, and, +in fact, the animal seems afraid to put his foot to the ground, and much +resembles a horse with an abscess in his foot, either from prick or picked +up nail. He absolutely nurses his foot. There is a certain amount of heat +always present. The disease being now well developed, pressure is caused by +the ends of the navicular bone, and they become involved at their points +by bony deposits. The causes of this disease I attribute, firstly, to +hereditary predisposition; and, secondly the exciting cause, standing +confined on board ship, where no doubt pedal congestion takes place. And +perhaps some subjects start it in their marches in mobs down country +in Australia. Concussion may be the cause among older horses, but the +specimens photographed were taken from remounts, that had either done no +work or only very gentle work, in a deeply littered riding school. + +[Illustration: FIG. 153.--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +'_Treatment_.--It is obvious from the position of this disease that +treatment will be of no avail in producing a cure. As already stated, the +disease is insidious and progressive, and it is hopeless to expect to +arrest the growths once they are started. Unnerving would no doubt remove +the symptom (lameness) of the disease, but an unnerved horse is not of much +good for army purposes. I therefore consider that once the disease becomes +firmly established it is an unfortunate and incurable one. + +[Illustration: FIG. 154, 155--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +'Post-mortem reveals the small nodular growths on the inner surfaces of the +wings of the pedal bone, and if long established the ends of the navicular +bone are also involved. Exudation and gradual growth of false material +around the nodules takes place, which also serves to increase pressure.'[A] + +[Footnote A: Captain L.M.Smith, A.V.D., _Veterinary Record_, vol. xi., p. +229.] + +3. 'This case was brought for my opinion. The horse was lame, and walked +similar to one that had had laminitis, putting the heel down first upon +the ground. I ordered the patient to be destroyed. You will note the +ossification of the flexor pedis at its attachment to the pedal bone. +I enclose photos of the ground, also of the articular, surfaces of the +bone.'[A] + +[Footnote A: F.B.Jones, M.R.C.V.S., _Veterinary Record_, vol. xi., p. 230.] + + +B. PYRAMIDAL DISEASE, BUTTRESS FOOT, OR LOW RINGBONE. + +_Definition_.--A condition of periostitis and ostitis in the region of +the pyramidal process of the os pedis, usually preceded, but sometimes +followed, by fracture of the process, and characterized by deformity of the +hoof and an alteration in the normal angle of the joint. + +_Causes_.--In the majority of cases buttress foot is brought about by +fracture of the pyramidal process. Thus, although distinct evidence of such +is nearly always wanting, we may assume that the original cause is violent +injury to the part in question. Properly, therefore, one would say that +this condition should be described under Fractures of the Os Pedis. It +appears, however, that other cases of the kind arise in which fracture is +altogether absent, or in which it is plainly seen to be subsequent to the +diseased processes in the bone. For that reason, and also for the reason +that the condition has come to be known by the name we have given, we give +it special mention. + +_Symptoms and Diagnosis_.--Even when the condition arises as the result +of fracture, the ordinary manifestations of such a lesion are absent. By +reason of the situation of the parts within the hoof we are unable to +detect crepitation, and the resulting lameness is perhaps--in fact, nearly +always is--neglected until such time as any heat or swelling caused by the +injury has disappeared, in which case we are denied what evidence we might +have obtained from that. All that is presented is lameness, and lameness +that is at times excessive. But with the lameness there is nothing +distinctive. The foot is tender on percussion, and the gait suggestive of +foot lameness, that is all. We are unable, therefore, to make an exact +diagnosis, and the condition goes for some time undetected. + +Later, however, changes in the form of the hoof and the coronet begin to +appear. The skin of the coronet, especially in the region of the toe, +becomes more or less thickened and indurated, and the same remark applies +to the subcutaneous tissues. The most marked change, however, is the +alteration in the shape of the hoof. The wall protrudes at the toe in a +manner that has been termed 'buttress-like,' and has given to the condition +one of its names. This, of course, entirely alters the contour of the horny +box. From being more or less U-shaped, it approaches nearer the formation +of the letter V, the point of the V being at the toe. + +In the later stages the coronary enlargement is plainly seen to be due to +an extensive formation of bone. It is, in fact, a reparative callus, and +the reason it reaches so large a size is probably to be accounted for by +the pull of the extensor pedis upon the detached pyramidal process. As +might be expected, this displacement of the fractured portion, with its +effect of giving greater length to the extensor pedis, leads to a backward +displacement of the os coronæ upon the pedal bone. As a result there is a +marked depression at the coronet, the depression being heightened in effect +by the exostosis in front. Pyramidal disease is, as a rule, met with in the +hind-feet, but occurs also in the fore. + +_Pathological Anatomy_.--When occurring without fracture, the first +observable change is a thinning of the articular cartilage of the pyramidal +process, through which the bone beneath appears abnormally white. Later +the thinning of the cartilage progresses until at last it becomes entirely +obliterated. This destruction of the cartilage commences first at the +highest point of the articular surface of the pyramid, and gradually +reaches further backward into the joint. While this is taking place the new +bone is being formed on the front of the os pedis, below and around the +process, until, as we have already seen, an exostosis is formed, large +enough to be noticeable at the coronet. This, of course, partly implicates +the joint and the points of the insertion of the extensor tendon. + +Finally, fracture may, or may not, take place. When it does, the exostosis +is larger, and the general deformity of the hoof greater. + +_Treatment_.--Ordinary treatment, such as point or line firing, repeated +blisters, or hoof section, each of which we have tried, appears to be +utterly useless. So far as we have been able to gather from the writings of +other practitioners, however, neurectomy returns the animal for a time to +usefulness. If the fore-limb is the seat of trouble, either plantar or +median neurectomy may be practised; if the hind, then the best results are +obtained by section of the posterior tibial. + +_Reported Cases_.--1. This animal, a mare, had been rested for lameness +behind for two or three weeks, and then sent out to work, going sound. This +was repeated several times, and each time the coachman reported, "Goes very +lame behind after she has been at work about fifteen to twenty minutes." +She always pulled out sound when I saw her in a halter on the following +day, so I had her ridden, and after about seven or eight minutes she began +to go lame in a hind-limb. Her lameness got rapidly worse as she was being +ridden, and within a quarter of mile of her first showing lameness, she +dropped and carried the lame foot in a way that suggested a badly fractured +pastern. There was no recognisable disease in the limb to account for this +lameness. + +'I divided the posterior tibial nerve, and she went back to work moving +sound, and continued to work sound up to her death from one of the +regularly fatal bowel lesions twist or rupture. + +'She worked nearly two years after unnerving, and developed the usual +thickening at the coronet.'[A] + +[Footnote A: W. Willis, M.K.C.V.S., _Journal of Comparative Pathology and +Therapeutics_, vol. xv., p. 366.] + +2. 'The subject of this note was a chestnut mare, nine years old, and used +for omnibus work. + +'_History_.--For about two months the mare was lame on the off fore-leg, +and in spite of treatment the condition became steadily worse. The off +fore-foot was rather long and narrow, and the fetlock-joint was inclined +to be bowed outwards, but the degree of lameness was out of proportion to +these defects, and the diagnosis was obscure. + +'Median neurectomy was performed on May 10, 1902, and reduced the lameness +to about half of what it was before. On June 5 ulnar neurectomy was +performed, with the result that the mare became sound, and went to work +three weeks later. She continued to work soundly and well, being inspected +from time to time. + +'During February of 1903 the coronet began to enlarge in front and slightly +to the outer side, and gradually a ridge of bone grew down from the coronet +to the toe. The case, in fact, became a typical one of so-called "buttress +foot," which my friend Mr. Willis has described as diagnostic of disease +of the pyramidal process of the pedal bone. Meanwhile the swelling of the +coronet, which appeared to be mainly composed of fibrous tissue, increased +in size, until the whole of the front and sides became involved, assuming +the appearance shown in Fig. 156. + +'In spite of the coronary enlargement the mare worked well, and remained +free from lameness till June 8, 1903, on which day the limb became swollen +up to the site of the median operation. The appearance of the limb closely +simulated an attack of lymphangitis. The mare was kept under observation +till the 13th of the same month, during which time the swelling increased, +as did also the lameness to a slight degree. During progression she brought +the heel to the ground and "rocked the toe," as in a case of rupture of the +perforans tendon. The mare was killed on June 13. + +[Illustration: FIG. 156.--A CASE OF BUTTRESS FOOT.] + +[Illustration: FIG. 157.--FRACTURE OF THE PYRAMIDAL PROCESS IN BUTTRESS +FOOT.] + +'_Post-mortem_.--In trying to pull away the hoof from the sensitive +structures with a pair of farrier's pincers, the tendons and ligaments of +the corono-pedal articulation gave way, leaving the pedal bone _in situ_. +The flexor perforans tendon showed inflammatory softening, and was very +nearly ruptured through at the level of the navicular bone. There was +slight evidence of navicular disease. The articular cartilage of the +corono-pedal joint had been almost completely removed, and there was +sclerosis of the opposed bony surfaces, which by unequal wear had brought +about deformity of the os coronæ and os pedis. + +There was very old-standing fracture of the pyramidal process (see Fig. +157), with the formation of a false joint between the process and the pedal +bone. There was also a recent fracture of the part of the pedal bone which +carries the articulation for the navicular bone, and this and the tendon +lesions probably accounted for the final symptoms of 'break-down.' + +Neurectomy enabled us to get a year's useful work out of what would +otherwise have been a hopeless cripple.[A] + +[Footnote A: A.R. Routledge, M.R.C.V.S., _Journal of Comparative Pathology +and Therapeutics_, vol. xvi., p. 371.] + + +C. FRACTURES OF THE BONES. + +More or less by reason of the protection afforded them by the hoof +fractures of the bones of the foot are rare. When occurring they are more +often than not the result of direct injury, as, for example, violent blows, +the trapping of the foot in railway points, the running over of the foot +with a heavily-laden waggon, or violent kicking against a gate or a wall. +They occur also as a result of an uneven step upon a loose stone when going +at a fast pace, and as a result of sudden slips and turns, in which latter +case they are met with when animals have been galloping unrestrained in +a field, or when an animal, ridden or driven at a fast pace, is suddenly +pulled up, or just as suddenly turned. + +At other times fractures in this region take place without ascertainable +cause, and cases are on record where animals turned overnight into a +loose box in their usual sound condition have been found in the morning +excessively lame, and fracture afterwards diagnosed. + +1. FRACTURES OF THE OS CORONÆ. + +Fractures of the os coronæ result from such causes as we have just +enumerated, and are nearly always seen in conjunction with fractured +os suffraginis. When this latter bone is also fractured diagnosis is +comparatively easy, a certain amount of crepitus, even when the suffraginis +is only split, being obtainable. When the os corona alone is fractured +then diagnosis is extremely difficult, the smallness of the bone and the +comparative rigidity of the parts rendering manipulation almost useless, +and effectually preventing the obtaining of crepitus. It is, in fact, only +when the bone is broken into many pieces that crepitus may be detected, and +even then it is slight. + +_Reported Cases_.--1. 'The subject was a four-year old hunter. While at +exercise in the morning of August 10 he bolted, got rid of his rider, and +ran about in a mad fashion, came into contact with a wheelbarrow in a +narrow passage, and finally came into violent contact with a wall, which +had the effect of throwing him down. The rider stated that the animal +suddenly put down his head and managed to get off the bridle; he then +bolted, and the only chance for the rider was to throw himself off. + +'On examination I found the horse unable to place any weight on the off +fore-leg, the pastern was swollen and painful, the hollow of the heel was +also swollen, and there was marked constitutional disturbance. + +'After a short time he would place the heel on the ground and elevate the +toe to a slight degree. On manipulating the pastern slight crepitation +could be discovered, and there was abnormal mobility in the corono-pedal +articulation. On the near fore-leg there were extensive wounds in the +region of the knee, and great laceration of the tissues. The animal was +destroyed. + +'On examining the leg I found the subcutaneous tissues infiltrated from +below the knee to the foot, large masses of gelatinous blood-stained +material being present along the flexor tendons and in the hollow of the +heel. The inferior articular surface of the os suffraginis was denuded +of cartilage anteriorly; the os coronæ was fractured into eight moderate +sized, irregular fragments, and ten minute pieces. The surface of the +perforans tendon as it glides over the smooth surface at the back of the os +coronæ was lacerated, and minute portions of the bone were found embedded +therein.'[A] + +[Footnote A: E. Wallis Hoare, F.R.C.V.S., _Veterinary Record_, vol. xiv., +p. 133.] + +2. 'Here, again, fracture was the result of the animal bolting with his +rider. Trying to avoid collision with a conveyance coming towards him, the +animal slipped on a wooden pavement, sliding along until his near fore-leg +came in contact with the wheel of a standing cab. There was considerable +swelling from the knee downwards, great pain, and evidence of fracture in +the region of the pastern. + +'Post-mortem revealed the os suffraginis broken into about thirty pieces, +and the os coronæ with a piece broken off the inside of its proximal +end.[A] + +[Footnote A: A.F. Appleton, M.R.C.V.S., _Veterinary Journal_, vol. xiii., +p. 411.] + +3. 'The patient was a brown mare used for heavy van work in London. About +January 10 she was lame, and as she had a cracked heel, was treated by +poulticing for a day, and then by antiseptic lotions. In a week she was +sent to work, but the following day lameness returned, and continued till +about February 15. No special symptom was detected which indicated the +exact position of any cause of lameness. Then the lameness increased in +severity, and some swelling around the coronet began to show itself. + +'In consultation with another veterinary surgeon, two possible causes of +this intense lameness were discussed: one, that we had septic infection of +the coronet, and that probably the swelling of this part would soften, and +sloughs occur; the other, that a fracture of the os pedis or os coronæ +existed. The enlargement of the coronet was hard and firm, not particularly +sensitive. It was decided to do nothing for a few days. In a week the +pain abated, and the mare would put her foot on the ground, and ceased to +"nurse" the limb as she had done. When moved over in the box she put a +little weight on the foot, but limped very decidedly. + +'Another week passed, and the pain and lameness further abated, but the +swelling around the coronet continued. Perhaps it was a little less in +front, but it had not decreased on the inside. It remained firm, and was +not painful on pressure. It showed no soft places, and the upper part of +the leg remained free from oedema. + +[Illustration: FIG. 158.--FRACTURE IN SITU (OS CORONÆ).] + +'The diagnosis was now that a fracture existed, and it was proposed to +send the mare to grass for a few months. The consulting veterinary surgeon +suggested that before doing so a blister might be applied to the coronet. +This was done. The mare was found next day again on three legs. She had +apparently been down during the night. In a few days the coronet increased +again in size, and within a week "broke out" in two places. + +'The opinion now formed was that, with a fracture and this additional cause +of inflammation around the joint, it would be most economical for the owner +to have her killed. This was done, and a post-mortem examination was made +by Mr. Hunting and Mr. Willis. + +[Illustration: FIG. 159.--WITH BROKEN PORTION REMOVED.] + +'_Post-mortem_.--The foot, cut off at the fetlock-joint, showed extensive +swelling all round the coronet. There were two wounds on the skin--one on +the front of the coronet, the other on the inner side. From both pus and +blood had escaped. They both communicated under the skin with a large +abscess cavity. The abscess did not communicate with the joint. The pastern +bone was sound. On separating the pastern from the coronet bone the +articular surfaces were of a healthy colour, but the soft tissues +immediately surrounding them were inflamed. On the centre of the articular +surface of the coronary bone a thin red ring was noticed, and the portion +of cartilage within it seemed raised. With the point of a scalpel this +portion was lifted, and was found to be not only cartilage, but a layer of +bone completely detached from the os coronæ. On removing the bones from the +hoof the rest of the bone was quite normal, as was the pedal bone. + +'Fig. 158 shows the articular surface of the coronet with the fracture _in +situ_; and Fig. 159 the surface from which the broken portion is removed +and laid to the side of the foot. + +'Some interesting questions arise. How was the fracture caused? When did it +occur? Between the broken portion and the main bone there was a layer of +granulation tissue, so that it is certain the injury existed before the +blister was applied, and it may possibly have existed from the commencement +of the lameness.'[A] + +[Footnote A: R. Crawford, M.R.C.V.S., _Veterinary Record_, vol. viii., p. +478.] + +2. FRACTURES OF THE OS PEDIS. + +These also are a result of the causes we have before given. The os pedis +is also liable to fractures from pricks, from treads in the region of the +wings, and from the malnutrition and careless use of the foot sometimes +following neurectomy. + +It is interesting to note that, with fracture of this bone, lameness is +nearly always excessive, but that at times it may be entirely absent. +Crepitus is, of course, denied us, and in nearly every instance the case +is only diagnosed when the lameness persists and pus commences to form, or +when grave changes in the normal shape of the foot compel our attention to +the parts. When it is the continued formation of pus that draws our notice +to something more than ordinarily grave, it is in giving exit to the pus +that the fracture is nearly always discovered. + +_Reported Cases_.--Two interesting cases of fractured os pedis are reported +by Mr. Gladstone Mayall, M.R.C.V.S., in the _Veterinary Record_, vol. xiv., +p. 54: + +1. 'The horse was brought in markedly lame on the off hind-foot, knuckling +at the fetlock, and taking a long stride with the injured limb. There was +a punctured wound at the toe. The horn was pared, and antiseptic poultices +applied. Notwithstanding the antiseptic treatment pus continued to form. At +the end of a week sufficient horn was removed to ascertain the cause of +the constant suppuration. A movable object was found at the bottom of the +wound, and a piece of bone as large as a sixpence finally removed. Recovery +was uneventful.' + +[Illustration: FIG. 160.--FRACTURED OS PEDIS.] + +2. 'A filly was attended for a discharging fistula at the coronet. +Externally it had all the appearances of a quittor. At first no history +was given. The filly went scarcely lame at all, and had never been shod. +Treatment with poultices and caustic injections was useless. Finally the +filly was cast and the foot examined. A piece of bone, apparently part of +the wing of the os pedis, was removed, and the case made a good recovery. +Subsequent inquiries elicited the fact that the animal had kicked at and +hit a gate-post, and it was judged that then the injury had occurred.' + +3. 'The subject was a bay horse, nine years old, used for railway shunting. +On August 7 he was found to be intensely lame of the near hind-limb, and, +after inquiries, there was no evidence bearing on the cause, as is often +the case, and at times this comes to light when least expected. + +'I was called in consultation on September 2, and found him suffering +acute pain, with great swelling around the coronet. The foot was examined +thoroughly, and the diagnosis was fracture of the pedal bone, and immediate +slaughter was recommended. However, that was not carried out, and he died +on September 22. + +'The post-mortem inspection revealed a complete fracture of nearly the +whole of the articulating surface and the left wing of the pedal bone (as +shown in Fig. 160).'[A] + +[Footnote A: J. Freeman, M.R.C.V.S., _Veterinary Journal_, vol. xxxi., p. +324.] + +4. A further interesting case is reported by Mr. William Hurrell.[A] Here +the cause was presumably galloping in the field, for the subject, a cart +mare running out at grass with her foal, was suddenly found to be lame. + +[Footnote A: _Ibid_., vol. v., p. 408.] + +As the lameness continued to increase in severity, Mr. Hurrell was called +in on August 1, and diagnosed the case as one of foot lameness. On this +date the foot was pared out, and a large accumulation of pus discovered, +Poulticing and antiseptic dressings were continued until August 16, when a +movable piece of the os pedis was found at the toe. + +On August 25 this detached portion of the bone was removed, and turned out +to be the whole of the anterior margin of the os pedis, measuring 3-1/2 +inches long, and varying in width from 1/2 inch to 1-1/2 inches. On +September 20 the mare was working without lameness. + +3. FRACTURES OF THE NAVICULAR BONE. + +Hidden within the wings of the os pedis, and protected as it is by its +tendinous covering and the yielding substance of the plantar cushion, the +navicular bone is even less liable to fracture than either of the other +bones of the foot. + +The most common cause of fracture of the navicular is that of stabs or deep +pricks in the region of the point of the frog (see p. 216). Following that, +the next most common cause is violent injury. We thus find the navicular +bone fractured, together with one or both of the other bones of the foot, +when the foot is run over by a heavy vehicle. One such case is reported +by Mr. J.H. Carter, F.R.C.V.S., where the horse's foot was run over by a +tram-engine, in which the os pedis and the navicular were fractured in +several places.[A] A further case is on record where a sharp blow on the +front of the hoof was the cause. In this case the os pedis and other +structures were uninjured, but the navicular bone was fractured into three +large, and about half a dozen small, pieces.[B] + +[Footnote A: _Veterinary Journal_, vol. xxxi., p. 246.] + +[Footnote B: _Veterinarian_ for 1857, p. 73.] + +Fractures of the navicular may occur, however, in which history of a prick +or of a violent injury is absent. See reported case below. + +As with fractures of the os pedis and the os coronæ, so with this exact +diagnosis is difficult--we may say almost impossible. With a history of +violent injury, however, some little regard may be paid to a continued heat +and tenderness of the foot, and a distinct inclination on the part of the +animal to go on the toe. Even when the fracture is the result of a prick, +and the bone is plainly felt with the probe, we still cannot be positive as +to fracture. + +_Reported Case_.--'The animal was a Hungarian, a troop-horse in the 3rd +Hussars (G. 15). On November 22, 1881, on the march from Norwich to +Aldershot, the horse suddenly made a violent stumble, very nearly coming +on to his knees. The rider declared that he put his foot on a stone. The +accident caused great lameness in the near fore-leg, and the horse had to +be led the remainder of that day's march. On the following day he was also +led; but, after going some sixteen or eighteen miles, he was so lame that +he was left at the nearest billet (in Edmonton). He was here attended by +Mr. Stanley, M.R.C.V.S., of Edmonton, who pronounced it a case of navicular +disease. I first saw the animal on December 1, 1881, and quite agreed with +Mr. Stanley that it was a case of foot lameness, though, from the horse's +former history, I could not think it a case of ordinary navicular disease. +I diagnosed it a case of fracture, without displacement, either of the os +coronæ or the navicular bone, but was more inclined to the former than the +latter. This was after a full hour's examination. I failed to find any heat +in, or any flinching by manipulation of, any part of the limb; but, in +walking, the horse was excessively lame, going on the toe, and, indeed, +trying if possible to keep the foot entirely off the ground. + +'On December 6 the horse was sent on to Aldershot by rail. He was then +walking better, though still very lame. My only treatment for a short time +was to apply cold water constantly to the coronet and foot. For two hours +daily this was done by a hose, the remainder of the time by a cold swab. On +December 14 I applied a strong blister over the coronet, reaching up to the +fetlock. This was washed off about the end of December. The horse was then +not nearly so lame. I then resumed the cold-water treatment, and he got +gradually better, and was sent to light duty on February 18, 1882. He, +however, only attended one field-day, and was taken into the Horse +Infirmary again on March 8, very lame. Again, there was an entire absence +of heat or pain on pressure, but the same action, viz., going on the toe. +I forgot to remark that he always pointed the toe of the affected leg when +standing in the stable, and this symptom continued. I put him under the +cold-water treatment for a short time, and about the middle of March again +applied a strong blister over the coronet up to the fetlock. This was +washed off about the end of the month, and was succeeded by the cold water +again. Towards the end of April there was no improvement at all, and I +applied for permission to destroy the horse. This was carried out on April +27, at the recommendation of Mr. Gudgin, I.V.S., Aldershot, and a Board of +veterinary surgeons. + +'On making the post-mortem examination I first thought the bone was only +partly fractured or cracked, but on manipulating it, after its being in hot +water a short time, I saw the fracture was complete.'[A] + +[Footnote A: S.W. Wilson, M.R.C.V.S., A.V.D., _Veterinary Journal_, vol. +xv., p. 12.] + +_Treatment of Fractures of the Bones of the Foot_.--It will be seen at once +that in most cases anything in the way of bandaging is well-nigh useless. +When the os coronæ is fractured, however, a little more may be added to the +natural rigidity of the parts by enclosing the region of the pastern and +the foot in a plaster-of-Paris bandage. The main treatment, however, in +every case, will be a continual use of the slings for at least seven to +eight weeks, by that means compelling the animal to give to the injured +parts the necessary amount of rest. + +With fracture of the os pedis, when such is caused by pricks and +complicated by a flow of pus, then attention must be given to removal of +the displaced piece of bone. The pus track is to be followed up with the +searcher, sufficient horn removed with the knife, and the broken piece of +bone removed with a scalpel and a pair of strong forceps, the operation to +be afterwards followed up by antiseptic dressings to the opening. Until +this is done the wound refuses to heal. + +Fracture of the navicular bone, if in any way diagnosed with certainty, +offers us an almost hopeless case, for it appears to be a commonly reported +fact that attempts at reunion are rare. This, in all probability, is due +to the pressure put upon it every now and again, when the animal's weight +presses the bone between the os coronæ and the os pedis above and the +perforans tendon below. Even should reunion take place, the resulting +callus, interfering as it does with the movements of the perforans, leaves +us a case of incurable lameness. When the fracture is complicated by +the formation of pus, as in the case of prick, then the case, with the +attendant purulent synovitis and arthritis, is even more hopeless still. + +Diagnosis of fracture of either of the bones of the foot is, as we have +said before, extremely difficult. It so happens, therefore, in those cases +caused by violent blows, that anything approaching an accurate opinion +cannot be given until some months after the injury. After some time we are +met with unmistakable changes in the form of the foot, and are able to +assume that the persisting lameness is due to pressure of a reparative +callus within the hoof. In such cases the only treatment of any use is that +of neurectomy. + + + +CHAPTER XII + +DISEASES OF THE JOINTS[A] + + +[Footnote A: Properly speaking, we have in the foot of the horse but _one_ +joint--namely, the corono-pedal articulation. + +Although not a joint in the strict sense of the word, we, nevertheless, +intend here to consider the navicular bursa as such. In this apparatus, +although we have no articular cartilage proper, and no apposition of bone +to bone, we still have a large synovial cavity, and in close proximity to +it bone. We may, in fact, and do get in it exactly similar changes to those +termed 'synovitis' and 'arthritis' elsewhere. Therefore, we include the +changes occurring in it in this chapter, and hence the plural use of the +word to which this note refers.] + + +A. SYNOVITIS. + +_Definition_.--By the term 'synovitis' is indicated an inflammation of the +synovial membrane. It may be either (_a_) _Simple_ or _Acute_, or it may be +(_b_) _Purulent_ or _Suppurative_. + +In the simple form there is little or no tendency for the affection to +implicate the other structures of the joint, whereas in the suppurative +form the joint capsule, the ligaments, and the bones soon come to +participate in the diseased processes, giving us a condition which we shall +afterwards describe as acute arthritis. + +(_a_) SIMPLE SYNOVITIS. + +1. _Acute--(Causes)_.--Simple or acute synovitis is nearly always brought +about by injury to the joint--by blows or bruises, or by sprains of the +ligaments. At other times it occurs without ascertainable cause, and is +then put down to the influence of cold, or to poisonous materials (as, for +example, that of rheumatism) circulating in the blood-stream. + +_Pathology_.--Uncomplicated acute synovitis never causes death. The +pathological changes in connection with it have therefore been studied in +cases purposely induced, and the animal afterwards slaughtered. It is then +found that, as in inflammation elsewhere, the synovial membrane is showing +the usual inflammatory phenomena--that it is thick and swollen as a result +of the inflammatory hyperæmia and commencing exudation. Later, the synovial +fluid becomes increased in quantity, is thin and serous, and after a time +is seen to be mixed with the inflammatory exudation poured into it. We then +find that it has lost its clear appearance, has become thick and muddy, and +has floating in it flakes of fibrin. + +If the case progresses favourably these materials are soon absorbed and +resolution occurs. In rarer cases the thickening and congestion of the +membrane increases, and the articular capsule becomes so distended with the +increased synovia and accumulated inflammatory discharges that a kind +of chemosis occurs. In other words, there oozes through, without actual +rupture of the membrane, a thin, blood-stained, and purulent-looking +discharge. + +It is an important point to note that in cases of synovitis the fringes of +the synovial membrane become swollen and blood-injected, forming noticeable +red elevations at the margins of the cartilages. It is then that the +diseased condition soon spreads and runs into arthritis. + +Further, it is important, especially with regard to the question of the +degree of pain and lameness likely to be caused, to note that often +granulations are thrown out upon the looser folds of the membrane. As +these increase in size they come to form fringed and villous membranous +projections inserting themselves between the bones forming the +articulation. In such cases there is no doubt that the intense pain +sometimes observed in these cases is due to pinching of these prolongations +of the synovial membrane by the opposing bones of the joint. + +_Symptoms and Diagnosis_.--Acute synovitis of a joint leads to heat of the +parts, pain, distension of the capsule, and, where the joint may be easily +felt, fluctuation. In the articulation with which we are dealing, however, +these last two symptoms are not easily detected, for the surrounding +structures--namely, the lateral and other ligaments of the joint, the +extensor pedis tendon in front, and the perforans behind, together with the +dense and comparatively unyielding nature of the skin of the parts--are +such as to prevent distension and fluctuation becoming marked to a visible +extent. We are able to diagnose the case as one of foot lameness, and, with +a history of a severe blow or other injury, are able to assume that this +condition, perhaps attended with periostitis, is in existence. + +When other symptoms present themselves diagnosis may be more certain. The +animal becomes slightly fevered, throbbing pains in the joint manifest +themselves by irregular pawing movements on the part of the patient. The +animal comes out from the stable stiff, even dead-lame, and the limb is +carried with the lower joints semiflexed. The breathing is hurried and the +pulse firm and frequent, while in a bad case patchy perspiration breaks out +at intervals on various parts of the body. If with this we get a puffy and +tender swelling in the hollow of the heel, our diagnosis may be certain at +any rate as to the existence of joint trouble, although, from reasons we +have given, we may not be able to mark its exact nature. + +2. _Chronic_.--Simple synovitis may in many instances become chronic. In +this case we have simply a pouring into the synovial capsule of serous +fluid, and with it an increased quantity of synovia--this time with an +absence of the usual inflammatory phenomena. Beyond the swelling of the +capsule there is little to be noticed. The joint becomes perhaps a little +weaker, but pain or tenderness and heat are entirely absent. Such a +condition, by reason of the natural rigidity of the parts, is not to be +observed in the foot, although at times it must most certainly occur. +Examples of such a condition are to be found in bog-spavin, in hygroma of +the stifle, and sometimes in the fetlock. From a study of these, we know +that they may be induced by frequent attacks of acute synovitis, from +repeated slight injuries or bruises, or from strains to the ligaments of +the joint; or that they may be chronic from the outset. We know, too, that +in such cases the synovial membrane becomes thickened, and that in places +it may have extended somewhat over the edges of the articular cartilages. +It is only fair to suppose that such changes occur also in the pedal +articulation. In that case we may take it for certain that the natural +rigidity of the surrounding structures has the effect of pushing the +thickened membrane further between the bones of the joint than occurs in a +like condition elsewhere, leading, of course, to a lameness that is marked +in degree but occult as to cause. + +In our minds there is no doubt that many of the occult and chronic forms of +foot-lameness we meet with in practice are in this way to be accounted for. +We may, in fact, explain them by suggesting either a chronic synovitis +alone, or a synovitis complicated with periostitis. + +_Treatment of Synovitis_.--If a joint has been injured, as we have +suggested, by slight blows or other causes--in other words, if the injury +is subcutaneous, and no wound is in existence--then there is no treatment +which offers better results than does the continued application of cold. + +At the same time, the animal should be slung, or, if non-excitable and +inclined to rest, allowed at intervals to lie on a thick and comfortable +straw bed, the cold fomentations during such intervals being discontinued. +When the case is a marked one and the animal valuable, benefit will be +derived from the application of crushed ice. + +The animal's condition must be watched, and the case helped as far as is +possible by the administration of a mild dose of physic, by saline drinks, +and, when necessary, by the giving of small but repeated doses of Fleming's +tincture of Aconite in order to relieve the pain. In a chronic case the +repeated application of a blister is indicated. + +(b) PURULENT OR SUPPURATIVE SYNOVITIS. + +In this condition we have synovitis complicated by the presence of pus. +Unlike the simple form, it shows a marked disposition to spread, and +quickly involves the surrounding structures. Very soon the ligaments of +the joint, the periosteum, the articular cartilages, and the bones are +implicated. This, of course, constitutes a condition of acute purulent +arthritis. Under that heading, therefore, the condition will be later +discussed. + + +B. ARTHRITIS. + +(a) SIMPLE OR SEROUS ARTHRITIS. + +With an attack of simple synovitis it may be always assumed that the +changes commenced in the synovial membrane, communicate themselves more +or less readily to the surrounding tissues, and are not confined to the +synovial membrane alone. We may thus have the inflammatory phenomena +asserting themselves in the surrounding ligaments, in the periosteum, in +the bone, and in the articular cartilages. It depends, in fact, upon the +severity of our case whether we call it synovitis or arthritis. The two +conditions merge so the one into the other that no hard-and-fast rule +may be laid down whereby they may with certainty be differentiated. Such +symptoms, therefore, as we have given for synovitis may be also read as +indicating a condition of simple arthritis. The course of the case will be +very similar, and the treatment to be followed identical with that just +given. + +(b) ACUTE ARTHRITIS. + +_Causes_.--An attack of acute arthritis may commence with the affection of +the synovial membrane, and spread from that to the other structures. In +other cases the disease of the synovial membrane, and after it the disease +of the joint, may be secondary to diseases commencing in the structures +around the joint. This affection may therefore follow on a case of acute +coronitis, a case of suppurating corn, a case of quittor, a severe case of +tread, or may attend a case of laminitis. + +_Symptoms_.--In our cases we get very little beyond a magnification of such +symptoms as we have described under acute synovitis. The heat and the pain +is perhaps greater, and the lameness more marked. It is rather to the +constitutional disturbance we must look, however, for a confirmation of our +opinion that arthritis is in existence. This is always severe, and of +an acute febrile nature. The pulse is fast, thin, and thready, the +respirations enormously increased, and the temperature high. The appetite +is in abeyance, the animal quickly becomes what is termed 'tucked-up,' or +greyhound-like, in the body, and patchy perspirations break out about him. +The limb is held with the joints all semiflexed, and severe and intense +throbbing pains are indicated by the frequent pawing movements the animal +makes in the air. Manipulation of the foot is resented, and the agonizing +intensity of the pain so caused is shown by the drawn and haggard +appearance of the eyes. + +In a favourable case the symptoms from now onwards may gradually subside. +The appetite returns, the breathing and other signs of disturbance show a +return to the normal, weight is placed on the limb, and resolution slowly +but surely takes place. In many of these, our favourable cases, however, +resolution is incomplete, and recovery only takes place at the expense of +anchylosis of the joint, a condition we shall refer to later. + +In unfavourable cases, and these unfortunately are only too common, the +condition terminates in suppuration. + +(c) PURULENT OR SUPPURATIVE ARTHRITIS. + +_Definition_.--By this term we indicate an arthritis complicated by the +formation of pus within the joint. + +_Causes_.--The organisms of pus may infect the joint by extension of a +suppurating process from without. For example, in the case of a suppurating +corn, in quittor, in tread, or in the case of a suppurating wound caused +by a prick, the pus formed may in many instances be very near the capsular +ligament of the articulation. Under such circumstances, unless there is a +free and unhindered flow of the pus from an outside opening, inroads will +be made by it upon the thin capsule. The latter is quickly penetrated, and +pus is admitted to the interior of the joint. + +In other cases infection of the joint may proceed from within, from a +poisoned state of the blood-stream. The condition occurs, for instance, +in bad attacks of laminitis. We ourselves, too, have seen two cases where +suppuration of the pedal articulation occurred in the septic pyæmia of +foals, a disease known commonly as 'joint-ill,' and characterized by an +infected state of the circulation. Cases have also come under our notice +where this condition has resulted from slight injuries in the region of +the insertion of the extensor pedis inflicted by the animal himself when +galloping away. + +Perhaps, however, the most common cause of suppurative arthritis in the +foot is direct penetration of the articulation in the case of pricks. +The penetrating object is nearly always dirty--bacterially dirty, at any +rate--and suppuration only too readily commences. Even should such a wound +be inflicted by an aseptic body, infection would quickly ensue as a result +of the wound gathering dirt from the ground, or even from admission to the +joint of impure and bacilli-laden air. + +_Symptoms and Diagnosis_.--This is one of the most serious conditions we +are called upon to face when dealing with diseases of the foot, for in many +cases it quickly ends in exhaustion and death of the patient, while in even +the most favourable cases nothing better than a condition of complete and +bony anchylosis is to be expected. The owner, therefore, should be warned +accordingly. + +As in the other joint affections, so here, we get all the symptoms of +acute febrile constitutional disturbance. The pulse, the temperature, +the respirations, and the general haggard, 'tucked-up,' and distressed +appearances of the animal all tell too plain a tale. Our patient is in +constant pain, and the seat of the trouble is clearly enough shown by the +constant pawing movements of the affected foot. If he has room to get up +and down in comfort the animal adopts for long periods at a stretch the +recumbent position, and is not upon his legs long enough to take the +necessary amount of food to keep him going. Even when down, it is plain to +see that the animal is not at rest. The pawing movement is still maintained +with the foot, and every now and again the eyes are opened and the headed +lifted to give a troubled look round. The appetite, too, is capricious, and +in many cases almost entirely lost. + +In some slight degree the condition is less to be feared in a fore than in +a hind foot--that is, so far as absolutely fatal results are concerned. +With the condition confined to one fore-foot, the animal is able to get up +and down with a moderate degree of comfort. At intervals, therefore, he +rises to take nourishment, and as soon as his wants are satisfied again +lies down. + +With the disease in a hind-foot matters are not taken so comfortably. The +patient finds that with each day's increasing weakness the difficulty that +at first he had to raise himself with only one sound hind-foot becomes +enormously increased. The consequence is that he fears to go down, and the +standing position is maintained until sheer weakness overcomes him, and he +goes down, not to rise again without assistance. + +If judiciously attended he is, of course, put in slings before this stage +is reached; but there are instances, as in the case of a cart-mare heavy +with foal, where the use of slings is most decidedly contra-indicated. + +If doubt before existed as to the nature of the case, it is at a later +stage dispelled by the appearance, generally in the hollow of the heel, of +a hot and painful swelling. This at first is hard, but later fluctuates. +Finally it breaks at one or more spots, and there exudes from the opening +or openings a purulent and oftentimes sanious discharge, which coagulates +about each fistula after the manner of ordinary synovia. + +With the discharge of the abscess contents there is some slight improvement +in the symptoms. Here, with a suitable treatment, and with a patient of a +particularly robust constitution, the case appears to turn, and slowly but +surely progresses towards the only end we can hope for--namely, a more or +less painless anchylosis of the articulation. + +In less favourable cases the purulent discharge continues, and (always a +bad sign) becomes more or less chocolate-like in colour, distinctly thin, +and stinking. The diseased process spreads until the ligaments of the +joint, both by reason of their infiltration with the inflammatory +discharges, and also on account of the ravages made on them by the invading +pus, either greatly stretch or altogether rupture. + +The joint, after its ligaments have been destroyed in this manner, is +loosened, and the bones are now freely movable. Their manipulation gives +to the touch a sickening, grating sound--in other words, we have crepitus. +This, of course, indicates that the articular cartilages have become +greatly eroded by the inflammatory process, and so left what we may term +'raw' surfaces of bone to rub together. When the animal is put to the walk +the toe of the foot is elevated, and the extreme mobility of the foot gives +one the idea of fracture. With every step there is a peculiar sucking +noise, comparable to that of a foot moving in a boot of water, and +putrescent matter is squeezed from every opening each time the foot is put +to the ground. Although we have seen cases even advanced thus far recover, +it is questionable whether it is now wise to attempt to prolong life. +Slaughter is far more humane, and, in our opinion, except with a valuable +brood animal, more economical. + +If the animal is allowed to linger, other symptoms will nearly always +present themselves before death occurs. Whether in slings or not, a careful +watch should be kept upon the sound limb. For some time the patient stands +upon it incessantly, but sooner or later it happens that a farther visit +show us the animal standing with full weight on the diseased foot, and +making painful pawing movements with what before was the sound. We +immediately jump to the conclusion 'laminitis.' And so it is, but it is a +laminitis brought about by pyæmia. This is indicated by the swollen and +oedematous nature of the lymphatics of the limb. Plainly enough they +indicate the road by which the poison has travelled. It is in this way: Pus +and putrefactive organisms have gained entrance to the lymphatics of +the original diseased limb. From these they have rapidly gained the +blood-stream and set up infection elsewhere. In this particular instance it +is demonstrated by the laminitis and lymphangitis of the previously sound +limb. With the poison thus circulating in the blood-stream, we often +also get spots of infection commenced in one or other of the more vital +organs--notably the lungs or the kidneys. The end of our case is then +either a gangrenous pneumonia or complications induced by a condition of +widespread pyæmia. + +With the animal in slings there are one or two other symptoms that call +for attention. In many cases, especially with animals of a lymphatic and +indolent nature, the use made of them is inordinate. The patient rests +so continually in them that alarming swellings commence to make their +appearance about the rectum, or in the case of a mare about the vulva. The +animal must then be let down at regular intervals and again raised when +rest is obtained. + +A more alarming symptom still is when the animal, instead of resting in the +slings by his buttocks, casts his weight bodily into the belly-rest and +hangs with a heavy head into the head-stall. This indicates complete +exhaustion and a wish for death. Matters should therefore be explained to +the owner, and his consent obtained for immediate destruction. + +_Pathology_.--The pathological changes occurring in suppurative arthritis +we shall pass over briefly. It is almost sufficient, in fact, to say that +the whole of the joint becomes completely disorganized. + +The synovial membrane becomes so tremendously thickened and injected as to +be scarcely recognisable as such, the thickening in the later stages +being due to large growths of granulation tissue which entirely alter the +appearance of the membrane as we know it normally. In the early stages +the contents of the joint are composed of thin pus and synovia. Later, +as destruction of the synovial membrane proceeds, the flow of synovia is +stopped, while the pus formation goes on until finally nothing but pus and +dead tissue products fill the cavity. + +If the suppurative process has commenced from within, the pus that is +formed is, as a rule, thick and creamy, comparatively unstained, and free +from marked odour. If, on the other hand, air has gained access to the +joint, or the suppurative process has started from the materials introduced +by a foreign body, the joint contents are thin, blood-stained, and +stinking. + +The inflammatory changes in the joint soon spread to the ligaments, and to +the soft structures in contact with them. This means that the ligaments +become infiltrated with inflammatory exudate, that the fibrous bundles +composing them become separated, and that the ligaments are weakened and +easily stretched. As a consequence, a certain amount of displacement or +dislocation of the bones is allowed. + +In like manner the inflammatory changes keep spreading until we have the +periosteum next the ends of the bones affected. The periostitis thus set +up invariably takes the osteoplastic form, and as a result of this we have +growths of new bone in the near neighbourhood of the joint. It is in the +later stages of the disease--that is, when the pus has been evacuated and +reparative changes commenced--that this osteoplastic periostitis is most +marked, and it plays a large part in bringing about the condition of +anchylosis, which we shall afterwards describe. + +Grave changes also occur in the articular cartilages. They quickly lose +their peculiar glistening polish, their semitransparency is lost, and the +natural tint of a pearl-like blue gives way to a dirty yellow. Later this +is followed by erosion of the cartilages at such points as they happen to +be in greatest contact. The ends of the bones are thus exposed, and their +medullary cavities exposed to infection. As a result we get in them the +changes we have already described under Ostitis. + +_Treatment_--_(a) Preventive_.--Seeing that many of these cases have their +starting-point in stabs or penetrating wounds of the sole, we shall be +concerned first with a consideration of the correct treatment to be adopted +when we know the wound to have reached the articulation. + +Only too frequently the treatment practised is that of poulticing. In other +portions of this work we have pointed out the advantages that a continued +antiseptic bathing has over the application of a poultice, the greater +readiness with which the solution comes into contact with the deeper parts +of the wound, and the far greater chance there is of maintaining water in +an antiseptic condition than there is of keeping a poultice in the same +state. There is no doubt, that in this case also, the cold or warm +antiseptic bath is to be preferred to the poultice. It is questionable, +however, whether even the bath is sufficient for our purpose here. We have +in this case a deep punctured wound, and a wound that in every probability +is infected with the organisms of pus or of putrefaction. It is a wound, +moreover, which is likely to impede the thorough access to it of the +solution in which the foot is fomented, on account of the flakes of +coagulated fibrin which fill it. + +The most rational treatment, therefore, if we get to the case early enough, +is to irrigate the wound freely with a solution of carbolic acid in water +(1 in 20), or with a solution of perchloride of mercury (1 in 1,000), +injected by means of a glass syringe, or the pattern of syringe devised for +quittor. This injecting should be done thoroughly, and by that we mean that +several syringefuls of the solution should be injected, the joint after +each injection being manipulated so as to distribute the solution as far as +possible over it. When this is done the opening in the sole may be plugged +with a little perchloride of mercury, or, better still, with a little piece +of tow saturated with a concentrated solution of perchloride of mercury +or a solution of iodoform in alcohol and an antiseptic pad of tow or lint +placed over all. The foot should then be bandaged and encased in a boot or +sacking protective. The bandage should be removed daily and the antiseptic +pad changed. At each visit the animal's condition must be carefully +noted. So long as constitutional disturbance is slight, the foot appears +comfortable, is free from marked heat and tenderness, and pawing movements +are absent, and so long as the discharge on the pad appears non-purulent, +free from marked odour, and small in quantity, then this dressing may be +persisted in. + +This treatment of open joint, preventive as it is of arthritis, is also +indicated in the case of open navicular bursa. In several instances we have +practised this treatment for the dressing of wounds implicating the bursæ +of tendons and the capsules of joints. It is also spoken of favourably by +Mr. C.H. Flynn in the _American Veterinary Review_ for June, 1888, whose +treatment is as follows: 'Place the patient in a clean, well-ventilated, +and drained stable. Have all the litter removed, and insist on the stall +being kept clean. Either place the animal in slings, or tie the head so as +to prevent lying down. Clip the hair and cleanse the parts well. He prefers +the corrosive sublimate solution (1 in 1,000). Should the wound be of two +or more days' standing, inject the joint with the corrosive sublimate +solution. Now dry the parts with a clean towel and sprinkle the wound with +iodoform. Over this place a thick layer of absorbent cotton-wool, filled +with iodoform, bandage securely, and keep the patient on a moderate diet, +preserving the utmost quietude possible. Should the bandage remain in +position and the animal free from pain, leave the bandage and dressing in +place from five days to a week. Then change it, and should the discharge +be little, do not disturb it, but renew the iodoform and cotton dressing, +leaving it on for another week.' + +Other treatments for the same condition are practised, in which the wound +is dusted with powdered iodoform, with potassium permanganate, or with +corrosive sublimate, or where the wound, instead of being dusted, has +the corrosive sublimate applied in the form of a plug. In each case the +preliminary irrigation with the corrosive sublimate solution is dispensed +with. This, however, should on no account be omitted. In our opinion it +constitutes the very essence of the rationality of the treatment. + +_(b) Curative_.--It may happen, however, and often does, that this first +injection of an antiseptic is unsuccessful in preventing organismal +infection of the wound. In this case grave constitutional disturbance and +other untoward symptoms such as we have already described quickly make +their appearance. + +The animal should now be placed in slings and preparations made for +actively treating the wound with antiseptics. Whether we fail or not, we +have the satisfaction of knowing that we have given to the patient the best +and the only chance of recovery. + +It should be remembered, however, and should be pointed out to the owner, +that with purulent arthritis fully developed, with the grave constitutional +changes it occasions, and with the ever-present danger of a general +septic invasion of the blood-stream, that the human surgeon under such +circumstances offers to his patient the alternatives of amputation or +probable death. With us no such alternative is possible. It is either +return the joint to some semblance of its former usefulness, or destroy the +patient. + +In this case we advise the injection of the original wound, and also such +fistulous openings as may have formed, with the 1 in 1,000 sublimate +solution. Also, in order to avoid the sometimes abortive attempts of the +antiseptic pad, to maintain a condition of asepsis around the wound, we +advise the continual soaking of the whole foot in a cold antiseptic bath. +This may be either carbolic acid 1 in 20, or--what is less volatile, +perhaps more effectual, and certainly more economical--perchloride of +mercury 1 in 1,000. + +It has been our good fortune, even when we have seen the foot almost +detached from the limb by the devastating inroads of the pus, to see +the suppurative process by this means gradually overcome, a reparative +anchylosis set in, and the animal restored to good health and usefulness, +if not to soundness. + +Once the suppurative process is checked and anchylosis commences, it is +good treatment to smartly blister the whole of the region of the coronet, +the pastern, and the wound itself with a mixed blister of cantharides and +biniodide of mercury, repeated at intervals of a fortnight. This prevents +to some extent further infection of the wound, and assists also in +promoting the changes that tend to anchylosis. + +_(d)_ ANCHYLOSIS. + +The word anchylosis signifies the stiffening of a joint. When one has read +the serious changes occurring within the joint in the more serious forms +of arthritis, it is easy to understand how it comes about. In suppurative +arthritis, for instance, we have the synovial membrane destroyed, the +articular cartilages partly or wholly obliterated, and the former +boundaries of the joint entirely lost. If the animal lives, nature is +bound to make repair of a sort. The synovial membrane and the articular +cartilages utterly destroyed, as we have described, cannot again be +replaced. Nature can only build again from such materials as are left to +her. In this case the material is bone. + +It must be remembered, however, that often the bone has been so diseased +that spots of necrosis or caries within it are bound to remain unless moved +by operative interference. Such diseased portions, when dealing with the +foot, are beyond reach of the surgeon's knife, and we have no alternative +but to allow them to remain. We get, therefore, in many cases, a condition +of rarefactive ostitis occurring side by side with a slowly progressive +caries within the bone, while outside is occurring an osteoplastic +periostitis. The concurrence of these conditions leads in time to great +increase in size of the parts, together with increasing anchylosis and +deformity. + + +C. NAVICULAR DISEASE. + +_Definition_.--Chronic inflammatory changes occurring in connection with +the navicular bursa, affecting variously the bursa itself, the perforans +tendon, or the navicular bone, and characterized by changes in the form +of the hoof and persisting lameness. The disease is commonly noticed +in thoroughbreds or in horses of the lighter breeds, and is but seldom +observed in heavy cart animals. Usually it is met with in one or both +fore-feet. Although of extremely rare occurrence, it has been noticed in +the hind. + +_History_.--To English veterinarians appears to belong the credit of +discovering navicular disease. As early as 1752 we find one, Jeremiah +Bridges, in 'No Foot, No Horse,' drawing attention to 'coffin-joint +lameness,' and advocating for its treatment setoning of the frog. It +appears, too, that Moorcroft, prior to his departure for India in 1808, was +acquainted with what was then known as coffin-joint[A] lameness, having +drawn attention to it in 1804 in a letter to Sir Edward Codrington.[B] In +1819 Moorcroft made it even plainer still that he was fully acquainted with +what we now know as navicular disease. This we learn from a letter written +by him to Sewell, in which he laid claim to being the originator of +neurectomy. In this letter he says: + +[Footnote A: The coffin-joint at this time included the navicular bursa.] + +[Footnote B: Percival's 'Hippopathology,' vol. iv., p. 132.] + +'On dissecting feet affected with these lamenesses, the flexor tendon was +now and then observed to have been broken, partially or entirely, but +more commonly to have been bruised and inflamed in its course under the +navicular or shuttle bone, or at its insertion into the bone of the foot. +Sometimes, although seldom, the navicular bone itself has been found to +have been fractured; at others its surface has been deprived of its usual +coating, and studded with projecting points or ridges of new growth, or +exhibiting superficial excavations more or less extensive.'[A] + +[Footnote A: _Ibid_.] + +_Pathology and Point of Commencement of the Disease_.--The exact position +in which the diseased process starts has for a long time been a subject +of discussion, and even now it is doubtful whether the point has been +definitely settled. To mention but a few among many: We find Mr. Broad, of +Bath, strenuously insisting on the fact that the disease commences in the +interior of the navicular bone. Just as strenuously we find the editor of +the journal in which the matter is being discussed, the late Mr. Fleming, +asserting that the disease commences in the bursa.[A] Others, too, hold +that the disease commences primarily in the tendon. Wedded to this view was +the discoverer, Mr. Turner, of Croydon; while Percival commits himself to +the statement that it is either the central ridge or the postero-inferior +surface of the navicular bone, or the opposed concavity in the perforans +tendon, that shows the earliest signs of the disease. The observations made +by Dr. Brauell, the first Continental writer to fully describe the disease, +led him to the statement that neither the bone nor the bursa was the +_invariable_ starting-point of the trouble, but that usually it commenced +in inflammation of the bursa itself. + +[Footnote A: Percival's 'Hippopathology,' vol. iv., p. 132.] + +Without, therefore, committing ourselves to an expression of opinion as +to the precise starting-point of the affection, we shall describe the +pathological changes occurring in navicular disease as noted in (1) the +bursa, (2) the cartilage, (3) the tendon, and (4) the bone. + +1. _Changes in the Bursa_.--Upon the internal surface of the bursal +membrane is first noticed a slight inflammatory hyperæmia, accompanied +by more or less swelling and tumefaction, owing to its infiltration with +inflammatory exudate. The portion covering the hyaline cartilage of the +navicular bone has lost its peculiar pearl-blue shimmer, and become a dirty +yellow. + +Remembering that the bursal membrane is a synovia-secreting one, and +bearing in mind what happens in ordinary synovitis and arthritis (with +which, of course, this may be very closely compared), we shall first expect +changes in the bursal contents. It is highly probable, though difficult of +proof, that in the very early stages the chronic inflammatory stimulus has +the effect of increasing the flow of synovia. In every case, however, where +it can with any certainty be said that navicular disease exists, it is too +late to meet with this condition. The disease has then progressed until +destruction of the secreting layer of the bursal membrane has been +seriously interfered with, and in this case we find a distinct deficiency +in the quantity of synovia in the bursa. In advanced cases it is even found +that the bursa is _absolutely dry_. + +2. _Changes in the Cartilage_.--Directly that portion of the bursal +membrane covering the cartilage is the subject of inflammatory change, the +cartilage itself, by reason of its low vitality, soon suffers. + +Under a process, which we may term 'dry ulcerative,' the cartilage covering +the ridge on the lower surface of the bone commences to become eroded, and +in appearance has been likened, both by English and Continental writers, to +a piece of wood that has been worm-eaten (see Fig. 161). + +[Illustration: FIG. 161.--NAVICULAR BONE (POSTERO-INFERIOR SURFACE) SHOWING +THE 'WORM-EATEN' APPEARANCE CAUSED BY EROSION OF THE HYALINE CARTILAGE, AND +COMMENCING RAREFACTIVE ARTHRITIS.] + +'At this stage, or much earlier'--we are quoting Colonel Smith, +A.V.D.--'may be found calcareous deposits in the fibro-cartilage and the +bone. They are scattered like fine sand here and there, generally across +the inferior half of the face of the bone; they are sometimes numerous, +frequently scanty, occasionally entirely absent. The amount of calcareous +degeneration depends upon the lesions present. If much destruction of bone +exists, there will be but few calcareous deposits; whilst if there are many +calcareous deposits, there may be but slight ulceration of bone tissue, and +perhaps none at all. In fact, I have held the opinion, and see no reason to +modify it, that calcareous deposits are safeguards against caries.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. vi., +p. 195.] + +3. _Changes in the Tendon_.--The effect of these calcareous deposits on +the under surface of the bone is to produce a certain amount of roughness. +Seeing that with every movement of the foot the perforans tendon is called +upon to glide over this surface, it is clear that a secondary effect must +be that of inducing erosion and destruction of the tendon. The point at +which this usually commences is at the bottom of the depression that +accommodates the ridge on the bone. With erosion of the cartilage and of +the tendon at points exactly opposite each other, we have two surfaces come +together that are prone to readily unite, and fibrous tissue adhesions +often take place between the bone and the tendon. In some measure this +accounts for the torn and ragged appearance of the tendon. Adhesions take +place, and, under some small strain, are broken down. This may happen more +than once or twice, and with each breaking of the adhesion between the bone +and tendon, fibres from the latter are lacerated and torn from their place +(see Fig. 162). + +4. _Changes in the Bone_.--The changes occurring in the bone are +essentially those of a rarefactive ostitis. These changes are described by +many writers, and, whether originating primarily in the bone or not, it +seems certain that extensive changes may have occurred within the bone, +with but little or nothing to be noted on its outer surface. It would seem +that the first change is one of congestion of the vessels of the bone's +cancellous tissue. With the cause, whatever it may be, in constant +operation, the congestion persists until a low type of inflammation is set +up, interfering, not only with the flow of synovia in the adjoining bursa, +but with the nutrition of the bone itself. As the disease progresses, there +is softening and enlarging of the cancellated tissue towards the centre +of the bone. The cells break up, and absorption takes place. This goes on +until a large portion of the interior of the bone is in a state of dry +necrosis, with, in many cases, but slight signs of mischief on the exterior +of the bone. + +In other cases, however, the changes in the interior of the bone are +accompanied by well-marked lesions on its gliding or postero-inferior +surface, and by evidences of an osteoplastic periostitis along its edges. + +That an osteoplastic periostitis has been in existence is witnessed by the +appearance along the edges of the bone of numerous outgrowths of bone, +termed osteophytes (see Fig. 163). + +[Illustration: FIG. 162.--A FOOT WITH THE SEAT OF NAVICULAR DISEASE +EXPOSED. On the anterior surface of the perforans fibres of the tendon are +seen to be torn away from their abnormal adhesion with the navicular bone, +while others are seen to be still attached thereto. The surface of the +navicular bone itself exhibits small defects in the bony substance, which +have been brought about by a rarefactive ostitis. _a_, The perforans tendon +cut through and reflected; _b_, the sole.] + +The interosseous and postero-lateral ligaments of the articulation +often participate in the inflammatory changes, and in many cases become +completely ossified. The true articulatory surface of the bone, that +articulating with the os pedis and with the os coronæ, is never affected. + +_Causes_.--In enumerating the causes of navicular disease, we shall +follow the example of Colonel Smith and classify them under certain +headings--namely, (1) _Hereditary Predisposition_; (2) _Compression_; (3) +_Concussion_; (4) _A Weak Navicular Bone_; (5) _A Defective or Irregular +Blood-supply to the Bone_; and (6) _Senile Decay_. + +[Illustration: FIG. 163.--THE NAVICULAR BONE FROM A CASE OF LONG-STANDING +NAVICULAR DISEASE. The erosion of the cartilage on its central ridge is +most marked, and the porous appearance of the bone thus uncovered points +to the existence within it of a rarefactive ostitis. Along its edges +large osteophytic outgrowths speak of the effects of an osteoplastic +periostitis.] + +1. _Hereditary Predisposition_.--That navicular disease is hereditary is +a fact that has for a long time been insisted on, and has come to be so +generally admitted that we do not intend to dwell on it here. As we have +said before, it is found in the lighter breeds of horses (and, according +to Zundel, especially in the English breeds), and is there seen to be +frequently transmitted from parent to offspring. + +2. _Compression_.--By this is meant the compression of the navicular bone +between the os pedis and the os coronæ in front, and the perforans tendon +behind. + +In order to appreciate this explanation of the causation of navicular +disease at its true value, it will be well to consider briefly the +physiology of the parts in question. + +The navicular bone is what we may term a complement of the os pedis. It +exists, in fact, simply in order that the os coronæ may have a sufficiently +large articulatory surface to play upon. One wonders at first that Nature +did not arrive at this by originally placing a larger bone below. Colonel +Smith explains this by suggesting that this would in all probability have +meant its fracture. In progression the hind part of the foot comes to the +ground first, and upon the hinder portion of the articulation would fall +the first effects of concussion, together with the greater part of the +body-weight. A yielding joint was in this position necessary, and that +formed by the navicular bone fills all requirements. + +In this connection one next considers the part played by the front limbs +during progression. As Zundel expresses it, they are columns of support +rather than of impulsion, and, as the body-weight is thrown forward by the +hind-limbs, it is the duty of the fore-limbs to receive it. The shock or +concussion of the body-weight thus thrown forwards is first received by +the muscles uniting the limb to the trunk, and a great part of it there +minimized by their sling-like attachment. It is further absorbed by the +shoulder-joint, and from there passed on to the almost vertical bony column +represented by the radius and ulna, the knee, and the metacarpus. On +reaching the first phalanx, a portion of the remaining force is passed on +to the front of the phalanges and loses itself in front of the hoof, while +the other portion is transmitted to the flexor tendons, finally to the +perforans, and to the posterior parts of the foot. During progression, +therefore, the navicular bone is constantly pushed downwards and backwards +by the bony column, and is just as constantly pushed forwards and upwards +by the resistance of the perforans tendon. This means, of course, that +the navicular bone is more or less constantly subject to compression, +and constant pressure, as we know full well, is a pretty sure factor +in bringing about malnutrition of the parts, with atrophy or chronic +inflammatory changes as an end result. + +Even with the limb at rest the pressure on both sides of the navicular bone +is still constant. The only circumstances under which we can conceive of +it being entirely absent, in fact, are when the tension on the tendon is +relaxed, and the body-weight altogether removed by the animal adopting the +recumbent position. + +The compression theory as to the causation of navicular disease was, we +believe, first originated by Colonel Smith. He, at any rate, has laid much +stress on it in his writings. If we accept it, and we see every reason +that we should, then we must, with the author, admit the possibility of +navicular disease arising from long standing in one position. + +3. _Concussion_.--This we are bound to admit as a cause, and in so doing +partly explain the comparative, almost total, immunity of the hind-feet +from the disease. The fore-limbs, as we have already pointed out, are +little more than props of support, and the force of the propelled +body-weight is transmitted largely down their almost vertical lines, to +end largely in concussion in the foot. With the hind-limbs matters are +different. 'These,' as Percival explains it, 'have their bones obliquely +placed, so as to constitute, one with the other, so many obtuse angles, to +the end, that by forming powerful levers, and affording every advantage for +action to the muscles attached to them, they may be fitted for the purpose +of propulsion of the body onward.' + +The effect of these several obtuse-angled joints in the limb is to absorb +the greater part of the force exerted by the body-weight before it reaches +the foot. When with this we take the facts that the fore-limbs have to +carry the head and neck, and that they have to bear this added weight, plus +a propelling force from behind, we see why it is that they should be so +subject to the disease, and the hind-limbs so exempt. + +As pointing out the part that concussion plays in its causation, we may +mention that navicular disease is a disease of the middle-aged and the +worked animal. It is interesting to note, too, that it occurs in animals +with well developed frogs--in feet in which frog-pressure with the ground +is most marked. This at first sight appears to flatly contradict what we +have said with regard to frog-pressure in other portions of this work. With +this, however, must be reckoned other predisposing causes. In this case it +is not to frog-pressure alone we must look, but to the condition of the +frog itself, and that of the neighbouring parts. It is when we have a frog +which, though well developed and apparently satisfying all demands as +to size and build, is at the same time composed of a hard, dry, and +non-yielding horn that we must look for trouble. + +The foot predisposed to navicular disease is the strong, round, short-toed +or clubby foot, open at the heels, with a sound frog jutting prominently +out between them. Here is a frog exposed to all the pressure that might +be desired for it, bounded at its sides by heels thick and strong, and +indisposed to yield, and itself liable, from its very exposure, to become, +in the warm stable, hard and dry, and incompressible' (Percival). + +Here, instead of acting, as normally it should, as a resilient body, and an +aid to the absorption of concussion, it seems rather to play the part of +a foreign body, and to bring concussion about. Seeing, then, that the +navicular bursa is in very near contact with it, it is conceivable that +this joint-like apparatus should suffer, and the pedal articulation be left +unaffected, the more so when we take into consideration the compression +theory just described. + +4. _A Weak Navicular Bone_.--When the disease commences first in the +bone--and there is no denying the fact that sometimes, although not +invariably, it does--it may be explained by attributing to the structure of +the bone an abnormal weakness in build. + +The navicular bone consists normally of compact and cancellated tissue +arranged in certain proportions, the compact tissue without, and the +cancellated within. These proportions can only be judged of by the +examinations of sections of the bone, and when it is found in any case that +the cancellated tissue bulks more largely in the formation of the bone than +normally it should, we have what we may term a weak navicular bone. In this +connection Colonel Smith says: 'Though it is far from present in every case +of the disease, still I consider it a factor of great importance.' + +5. _A Defective or Irregular Blood-supply to the Bone_.--This, Colonel +Smith considers, is brought about by excessive and irregular work, and by +the opposite condition--rest. The author points out that the bloodvessels +passing to and from the navicular bone run in the substance of the +interosseous ligaments, or in such proximity to them that it is conceivable +that under certain circumstances mechanical interference may occur to the +navicular circulation. He further points out a fact that is, of course, +well known to every veterinarian, that in periods of work the circulation +of the foot is hurried, and that in rest there is always a tendency to +congestion; and he says in conclusion: 'I cannot help thinking that +irregularities in the blood-supply in a naturally weak bone must be a +factor of some importance, especially when the kind of work the horse is +performing is a series of vigorous efforts followed by rest.' + +6. _Senile Decay_.--With approaching age the various tissues lose their +vigour, and are prone to disease. The navicular bone and surrounding +structures are not exempt. With the other and more active causes we have +described acting at the same time it is not surprising that navicular +disease is seen as a result. + +In conclusion, it is well, perhaps, to say that, no matter to which +particular theory of causation we may lean, we should make up our minds to +consider them as a whole. While one cause may be exciting, the other may +be predisposing, and the two must act together before evil results are +noticed. It may be that even more than two are concerned in bringing on the +disease, and to each the careful veterinarian will give due consideration. + +_Symptoms and Diagnosis_.--In the early stages of navicular disease the +symptoms are obscure. Pointing of the affected limb is the first evidence +the animal gives. This, however, more often than not, goes unnoticed, +and the first symptom usually observed by the owner or attendant is the +lameness. Even this is such as to at first occasion no alarm, being +intermittent and slight, and only very gradually becoming marked. In a few +cases, however, lameness will come on suddenly, and is excessive from the +commencement. It is the lameness, slow in its onset, intermittent in +its character, and gradual in its progress, however, that is ordinarily +characteristic of navicular disease. + +The animal is taken out from the stable sound, with just a vague suspicion, +perhaps, that he moved a bit stiffly. While out he is thought by his driver +or rider to be going feelingly with one foot or with both. Even this is not +marked, and the driver has some difficulty in assuring himself whether or +no he really observed it, or whether it was but imagination. + +On the return home the limb is examined, and nothing abnormal is to be +found. The leg is of its normal appearance, and neither heat nor tenderness +is to be observed in it or in the foot. On the following day the animal +again is sound, and the lameness of the previous day is put down to a +slight strain or something equally simple. The patient is then, perhaps, +rested for a day or two. When next he is worked he again moves out from the +stable sound, but again during the going gives the driver the unpleasant +impression that something is amiss; and so the case goes on. One day the +owner fears the animal is becoming seriously enough affected to warrant him +in calling in his veterinary surgeon; the next he is confidently assuring +himself that nothing is wrong. + +Perhaps the animal is now rested for a week or two, or even for a month or +two, hoping that this will put him sound. Immediately on commencing work, +however, the same symptoms as before assert themselves, and the veterinary +surgeon is called in. + +With a history such as we have given the veterinarian's suspicions are +aroused. He has the animal trotted, and may notice at this stage that there +is an inclination to go on the toes, that the lame limb or limbs are not +put forward freely, and that progression is stilty and uncertain; it +is such, in fact, as to at once suggest the possibility of corns being +present. + +In some cases there is just the suspicion of a limp with one limb, and +this only at intervals during the trot. At one moment the veterinarian +is positive that he sees the animal going lame; at another he is just as +confident he sees him coming towards him sound. + +Nothing is found in the limb--neither heat, tenderness, nor swelling. There +is nothing in the gait (either a limited movement of the radius, or a +circular sweep with the leg) to indicate shoulder or other lameness, and +the veterinary surgeon, by eliminative evidence, is bound to conclude that +the trouble is in the foot. + +The foot is then examined--pared, percussed, pinched, and in other ways +manipulated--but nothing further is forthcoming. In such a case the +veterinary surgeon is wise to declare the abortive result of his +examination, to hint darkly of his suspicions, and to suggest a second +examination at some future date. It may be that two, three, four, or even +more, such examinations are necessary before he can justly pronounce a +positive verdict. + +Later he is enabled to do this by an increase in the severity of the +symptoms, and by the changes that take place in the form of the foot. +The lameness is now more marked, and the 'pointing' in the stable more +frequent. With regard to the latter symptom, it has been seriously +discussed whether the horse with navicular disease points with the heel +elevated or with it pressed to the ground. In either case, of course, the +limb is advanced; but while some hold that the phalangeal articulations are +flexed and the heel slightly raised, in order to relieve the pressure of +the perforans tendon on the affected area, and so obtain ease, there are +others who hold that the heel is pressed firmly to the ground in order to +deaden the pain. It may be, and most probably is, that both are right; but, +in our opinion, there is no doubt whatever that pointing with the heel +elevated is by far the most common. + +The lameness is now excessive, and is especially noticeable when the animal +is put to work on a rough or on a hard ground. Even now, however, heat of +the foot or tenderness is so slight as to be out of all proportion to the +alteration in gait. + +With the case thus far advanced, evidence of pain may be obtained by +pressing with the thumb in the hollow of the heel. Evidence of pain may +also be obtained by using the farrier's pincers on the frog. These methods, +however, are never wholly satisfactory, as a horse with the soundest of +feet will sometimes flinch under these manipulations. + +Extreme and forcible flexion of the corono-pedal articulation also +sometimes gives evidence of tenderness. In this case the foot is held up, +the animal's metacarpus resting on the operator's knee, and the toe of the +hoof pushed downwards with some degree of force. + +The same movement of the joint is given by causing the animal to put full +weight upon the diseased limb, a small wedge of wood being first placed +under the toe. In this manner the pressure of the perforans tendon upon the +bursa is greatly increased, and the animal is caused to show symptoms of +distress. + +The lameness may also be increased, and diagnosis helped, by paring +the heels, so as to leave the frog prominent and take the whole of the +body-weight. The same end is also obtained by applying a bar shoe. This was +originally pointed out by Brauell, and is quoted by Zundel and by Möller. + +The changes in the form of the hoof may now be noticed. These are largely +dependent on the fact that more or less constantly the patient saves the +heel. The horn of the walls in this region, and the horn of the frog, +is thereby put out of action and induced to atrophy. The hoof gradually +assumes a more upright shape, and the heels contract. We thus get a hoof +which is visibly narrowed from side to side, with a frog that is atrophied +and often thrushy, and with a sole that is abnormally concave, hard, and +affected with corns. + +When occurring in the hind-feet--a condition that is rare, but which has +been noticed by Loiset, and quoted by Zundel--the animal is stiff behind, +walks on his toes, and gives one the impression that he is suffering from +some affection in the region of the loins. + +One such case is reported by an English veterinary surgeon, and we quote it +here: + +'A gray gelding, and a capital hunter, the property of a gentleman in this +neighbourhood, became lame in the near fore-foot after the hunting season +of 1859. The lameness was believed to be due to navicular disease. +The operation of neurectomy was ultimately had recourse to. The horse +subsequently did his work as well as ever, and was ridden to hounds +regularly till the end of the year 1861, when he went lame of the off +fore-foot. From this date he also showed very peculiar action behind, and +was at times lame of both hind-limbs without any apparent cause. + +'In the year 1862, from the groom's indiscreet use of physic, +superpurgation was brought on which caused the animal's death. On a +post-mortem examination being made, the horse was found to have _navicular +disease of all four feet_. It is worthy of note that this horse had +always "extravagant" action behind, but was a remarkably quick and good +jumper.'[A] + +[Footnote A: F. Blakeway, M.R.C.V.S., _Veterinarian_, vol. ii., p. 21.] + +_Differential Diagnosis_.--Navicular disease may be mistaken for ordinary +contracted foot. It will be remembered, however, that in the early stages +of navicular disease contraction is absent, and that it is only when the +disease in the bursa is of long standing that contraction comes on. With +ordinary contracted foot, too, careful paring and suitable shoeing soon +sees a diminution in the degree of lameness, and a return to the normal in +shape (see Treatment of Contracted Foot, p. 125). With navicular disease, +however, such shoeing as is beneficial in the treatment of contracted foot +(notably the various methods of giving to the frog counter-pressure with +ground) soon brings on an aggravation of the lameness. + +It is, perhaps, even more likely to be confounded with contraction when we +have with the contraction a state of atrophy and thrush of the frog. With +a frog in this condition pressure will give rise to pain, and navicular +disease be erroneously judged to be present. In such a case we must rely +wholly upon either extreme flexion or extreme extension of the joint to +guide us, when, if contraction _only_ is the offending condition, no +symptom of pain will be shown. + +Navicular disease may also be confused with rheumatic affections, +with sprain of the posterior ligaments of the first interphalangeal +articulation, and with sesamoid lameness. Mistakes are sometimes made, too, +especially with a hasty observer, in confounding it with shoulder lameness. + +In rheumatism the constant changing of the seat of pain, the sometimes +elevated temperature, and the appearance of symptoms of heat, tenderness, +and swelling in the affected area should guide one to a right conclusion. + +In sprain of the posterior ligaments of the coronet and in sesamoid +lameness, nothing but a careful examination and manipulation of the parts +will ward off error, for in each of these cases there is 'pointing' and +resting of the limb, and considerable disinclination to put weight firmly +upon it. If at the same time manipulation gives distinct evidence of pain, +all doubt may be set at rest. + +Roughly speaking, sesamoid lameness is a condition of the gliding surface +of the sesamoids, and the face of the tendon playing over them, similar to +that found in navicular disease. All symptoms of pointing, the constant +maintaining of the limb in a state of flexion, and a feeling manner of +progression are again all present. It is plain from this that in all cases +where an animal with a gait at all suggestive of navicular disease is +brought for our examination, the manipulation of the limb should be +thorough. The character of the lameness is almost sure to deceive us; and +it is not until we are able to obtain local symptoms pointing to the one or +the other of the conditions we have enumerated that a decisive opinion may +be given. In sesamoid lameness the local symptoms are those of heat and +pain in the fetlock on palpation, and a swelling of the affected parts, +such swelling being at first slight, yielding, and barely distinguishable, +and afterwards larger, bony and hard, and more marked. Later still there is +distinct evidence of 'knuckling' over at the fetlock and inability to fully +flex it. + +In cases of shoulder lameness the gait alone should be sufficient to render +liability of error small, for with nearly every case there is a manifest +inability to 'get the limb forward', and this is best seen at a side view +when the animal is trotting past the observer. When trotting towards +one, there is a further and unmistakable symptom common to most shoulder +lamenesses that serves to distinguish it at once, and that is the peculiar +'sweeping' outwards with the affected limb. + +Lastly, with either of the conditions we have just mentioned, it is the +exception to get contracted foot follow on. With navicular disease it +sooner or later makes its appearance. + +_Prognosis_.--The prognosis of navicular disease (once diagnosed with +certainty) must almost of necessity be unfavourable. The facts that the +disease has made serious progress before it is really noticeable, that +the situation of the parts prohibits operative interference, and that the +disease is one of a chronic and slowly progressive type, all point to an +unfavourable termination. + +_Treatment_.--We have seen from the pathology of this disease that it may +commence either as a rarefactive ostitis, or as a synovitis and tenositis +in connection with the bursa. With the former condition in existence, or +when this and the synovitis has led to erosion of the cartilage, treatment +is probably of no avail, on account of the more chronic nature of these two +conditions. When, however, the condition is simply that of synovitis or +tenositis, a more or less acute condition, we may assume that suitable +treatment and a long rest will bring about resolution. + +The first indications in treatment are those of what we may term 'nursing' +the foot. It should have sufficient rest, should be placed so as to +minimize as far as possible compression of the parts, and should have +its posterior half treated so as to render it softer and less liable to +concussion. + +The period of rest required cannot be satisfactorily advised, and the +practitioner is wise who makes it a long one. Best should be advised, in +fact, long after symptoms of lameness have disappeared and recovery is +judged to have taken place. + +Compression of the parts may be somewhat minimized, if the animal be kept +in the stable, by allowing the floor upon which the front-feet are to stand +to be slightly sloping from behind forwards. The same effect, though not so +marked, is obtained by removing the shoes, and considerably lowering the +wall at the toe, while allowing that of the heels to remain. It may here be +remarked that it is a good practice to allow the shoes to remain on, and +this even when the animal is at grass. They should, however, be frequently +removed, and the foot trimmed as we have directed. + +With the foot thus trimmed so as to most suitably adjust the angles of +the articulations, it should next be thoroughly pared and rasped in its +posterior half, so as to render the horn of the sole and the frog and the +horn of the quarters as thin as possible. The heels, however, should not be +excessively lowered, _if at all_. We now have the foot in a soft condition, +and easily expanded. It should, if possible, be kept so; and this may be +done either by the use of poultices, by tepid baths, or by standing the +animal upon a bedding that may easily be kept constantly damp. Such +materials as tan, peat moss, or sawdust, are either of them suitable. + +All this, of course, calls for keeping the animal in the stable. It is far +better, however, more especially if a piece of marshy land is at hand, to +turn him out in that. A moderate amount of exercise is beneficial rather +than not, and the feet are thus constantly kept damp without trouble to the +attendants. + +The second indication in the treatment is that of applying a +counter-irritant as near to the diseased parts as possible. Regarding its +efficacy we must confess to being somewhat sceptical. The treatment has +been constantly practised and advised, however, and we feel bound to give +it mention here. A smart blister may, therefore, be applied to the whole of +the coronet, and need not be prevented from running into the hollow of the +heel. + +Instead of blistering the coronet (or in conjunction with that treatment), +the counter-irritant may be applied by passing a seton through the plantar +cushion or fibro-fatty frog. Setoning the frog appears to have been +introduced by Sewell. In many cases great benefit is claimed to have been +derived from it, especially by English veterinarians of Sewell's time, and +by others on the Continent. Percival, however, was not an advocate for it, +and, at the present day, it is a practice which appears to have dropped out +of use altogether. + +[Illustration: FIG. 164.--FROG SETON NEEDLE.] + +To perform this operation a seton needle of a curved pattern is needed +(see Fig. 164). This is threaded with a piece of stout tape dressed with a +cantharides, hellebore, or other blistering ointment, and then passed in at +the hollow of the heel, emerging at the point of the frog. The course the +needle should take will be understood from a reference to Fig. 165. + +The seton may be passed with the horse in the standing position. Previously +the point of the frog should be thinned, and the animal should be twitched. +After-treatment consists simply in moving the seton daily, and dressing it +occasionally with any stimulating ointment, or with turpentine. + +If, in spite of these treatments, the disease persists, then nothing +remains but neurectomy. + + +D. DISLOCATIONS. + +The firm and rigid manner in which the bones of the pedal articulation +are held together renders dislocation of this joint an exceedingly rare +occurrence, and then it is only liable to happen under the operation of +great force. In the literature to our hand we have only been successful +in discovering one reported instance, and, strange to say, in this, a +well-marked case, the cause was altogether obscure. We quote the case at +the end of this section. + +[Illustration: FIG. 165.--DIAGRAM SHOWING THE COURSE TAKEN BY THE NEEDLE +WHEN SETONING THE FROG. This is shown by the dotted curved line _a, b_. +1, The navicular bone; 2, the plantar cushion; 3, the os pedis; 4, the +perforans tendon.] + +A partial dislocation of this articulation is the condition met with in +'Buttress Foot.' In this case the fracture of the pyramidal process, and +the consequent lengthening of the tendon of the extensor pedis, allows the +os coronæ to occupy upon the articulatory surface of the os pedis a more +backward position than normally it should. + +It is quite probable, too, that slight lesions of the other restraining +ligaments and tendons of the articulation may bring about a similar though +less marked condition. We may be quite sure of this--that whenever such +lesions (as, for example, sprain and partial rupture of the lateral +ligaments) do occur, and the normal position of the opposing bones is +changed, if only slightly, that great pain and excessive lameness must be +the result, and this with but little to show in the foot. Many of our cases +of obscure foot lameness might, if capable of demonstration, turn out to be +cases of sprain and partial dislocation of the pedal articulation. + +_Recorded Case_.--'The animal, a trooper of the 8th Hussars, was found on +the morning of April 17 unable to bear any weight on the limb (the +near hind). Cause not known--the heel-rope I thought at first; but on +investigation I found the heel-rope had been on the other leg. + +_Diagnosis_.--Dislocation of the left os coronæ from the articulating +surface of the os pedis in a backward direction. + +'Every devisable means were unsuccessful in reducing the limb to its +natural position. The horse was thrown, and a strong rope, with four men +pulling at it, was fastened round the hoof, whilst I put my knee to the +back of the pastern, using all possible force, with one hand to the foot +and the other to the fetlock, but all to no purpose. Next day other means +were tried. First by throwing the horse and placing him on his belly, with +the fore-legs stretched out forwards, and the hind-legs backwards. This I +did so as to get the injured limb placed as nearly flat on the ground as +possible, with its anterior aspect downwards. Then a very heavy man, with +his boots off, was made to jump on the back of the pastern, where the +prominence showed most; and afterwards, when these means failed, a strong +piece of wood, well covered with leather, was placed (where the hollow of +the heel ought to have been) on the most prominent part, and hit several +times with a heavy hammer; but all efforts were futile. + +'_Prognosis_.--Unfavourable. During the latter operations I had a very +strong pressure applied to the hoof, and the horse firmly fastened in every +way, and it appeared as though no amount of force would ever reduce the +dislocation. + +'_Tautological_.--The case was destroyed on April 30, being of no further +use to the service. + +'_Post-mortem_.--The os coronæ was found to have slipped out of the +articulating cavity of the os pedis, backwards and past the lateral +ligaments. These last-named structures prevented the bone being forced +forward into its proper position, being firmly locked over the lateral +prominences. The capsular ligament was considerably lacerated and inflamed, +causing slight effusion and swelling about the region of the coronet.'[A] + +[Footnote A: T. Flintoff, A.V.D., _Veterinary Journal_, vol. xix., p. 74.] + +_Treatment_.--After the forcible means of reduction related by Mr. +Flintoff, we may add that when they are successful, they should be followed +by suitable bandaging of the parts, and rest. The first is effected by +applying plaster of Paris and linen, and the second by having the animal +put in slings. + + + +INDEX + +Accidental tearing off of the entire hoof +Acute arthritis + causes of + symptoms of + treatment of +Acute laminitis + causes of + complications in + congestion in + course of + definition of + diagnosis in + exudation in + pathological anatomy of + prognosis in + suppuration in + symptoms of + treatment of +Acute periostitis simple +Acute simple coronitis + causes of + definition of + symptoms of + prognosis of + treatment of +Acute simple synovitis +Advantages of neurectomy +Amputational neuroma after neurectomy +Anatomy, pathological, of corn +Applying poultices, method of +Arteries of the foot +Arthritis, acute + causes of + symptoms of + treatment of +Arthritis, simple or serous +Arthritis, suppurative + causes of + definition of + diagnosis of + pathology of + symptoms of + treatment of +Articulation, the first interphalangeal +Articulation, the second interphalangeal + +Bar pad and a half-shoe in the treatment of contracted feet +Bar shoes in the treatment of contraction +Bayer's treatment for chronic laminitis +Bermbach's treatment for canker +Bind +Bone, caries of +Bones, fracture of the, after neurectomy +Bones, fracture of the +Bones, necrosis of +Bones, the +Brittle hoof + causes of + definition of + symptoms of + treatment of +Broad's treatment of laminitis +Broué's expansion shoe +Bruised sole, chronic +Buttress foot + +Canker + Bermbach's treatment of + causes of + definition of + differential diagnosis in + history of + Hoffmann's treatment of + Imminger's treatment of + Malcolm's treatment of + pathological anatomy of + prognosis in + Rose's treatment of + symptoms of + treatment of +Caries of bone +Caries of the os pedis in pricked foot +Cartilage, the lateral +Cartilaginous quittor +Causes of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of corn + of contracted feet + of coronary contraction of the + foot + of crooked foot + of curved hoof + of false quarter + of flat-foot + of keraphyllocele + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of ringed hoof + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of simple cutaneous quittor + of specific coronitis + of sub-horny quittor + of thrush + of weak heels +Caustic solution, Villate's +Changes in the bone in navicular disease + in the bursa in navicular disease + in the cartilage in navicular disease + in the internal structures of the foot in contraction + in the tendon in navicular disease +Charlier shoe, the +Charlier shoeing for contracted foot +Chemical properties of horn +Chronic coronitis, simple + causes of + definition of + symptoms of + treatment of +Chronic bruised sole + treatment of +Chronic laminitis + Bayer's treatment of + causes of + definition of + Gross's treatment of + Gunther's treatment of + Imminger's treatment of + Joly's treatment of + Meyer's treatment of + pathological anatomy of + surgical shoeing for + symptoms of + treatment of + treatment of, by ligaturing the digital arteries +Chronic oedema of the leg after neurectomy +Chronic synovitis +Clamp, sand-crack, Koster's + McGill's + Vachette's +Clamping sand-cracks, methods of +Classification of corns + of punctured foot according to the situation of the wound + of sand-crack + of quittor +Club-foot + causes of + definition of + symptoms of + treatment of +Cocaine injections as an aid to diagnosis in foot lamenesses +Colic, metastatic, in laminitis +Commencement, point of, in navicular disease +Common situations of the wound in punctured foot. +Complicated sand-crack, operations for +Complications in coronitis + in laminitis + in pricked foot + in sand-crack + in simple or cutaneous quittor + in sub-horny quittor +Compression as a cause of navicular disease +Concussion as a cause of navicular disease +Conformation, faulty +Congestion in laminitis +Contracted foot + causes of + changes in the internal structures of + definition of + local or coronary + prognosis of + surgical shoeing for + symptoms of + treatment of +Contraction of the foot, a bar pad and a half-shoe in the treatment of + bar shoes in the treatment of + expansion shoes in the treatment of +Corn + causes of + classification of + definition of + pathological anatomy of + prognosis in + surgical shoeing in + symptoms of + the dry + the moist + the suppurating + treatment of +Coronary contraction of the foot + causes of + definition of + symptoms of + treatment of +Coronary cushion, the +Coronary edge of the wall, expansion and contraction of the +Coronitis + acute simple + causes of + complications in + definition of + prognosis of + symptoms of + treatment of +Coronitis, simple chronic + causes of + definition of + symptoms of + treatment of +Coronitis, specific + causes of + definition of + symptoms of + treatment of +Course of acute laminitis +Crooked foot + causes of + definition of + symptoms of + treatment of +Curved hoof + causes of + definition of + treatment of +Cushion + the coronary + the plantar +Cutaneous or simple quittor + +De Fay's expansion shoe. +Defective or irregular blood-supply to the bone a cause of navicular + disease +Definition + of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of contracted foot + of corn + of coronary contraction of the foot + of crooked foot + of curved hoof + of false quarter + of flat-foot + of keraphyllocele + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of pyramidal disease + of quittor + of ringed hoof + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of specific coronitis + of spongy hoof + of sub-horny quittor + of thrush + of weak heels +Development of the hoof +Diagnosis + of acute laminitis + of canker + of foot lameness by injections of cocaine + of navicular disease + of punctured foot + of pyramidal disease + of side-bone + of sub-horny quittor +Differential diagnosis in canker + in navicular disease +Diseases arising from faulty conformation +Dislocation of the os coronæ + recorded case of +Dislocations +Dry corn + +Einsiedel's expansion shoe +Examining the foot method of +Exercise, forced, in the treatment of laminitis +Expansion and contraction + of the coronary edge of the wall + of the hoof under the body-weight + of the solar edge of the wall + of the sole +Expansion shoe Broué's + De Fay's + Einsiedel's + Hartmann's + Smith's +Expansion shoes in the treatment of contraction +Extensor pedis tendon, the +Extirpation + of the lateral cartilage in quittor + of the lateral cartilage, after Moller and Frick + of the lateral cartilage, after Bayer +Exudation in laminitis + +False quarter + causes of + definition of + symptoms of + treatment of +Faulty conformation + diseases arising from +Feeding a cause of laminitis +Flat-foot + causes of + definition of + symptoms of + treatment of +Flexor pedis perforans tendon, the +Flexor pedis perforatus tendon, the +Foot, buttress +Foot, changes in the internal structures in contraction of the +Foot, contracted + causes of + definition of + prognosis of + symptoms of + treatment of +Forced exercise in laminitis +Fractures +Fractures of the bones after neurectomy + of the navicular bone + of the os coronæ + of the os pedis +Frog, the +Functions of the lateral cartilages + +Gangrene of the sensitive structures in laminitis +Gathered nail +Gelatinous degeneration after neurectomy +Grooving the wall + in laminitis (Smith's operation) + in treatment of sand-crack + in treatment of side-bone (Smith's operation) +Gross's treatment of chronic laminitis +Growth of hoof, rate of +Gunther's treatment of chronic laminitis + +Hartmann's expansion shoe +Heels, weak + causes of + definition of + symptoms of + treatment of +Heredity + as a cause of navicular disease + as a cause of side-bone +Histology of horn +History + of canker + of navicular disease + of neurectomy +Hind-feet, navicular disease in the +Hind-limb with the side-line, method of securing +Hoffmann's treatment of canker +Hoof, the + accidental tearing off of + expansion and contraction of + development of + rate of growth of +Horn + chemical properties of + histology of +Hutlederkitt + +Imminger's treatment + for chronic laminitis + for canker +Immobilizing a sand-crack by grooving the wall, methods of +Infection of the limb, septic +Injections of cocaine as an aid to diagnosis in foot lameness +Interphalangeal articulation + the first + the second +Instruments + required in plantar neurectomy + in operations on the foot +Irregular blood-supply to the bone as a cause of navicular disease + +Joly's treatment of chronic laminitis + +Koster's sand-crack clamp +Keraphyllocele + causes of + definition of + pathological anatomy of + symptoms of + treatment of +Keratoma + +Lameness, cocaine injections as an aid to diagnosis in +Laminæ, the sensitive +Laminitis + acute + Broad's treatment of + causes of + complications in + congestion in + course of + definition of + diagnosis in + exudation in + feeding, a cause of + forced exercise in the treatment of + gangrene of the sensitive structures in + grooving the wall in the treatment of + local applications in the treatment of + local bleeding in the treatment of + metastatic colic in + metastatic pneumonia in + neurectomy in + opening the sole in the treatment of + parturient + pathological anatomy of + periostitis and ostitis in + phlebotomy in the treatment of + prognosis in + rocker bar shoes in the treatment of + Smith's operation in + suppuration in + symptoms of + symptoms of, in the four feet + symptoms of, in the fore-feet alone + symptoms of, in the hind-feet alone + treatment of +Laminitis + chronic + Bayer's treatment of + causes of + definition of + Gross's treatment of + Gunther's treatment of + Imminger's treatment of + Joly's treatment of + Meyer's treatment of + pathological anatomy of + surgical shoeing for + symptoms of + treatment of +Laminitis, parturient +Lateral cartilage, the + extirpation of, in quittor, after Holier and Frick + extirpation of, in quittor, after Bayer + functions of + necrosed, pathological anatomy of + necrosis of + ossification of + wounds of +Leg, chronic oedema of the, after neurectomy +Length of rest required after neurectomy +Ligaments, the +Ligaturing the digital arteries, in chronic laminitis +Limb, septic infection of +Local applications in laminitis +Local bleeding in laminitis +Local or coronary contraction of the foot +Low ringbone + +Malcolm's treatment of canker +McGill's sand-crack clamp +Median neurectomy +Metal plates in the treatment of sand-crack +Metastatic colic in laminitis +Metastatic pneumonia in laminitis +Methods of applying poultices + of examining the foot + of immobilizing sand-crack by grooving the wall +Methods of restraint + of securing a hind-limb with the side-line + of securing the foot to the cannon of another limb +Meyer's treatment of chronic laminitis +Moist corn + +Nail-bound + causes of + definition of + symptoms of + treatment of +Nail-tread +Navicular bone, the + fracture of +Navicular bursa, puncture of the, in pricked foot +Navicular bursa punctured, treatment of +Navicular disease + causes of + changes in the bone in + changes in the bursa in + changes in the cartilage in + changes in the tendon in + definition of + diagnosis of + differential diagnosis of + history of + in the hind-feet + point of commencement of + prognosis of + symptoms of + treatment of +Necrosed lateral cartilage + pathological anatomy of +Necrosis of bone + of tendon and ligament in sub-horny quittor + of the lateral cartilage (cartilaginous quittor) +Necrotic plantar aponeurosis, treatment of +Nerve, reunion of, after neurectomy +Nerves, the +Neurectomy + advantages of + amputational neuroma in + fracture of the bones after + gelatinous degeneration after + history of + instruments required in + in laminitis + length of rest required after + persistent pruritus after + pricked foot after + reunion of divided nerve after + sequelæ of + stumbling after + use of the horse after +Neurectomy + median + plantar +Neuroma, amputational, after neurectomy + +Oedema of the leg after neurectomy +Opening the sole in the treatment of laminitis +Operation for complicated sand-crack + for laminitis + for necrosed lateral cartilage in quittor + for necrosed plantar aponeurosis + for side-bone +Operations on the foot, instruments required in +Operations on the horn, treatment of contracted foot by +Os coronæ, the + dislocation of + fracture of +Os pedis, the + caries of, in pricked foot + fracture of +Osteoplastic ostitis +Osteoplastic periostitis +Ostitis in laminitis +Ostitis, + rarefying + osteoplastic +Ossification of the lateral cartilages (side-bone) +Overreach + shoeing for + treatment of + +Parturient laminitis +Pathological anatomy of acute laminitis + of canker + of chronic laminitis + of corn + of keraphyllocele + of necrosed lateral cartilage + of pyramidal disease + of simple cutaneous quittor + of navicular disease +Pedal articulation, puncture of the +Perforans tendon, the flexor pedis +Perforates tendon, the flexor pedis +Periople, the +Periostitis and ostitis in laminitis +Periostitis, osteoplastic +Periostitis, recorded cases of +Periostitis, + simple acute + suppurative +Periostitis, treatment of +Persistent pruritus after neurectomy +Phlebotomy in laminitis +Plantar aponeurosis, + wounds of the + treatment of necrosed +Plantar cushion +Plantar neurectomy + history of + instruments required in + operation of +Pneumonia in laminitis + metastatic +Point of commencement of navicular disease +Poultices, methods of applying +Preventive treatment of cutaneous quittor +Pricked foot + after neurectomy + complications of +Prognosis + in acute simple coronitis + in canker + in contracted foot + in corn + in laminitis + in navicular disease + in punctured foot + in sand-crack + in simple cutaneous quittor +Properties of horn, chemical +Protection of sand-crack by metal plates +Pruritus after neurectomy +Pumiced foot + causes of + definition of + symptoms of + treatment of +Punctured foot + causes of + classification of + common situation of the wound in + complications in + definition of + diagnosis of + prognosis of + symptoms of + treatment of +Puncture of the navicular bursa + treatment of +Puncture of the pedal articulation +Purulent synovitis +Pyramidal disease + +Quittor + classification of + definition of +Quittor, simple or cutaneous + causes of + complications in + curative treatment of + definition of + pathological anatomy of + preventive treatment of + prognosis of + symptoms of + treatment of + sub-horny + causes of + complications in + definition of + diagnosis of + extirpation of the lateral cartilage in, after Moller and Frick + extirpation of the lateral cartilage in, after Bayer + necrosis of the lateral cartilage in (cartilaginous quittor) + necrosis _of_ tendon and ligament in (tendinous quittor) + surgical shoeing in + symptoms of + treatment of + +Rarefying ostitis +Recorded case of dislocation + of the os coronæ + of navicular disease in both hind-feet + of periostitis + of pyramidal disease +Rest required after neurectomy, length of +Restraint, methods of +Reunion of the divided nerve after neurectomy +Ringbone, low +Ringed hoof + causes of + definition of + treatment of +Rocker bar shoes in laminitis +Rose's treatment of canker + +Sand-crack + causes of + clamp + Koster's + McGill's + Vachette's + clamping, methods of + classification of + complications in + definition of + operations for complicated + prognosis in + surgical shoeing for + symptoms of + treatment of + treatment of, by grooving the wall + treatment of, by wedging the fissure +Second interphalangeal articulation, the +Securing a hind-limb with the side-line, method of +Securing the foot to the cannon of another limb, method of +Seedy-toe + causes of + definition of + symptoms of + treatment of +Senile decay as a cause of navicular disease +Sensitive laminæ, the +Sensitive structures, gangrene of, in laminitis +Septic infection of the limb +Sequelæ of neurectomy +Serous arthritis +Shoe, bar + Charlier's + Charlier's tip + expansion + Broué's + De Fay's + Einsiedel's + Hartmann's + Smith's + for overreach + plate + rocker bar + slipper, Broué's + slipper and bar-clip, Einsiedel's + three-quarter + three-quarter bar + thinned tip + tip + with 'dropped' heel + with extended toe-piece + with extended toe-piece (Nunn's) + with heel-clip + with 'set' heel +Side-bone + causes of + definition of + diagnosis of + heredity a cause of + Smith's operation for + symptoms of + treatment of +Side-line, the +Simple acute coronitis +Simple acute periostitis +Simple coronitis + acute + chronic +Simple or cutaneous quittor + causes of + complications in + curative treatment of + definition of + pathological anatomy of + preventive treatment of + prognosis of + symptoms of + treatment of +Simple serous arthritis +Simple synovitis, acute +Smith's expansion shoe + operation for laminitis + operation for side-bone +Solar edge of the wall, expansion and contraction of the +Sole, chronic bruised +Sole, expansion and contraction of the +Sole, the +Specific coronitis + causes of + definition of + symptoms of + treatment of +Spongy hoof + definition of + symptoms of + treatment of +Stumbling after neurectomy +Sub-horny quittor + causes of + complications in + definition of + diagnosis of + necrosis of the lateral cartilage in (cartilaginous quittor) + necrosis of tendon and ligament in (tendinous quittor) + symptoms of + treatment of + surgical shoeing for +Suppurating corn +Suppuration in laminitis +Suppurative arthritis + causes of + definition of + diagnosis of + pathology of + symptoms of + treatment of +Suppurative periostitis +Suppurative synovitis +Surgical shoeing for corn + for chronic laminitis + for laminitis, acute + for sand-crack + for quittor +Symptoms + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of contracted foot + of corn + of coronary contraction of the foot + of crooked foot + of false quarter + of flat-foot + of keraphyllocele + of laminitis + of laminitis in all four feet + of laminitis in the fore-feet alone + of laminitis in the hind-feet alone + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of pyramidal disease + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of simple cutaneous quittor + of specific coronitis + of spongy hoof + of sub-horny quittor + of synovitis, chronic + of synovitis, purulent or suppurative + of synovitis, simple acute + of thrush + of weak heels +Synovitis, acute simple + causes of + treatment of + +Tearing off of the entire hoof, accidental +Tendon + the extensor pedis + the flexor pedis perforans + the flexor pedis perforatus +Tendons, the +Thrush + causes of + definition of + symptoms of + treatment of +Tight-nailing +Tip-shoes +Tissue, the velvety +Tread, See Overreach +Treatment + of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of canker + Bermbach's + Hoffmann's + Imminger's + Malcolm's + Rose's + of chronic bruised sole + of chronic coronitis + of chronic laminitis + of chronic laminitis by ligaturing the digital arteries + of club-foot + of contracted feet + of contracted feet by expansion shoes + of contracted feet by operations on the horn + of corns + of coronary contraction of the foot + of crooked foot + of curved hoof + of cutaneous quittor + of false quarter + of keraphyllocele + of nail-bound + of navicular disease + of necrotic plantar aponeurosis + of periostitis + of pumiced foot + of punctured foot + of punctured navicular bursa + of pyramidal disease + of ringed hoof + of sand-crack + of sand-crack by clamping the fissure + of sand-crack by grooving the wall + of sand-crack by wedging the fissure + of seedy-toe + of side-bone + of simple chronic coronitis + of specific coronitis + of spongy hoof + of sub-horny quittor + of synovitis + of thrush + of weak heels +Use of the horse that has undergone neurectomy +Vachette's sand-crack clamp +Veins, the +Velvety tissue, the +Villate's caustic solution + +Wall, the +Weak heels + causes of + definition of + symptoms of + treatment of +Wedging the fissure in the treatment of sand-crack +Wound in punctured foot, common situations of the +Wounds of the lateral cartilages +Wounds of the plantar aponeurosis + + + +THE END + + + + + + + + + + + + +End of the Project Gutenberg EBook of Diseases of the Horse's Foot +by Harry Caulton Reeks + +*** END OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + +***** This file should be named 11204-8.txt 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CAULTON REEKS" /> + <meta name="Keywords" content="" /> + <meta name="Description" content="" /> + <meta http-equiv="Content-Type" content="text/html; charset=us-ascii" /> + <style type="text/css"> +<![CDATA[ + <!-- + body {margin:10%; text-align:left} + h1,h2,h3,h4,h5,h6{text-align: center} + ul{list-style-type: none} + --> +]]> + </style> + </head> + <body> + + +<pre> + +Project Gutenberg's Diseases of the Horse's Foot, by Harry Caulton Reeks + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Diseases of the Horse's Foot + +Author: Harry Caulton Reeks + +Release Date: February 21, 2004 [EBook #11204] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + + + + +Produced by Juliet Sutherland, Leonard D Johnson and the Online +Distributed Proofreading Team. + + + + + + +</pre> + + <h1>DISEASES</h1> + <h6>OF</h6> + <h2>THE HORSE'S FOOT</h2> + <h6>By</h6> + <h3>H. CAULTON REEKS</h3> + <h5>Fellow of the Royal College of Veterinary Surgeons Author of 'The Common Colics + of the Horse'</h5> + <h5>1906</h5> + <br /> + <br /> + <h4>To</h4> + <h3>J. MacQueen, F.R.C.V.S.,</h3> + <h5>PROFESSOR OF SURGERY AT THE ROYAL VETERINARY COLLEGE, LONDON,<br /> + AS A SLIGHT ACKNOWLEDGMENT OF HIS ABILITY AS A TEACHER,<br /> + AND IN RETURN FOR MANY KINDLY SERVICES,<br /> + THIS VOLUME IS GRATEFULLY INSCRIBED BY</h5> + <h3>THE AUTHOR.</h3> + <p>PREFACE</p> + <p>Stimulated by the reception accorded my 'Common Colics of the Horse,' both in this + country and in America, and assured by my publishers that a work on diseases of the + foot was needed, I have been led to give to the veterinary profession the present + volume.</p> + <p>While keeping the size of the book within reasonable limits, no effort has been + spared to render it as complete as possible. This has only been achieved by adding to + my own experience a great deal of the work of others. To mention individually those + who have given me permission to use their writings would be too long a matter here. + In every case, however, where the quotation is of any length, the source of my + information is given, either in the text or in an accompanying footnote. A few there + are who will, perhaps, find themselves quoted without my having first obtained their + permission to do so. They, with the others, will, I am sure, accept my hearty + thanks.</p> + <p>The publishers have been generous in the matter of illustrations and diagrams, and + although to the older practitioner some of these may appear superfluous, it is hoped + they will serve to render the work an acceptable textbook for the student.</p> + <p>H. CAULTON REEKS.</p> + <p>SPALDING, <i>January, 1906</i>.</p> + <br /> + <br /> + <h3>CONTENTS</h3> + <h3>CHAPTER I</h3> + <a href="#intro">INTRODUCTION</a> + <h3>CHAPTER II</h3> + <p><a href="#anat">REGIONAL ANATOMY</a></p> + <ul> + <li>A. The Bones</li> + <li>B. The Ligaments</li> + <li>C. The Tendons</li> + <li>D. The Arteries</li> + <li>E. The Veins</li> + <li>F. The Nerves</li> + <li>G. The Complementary Apparatus of the Os Pedis</li> + <li>H. The Keratogenous Membrane</li> + <li>I. The Hoof</li> + </ul> + <h3>CHAPTER III</h3> + <p><a href="#general">GENERAL PHYSIOLOGICAL AND ANATOMICAL OBSERVATIONS</a></p> + <ul> + <li>A. Development of the Hoof</li> + <li>B. Chemical Properties and Histology of Horn</li> + <li>C. Expansion and Contraction of the Hoof</li> + <li>D. The Functions of the Lateral Cartilages</li> + <li>E. Growth of the Hoof</li> + </ul> + <h3>CHAPTER IV</h3> + <p><a href="#exam">METHOD OF EXAMINING THE FOOT</a></p> + <h3>CHAPTER V</h3> + <p><a href="#operations">GENERAL REMARKS ON OPERATIONS ON THE FOOT</a></p> + <ul> + <li>A. Methods of Restraint</li> + <li>B. Instruments required</li> + <li>C. The Application of Dressings</li> + <li> + D. Plantar Neurectomy + <ul> + <li>History of the Operation</li> + <li>Preparation of the Subject</li> + <li>The Operation</li> + <li>After-treatment</li> + </ul> + </li> + <li>E. Median Neurectomy</li> + <li>F. Length of Rest after Neurectomy</li> + <li> + G. Sequelæ of Neurectomy + <ul> + <li>Liability of Pricked Foot going undetected</li> + <li>Loss of Tone in the Non-sensitive Area</li> + <li>Gelatinous Degeneration</li> + <li>Chronic Oedema of the Leg</li> + <li>Persistent Pruritus</li> + <li>Fracture of the Bones</li> + <li>Neuroma</li> + <li>Reunion of the Divided Nerve</li> + <li>The Existence of an Adventitious Nerve-supply</li> + <li>Stumbling</li> + </ul> + </li> + <li>H. Advantages of the Operation</li> + <li>I. The Use of the Horse that has undergone Neurectomy</li> + </ul> + <h3>CHAPTER VI</h3> + <p><a href="#conform">FAULTY CONFORMATION</a></p> + <ul> + <li>A. Weak Heels</li> + <li> + B. Contracted Foot + <ul> + <li>(<i>a</i>) Contracted Heels</li> + <li>(<i>b</i>) Local or Coronary Contraction</li> + </ul> + </li> + <li>C. Flat-foot</li> + <li>D. Pumiced-foot, Dropped Sole, or Convex Sole</li> + <li>E. 'Ringed' or 'Ribbed' Hoof</li> + <li> + F. The Hoof with Bad Horn + <ul> + <li>(<i>a</i>) The Brittle Hoof</li> + <li>(<i>b</i>) The Spongy Hoof</li> + </ul> + </li> + <li>G. Club-Foot</li> + <li> + H. The Crooked Foot + <ul> + <li>(<i>a</i>) The Foot with Unequal Sides</li> + <li>(<i>b</i>) The Curved Hoof</li> + </ul> + </li> + </ul> + <h3>CHAPTER VII</h3> + <p><a href="#diseases">DISEASES ARISING FROM FAULTY CONFORMATION</a></p> + <ul> + <li> + A. Sand-crack + <ul> + <li>Definition</li> + <li>Classification</li> + <li>Causes</li> + <li>Complications</li> + <li>Treatment</li> + <li>Surgical Shoeing for Sand-crack</li> + </ul> + </li> + <li> + B. Corns + <ul> + <li>Definition</li> + <li>Classification</li> + <li>Causes</li> + <li>Pathological Anatomy and Histology</li> + <li>Treatment</li> + <li>Surgical Shoeing for Corn</li> + </ul> + </li> + <li>C. Chronic Bruised Sole</li> + </ul> + <h3>CHAPTER VIII</h3> + <p><a href="#wounds">WOUNDS OF THE KERATOGENOUS MEMBRANE</a></p> + <ul> + <li> + A. Nail-bound + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + <li> + B. Punctured Foot + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Common Situations of the Wound</li> + <li>Classification</li> + <li>Symptoms and Diagnosis</li> + <li>Complications</li> + <li>Prognosis</li> + <li>Treatment</li> + </ul> + </li> + <li> + C. Coronitis (Simple) + <ul> + <li> + 1. Acute + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Complications</li> + <li>Prognosis</li> + <li>Treatment</li> + </ul> + </li> + <li> + 2. Chronic + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + </ul> + </li> + <li> + D. False Quarter + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Treatment</li> + </ul> + </li> + <li>E. Accidental Tearing off of the Entire Hoof</li> + </ul> + <h3>CHAPTER IX</h3> + <p><a href="#inflam">INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS</a></p> + <ul> + <li> + A. ACUTE + <ul> + <li> + Acute Laminitis + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Pathological Anatomy</li> + <li>Complications</li> + <li>Diagnosis and Prognosis</li> + <li>Treatment</li> + <li>Broad's Treatment for Laminitis</li> + <li>Smith's Operation for Laminitis</li> + </ul> + </li> + </ul> + </li> + <li> + B. CHRONIC + <ul> + <li> + 1. Chronic Laminitis + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Pathological Anatomy</li> + <li>Treatment</li> + </ul> + </li> + <li> + 2. Seedy-Toe + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + <li> + 3. Keraphyllocele + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + <li>4. Keratoma</li> + <li> + 5. Thrush + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + <li> + 6. Canker + <ul> + <li>Definition</li> + <li>Causes, Predisposing and Exciting</li> + <li>Symptoms and Pathological Anatomy</li> + <li>Differential Diagnosis and Prognosis</li> + <li>Treatment</li> + <li>Malcolm's, Lieutenant Rose's, Bermbach's, Hoffmann's and Imminger's + Treatment for Canker</li> + </ul> + </li> + <li> + 7. Specific Coronitis + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Treatment</li> + </ul> + </li> + </ul> + </li> + </ul> + <h3>CHAPTER X</h3> + <p><a href="#cartilage">DISEASES OF THE LATERAL CARTILAGES</a></p> + <ul> + <li>A. Wounds Of The Cartilages</li> + <li> + B. Quittor + <ul> + <li>Definition</li> + <li>Classification</li> + <li> + 1. Simple or Cutaneous Quittor + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms</li> + <li>Pathological Anatomy</li> + <li>Prognosis</li> + <li>Complications</li> + <li>Treatment, Preventive and Curative</li> + </ul> + </li> + <li> + 2. Sub-horny Quittor + <ul> + <li>Definition</li> + <li>Causes</li> + <li>Symptoms and Diagnosis</li> + <li>Complications</li> + <li>Necrosis of the Lateral Cartilage</li> + <li>Pathological Anatomy of the Diseased Cartilage</li> + <li>Necrosis of Tendon and of Ligament</li> + <li>Ossification of the Cartilage</li> + <li>Treatment</li> + <li>Operations for Extirpation of the Cartilage</li> + </ul> + </li> + </ul> + </li> + <li> + C. Ossification of the Lateral Cartilages (Side-bones) + <ul> + <li>Definition</li> + <li>Symptoms and Diagnosis</li> + <li>Causes</li> + <li>Treatment</li> + <li>Smith's Operation for Ossification of the Lateral Cartilages</li> + </ul> + </li> + </ul> + <h3>CHAPTER XI</h3> + <p><a href="#bone">DISEASES OF THE BONES</a></p> + <ul> + <li> + A. Periostitis and Ostitis + <ul> + <li> + 1. Periostitis + <ul> + <li>(<i>a</i>) Simple Acute Periostitis</li> + <li>(<i>b</i>) Suppurative Periostitis</li> + <li>(<i>c</i>) Osteoplastic Periostitis</li> + </ul> + </li> + <li> + 2. Ostitis + <ul> + <li>(<i>a</i>) Rarefying Ostitis</li> + <li>(<i>b</i>) Osteoplastic Ostitis</li> + <li>(<i>c</i>) Caries and Necrosis</li> + </ul> + </li> + <li>Treatment of Periostitis</li> + <li>Recorded Cases of Periostitis</li> + </ul> + </li> + <li> + B. Pyramidal Disease, Buttress Foot, or Low Ringbone + <ul> + <li>Definition</li> + <li>Symptoms and Diagnosis</li> + <li>Pathological Anatomy</li> + <li>Treatment</li> + <li>Recorded Cases of Buttress Foot</li> + </ul> + </li> + <li> + C. Fractures of the Bones + <ul> + <li> + 1. Fractures of the Os Coronæ + <ul> + <li>Recorded Cases of Fractures of the Os Coronæ</li> + </ul> + </li> + <li> + 2. Fractures of the Os Pedis + <ul> + <li>Recorded Cases of Fractures of the Os Pedis</li> + </ul> + </li> + <li> + 3. Fractures of the Navicular Bone + <ul> + <li>Recorded Case of Fracture of the Navicular Bone</li> + </ul> + </li> + <li>Treatment of Fractures of the Bones of the Foot</li> + </ul> + </li> + </ul> + <h3>CHAPTER XII</h3> + <p><a href="#joint">DISEASES OF THE JOINTS</a></p> + <ul> + <li> + A. Synovitis + <ul> + <li> + (<i>a</i>) Simple + <ul> + <li>(1) Acute</li> + <li>(2) Chronic</li> + </ul> + </li> + <li>(<i>b</i>) Purulent or Suppurative</li> + </ul> + </li> + <li> + B. Arthritis + <ul> + <li>(<i>a</i>) Simple or Serous</li> + <li>(<i>b</i>) Acute</li> + <li>(<i>c</i>) Purulent or Suppurative</li> + <li>(<i>d</i>) Anchylosis</li> + </ul> + </li> + <li> + C. Navicular Disease + <ul> + <li>Definition</li> + <li>History</li> + <li> + Pathology + <ul> + <li>Changes in the Bursa</li> + <li>Changes in the Cartilage</li> + <li>Changes in the Tendon</li> + <li>Changes in the Bone</li> + </ul> + </li> + <li> + Causes + <ul> + <li>Heredity</li> + <li>Compression</li> + <li>Concussion</li> + <li>A Weak Navicular Bone</li> + <li>An Irregular Blood-supply to the Bone</li> + <li>Senile Decay</li> + </ul> + </li> + <li>Symptoms and Diagnosis</li> + <li>Differential Diagnosis</li> + <li>Prognosis</li> + <li>Treatment</li> + </ul> + </li> + <li>D. Dislocations</li> + </ul> + <br /> + <br /> + <h3>LIST OF ILLUSTRATIONS</h3> + <br /> + <a href="#a1">1. The Bones of the Phalanx</a> <br /> + <a href="#a2">2. The Os Coronæ (Anterior View)</a> <br /> + <a href="#a3">3. The Os Coronæ (Posterior View)</a> <br /> + <a href="#a4">4. The Os Pedis (Postero-lateral View)</a> <br /> + <a href="#a5">5. The Os Pedis (viewed from Below)</a> <br /> + <a href="#a6">6. The Navicular Bone (viewed from Below)</a> <br /> + <a href="#a7">7. The Navicular Bone (viewed from Above)</a> <br /> + <a href="#a8">8. Ligaments of the First and Second Interphalangeal Articulations + (Lateral View). (<i>After Dollar and Wheatley</i>)</a> <br /> + <a href="#a9">9. Ligaments of the First and Second Interphalangeal Articulations + (viewed from Behind). (<i>After Dollar and Wheatley</i>)</a> <br /> + <a href="#a10">10. The Flexor Tendons and the Extensor Pedis. (<i>After + Haübner</i>)</a> <br /> + <a href="#a11">11. The Flexor Perforans and Perforatus</a> <br /> + <a href="#a12">12. The Flexor Perforans and Perforatus (the Perforans cut through + and deflected)</a> <br /> + <a href="#a13">13. Median Section of Normal Foot</a> <br /> + <a href="#a14">14. The Arteries of the Foot</a> <br /> + <a href="#a15">15. The Veins and Nerves of the Foot</a> <br /> + <a href="#a16">16. The Lateral Cartilage</a> <br /> + <a href="#a17">17. The Keratogenous Membrane (viewed from the Side)</a> <br /> + <a href="#a18">18. The Keratogenous Membrane (viewed from Below)</a> <br /> + <a href="#a19">19. The Wall of the Hoof</a> <br /> + <a href="#a20">20. Internal Features of the Hoof</a> <br /> + <a href="#a21">21. Inferior Aspect of the Hoof</a> <br /> + <a href="#a22">22. Hoof with the Sensitive Structures removed</a> <br /> + <a href="#a23">23. Section of Epidermis</a> <br /> + <a href="#a24">24. Section of Skin with Hair Follicle and Hair</a> <br /> + <a href="#a25">25. Section of Human Nail and Nail-bed</a> <br /> + <a href="#a26">26. Section of Foot of Equine Foetus. (<i>Mettam</i>)</a> <br /> + <a href="#a27">27. Section from Foot of Sheep Embryo. (<i>Mettam</i>)</a> <br /> + <a href="#a28">28. Section from Foot of Calf Embryo. (<i>Mettam</i>)</a> <br /> + <a href="#a29">29. Section from Foot of Equine Foetus. (<i>Mettam</i>)</a> <br /> + <a href="#a30">30. Section through Hoof and Soft Tissues of a Foal at Term. + (<i>Mettam</i>)</a> <br /> + <a href="#a31">31. Perpendicular Section of Horn of Wall</a><br /> + <a href="#a32">32. Horizontal Section of Horn of Wall</a> <br /> + <a href="#a33">33. Horizontal Section through the Junction of the Wall with the + Sole</a> <br /> + <a href="#a34">34. Section of Frog. (<i>Mettam</i>)</a> <br /> + <a href="#a35">35. Professor Lungwitz's Apparatus for Examining the Foot + Movements</a> <br /> + <a href="#a36">36. Professor Lungwitz's Apparatus for Examining the Foot + Movements</a> <br /> + <a href="#a37">37. The Movements of the Solar and Coronary Edges of the Hoof + illustrated.</a> (<i>Lungwitz</i>) <br /> + <a href="#a38">38. The Blind</a> <br /> + <a href="#a39">39. The Side-line</a> <br /> + <a href="#a40">40. Method of securing the Hind-foot with the Side-line</a> <br /> + <a href="#a41">41. The Hind-foot secured with the Side-line</a> <br /> + <a href="#a42">42. The Casting Hobbles</a> <br /> + <a href="#a43">43. Method of securing the Hind-leg upon the Fore</a> <br /> + <a href="#a44">44. The Hind-leg secured upon the Fore</a> <br /> + <a href="#a45">45. The Drawing-knife (Ordinary Pattern)</a> <br /> + <a href="#a46">46. Modern Forms of Drawing-knives</a> <br /> + <a href="#a47">47. Symes's Knife</a> <br /> + <a href="#a48">48-51. Illustrating Colonel Nunn's Method of applying a Poultice to + the Foot</a> <br /> + <a href="#a52">52. Poultice-boot of Canvas and Steel</a> <br /> + <a href="#a53">53. Poultice-boot of Cocoa-fibre</a> <br /> + <a href="#a54">54. Foot-swab</a> <br /> + <a href="#a55">55. The Shoe with Plates</a> <br /> + <a href="#a56">56. Quittor Syringe</a> <br /> + <a href="#a57">57. The Esmarch Bandage and Tourniquet</a> <br /> + <a href="#a58">58. Tourniquet with Wooden Block</a> <br /> + <a href="#a59">59. Neurectomy Bistoury</a> <br /> + <a href="#a60">60. Neurectomy Needle</a> <br /> + <a href="#a61">61. Double Neurectomy Tenaculum</a> <br /> + <a href="#a62">62. Adventitious Nerve-supply to Foot. (<i>Sessions</i>)</a> <br /> + <a href="#a63">63. Tip Shoe</a> <br /> + <a href="#a64">64. The Tip Shoe 'let in' to the Foot</a> <br /> + <a href="#a65">65. The Thinned Tip</a> <br /> + <a href="#a66">66. Drawing-knife for Charlier Shoeing</a> <br /> + <a href="#a67">67. The Foot prepared for the Charlier Shoe</a> <br /> + <a href="#a68">68. Bar Shoe</a> <br /> + <a href="#a69">69. Rubber Bar Pad on Leather</a> <br /> + <a href="#a70">70. The Bar Pad applied with a Half-shoe</a> <br /> + <a href="#a71">71. Frog Pad</a> <br /> + <a href="#a72">72. Frog Pad applied</a> <br /> + <a href="#a73">73. Smith's Expansion Shoe for Contracted Feet</a> <br /> + <a href="#a74">74. A Contracted Foot treated with Smith's Shoe</a> <br /> + <a href="#a75">75. De Fay's Vice</a> <br /> + <a href="#a76">76. Hartmann's Expanding Shoe</a> <br /> + <a href="#a77">77. Broué's Slipper Shoe. (<i>Gutenacker</i>)</a> <br /> + <a href="#a78">78. Einsiedel's Slipper and Bar-clip Shoe. (<i>Gutenacker</i>)</a> + <br /> + <a href="#a79">79. Hoof showing Coronary Contraction. (<i>Gutenacker</i>)</a> <br /> + <a href="#a80">80. Flat-foot (Solar Surface). (<i>Gutenacker</i>)</a> <br /> + <a href="#a81">81. Hoof showing Laminitis Rings on the Wall. <i>(Gutenacker)</i></a> + <br /> + <a href="#a82">82. Hoof showing 'Grass' Rings on the Wall. (<i>Gutenacker</i>)</a> + <br /> + <a href="#a83">83. Club-foot. (<i>Gutenacker</i>)</a> <br /> + <a href="#a84">84. Shoe with extended Toe-piece. (<i>Gutenacker</i>)</a> <br /> + <a href="#a85">85. A Crooked Foot in Cross-section. (<i>Gutenacker</i>)</a> <br /> + <a href="#a86">86. Sand-crack Firing-iron</a> <br /> + <a href="#a87">87. Sand-crack Forceps and Clamp. (<i>Vachette's</i>)</a> <br /> + <a href="#a88">88. McGill's Sand-crack Clamp</a> <br /> + <a href="#a89">89. Koster's Sand-crack Clamp</a> <br /> + <a href="#a90">90. Sand-crack Belt</a> <br /> + <a href="#a91">91. Method of 'Easing' the Bearing of the Wall on the Shoe in the + Treatment of Sand-crack</a> <br /> + <a href="#a92">92. Method of 'Easing' the Bearing of the Wall on the Shoe in the + Treatment of Sand-crack</a> <br /> + <a href="#a93">93. Method of 'Easing' the Bearing of the Wall on the Shoe in the + Treatment of Sand-crack</a> <br /> + <a href="#a94">94 96. Grooving the Wall in the Treatment of Sand-crack</a> <br /> + <a href="#a97">97. Removing the Wall in the Treatment of Sand-crack</a> <br /> + <a href="#a98">98. Removing the Wall in the Treatment of Sand-crack</a> <br /> + <a href="#a99">99. Horizontal Section of Corn. (<i>Gutenacker</i>)</a> <br /> + <a href="#a100">100. Inner Surface of the Wall, showing Changes in Chronic Corn. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a101">101. Perpendicular Section of the Wall in a Case of Chronic Corn. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a102">102. Three-quarter Shoe</a> <br /> + <a href="#a103">103. Three-quarter Bar Shoe</a> <br /> + <a href="#a104">104. Shoe with a 'Dropped' Heel</a> <br /> + <a href="#a105">105. Shoe with a 'Set' Heel</a> <br /> + <a href="#a106">106. Curette, or Volkmann's Spoon</a> <br /> + <a href="#a107">107. Resection of the Terminal Portion of the Perforans Tendon + (<i>Gutenacker</i>)</a> <br /> + <a href="#a108">108. Shoe with extended Toe-piece. (<i>Colonel Nunn</i>)</a> <br /> + <a href="#a109">109. Mesian Section of Foot with Lesions following Coronitis. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a110">110. Toe of Ordinary Hind-shoe</a> <br /> + <a href="#a111">111. Toe of Hind-shoe Bevelled for the Prevention of Overreach</a> + <br /> + <a href="#a115">112. Hoof showing Lesion in the Wall following Coronitis. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a113">113. Foot with Lesions of Chronic Coronitis. (<i>Gutenacker</i>)</a> + <br /> + <a href="#a114">114. Hoof Accidentally Tom from Foot. (<i>Cartledge</i>)</a> <br /> + <a href="#a115">115. Hoof Accidentally Tom from Foot. (<i>Rogerson</i>)</a> <br /> + <a href="#a116">116. Section of Foot with Laminitis of Eight Days' Duration. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a117">117. Section of Foot with Laminitis of Fourteen Days' Duration. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a118">118. Chronic Ostitis of the Os Pedis in Laminitis.</a> <br /> + <a href="#a119">119. Broad's Rocker Bar Shoe for Laminitis.</a> <br /> + <a href="#a120">120. The Foot showing Grooves made in the Wall for Treatment of + Laminitis (Anterior Surface).</a> <br /> + <a href="#a121">121. The Foot showing Grooves made for the Treatment of Laminitis + (Solar Surface).</a> <br /> + <a href="#a122">122. Foot with Chronic Laminitis. (<i>Gutenacker</i>)</a> <br /> + <a href="#a123">123. Inferior Aspect of Foot with Chronic Laminitis. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a124">124. Section of Foot with Laminitis of Three Weeks' Duration. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a125">125. Section of Foot with Laminitis of Several Years' Duration. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a126">126. Diagram showing Position of the Abnormal Growth of Horn in + Chronic Laminitis.</a> <br /> + <a href="#a127">127. Diagram showing the same Abnormal Growth of Horn Removed prior + to Shoeing.</a> <br /> + <a href="#a128">128. Shoe with Heel-clip.</a> <br /> + <a href="#a129">129. Internal Seedy-Toe.</a> <br /> + <a href="#a130">130. External Seedy-Toe. (<i>Colonel Nunn</i>)</a> <br /> + <a href="#a131">131. External Seedy-Toe. (<i>Colonel Nunn</i>)</a> <br /> + <a href="#a132">132. A Keraphyllocele on the Inner Surface of the Horn of the Wall + at the Toe. (<i>Gutenacker</i>)</a> <br /> + <a href="#a133">133. Os Pedis showing Absorption of Bone caused by the Pressure of a + Keraphyllocele. (<i>Gutenacker</i>)</a> <br /> + <a href="#a134">134. Foot with Canker of the Frog and Heels. (<i>Gutenacker</i>)</a> + <br /> + <a href="#a135">135. Foot with Canker extending to the Wall. (<i>Malcolm</i>)</a> + <br /> + <a href="#a136">136. Foot with Advanced Canker. (<i>Gutenacker</i>)</a> <br /> + <a href="#a137">137. Feet affected with Specific Coronitis. (<i>Taylor</i>)</a> + <br /> + <a href="#a138">138. Fore-foot with Specific Coronitis. (<i>Taylor</i>)</a> <br /> + <a href="#a139">139. Excision of the Lateral Cartilage (Old Method). + (<i>Gutenacker</i>)</a> <br /> + <a href="#a140">140. Excision of the Lateral Cartilage. (<i>After Moller and + Frick</i>). (<i>Gutenacker</i>)</a> <br /> + <a href="#a141">141. Excision of the Lateral Cartilage. (<i>After Bayer</i>.) + (<i>Gutenacker</i>)</a> <br /> + <a href="#a142">142. Partial Excision of the Lateral Cartilage</a> <br /> + <a href="#a143">143. Ossified Lateral Cartilages, or Side-bones.</a> <br /> + <a href="#a144">144. Smith's Side-bone Saw (Old Pattern).</a> <br /> + <a href="#a145">145. Smith's Side-bone Saw (Improved Pattern).</a> <br /> + <a href="#a146">146. Smith's Hoof Plane.</a> <br /> + <a href="#a147">147. Hodder's Hoof Chisel.</a> <br /> + <a href="#a148">148. Foot showing the Grooves made in Smith's Operation for + Side-bones (viewed from the Side).</a> <br /> + <a href="#a149">149. Foot showing the Grooves made in Smith's Operation for + Side-bones (viewed from Below).</a> <br /> + <a href="#a150">150. Periostitis involving the Pedal and Navicular Bones. + (<i>Litt</i>)</a> <br /> + <a href="#a151">151. Periostitis involving the Pedal and Navicular Bones. + (<i>Litt</i>)</a> <br /> + <a href="#a152">152. Effects of Periostitis on the Os Pedis. (<i>Smith</i>)</a> + <br /> + <a href="#a153">153. Effects of Periostitis on the Os Pedis. (<i>Smith</i>)</a> + <br /> + <a href="#a154">154. Effects of Periostitis on the Os Pedis. (<i>Jones</i>)</a> + <br /> + <a href="#a155">155. Effects of Periostitis on the Os Pedis. (<i>Jones</i>)</a> + <br /> + <a href="#a156">156. Case of Buttress Foot. (<i>Routledge</i>)</a> <br /> + <a href="#a157">157. Foot showing Fracture of the Pyramidal Process in a Case of + Buttress Foot. (<i>Routledge</i>)</a> <br /> + <a href="#a158">158. Fracture of the Os Coronæ. (<i>Crawford</i>)</a> <br /> + <a href="#a159">159. Fracture of the Os Coronæ. (<i>Crawford</i>)</a> <br /> + <a href="#a160">160. Fractured Os Pedis. (<i>Freeman</i>)</a> <br /> + <a href="#a161">161. Navicular Bone showing Lesions of Navicular Disease. + (<i>Gutenacker</i>)</a> <br /> + <a href="#a162">162. Foot with the Seat of Navicular Disease exposed (showing + Lesions). (<i>Gutenacker</i>)</a> <br /> + <a href="#a163">163. Navicular Bone showing Lesions of Navicular Disease (a Case of + Long-standing). (<i>Gutenacker</i>)</a> <br /> + <a href="#a164">164. Frog Seton Needle.</a> <br /> + <a href="#a165">165. Diagram showing Course of the Needle in Setoning the Frog.</a> + <br /> + <br /> + <br /> + <br /> + <h1>DISEASES OF THE HORSE'S FOOT</h1> + <h3>CHAPTER I</h3> + <h3><a name="intro" id="intro">INTRODUCTION</a></h3> + <p>The importance of that branch of veterinary surgery dealing with diseases of the + horse's foot can hardly be overestimated. That the animal's usefulness is dependent + upon his possession of four good feet is a fact that has long been recognised. Who, + indeed, is there to be found entirely unacquainted with one or other of such + well-known aphorisms as: 'Whoever hath charge of a horse's foot has the care of his + whole body'; 'As well a horse with no head as a horse with no foot'; or the perhaps + better known, and certainly more epigrammatic, 'No foot, no horse.'</p> + <p>Without taking these sayings literally, it will be admitted by almost everyone + that they contain a vast amount of actual truth. This allowed, it at once becomes + clear that a ready understanding of the diseases to which the foot is liable, the + means of holding them in check, and the correct methods of treating them should + figure largely in the knowledge at the command of the veterinary surgeon.</p> + <p>In the very great majority of instances the horse's ability to perform labour is + the one thing that justifies his existence, and to that end the presence of four + good, sound feet is an almost indispensable qualification. And yet how many + circumstances do we see tending to militate against that one essential.</p> + <p>Even in colthood the foot, if neglected, may become a source of trouble. Unless + periodically examined and properly trimmed, its shape is liable to serious + alteration. From that in which it is best calculated to withstand the effects of the + wear it will be called upon to endure in after life, it may become so changed for the + worse as to seriously affect the animal's value.</p> + <p>In the matter of feeding, too, trouble is likely to ensue. Particularly is this + the case where the colt shows points of exceptional merit. He is 'got up' for show, + and the feet are likely to fall victims to the mismanagement that frequent exhibition + so often carries with it. An extra allowance of peas, beans, wheat, or other equally + injurious food is given. The result is a severe attack of laminitis, and an otherwise + valuable and promising colt is permanently ruined.</p> + <p>Exposed as it is, too, to injury, the foot of a young horse, even at grass, is + frequently the seat of injuries from picked up nails, stakes, or other agents which, + unless detected and carefully treated, may terminate in a troublesome case of quittor + and incurable lameness.</p> + <p>With the passing of colthood, and the coming into effect of the evils of further + domestication, the troubles to which the foot is open become more numerous. Foremost + among them will come those having their starting-point in errors of practice + originating in the forge; for, in spite of attempts at their education, smiths, as a + class, are as yet grievously unversed in even the elementary knowledge of the + delicate construction of the member that is entrusted to their care.</p> + <p>This fact has been dilated on in books devoted to shoeing, and in the prefatory + note to the last edition of Fleming's manual on this subject we find the following + statement: 'The records of all humane societies show that, of prosecutions for + cruelty to animals, an overwhelming majority refer to the horse; and of these, a + large proportion are for working horses while suffering from lameness in one form or + other.</p> + <p>'So frequent are such cases that observers have concluded that their prevalence + must result from some specific cause, and, not unnaturally, attention has thus been + directed to the various modes of management practised in relation to the horse's + foot, to the manner of shoeing, and, in particular, to the way in which the foot is + prepared for the shoe.'</p> + <p>It must be remembered, however, that although harm in the forge may frequently + arise from culpable roughness or carelessness, such is not necessarily always the + case, and that quite as much injury may result from careful and conscientious + workmanship when it is unfortunate enough to be based upon principles wrong in + themselves to commence with.</p> + <p>It so happens, too, that shoeing, in itself a necessary evil, may be responsible + for injuries in the causation of which the smith can have played no part. Take, for + example, the ill effects following upon the animal's attendant allowing him to carry + his shoes for too long a time. In this case the natural growth of the horn carries + the heel of the shoe further beneath the foot than is safe for a correct bearing; in + fact, anterior to the point of inflection of the wall. The shoe, at the same time, is + greatly thinned from excessive wear. Result, a sharp and easily-bended piece of iron + situate immediately under the seat of corn. Pressure or actual cutting of the sole is + bound to occur, and the animal is lamed.</p> + <p>Again, apart from the question of negligence or otherwise on the part of the smith + or the animal's attendant, it must be remembered that the nailing on to the foot of a + plate of iron is not giving to the animal an easier means of progression. The reverse + is the case. In place of the sucker-like face of the natural horn is substituted a + smooth, and, with wear, highly-polished surface. Slipping and sliding attempts to + gain a foothold become frequent, and strains of the tendons and ligaments follow in + their wake.</p> + <p>As, however, this treatise is not intended to deal with the art of shoeing, the + reader must be referred to other works for further information. In addition to + Fleming's, there may be mentioned, among others, Hunting's 'Art of Horse Shoeing,' + and the very excellent volume of Messrs. Dollar and Wheatley on the same subject. + Leaving the forge, we may next look to the nature of the animal's work, and the + conditions under which he is kept, for active causes in the production of disorders + of the foot. From the yielding softness of the pasture he is called to spend the bulk + of his time upon the hard macadamized tracks of our country roads, or the still more + hard and more dangerous asphalt pavings or granite sets of our towns. The former, + with the bruises they will give the sole and frog from loose and scattered stones, + and the latter, with the increased concussion they will entail on the limb, are + active factors in the troubles with which we are about to deal. Upon these unyielding + surfaces the horse is called to carry slowly or rapidly, as the case may be, not only + his own weight, but, in addition, is asked to labour at the hauling of heavy loads. + The effects of concussion and heavy traction combined are bound primarily to find the + feet, and such diseases as side-bones, ringbones, corns, and sand-cracks commence to + make their appearance.</p> + <p>Again, as opposed to the comparative healthiness of the surroundings when at + grass, consideration must be given to the chemical changes the foot is frequently + subjected to when the animal is housed.</p> + <p>Only too often the bedding the animal has to stand upon for several hours of the + twenty-four can only be fitly described as 'filthy in the extreme.' The ammoniacal + exhalations from these collected body-discharges must, and do, have a prejudicial + effect upon the nature of the horn, and, though slow in its progress, mischief is + bound sooner or later to occur in the shape of a weakened and discharging frog, with + its concomitant of contracted heels. Lucky it is in such a case if canker does not + follow on.</p> + <p>Observers, too, have chronicled the occurrence in horse's feet of disease + resulting from the use of moss litter. Tenderness in the foot is first noticeable, + which tenderness is afterwards followed by a peculiar softening of the horn of the + sole and the frog. What should be a dense, fairly resilient substance is transformed + into a material affording a yielding sensation to the fingers not unlike that + imparted by a soft indiarubber, and as easily sliced as cheese-rind.</p> + <p>Lastly, though the foot is extremely liable to suffer from the effects of extreme + dryness or excessive humidity, especially with regard to the changes thus brought + about in the nature of the horn, it is perforce exposed at all times to the varying + condition of the roads upon which it must travel. The intense dryness of summer and + the constant damp of winter, each in their turn take part in the deteriorating + influences at work upon it.</p> + <p>Though this subject might be indefinitely prolonged, this brief + résumé of the adverse circumstances to which the foot of the horse is + exposed is sufficient to point out the extreme importance of its study to the + veterinary surgeon. So long as the horse is used as a beast of burden so long will + this branch of veterinary surgery offer a wide and remunerative field of labour.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER II</h3> + <h3><a name="anat" id="anat">REGIONAL ANATOMY</a></h3> + <p>Considered from a zoological standpoint, the foot of the horse will include all + those parts from the knee and hock downwards. For the purposes of this treatise, + however, the word foot will be used in its more popular sense, and will refer solely + to those portions of the digit contained within the hoof. When, in this chapter on + regional anatomy, or elsewhere, the descriptive matter or the illustrations exceed + that limit, it will be with the object of observing the relationship between the + parts we are concerned with and adjoining structures.</p> + <p>Taking the limit we have set, and enumerating the parts within the hoof from + within outwards, we find them as follows:</p> + <p>A. THE BONES.—The lower portion of the second phalanx or os coronæ; + the third phalanx, os pedis, or coffin bone; and the navicular or shuttle bone.</p> + <p>B. THE LIGAMENTS.—The ligaments binding the articulation.</p> + <p>C. THE TENDONS.—The terminal portions of the extensor pedis and the flexor + perforans.</p> + <p>D. THE ARTERIES.</p> + <p>E. THE VEINS.</p> + <p>F. THE NERVES.</p> + <p>G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS.</p> + <p>H. THE KERATOGENOUS MEMBRANE.</p> + <p>I. THE HOOF.</p> + <h3>A. THE BONES.</h3> + <p>THE SECOND PHALANX, OS CORONÆ, OR SMALL PASTERN BONE.—;This belongs to + the class of small bones, in that it possesses no medullary canal. It is situated + obliquely in the digit, running from above downwards and from behind to before, and + articulating superiorly with the first phalanx or os suffraginis, and inferiorly with + the third phalanx and the navicular bone.<br /> + <a name="a1" id="a1"></a></p> + <p><a href="images/image001.jpg"><img src="images/image001sm.jpg" + alt="THE BONES OF THE PHALANX" /></a></p> + <br /> + + <p>FIG. 1.—THE BONES OF THE PHALANX. 1, The os suffraginis; 2, the os + coronæ; 3, the os pedis; 4, the navicular bone, hidden by the wing of the os + pedis, is in articulation in the position indicated by the barbed line.<br /> + <a name="a2" id="a2"></a></p> + <p><a href="images/image002.png"><img src="images/image002sm.png" + alt="SECOND PHALANX OR OS CORONÆ" /></a></p> + <p>FIG. 2.—SECOND PHALANX OR OS CORONÆ (ANTERIOR VIEW). 1, Anterior + surface; 2, superior articulatory surface; 3, inferior articulatory surface; 4, pits + for ligamentous attachment.<br /> + <a name="a3" id="a3"></a></p> + <p><a href="images/image003.png"><img src="images/image003sm.png" + alt="SECOND PHALANX OR OS CORONÆ" /></a></p> + <p>FIG. 3.—SECOND PHALANX OR OS CORONÆ (POSTERIOR VIEW). 1, Posterior + surface; 2, gliding surface for passage of flexor perforans; 3, lower articulatory + surface.</p> + <p>Cubical in shape, it is flattened from before to behind, and may be described as + possessing six surfaces: <i>An anterior surface</i>, covered with slight imprints; + <i>a posterior surface</i>, provided above with a transversely elongated gliding + surface for the passage of the flexor perforans; <i>two lateral surfaces</i>, each + rough and perforated by foraminæ, and each bearing on its lower portion a + thumb-like imprint for ligamentous attachment, and for the insertion of the bifid + extremity of the perforatus tendon; <i>a superior surface</i>, bearing two shallow + articular cavities, separated by an antero-posterior ridge, for the accommodation of + the lower articulating surface of the first phalanx; <i>an inferior surface</i>, also + articulatory, which in shape is obverse to the superior, bearing two unequal + condyles, separated by an ill-defined antero-posterior groove, which surface + articulates with the os pedis and the navicular bone.</p> + <p><i>Development</i>.—The bone usually ossifies from one centre, but often + there is a complementary nucleus for the upper surface.</p> + <p>THE THIRD PHALANX, OS PEDIS, OR COFFIN BONE.—This also belongs to the class + of short bones. It forms the termination of the digit, and, with the navicular bone, + is included entirely within the hoof. For our examination it offers <i>three + surfaces</i>, <i>two lateral angles</i>, and <i>three edges</i>.</p> + <p><i>The Anterior or Laminal Surface</i>, following closely in contour the wall of + the hoof, is markedly convex from side to side, nearly straight from above to below, + and closely dotted with foraminæ of varying sizes. On each side of this surface + is to be seen a distinct groove, the <i>preplantar groove</i>, or <i>preplantar + fissure</i>, which, commencing behind, between the basilar and retrossal processes, + runs horizontally forwards from the angles or wings of the bone, and terminates + anteriorly in one of the larger foraminæ. As the name 'laminal' indicates, it + is this surface which in the fresh state is covered by the sensitive + laminæ.</p> + <p><i>The Inferior or Plantar Surface</i>, hollowed in the form of a low arch, + presents for our inspection two regions, an anterior and a posterior, divided by a + well-marked line, the <i>Semilunar Crest</i>, which extends forward in the shape of a + semicircle. The anterior region, as is the laminal surface, is covered with + foraminæ; in this case more minute. In the recent state it is covered by the + sensitive sole. The posterior region, lying immediately behind the semilunar crest, + shows on each side of a median process a large foramen, the <i>Plantar Foramen</i>. + From this foramen runs the <i>Plantar Groove</i>, a channel, bounded above by the + superior edge, and below by the semilunar crest of the bone, which conducts the + plantar arteries into the <i>Semilunar Sinus</i>, a well-marked cavity in the + interior of the bone.</p> + <p><i>The Superior or Articular Surface</i> consists of two shallow depressions, + divided by a slight median ridge. Its posterior part shows a transversely elongated + facet for articulation with the navicular bone.</p> + <p><i>The Superior Edge</i>, outlining the superior margin of the laminal surface, + describes a curve, with the convexity of the curve forward. In the centre of the + curve is a triangular process, the <i>Pyramidal Process</i>, which serves as the + point of attachment of the extensor pedis.</p> + <p><i>The Inferior Edge</i>, the most extensive of the three, separates the laminal + from the solar surface. It is semicircular in shape, sharp, and finely dentated, and + is perforated by eight to ten large foraminæ.</p> + <p><i>The Posterior Edge</i>, very slightly concave, divides the small, transversely + elongated facet of the superior surface from the posterior region of the inferior + surface.</p> + <p><i>The Lateral Angles</i> of the bone, also termed the <i>Wings</i>, are two + projections directed backwards. Each is divided by a cleft into an upper, the + <i>Basilar Process</i>, and a lower, the <i>Retrossal Process</i>. In old animals the + posterior portion of the cleft separating the two processes gradually becomes filled + in with bony deposit, thus transforming the cleft into a foramen, which gives passage + to the preplantar artery. We may mention in passing that the lateral angles give + attachment to the lateral fibro-cartilages, and that the lateral angles themselves in + old horses become increased in size owing to ossification of portions of the adjacent + lateral cartilages.</p> + <p><i>Development</i>.—The os pedis ossifies from two centres, one of which is + for the articular surface; but this epiphysis fuses with the rest of the bone before + birth.<br /> + <a name="a4" id="a4"></a></p> + <p><a href="images/image004.jpg"><img src="images/image004sm.jpg" + alt="THIRD PHALANX OR OS PEDIS" /></a></p> + <p>FIG. 4.—THIRD PHALANX OR OS PEDIS (POSTERO-LATERAL VIEW). 1, Anterior or + laminal surface; 2, preplantar foramen; 3, preplantar groove; 4, basilar process of + the wing; 5, retrossal process of the wing; 6, foramen caused by the ossifying + together posteriorly of the basilar and retrossal processes.<br /> + <a name="a5" id="a5"></a></p> + <p><a href="images/image005.jpg"><img src="images/image005sm.jpg" + alt="THIRD PHALANX OR OS PEDIS" /></a></p> + <p>FIG. 5.—THIRD PHALANX OR OS PEDIS (VIEWED FROM BELOW). 1, Plantar surface; + 2, plantar foramen and plantar groove; 3, semilunar crest; 4, tendinous surface; 5, + retrossal processes of the wings.</p> + <p>THE NAVICULAR BONE, SHUTTLE BONE, OR SMALL SESAMOID.—Placed behind the + articulating point of the second and third phalanges, this small shuttle-shaped bone + assists in the formation of the pedal articulation. It is elongated transversely, + flattened from above to below, and narrow at its extremities. In it we see two + surfaces, and two borders.</p> + <p><i>The Superior or Articular Surface</i> of the bone, which may easily be + recognised by its smoothness, is moulded upon the lower articular surface of the + second phalanx, being convex in its middle, and concave on either side.</p> + <p><i>The Inferior or Tendinous Surface</i> resembles the preceding in form, but is + broader and less smooth. In the recent state it is covered with fibro-cartilage for + the passage of the flexor perforans. <i>The Anterior Border</i> possesses above a + small transversely elongated facet for articulation with the os pedis, and below a + more extensive grooved portion, perforated by numerous foraminæ, affording + attachment to the interosseous ligaments of the articulation. <i>The Posterior + Border</i>, thick in the middle, but thinner towards the extremities, is roughened + for ligamentous attachment. <i>Development</i>.—The bone ossifies from a single + centre.</p> + <h3>B. THE LIGAMENTS.</h3> + <p>THE ARTICULATION OF THE FIRST WITH THE SECOND PHALANX, OR THE PASTERN + JOINT.—Adhering to the limit we have set, this articulation should not receive + our attention. As, however, we shall in a later page be concerned with fractures of + the os coronæ, which fractures may affect the articulation above mentioned, a + brief note of its formation will not be out of place.</p> + <p>It is an imperfect hinge-joint, permitting of extension and flexion, allowing the + first phalanx to pivot on the second, and admitting of the performance of slight + lateral movements. It is formed by the opposing of the inferior surface of the os + suffraginis with the superior surface of the os coronæ. The articulating + surface of the os coronæ is supplemented by the addition behind of a thick + piece of <i>fibro-cartilage (the glenoid</i>) attached inferiorly to the posterior + edge of the upper articulatory surface of the os coronæ, and superiorly by + means of three fibrous slips on each side to the os suffraginis. The innermost of + these three slips becomes attached to about the middle of the lateral edge of the + suffraginis, and the remaining two, beneath the first, attach themselves to nearer + the lower end of that bone. The posterior surface of the complementary cartilage + forms a gliding surface for the passage of the perforans.<br /> + <a name="a6" id="a6"></a></p> + <p><a href="images/image006.jpg"><img src="images/image006sm.jpg" + alt="THE NAVICULAR BONE" /></a></p> + <p>FIG. 6.—THE NAVICULAR BONE (VIEWED FROM BELOW).<br /> + 1, Inferior surface (smooth for the passage of the flexor perforans); 2, anterior + edge of inferior surface; 3, posterior edge of inferior surface.<br /> + <a name="a7" id="a7"></a></p> + <p><a href="images/image007.jpg"><img src="images/image007sm.jpg" + alt="THE NAVICULAR BONE" /></a></p> + <p>FIG. 7.—THE NAVICULAR BONE (VIEWED FROM ABOVE, THE BONE TILTED POSTERIORLY + TO SHOW ITS ANTERIOR BORDER).<br /> + 1, Superior articulatory surface; 2, anterior border (grooved portion of); 3, + anterior border (articulatory portion of).<br /> + <a name="a8" id="a8"></a></p> + <p><a href="images/image008.png"><img src="images/image008sm.png" + alt="LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL ARTICULATIONS" /></a></p> + <p>FIG. 8.—LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL ARTICULATIONS + (VIEWED FROM THE SIDE). (AFTER DOLLAR AND WHEATLEY.)<br /> + 1, Outermost slip from the glenoidal fibro-cartilage; 2, lateral ligament of the + first interphalangeal articulation; 3, prolongations of the lateral ligament of the + first interphalangeal articulation attached to the end of the navicular bone to form + the postero-lateral ligament of the pedal joint; 4, end of the navicular bone; 5, + antero-lateral ligament of the pedal joint.</p> + <p><i>The Lateral Ligaments</i>.—These are large and thick, an outer and an + inner, running obliquely from above downwards and backwards. Each is inserted + superiorly into the lateral tubercle of the lower end of the first phalanx, and + inferiorly to the side of the second phalanx, their most inferior fibres becoming + finally fixed to the extremities of the navicular bone, where they form the + postero-lateral ligaments of the pedal articulation. In front of the joint the + extensor pedis plays the part of an additional ligament.</p> + <p><i>The Synovial Membrane</i>.—This is limited in front by the tendon of the + extensor pedis, on each side by the lateral ligaments of the joint, and behind by the + glenoid fibro-cartilage. At this point it is prolonged upwards as a pouch behind the + lower extremity of the first phalanx.</p> + <p>THE ARTICULATION OF THE SECOND PHALANX WITH THE THIRD, THE PEDAL, OR THE COFFIN + JOINT.—This also is an imperfect hinge-joint, permitting only of flexion and + extension, which movements are more restricted than in the previous articulation. + Three bones enter into its formation: the second phalanx, the third phalanx, and the + navicular bone. The lower articulatory surface is formed by the third phalanx and the + navicular bone combined. To effect this the navicular is closely and firmly attached + to the third phalanx by an interosseous ligament. The two bones, as one, are then + connected to the second phalanx by four lateral ligaments, an anterior and a + posterior on each side.</p> + <p><i>The Interosseous Ligament</i> consists of extremely short fibres running from + the extensively grooved portion of the anterior surface of the navicular bone to + become attached to the os pedis immediately behind its articular surface.</p> + <p><i>The Antero-lateral Ligaments</i> are attached by their superior extremities to + the lateral surfaces of the second phalanx, and by their inferior extremities into + the depressions on either side of the pyramidal process of the os pedis.</p> + <p><i>The Postero-lateral Ligaments</i>.—As mentioned when describing the first + interphalangeal articulation, these are in reality continuations of the lateral + ligaments of that joint. Running obliquely downwards and backwards from their point + of attachment to the first phalanx they curve round the lower part of the side of the + second phalanx and end on the extremities and posterior surface of the navicular + bone. Having reached that position, they send short attachments to the retrossal + process of the os pedis and to the inner face of the lateral cartilage.<br /> + <a name="a9" id="a9"></a></p> + <p><a href="images/image009.png"><img src="images/image009sm.png" + alt="LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL ARTICULATIONS" /></a></p> + <br /> + + <p>FIG. 9.—LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL ARTICULATIONS + (VIEWED FROM BEHIND). (AFTER DOLLAR AND WHEATLEY.) 1, Suspensory ligament; 2, + innermost slip from complementary cartilage of pastern joint; 3, middle slip from + complementary cartilage of pastern joint; 4, outermost slip from complementary + cartilage of pastern joint; 5, glenoid or complementary cartilage of pastern joint; + 6, postero-lateral ligaments of the pedal joint; 7, the navicular bone; 8, + interosseous ligaments of the pedal joint; 9, semilunar crest of os pedis; 10, + plantar surface of os pedis.</p> + <p><i>Synovial Membrane</i>.—This extends below the facets uniting the + navicular to the pedal bone, and offers for consideration two sacs. A large one + posteriorly running up behind the second phalanx to nearly adjoin the sesamoidean + bursæ, and a small one, a prolongation of the synovial membrane between the + antero-lateral and postero-lateral ligaments of the same side. This latter is often + distended, and on account of its close proximity to the seat of operation, is liable + to be accidentally opened in excision of the lateral cartilage for quittor.</p> + <h3>C. THE TENDONS</h3> + <p>In order to convey an intelligent understanding of the tendons it will be wise to + briefly describe the course of their parent muscles from their commencement.</p> + <p>THE EXTENSOR PEDIS.—The extensor pedis arises from the lower extremity of + the humerus in two distinct portions of unequal size, a muscular and a tendinous. + These are succeeded by two tendons passing in common through a vertical groove at the + lower end of the radius. Lower in the limb these tendons separate, the outer and + smaller joining the tendon of the extensor suffraginis, and the inner and main tendon + continuing its course downwards. With the exception of the navicular, it is attached + to all the bones of the foot, and is covered internally by the capsular ligaments of + the joints over which it passes, those with which we are concerned being the pastern + joint and the pedal joint. Before its attachment to the os pedis it receives on each + side of the middle of the first phalanx reinforcement in the shape of a strong band + descending obliquely over the fetlock from the suspensory ligament. Widening out in + fanlike fashion, it is inserted into the pyramidal process of the os pedis.</p> + <p><i>Action</i>.—The action of this muscle is to extend the third phalanx on + the second, the second on the first, and the first on the metacarpus. It also assists + in the extension of the foot on the forearm.<br /> + <a name="a10" id="a10"></a></p> + <p><a href="images/image010.png"><img src="images/image010sm.png" + alt="THE FLEXOR TENDONS AND EXTENSOR PEDIS" /></a></p> + <br /> + + <p>FIG. 10.—THE FLEXOR TENDONS AND EXTENSOR PEDIS. (AFTER HAÜBNER.) 1, + Tendon of flexor perforans; 2, its supporting check-band from the posterior ligament + of the carpus; 3, tendon of the flexor perforatus; 4, ring and sheath of the flexor + perforatus; 5, widening out of the flexor perforatus to form the plantar aponeurosis; + 6, suspensory ligament; 7, reinforcing band from the suspensory ligament to the + extensor pedis; 8, the extensor pedis.</p> + <p>THE FLEXOR PEDIS PERFORATUS, OR THE SUPERFICIAL FLEXOR OF THE PHALANGES.—In + common with the perforans, this muscle arises from the inner condyloid ridge of the + humerus. It is reinforced at the lower end of the radius by the superior carpal + ligament, passes through the carpal and metacarpo-phalangeal sheaths, and, arriving + behind the fetlock, forms a ring for the passage of the flexor perforans. Its + termination is bifid, and it is inserted on either side to the lateral surface of the + second phalanx.<br /> + <a name="a11" id="a11"></a></p> + <p><a href="images/image011.jpg"><img src="images/image011sm.jpg" + alt="THE FLEXOR PERFORANS AND FLEXOR PERFORATUS TENDONS" /></a></p> + <br /> + + <p>FIG. 11.—THE FLEXOR PERFORANS AND FLEXOR PERFORATUS TENDONS. The + metacarpo-phalangeal sheath and the ring of the perforatus laid open posteriorly, and + the cut edges reflected to show the passage of the perforans. 1, Reflected cut edges + of the perforatus ring and the metacarpo-phalangeal sheath; 2, the perforans tendon; + 3, point of insertion of the perforans tendon into the semilunar crest of the os + pedis (this widened and thickened extremity of the perforans is known as the plantar + aponeurosis).<br /> + <a name="a12" id="a12"></a></p> + <p><a href="images/image012.jpg"><img src="images/image012sm.jpg" + alt="THE FLEXOR PERFORATUS AND FLEXOR PERFORANS TENDONS" /></a></p> + <br /> + + <p>FIG. 12.—THE FLEXOR PERFORATUS AND FLEXOR PERFORANS TENDONS. The + metacarpo-phalangeal sheath and the ring of the perforatus laid open posteriorly, and + the cut edges reflected; the flexor perforans cut through at about the region of the + sesamoids, and its inferior portion deflected. 1, Superior end of severed perforans + tendon; 2, inferior end of severed perforans tendon; 3, insertion of flexor perforans + into semilunar crest of os pedis; 4, the cut and reflected edges of the + metacarpo-phalangeal sheath and perforatus ring; 5, the bifid insertion of the flexor + perforatus into the lateral surfaces of the os corona; 6, the capsular ligament of + the pedal joint; 7, the navicular bone; 8, the posterior surface and glenoid + fibro-cartilage of the os coronæ.</p> + <p><i>Action</i>.—This muscle flexes the second phalanx on the first, the first + on the metacarpus, and the entire foot on the forearm. Mechanically, it acts as a + stay when the animal is standing by maintaining the metacarpo-phalangeal angle.<br /> + <a name="a13" id="a13"></a></p> + <p><a href="images/image013.png"><img src="images/image013sm.png" + alt="MEDIAN SECTION OF FOOT" /></a></p> + <br /> + + <p>FIG. 13.—MEDIAN SECTION OF FOOT. <i>A</i>, Os suffraginis; <i>B</i>, os + coronæ; <i>C</i>, os pedis; <i>D</i>, navicular bone; <i>E</i>, tendon of the + extensor pedis; <i>F</i>, insertion of the extensor pedis into the pyramidal process + of the os pedis; <i>G</i>, the tendon of the flexor perforatus; <i>H</i>, insertion + of perforatus into the os coronæ; <i>I</i>, tendon of the flexor perforans; + <i>J</i>, its passing attachment to the os coronæ; <i>K</i>, its final + insertion into the semilunar crest of os pedis; <i>a</i>, section of coronary + cushion; <i>b</i>, section of plantar cushion; <i>c</i>, semilunar sinus of os + pedis.</p> + <p>THE FLEXOR PEDIS PERFORANS, OR THE DEEP FLEXOR OF THE PHALANGES.—This muscle + consists of three easily-divided portions: an ulnar, a humeral, and a radial, and has + for points of origin the olecranon process of the ulna, the inner condyloid ridge of + the humerus, and the posterior surface of the radius. These portions are continued by + a common tendon which enters the carpal sheath with the tendon of the perforatus, and + continues with it through the synovial sheath of the metacarpo-phalangeal region. + Like the last-named tendon, it receives a supporting check-band, in this case from + the posterior ligament of the carpus. Passing down between the suspensory ligament in + front, and the perforatus tendon behind, it glides over the sesamoid pulley and + passes through the ring formed by the perforatus. Continuing its course, it passes + between the bifurcating portions of the extremity of the perforatus, glides over the + smooth posterior surface of the supplementary glenoid cartilage of the articulation + of the first and second phalanges, plays over the inferior surface of the navicular + bone, and finally becomes inserted into the semilunar crest of the os pedis. On + reaching the posterior border of the navicular bone it widens out to form the plantar + aponeurosis.</p> + <p>In connection with the lower portion of this tendon must be noticed the Navicular + Sheath. This is a synovial sheath lining the deep face of the tendon, and reflected + on to the navicular bone and the interosseous ligament of the pedal joint. This will + be of particular interest when we come to deal with cases of pricked foot from picked + up nails. Above, it is in connection with the synovial membrane of the pedal + articulation and that of the metacarpo-phalangeal sheath.</p> + <p><i>Action</i>.—The action of the perforans is to flex the third on the + second, and the second on the first phalanx. The latter it flexes in turn on the + metacarpus. It also assists in the flexion of the entire foot on the forearm, and in + supporting the angle of the metacarpo-phalangeal articulation when the animal is + standing.</p> + <h3>D. THE ARTERIES.</h3> + <p>So far as the arteries supplying the foot are concerned, we shall be interested in + following up the distribution of the two digitals, which are the terminal branches of + the Large Metacarpal.</p> + <p>THE LARGE METACARPAL, OR COLLATERAL ARTERY OF THE CANNON.—This, the larger + terminal branch of the posterior radial artery, needs brief mention, for the reason + that we shall be afterwards concerned with it in the operation of neurectomy. Its + point of origin is the inside of the inferior extremity of the radius. Descending in + company with the flexor tendons, and passing behind the carpus and beneath the carpal + sheath, it continues its descent, in company with the internal plantar nerve and the + internal metacarpal vein, on the inner side of the flexor tendons until just above + the fetlock. At this point it bifurcates into the digital arteries.</p> + <p>From the carpus downwards the large metacarpal artery, the internal metacarpal + vein, and the internal plantar nerve are in close relation with each other. The vein + holds the anterior position. The artery is between the two, and has the nerve in + close contact with it behind.</p> + <p>THE DIGITAL ARTERIES, OR COLLATERAL ARTERIES OF THE DIGIT.—These are of + large volume, and carry the blood to the keratogenous apparatus of the foot. They + separate from each other at an acute angle, and pass over the side of the fetlock, + one to the inside, the other to the outside, to reach the internal face of the + basilar process of the os pedis, where they bifurcate to form the <i>Plantar</i> and + <i>Preplantar</i> arteries. In the whole of their course the digital arteries follow + the flexor tendons, and are related in front to the digital vein, and behind to the + posterior branch of the plantar nerve. This is the nerve implicated in the lower + operation of neurectomy, and its relation to adjoining structures will be detailed + under Section F. of this chapter. During its course the digital artery gives off + branches in the following positions:</p> + <p>1. <i>At the Fetlock</i> numerous branches to the metacarpo-phalangeal + articulation, the sesamoid sheath, and the tendons.</p> + <p>2. <i>At the Upper Extremity of the First Phalanx</i> branches for the supply of + the surrounding tissues, and for the tissues of the ergot.</p> + <p>3. <i>Towards the Middle of the Third Phalanx</i>, the <i>Perpendicular</i> artery + of Percival. This arises at a right angle from the main vessel, and immediately + divides into two series of ramifications—an ascending and a descending. The + ramifications of these series freely anastomose with corresponding vessels of the + opposite side.</p> + <p>4. <i>At the Superior Border of the Lateral Cartilage</i>, the <i>Artery of the + Plantar Cushion</i>. This is directed obliquely downwards and backwards, under cover + of the cartilage, and is distributed to the middle portion of the complementary + apparatus of the os pedis, as well as to the villous tissue and the coronet. A branch + of it is turned forwards to join with the coronary circle in forming the + <i>circumflex artery of the coronet</i>.<br /> + <a name="a14" id="a14"></a></p> + <p><a href="images/image014.png"><img src="images/image014sm.png" + alt="THE ARTERIES OF THE FOOT" /></a></p> + <br /> + + <p>FIG. 14.—THE ARTERIES OF THE FOOT. The digital; 2, the + perpendicular—(<i>a</i>) its ascending branch, (<i>b</i>) its descending + branch; 3, circumflex artery of coronary cushion; 4, the preplantar (ungual) + artery—this is seen issuing from the preplantar foramen, and distributing + numerous ascending (<i>c</i>) and descending (<i>d</i>) branches (the latter concur + in forming the circumflex artery of the toe); 5, the circumflex artery of the toe; 6, + at the point marked (*) the terminal branch of the digital—namely, the plantar + ungual—is hidden behind the lateral cartilage; 7, the lateral cartilage.</p> + <p>5. <i>Under the Lateral Cartilage</i> two transverse branches, an anterior and a + posterior, to form the <i>Coronary Circle</i>. The numerous ramifications of these + branches anastomose both anteriorly and posteriorly with their corresponding branches + of the artery of the opposite side. This circle closely embraces the os coronæ. + Among the larger branches given off from its anterior portion are two descending, one + on each side of the extensor pedis, to assist in the formation of the <i>Circumflex + Artery of the Coronary Cushion</i>. The formation of this last-named artery is + completed posteriorly by the before-mentioned branch from the artery of the plantar + cushion.</p> + <p>THE PREPLANTAR (UNGUAL[A]) ARTERY.—This, the smaller of the two terminal + branches of the digital, is situated inside the basilar process of the os pedis. It + turns round this to gain the fissure between the basilar and retrossal processes, and + becomes lodged in the preplantar fissure. Here it terminates in several divisions + which bury themselves in the os pedis. Before leaving the inner aspect of the pedal + wing it supplies a deep branch to the heel and the villous tissue. Gaining the outer + aspect of the wing, it distributes a further backward branch, which passes behind the + circumflex artery of the pedal bone, and, during its passage in the preplantar + fissure, gives off ascending and descending branches, which ramify in the laminal + tissue.</p> + <p>THE PLANTAR (UNGUAL[A]) ARTERY.—This, the larger of the two terminals of the + digital, may be looked upon as a continuation of the main vessel. Running along the + plantar groove, it gains the plantar foramen. Here it enters the interior of the bone + (the semilunar sinus) and anastomoses with the corresponding artery of the opposite + side. The circle of vessels so formed is called the <i>Plantar Arch</i> or the + <i>Semilunar Anastomosis</i>.</p> + <p>[Footnote A: The epithet 'ungual' is added by Chauveau to distinguish these + arteries from the properly so-called plantar arteries—the terminal divisions of + the posterior tibial artery.]</p> + <p>From the semilunar anastomosis radiate two main groups of arterial branches, an + ascending group and a descending one. The <i>ascending</i> branches penetrate the + substance of the os pedis, and emerge by the numerous foraminæ on its laminal + surface. The <i>descending</i> branches, larger in size, also penetrate the substance + of the pedal bone, and emerge in turn from the foraminæ cribbling its outer + surface—in this case the set of larger foraminæ opening on its inferior + edge. Having gained exit from the bone, their frequent anastomosis, right and left, + with their fellows forms a large vessel following the contour of the inferior edge of + the os pedis. This constitutes the <i>Circumflex Artery of the Toe</i>.</p> + <h3>E. THE VEINS.</h3> + <p>These commence at the foot with a series of plexuses, which may be described as + forming (1) AN INTERNAL OR INTRA-OSSEOUS VENOUS SYSTEM, and (2) AN EXTERNAL OR + EXTRA-OSSEOUS VENOUS SYSTEM.</p> + <p>1. THE INTRA-OSSEOUS VENOUS SYSTEM.—This is a venous system within the + structure of, and occupying the semilunar sinus of the os pedis. It follows in every + respect the arrangement of the arteries as before described in the same region. + Efferent vessels emerge from the plantar foraminæ, follow the plantar fissures, + and ascend within the basilar processes of the os pedis. Here they lie under shelter + of the lateral cartilages, and assist in the formation of the deep layer of the + coronary plexus of the extra-osseous system.</p> + <p>2. THE EXTRA-OSSEOUS VENOUS SYSTEM.—This may be regarded as a close-meshed + network enveloping the whole of the foot. Although a continuous system, it is best + described by recognising in it three distinct parts:</p> + <p><i>(a) The Solar Plexus</i>.<br /> + <i>(b) The Podophyllous Plexus</i>.<br /> + <i>(c) The Coronary Plexus</i>.</p> + <p><i>(a) The Solar Plexus</i>.—The veins of this plexus discharge themselves + in two directions: (1) <i>By a central canal</i> or canals running along the bottom + of the lateral lacunæ of the plantar cushion to gain the deep layer of the + coronary plexus. (2) <i>By the Circumflex or Peripheral Vein of the Toe</i>, a canal + formed by ramifications from the solar and the podophyllous plexuses, and following + the direction of the artery of the same name. The circumflex vein terminates by + forwarding branches to concur in the formation of the superficial coronary + plexus.</p> + <p><i>(b) The Podophyllous or Laminal Plexus</i>.—The podophyllous veins + anastomose below with the circumflex vein of the solar plexus, and above with the + veins of the coronary plexus.</p> + <p><i>(c) The Coronary Plexus</i>.—This proceeds from the podophyllous, the + intra-osseous, and the solar networks, and consists of a <i>central</i> and <i>two + lateral parts</i>.</p> + <p>The <i>central</i> portion lies between the lateral cartilages and immediately + under the coronary cushion. The <i>lateral portions</i> are ramifications on both + surfaces of the lateral cartilages. The ramifications on the lateral cartilages may + be again distinguished as <i>superficial</i> and <i>deep</i>. The superficial layer + is distributed over the external face of the cartilage, forming thereon a dense + network, and finally converges towards the superior limit of the plexus to form ten + or twelve principal branches, which again unite to form two large vessels. These + vessels, by their final fusion at the lower end of the first phalanx, constitute the + digital vein. The deep layer is formed, as before described, by ascending branches + from the posterior parts of the podophyllous and solar plexuses, and by branches from + the intra-osseous system of the pedal bone. The veins of this deep layer finally + drain into the two vessels proceeding from the superficial layer, which go to the + formation of the digital vein.</p> + <p>THE DIGITAL VEINS—These arise from the network formed on the surfaces of the + lateral cartilages, and ascend in front of the digital arteries to unite above the + fetlock, where they form an arch between the deep flexor and the suspensory ligament. + From this arch (named the <i>Sesamoidean)</i> proceed the Metacarpal Veins.</p> + <p>THE METACARPAL VEINS.—Three in number, they are distinguished as an + <i>Internal</i> and an <i>External Metacarpal</i>, and a <i>Deep</i> or + <i>Interosseous Metacarpal</i>. As we shall be concerned with these in the higher + operation of neurectomy, we may give them brief mention.</p> + <p>THE INTERNAL METACARPAL VEIN, the largest of the three, has relations with the + internal metacarpal artery and the internal plantar nerve. These relations were + shortly discussed under the section devoted to the arteries, to which the reader may + refer.</p> + <p>THE EXTERNAL METACARPAL VEIN.—This ascends on the external side of the + flexor tendons in company with the external plantar nerve.</p> + <p><i>The Interosseous Vein</i>.—This is an irregular vessel running up between + the suspensory ligament and the posterior face of the large metacarpal bone.</p> + <h3>F. THE NERVES.</h3> + <p>THE PLANTAR NERVES.—These are two in number, and are distinguished as + Internal and External.</p> + <p>THE INTERNAL PLANTAR NERVE lies behind and in close contact with the great + metacarpal artery during that vessel's course down the region of the cannon. A point + of interest is that it gives off at about the middle of the cannon a branch which + bends obliquely downwards and behind the flexor tendons to join its fellow of the + opposite side—namely, the external plantar. This it joins an inch or more above + the bottom of the splint bone. Measured in a straight line, this is about 2-1/2 + inches below its point of origin. Near the fetlock, at the level of the sesamoids, + the internal plantar nerve ends in several digital branches.</p> + <p>THE EXTERNAL PLANTAR NERVE.—This holds a position to the outside of the + metacarpal region, analogous to that of the internal plantar nerve on the inside of + the limb, running down on the external edge of the flexor tendons. Unlike the + internal nerve, it is accompanied by a single vessel only, the external metacarpal + vein, behind which it lies. At the level of the sesamoid bones it divides, as does + the <i>internal</i> nerve, into three main branches—the digital nerves.<br /> + <a name="a15" id="a15"></a></p> + <p><a href="images/image015.png"><img src="images/image015sm.png" + alt="THE VEINS AND NERVES OF THE FOOT" /></a></p> + <br /> + + <p>FIG. 15.—THE VEINS AND NERVES OF THE FOOT. 1, The digital vein; 2, its main + tributaries, draining the podophyllous plexus, and concurring to form the digital; 3. + the digital artery (the main trunk only of this is shown, in order to show its + relationship with the vein and nerve); 4, the plantar nerve, with its three + branches—(<i>a</i>) the anterior digital, (<i>b</i>) the middle digital, + (<i>c</i>) the posterior digital; 5, the podophyllous plexus; 6, superficial portion + of the coronary plexus; 7, the peripheral or circumflex vein of the toe.</p> + <p>THE DIGITAL NERVES.—These are distinguished as Anterior, Middle, and + Posterior.</p> + <p><i>The Anterior Branch</i> descends in front of the vein, distributing cutaneous + branches to the front of the digit, and terminating in the coronary cushion.</p> + <p><i>The Middle Branch</i> descends between the artery and the vein, and freely + anastomoses with the two other branches. It terminates in the coronary cushion and + the sensitive laminæ.</p> + <p><i>The Posterior Branch</i>.—This is the largest of the three, and may be + regarded as the direct continuation of the plantar. At the fetlock it is placed + immediately above the digital artery, but afterwards takes up a position directly + behind that vessel. Together with the digital artery it descends to near the basilar + process of the os pedis. Here it passes with the plantar artery into the interior of + the os pedis, and continues its main branch, with the preplantar artery, in the + fissure of the same name, to finally furnish supply to the os pedis and the sensitive + laminæ. It is this nerve which is divided in the low operation of + neurectomy.</p> + <p>Beyond the fact of this branch descending, in the region of the pastern, 1 inch + behind the digital artery, a further point of interest presents itself to the + surgeon, and one to which attention must be paid. This is the presence in close + proximity to the nerve of the Ligament of the Pad (Percival), or the Ligament of the + Ergot (McFadyean). This is a subcutaneous glistening cord originating in the ergot of + the fetlock, passing in an oblique direction downwards and forwards, and crossing + over on its way both the digital artery and the posterior branch of the digital + nerve.</p> + <p>In the foregoing description of the anatomy, we have taken the fore-limb as our + guide. In the hind-limb, where they reach the foot, the counterparts of the tendons, + arteries, veins, and nerves differ in no great essential from their fellows in the + fore. They will therefore need no special mention.</p> + <h3>G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS.</h3> + <p>This consists of two lateral pieces, the LATERAL CARTILAGES or + <i>Fibro-cartilages</i> of the pedal bone, united behind and below by the <i>Plantar + Cushion</i>.</p> + <p>1. THE LATERAL CARTILAGES.—Each is a flattened plate of cartilage, + possessing two faces and four borders separated by four angles.</p> + <p>The external face is convex, covered by a plexus of veins, and slightly overhangs + the pedal bone. The internal face is concave, and covers in front the pedal + articulation and the synovial sac, already mentioned as protruding between the + antero- and postero-lateral ligaments of that joint. We have already remarked that + this is a point of interest to be remembered in connection with the operation for + quittor. Below and behind, the internal face of the cartilage is united to the + plantar cushion.<br /> + <a name="a16" id="a16"></a></p> + <p><a href="images/image016.jpg"><img src="images/image016sm.jpg" + alt="EXTERNAL FACE OF THE OUTER LATERAL CARTILAGE" /></a></p> + <br /> + + <p>FIG. 16.—EXTERNAL FACE OF THE OUTER LATERAL CARTILAGE. 1, External face of + cartilage—(<i>a</i>) its upper border, (<i>b</i>) its posterior border, + (<i>c</i>) its anterior border, (<i>d</i>) its inferior border; 2, the os pedis; 3, + wing of os pedis.</p> + <p>The upper border, sometimes convex, sometimes straight, is thin and bevelled, and + may easily be felt in the living animal. It is this border that the digital vessels + cross to gain the foot, and the border is often broke by a deep notch to accommodate + them. The inferior border is attached in front to the basilar and retrossal + processes, behind which it blends with the plantar cushion. The posterior border is + oblique from before to behind, and above to below, and joins the preceding two. The + anterior border is oblique in the same direction, and is intimately attached to the + antero-lateral ligament of the pedal articulation. The cartilages of the fore-feet + are thicker and more extensive than those of the hind.</p> + <p>2. THE PLANTAR CUSHION on FIBRO-FATTY FROG.—Composed of a fibrous meshwork, + in the interstices of which are lodged fine elastic and connective fibres and fat + cells, this wedge-shaped body occupies the space between the two lateral cartilages, + the extremity of the perforans tendon, and the horny frog. It offers for + consideration an antero-superior and an infero-posterior face, a base, an apex, and + two borders.</p> + <p>The antero-superior face is in contact with the terminal expansion of the + perforans tendon. The infero-posterior face is covered by the keratogenous membrane, + and follows closely the shape of the horny frog, on whose inner surface it is + moulded. It presents, therefore, at its centre a single conical prolongation, the + <i>Pyramidal Body</i>, which is continued behind, as is the horny frog, in the shape + of two lateral ridges divided by a median cleft. The <i>base</i> of the cushion lies + behind, and consists of two lateral masses, <i>the Bulbs of the Plantar Cushion</i>. + In front these are continuous with the ridges of the pyramidal body, while behind + they become confounded with the lateral cartilages and the coronary cushion. The + <i>apex</i> is fixed into the plantar surface of the os pedis, in front of its + semilunar ridge. The <i>borders</i>, right and left, are wider behind than before, + and are in relation with the inner faces of the lateral cartilages.</p> + <h3>H. THE KERATOGENOUS MEMBRANE.</h3> + <br /> + <br /> + + <p>THE KERATOGENOUS, OR HORN-PRODUCING MEMBRANE, is in reality an extension of the + dermis of the digit. It covers the extremity of the digit as a sock covers the foot, + spreading over the insertion of the extensor pedis, the lower half of the external + face of the lateral cartilages, the bulbs of the plantar cushion, the pyramidal body, + the anterior portion of the plantar surface of the os pedis, and over the anterior + face of the same bone. In turn, as the human foot with its sock is covered by the + boot, this is encased by the hoof, the formation of which we shall study later.</p> + <p>To expose the membrane for study the hoof must be removed. This may be done in two + ways. By roasting in a fire, and afterwards dragging off the horny structures with a + pair of pincers, a knife having first been passed round the superior edge of the + horny box. Or by maceration in water for several days, when the hoof will become + loosened by the process of decomposition, and may be easily removed by the hands. The + latter method is less likely to injure the sensitive structures, and will expose them + with a fresh appearance for observation.</p> + <p>For purposes of description the keratogenous membrane is divided into three + regions:</p> + <p>1. The Coronary Cushion.<br /> + 2. The Velvety Tissue.<br /> + 3. The Podophyllous Tissue, or the Sensitive Laminæ.</p> + <p>1. THE CORONARY CUSHION. In the foot stripped of the hoof the coronary cushion is + seen as a rounded structure overhanging the sensitive laminæ after the manner + of a cornice. It extends from the inner to the outer bulbs of the plantar cushion, + and is bounded above by the perioplic ring, and below by the laminæ.</p> + <p>When <i>in situ</i> it is accommodated by the <i>Cutigeral Groove</i>, a cavity + produced by the bevelling out of the superior portion of the inner face of the wall + of the hoof. Its superior surface is covered by numerous elongated papillæ, set + so closely as to give the appearance of the 'pile' of velvet. This is observed to the + best advantage with the foot immersed in water.</p> + <p><i>The Superior Border</i> of the cushion is bounded by the <i>Perioplic Ring</i>, + the cells of which have as their function the secreting of the <i>Periople</i>, a + layer of thin horn to be noted afterwards as covering the external face of the wall. + From the perioplic ring the cushion is separated by a narrow and shallow, though + well-marked, groove.</p> + <p>The inferior border is bounded by the sensitive laminæ.<br /> + <a name="a17" id="a17"></a></p> + <p><a href="images/image017.jpg"><img src="images/image017sm.jpg" + alt="THE KERATOGENOUS MEMBRANE" /></a></p> + <br /> + + <p>FIG. 17.—THE KERATOGENOUS MEMBRANE (VIEWED FROM THE SIDE). (THE HOOF REMOVED + BY MACERATION.) 1. The sensitive laminæ, or podophyllous tissue; 2, the + coronary cushion; 3, the perioplic ring; 4, portion of plantar cushion; 5, groove + separating perioplic ring from coronary cushion; 6. the sensitive sole.</p> + <p>The upper portions of the laminæ, those in contact with the cushion, are + pale in contrast with the portions immediately below, and thus there is given the + appearance of a white zone adjoining the inferior border of the cushion.</p> + <p>Widest at its centre, the cushion narrows towards its extremities, which, arriving + at the bulbs of the plantar cushion, bend downwards into the lateral lacunæ of + the pyramidal body, where they merge into the velvety tissue of the sole and + frog.</p> + <p>The papillæ of the coronary cushion secrete the horn tubules forming the + wall, and the papillæ of the perioplic ring secrete the varnish-like veneer of + thin horn covering the outside surface of the hoof.<br /> + <a name="a18" id="a18"></a></p> + <p><a href="images/image018.jpg"><img src="images/image018sm.jpg" + alt="THE KERATOGENOUS MEMBRANE" /></a></p> + <br /> + + <p>FIG. 18.—THE KERATOGENOUS MEMBRANE (VIEWED FROM BELOW). (THE HOOF REMOVED BY + MACERATION.) 1, The sensitive sole; 2, the sensitive frog[A]—(a) its median + lacuna, (6) its lateral lacuna; 3. V-shaped depression accommodating the toe-stay; 4, + the sensitive laminæ which interleave with the horny laminæ of the + bar.</p> + <p>[Footnote A: The sensitive frog thinly invests the plantar cushion or fibre-fatty + frog, the outline of which is here indicated.]</p> + <p>2. THE VELVETY TISSUE.—This is the portion of the keratogenous membrane + covering the plantar surface of the os pedis and the plantar cushion. To the + irregularities of the latter body—its bulbs, pyramidal body, and its + lacunæ—it is closely adapted. Its surface may, therefore, be divided into + <i>(a) The Sensitive Frog</i>, and <i>(b) The Sensitive Sole</i>.</p> + <p><i>(a) The Sensitive Frog</i> is that part of the velvety tissue moulded on the + lower surface of the plantar cushion. The shape of the plantar cushion has already + been described as identical with that of the horny frog. It only remains to state + that, like the coronary cushion, the surface of the sensitive frog is closely studded + with papillæ. The cells clothing the papillæ are instrumental in forming + the horny frog.</p> + <p><i>(b) The Sensitive Sole</i>.—As its name indicates, this is the portion of + the keratogenous membrane that covers the plantar surface of the os pedis. It also is + clothed with papillæ, which again give rise to the formation of that part of + the horny box to which they are adapted—namely, the sole.</p> + <p>3. THE PODOPHYLLOUS TISSUE, OR SENSITIVE LAMINÆ.—This portion of the + keratogenous membrane is spread over the anterior face and sides of the os pedis, + limited above by the coronary cushion, and below by the inferior edge of the bone. It + presents the appearance of fine longitudinal streaks, which, when closely examined + with a needle, are found to consist of numerous fine leaves. These extend downwards + from the lower border of the coronary cushion to the inferior margin of the os pedis. + At this point each terminates in several large villous prolongations, which extend + into the horny tubes at the circumference of the sole. At the point of the toe this + membrane sometimes shows a V-shaped depression, into which fits a inverted V-shaped + prominence on the inner surface of the wall at this point.</p> + <p>The sensitive laminæ increase in width from above to below. Their free + margin is finely denticulated, while their sides are traversed from top to bottom by + several folds (about sixty), which, examined microscopically, are seen to consist of + secondary leaves, or <i>laminellæ</i>.</p> + <p>Examined on the foot, deprived of its horny covering, the sensitive laminæ + are, the majority of them, in close contact with each other. In the normal state this + is not so. The interstices between the leaves are then occupied by the horny leaves, + to be afterwards described as existing on the inner surface of the wall.</p> + <p>Reaching and rounding the heels, the sensitive laminæ extend forward for a + short distance, where they interleave with the horny laminæ of the bars.</p> + <p>Much discussion has centred round the point as to whether or no the cells of the + sensitive laminæ take any share in the formation of the horn of the wall. This + will be alluded to in a future chapter.</p> + <h3>I. THE HOOF.</h3> + <p>Removed from the foot by maceration a well-shaped hoof is cylindro-conical in + form, and appears to the ordinary observer to consist of a box or case cast in one + single piece of horn. Prolonged maceration, however, will show that the apparently + single piece is divisible into three. These are known as (1) THE WALL, (2) THE SOLE, + and (3) THE FROG. In addition to these, we have also an appendage or circular + continuation of the frog named (4) THE PERIOPLE, or CORONARY FROG BAND. These various + divisions we will study separately.</p> + <p>1. THE WALL is that portion of the hoof seen in front and laterally when the + horse's foot is on the ground. Posteriorly, instead of being continued round the + heels to complete the circle, its extremities become suddenly inflected downwards, + forwards, and inwards. These inflections can only be seen with the foot lifted from + the floor, and form the so-called <i>Bars</i>. It will be noticed, too, with the foot + lifted, that the wall projects beyond the level of the other structures of the + plantar surface, taking upon itself the bearing of the greatest part of the animal's + weight.</p> + <p>The horn of the wall, viewed immediately from the front, is known as the + <i>Toe</i>, which again is distinguished as <i>Outside Toe</i> or <i>Inside Toe</i>, + according as the horn to its inner or outer aspect is indicated. The remainder of the + external face of the wall, that running back to the heels, is designated the + <i>Quarters</i>.</p> + <p>In the middle region of the toe, the wall following the angle of the bones is + greatly oblique. This obliquity decreases as the quarters are reached, until on + reaching the heels the wall is nearly upright.<br /> + <a name="a19" id="a19"></a></p> + <p><a href="images/image019.png"><img src="images/image019sm.png" + alt="THE WALL OF THE HOOF" /></a></p> + <br /> + + <p>FIG. 19.—THE WALL OF THE HOOF. 1, The toe; 2, inner toe; 3, outside toe; 4, + the quarter; 5, entigeral groove; 6, horny laminæ.</p> + <p>For observation the wall offers two faces, two borders, and two extremities.</p> + <p><i>The External Face</i> is convex from side to side, but straight from the upper + to the lower border. Examined closely, it is seen to be made up of closely-arranged + parallel fibres running in a straight line from the upper to the lower border, and + giving the surface of the foot a finely striated appearance. In addition to these + lines, which are really the horn tubules, the external face is marked by a series of + rings which run horizontally from heel to heel. These are due to varying influences + of food, climate, and slight or severe disease. This will be noted again in a later + page. In a young and healthy horse the whole of the external face of the wall is + smooth and shining. This appearance is due to a thin layer of horn, secreted + independently of the wall proper, termed the periople.<br /> + <a name="a20" id="a20"></a></p> + <p><a href="images/image020.png"><img src="images/image020sm.png" + alt="INTERNAL FEATURES OF THE WALL, FROG, AND SOLE" /></a></p> + <br /> + + <p>FIG. 20.—INTERNAL FEATURES OF THE WALL, FROG, AND SOLE (MESIAN SECTION OF + HOOF). 1, Horny laminæ covering internal face of wall; 2, superior border of + wall; 3, junction of wall with horny sole; 4, the cutigeral groove; 5, the horny + sole; 6, the horny frog (that portion of it known as the 'frog-stay'); 7, inverted + V-shaped ridge on wall and sole (known as the 'toe-stay'); 8, anterior face of wall; + 9, inferior border of wall.</p> + <p><i>The Internal Face</i> of the wall, that adapted to the sensitive laminæ, + is closely covered over its entire surface with white parallel leaves + <i>(Keraphyllæ</i>, or horn leaves, to distinguish them from the + <i>Podophyllæ</i>, or sensitive leaves). These keraphyllæ dovetail + intimately with the sensitive laminæ, covering the os pedis. Running along the + superior portion of the inner face is the <i>Cutigeral Groove</i>. This cavity has + been mentioned before as accommodating the coronary cushion, whose shape and general + contour it closely follows, being widest and deepest in front, and gradually + decreasing as it proceeds backwards. It is hollowed out at the expense of the wall, + and shows on its surface numberless minute openings which receive the papillæ + of the coronary cushion.</p> + <p>At the bottom of the internal face, at the point where the toe joins the sole, + will be noted the before-mentioned inverted V-shaped prominence. Its position will be + clearly understood when we say that it gives the appearance of having been forced + there by the pressure of the toe-clip of the shoe. This will be noted again when + dealing with the sole.</p> + <p><i>The Inferior Border</i> of the wall offers little to note. It is that portion + in contact with the ground, and subject to wear. A point of interest is its union + with the sole. This will be noticed in a foot which has just been pared as a narrow + white or faint yellow line on the inner or concave face of the wall at its lower + portion. It marks the point where the horny leaves of the wall terminate and become + locked with corresponding leaves of the circumference of the sole.</p> + <p><i>The Superior Border</i> follows closely the line marked by the perioplic ring + and the groove separating the latter from the coronary cushion.</p> + <p><i>The Extremities</i> of the wall are formed by the abruptly reflected portions + of the wall at the heels. Termed by some the 'Inflexural Nodes,' they are better + known to us as the '<i>Points of the Heels</i>.'</p> + <p>2. THE SOLE.—The sole is a thick plate of horn which, in conjunction with + the bars and the frog, forms the floor of the foot. In shape it is irregularly + crescentic, its posterior portion, that between the horns of the crescent, being + deeply indented in a V-shaped manner to receive the frog. Its upper surface is + convex, its lower concave. It may be recognised as possessing two faces and two + borders.</p> + <p><i>The Superior or Internal Face</i> is adapted to the sole of the os pedis. Its + highest point, therefore, is at the point of its V-shaped indentation. From this + point it slopes in every direction downwards and outwards until near the + circumference. Here it curves up to form a kind of a groove in which is lodged the + inferior edge of the os pedis. In the centre of its anterior portion—that is to + say, at the toe—will be seen a small inverted V-shaped ridge, which is a direct + continuation of the same shaped prominence before mentioned on the internal face of + the wall. This Fleming has termed the toe-stay, from a notion that it serves to + maintain the position of the os pedis. The whole of the superior face of the sole is + covered with numerous fine punctures which receive the papillæ of the sensitive + sole.</p> + <p><i>The Inferior Face</i> is more or less concave according to circumstances, its + deepest part being at the point of the frog. Sloping from this point to its + circumference, it becomes suddenly flat just before joining the wall. Its horn in + appearance is flaky.<br /> + <a name="a21" id="a21"></a></p> + <p><a href="images/image021.jpg"><img src="images/image021sm.jpg" + alt="INFERIOR ASPECT OF HOOF" /></a></p> + <br /> + + <p>FIG. 21.—INFERIOR ASPECT OF HOOF. <i>a</i> The inferior face of horny sole; + <i>b</i>, inferior border of the wall; <i>c</i>, body or cushion of the frog; + <i>d</i>, median lacuna of the frog; <i>e</i>, lateral lacuna of the frog; <i>f</i>, + the bar; <i>g</i>, the quarter; <i>h</i>, the point of the frog; <i>i</i> the + heel.</p> + <p><i>The External Border</i> or Circumference is intimately dovetailed with the + horny laminæ of the wall. At its circumference the sole, if unpared, is + ordinarily as thick as the wall. This thickness is maintained for a short distance + towards its centre, after which it becomes gradually more thin.</p> + <p><i>The Internal Border</i> has the shape of an elongated V with the apex pointing + forwards. It is much thinner than the external border, and, like it, is dovetailed + into the horny laminæ of the inflections of the wall—namely, the bars. In + front of the termination of the bars it is dovetailed into the sides and point of the + frog. Where unworn by contact with the ground, the horn of the sole is shed by a + process of exfoliation.</p> + <p>3. THE FROG.—Triangular or pyramidal in shape, the frog bears a close + resemblance to the form of the plantar cushion, upon the lower surface of which body + it is moulded. It offers for consideration two faces, two sides, a base, and a point + or summit.<br /> + <a name="a22" id="a22"></a></p> + <p><a href="images/image022.jpg"><img src="images/image022sm.jpg" + alt="HOOF WITH THE SENSITIVE STRUCTURES REMOVED" /></a></p> + <br /> + + <p>FIG. 22.—HOOF WITH THE SENSITIVE STRUCTURES REMOVED. 1, Superior face of + horny frog; 2, the frog-stay; 3, the lateral ridges of the frog's superior surface; + 4, the horny laminæ at the inflections of the wall.</p> + <p><i>The Superior Face</i> is an exact cast of the lower surface of the plantar + cushion. It shows in the centre, therefore, a triangular depression, with the base of + the triangle directed backwards. Posteriorly, the depression is continued as two + lateral channels divided by a median ridge. The median ridge widens out as it passes + backwards, forming the larger part of the posterior portion of the frog. This median + ridge fits into the cleft of the plantar cushion. It serves to prevent displacement + of the sensitive from the horny frog, and has been rather aptly termed the + '<i>Frog-stay</i>.'</p> + <p><i>The Inferior Surface</i> is an exact reverse of the superior. The triangular + depression of the superior surface is represented in the inferior surface by a + triangular projection, and the ridge-like frog-stay of the upper surface is + represented below by a median cleft, the <i>Median Lacuna</i> of the frog. The + triangular projection in front of the median lacuna is the body or cushion of the + frog. It is continued backwards as two ridge-like branches, which, at the points of + the heels, form acute angles with the bars. On the outer side of each lateral ridge + is a fissure. These are known as the Lateral Lacunæ.</p> + <p><i>The Sides</i> of the frog are flat and slightly oblique. They are closely + united to the bars and to the triangular indentation in the posterior border of the + sole.</p> + <p><i>The Base</i> of the frog is formed by the extremities of its branches, which, + becoming wider and more convex as they pass backwards, form two rounded, flexible, + and elastic masses separated from each other by the median lacuna. These constitute + the 'glomes' of the frog. They are continuous with the periople.</p> + <p><i>The Point of the Frog</i> is situated, wedge-like, within the triangular notch + in the posterior border of the sole.</p> + <p>4. THE PERIOPLE, OR CORONARY FROG BAND.—This is a continuation of the + substance of the frog around the extreme upper surface of the hoof. It is widest at + the heels over the bulbs or glomes of the frog, and gradually narrows as it reaches + the front of the hoof. It is, in reality, a thin pellicle of semi-transparent horn + secreted by the cells of the perioplic ring. When left untouched by the farrier's + rasp it serves the purpose, by acting as a natural varnish, of protecting the horn of + the wall from the effects of undue heat or moisture.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER III</h3> + <h3><a name="general" id="general">GENERAL PHYSIOLOGICAL AND ANATOMICAL + OBSERVATIONS</a></h3> + <p>The matter embraced by the heading of this chapter will offer for discussion many + subjects of great interest to the veterinary surgeon. Around some of them debate has + for many years waxed more than keen. Of the points in dispute, some of them may be + regarded as satisfactorily settled, while others offer still further room for + investigation.</p> + <p>In this volume we can only hope to deal with them in brief, and must select such + as appear to have the greatest bearing on the veterinarian's everyday practice.</p> + <p>Always prolific of heated discussion has been one question: 'Are the horny + laminæ secreted by the sensitive?' To answer this satisfactorily, it will be + best to give a short account of the mode of production of the hoof in general.</p> + <h3>A. DEVELOPMENT OF THE HOOF.</h3> + <p>Starting with the statement that it is epidermal in origin, we will first consider + the structure of the skin, and follow that with a brief description of the structure + and mode of growth of the human nail, a short study of which will greatly assist us + when we come to investigate the manner of growth of the horse's hoof.</p> + <p>THE SKIN is composed of two portions, the EPIDERMIS and the CORIUM.</p> + <p>THE EPIDERMIS is a stratified epithelium. The superficial layers of the cells + composing it are hard and horny, while the deeper layers are soft and protoplasmic. + These latter form the so-called <i>Rete Mucosum</i> of Malpighi.<br /> + <a name="a23" id="a23"></a></p> + <p><a href="images/image023.png"><img src="images/image023sm.png" + alt="VERTICAL SECTION OF EPIDERMIS" /></a></p> + <br /> + + <p>FIG. 23.—VERTICAL SECTION OF EPIDERMIS (HUMAN). (AFTER RANVIER) <i>A</i>, + The horny layer of the epidermis; <i>B</i>, the rete mucosum; <i>a</i>, the columnar + pigment-containing cells of the rete; <i>b</i>, the polyhedral cells; <i>c</i>, the + stratum granulosum; <i>d</i>, the stratum lucidum; <i>e</i>, swollen horny cells; + <i>f</i> the stratum squamosum.</p> + <p>Commencing from below and proceeding upwards, we find that the lowermost cells of + the rete mucosum, those that are set immediately on the corium, are columnar in + shape. In animals that have a coloured skin these cells contain pigment granules. + Directly superposed to these we find cells which in shape are polyhedral. Above them, + and forming the most superficial layer of the rete mucosum, is a series of flattened, + granular-looking cells known as the <i>stratum granulosum</i>.</p> + <p>Immediately above the stratum granulosum the horny portion of the epidermis + commences. In the human skin this is formed of three distinct layers. Undermost a + layer of clear compressed cells, the <i>stratum lucidum</i>. Next above it a layer of + swollen cells, the nuclei of which are indistinguishable. Finally, a surface layer of + thin, horny scales, the <i>stratum squamosum</i>, which become detached and thrown + off in the form of scurf or dandruff. In the skin of the horse, except where it is + thickest, these layers are not clearly defined.</p> + <p>It is the Malpighian layer of the epidermis that is most active in cell division. + As they are formed the new cells push upwards those already there, and the latter in + their progress to the surface undergo a chemical change in which their protoplasm is + converted into horny material. This change, as we have already indicated, takes place + above the stratum granulosum.</p> + <p>In addition to its constant formation of cells to replace those cast off from the + surface, the active proliferation of the elements of the Malpighian layer is + responsible for the development of the various appendages of the skin, the hairs with + their sebaceous glands, the sweat glands, horny growths and the hoof, and, in the + human subject, the nail. These occur as thickenings and down-growths of the + epithelium into the corium.</p> + <p>The epidermis is devoid of bloodvessels, but is provided with fine nerve fibrils + which ramify between the cells of the rete mucosum.</p> + <p>THE CORIUM is composed of dense connective tissue, the superficial layer of which + bears minute papillæ. These project into the epidermis, which is moulded on + them. For the most part the papillæ contain looped capillary vessels, rendering + the superficial layer of the corium extremely vascular. Why this must be a moment's + reflection will show. The epidermis, as we have already said, is devoid of + bloodvessels. It therefore depends entirely for its nourishment upon the indirect + supply it receives from the vessels of the corium. The need for extreme vascularity + of the corium is further explained when we call to mind the constant proliferation + and casting off of the cells of the epidermis, the growth of the hairs, the + production of the horn of the hoof, and the work performed by the numerous sweat and + other glands.</p> + <p>Others of the papillæ contain nerves, ending here in tactile corpuscles, or + continuing, as we have mentioned before, to ramify as fine fibrils in the rete + mucosum of the epidermis.</p> + <p>THE HAIRS are growths of the epidermis extending downwards into the deeper part of + the corium. Each is developed in a small pit, the <i>Hair Follicle</i>, from the + bottom of which it grows, the part lying within the follicle being known as the + <i>Root</i>. It is important to note their structure, as it will be seen later that + they bear an extremely close relation to the horn of the hoof.</p> + <p>Under a high power of the microscope, and in optical section, the central portion + of a hair is tube-like. In some cases the cavity of the tube is occupied by a dark + looking substance formed of angular cells, and known as the <i>Medulla</i>. The walls + of the tube, or the main substance of the hair, is made up of a pigmented, <i>horny, + fibrous material</i>. This fibrous structure is covered by a delicate layer of finely + imbricated scales, and is termed the <i>Hair Cuticle</i>.</p> + <p>The root of the hair, that portion within the follicle, has exactly the same + formation save at its extreme end. Here it becomes enlarged into a knob-like + formation composed of soft, growing cells, which knob-like formation fits over a + vascular papilla projecting up in the bottom of the follicle.</p> + <p>We have already stated that the hairs are down-growths of the epidermis. It + follows, therefore, that the hair follicles, really depressions or cul-de-sacs of the + skin itself, are lined by epithelial cells and connective tissue. So closely does the + epidermal portion of the follicle invest the hair root that it is often dragged out + with it, and is known as the <i>Root Sheath</i>. This is made up of an outer layer of + columnar cells (<i>the outer root sheath</i>) corresponding to the Malpighian layer + of the epidermis, and of an inner horny layer, next to the hair, corresponding to the + more superficial layer of the epidermis, and known as the <i>inner root + sheath</i>.</p> + <p>The hair grows from the bottom of the follicle by a multiplication of the cells + covering the papilla upon which its root is moulded. When a hair is cast off a new + one is produced from the cells covering the papilla, or, in case of the death or + degeneration of the original papilla, the new hair is produced from a second papilla + formed in place of the first at the bottom of the follicle.</p> + <br /> + <a name="a24" id="a24"></a> + <p><a href="images/image024.png"><img src="images/image024sm.png" + alt="SECTION OF SKIN WITH HAIR FOLLICLE AND HAIR" /></a></p> + <br /> + + <p>FIG. 24.—SECTION OF SKIN WITH HAIR FOLLICLE AND HAIR. <i>a</i>, The hair + follicle; <i>b</i>, the hair root; <i>c</i>, the medulla; <i>d</i>, the hair cuticle; + <i>e</i>, the outer root sheath; <i>f</i>, the inner root sheath; <i>g</i>, the + papilla from which the hair is growing; <i>h</i>, a sebaceous gland; <i>i</i>, a + sudoriferous gland.</p> + <p>THE SEBACEOUS GLANDS are small saccular glands with their ducts opening into the + mouths of the hair follicles. They furnish a natural lubricant to the hairs and the + skin.</p> + <p>THE SUDORIFEROUS OR SWEAT GLANDS are composed of coiled tubes which lie in the + deeper portion of the skin, and send up a corkscrew-like duct to open on the surface + of the epidermis. They are numerous over the whole of the body.</p> + <br /> + <a name="a25" id="a25"></a> + <p><a href="images/image025.png"><img src="images/image025sm.png" + alt="LONGITUDINAL SECTION THROUGH NAIL AND NAIL-BED OF A HUMAN FOETAL FINGER" /> + </a></p> + <br /> + + <p>FIG. 25.—LONGITUDINAL SECTION THROUGH NAIL AND NAIL-BED OF A HUMAN FOETAL + FINGER.[A] <i>a</i>, The nail; <i>b</i>, the rete mucosum; <i>c</i>, the longitudinal + ridges of the corium.</p> + <p>[Footnote A: Seeing that the section is a longitudinal one, it would appear from + the way the ridges cut that they are running transversely beneath the nail. Their + extreme delicacy, however, prevents a single one showing itself along the length of + the section, and their constant accidental cutting makes them <i>appear</i> to run + transversely (H.C.R.).]</p> + <p>THE HUMAN NAILS are thickenings of the lowermost layer of the horny portion of the + epidermis, the stratum lucidum. They are developed over a modified portion of the + corium known as the nail-bed. The horny substance of the nail is composed of clear + horny cells, and rests immediately upon a Malpighian layer similar to that found in + the epidermis generally. Instead of the papillæ present elsewhere in the skin, + the corium of the nail-bed is marked by longitudinal ridges, a similar, though less + distinct, arrangement to that found in the laminæ of the horse's foot.</p> + <p>Having thus paved the way, we are now in a better position to discuss our original + question (Are the horny laminæ secreted by the sensitive?), and better able to + appreciate the work that has been done towards the elucidation of the problem.</p> + <p>A most valuable contribution to this study is an article published in 1896 by + Professor Mettam.[A] Here the question is dealt with in a manner that must + effectually silence all other views save such as are based upon similar methods of + investigation—namely, histological examination of sections of equine hoofs in + various stages of foetal development.</p> + <p>[Footnote A: The <i>Veterinarian</i>, vol. lxix., p.1.]</p> + <p>Professor Mettam commences by drawing attention to the error that has been made in + this connection by studying the soft structures of the foot separated by ordinary + putrefactive changes from the horny covering. "In this way," the writer points out, + "a wholly erroneous idea has crept in as to the relation of the one to the other, and + the two parts have been treated as two anatomical items, when, indeed, they are + portions of one and the same thing. As an illustration, and one very much to the + point at issue, the soft structures of the foot are to the horny covering what the + corium of the skin and the rete Malpighii are to the superficial portions of the + epidermis. Indeed, the point where solution of continuity occurs in macerating is + along the line of the soft protoplasmic cells of the rete."</p> + <p>In the foregoing description of the skin we have seen that the corium is not a + <i>plane</i> surface, but that it is studded by numerous papillary projections, and + that these projections, with the depressions between them, are covered by the cells + of the epidermis.</p> + <p>The corium of the horse's foot, however, although possessed of papillæ in + certain positions (as, for example, the papillæ of the coronary cushion, and + those of the sensitive frog and sole), has also most pronounced ridges (laminæ) + which run down the whole depth of the os pedis. Each lamina again carries ridges + (laminellæ) on its lateral aspects, giving a section of a lamina the appearance + of being studded with papillæ. We have already pointed out the ridge-like + formation of the human nail-bed, and noted that, with the exception that the + secondary ridges are not so pronounced, it is an exact prototype of the laminal + formation of the corium of the horse's foot.</p> + <p>The distribution of the laminæ over the foot we have discussed in the + chapter devoted to the grosser anatomy. In a macerated foot the sensitive + laminæ of the corium interdigitate with the horny laminæ of the hoof; + that is to say, there is no union between the two, for the simple reason that it has + been destroyed; they simply interlock like the <i>unglued</i> junction of a finely + dovetailed piece of joinery. But no further, however, than the irregularities of the + underneath surface of the epidermis of the skin can be said to interlock with the + papillæ of the corium does interlocking of the horny and sensitive laminæ + occur. It is only apparent. The horny laminæ are simply beautifully regular + epidermal ingrowths cutting up the corium into minute leaf-like projections.</p> + <p>In a macerated specimen, then, the exposed sensitive structures of the foot + exhibit the corium as (1) the <i>Coronary Cushion</i>, fitting into the cutigeral + groove; (2) the <i>Sensitive Laminæ</i>, clothing the outer surface of the + terminal phalanx, and extending to the bars; (3) the <i>Plantar Cushion</i>, or + sensitive frog; and (4) the <i>Sensitive Sole</i>.</p> + <p>The main portion of the wall is developed from the numerous papillæ covering + the corium of the coronary cushion. We have in this way numberless down-growing tubes + of horn. Professor Mettam describes their formation in a singularly happy fashion: + "Let the human fingers represent the coronary papillæ, the tips of the fingers + the summits of the papillæ, and the folds of skin passing from finger to finger + in the metacarpo-phalangeal region the depressions between the papillæ. Imagine + that all have a continuous covering of a proliferating epithelium. Then we shall have + a more or less continuous column of cells growing from the tip of the finger or + papilla (a hollow tube of cells gradually moving from off the surface of the finger + or papilla like a cast), and similar casts are passing from off all the fingers or + papillæ."</p> + <p>From this description it will be noticed that each down-growing tube of horn bears + a striking resemblance to the growth of a hair, described on p. 47. In fact, the horn + tube may be regarded as what it really is, a modified hair.</p> + <p>We next continue Professor Mettam's illustration, and note how the modified hairs + or horn tubes become as it were matted together to form the hoof wall. The cells + lining the depressions are also proliferating, and their progeny serve to cement + together the hollow casts of the papillæ, thus giving the <i>inter</i>-tubular + substance. We have thus produced hollow tubes, united together by cells, all arising + from the rete Malpighii of the coronary corium. Section of the lower part of the horn + tubes shows them to contain a cellular debris.</p> + <p>Thus, in all, in the horn of the wall we find a tubular, an intertubular, and + intratubular substance. In fact, hairs matted together by intertubular material, and + only differing from ordinary hairs in their development in that they arise, not from + papillæ sunk in the corium, but from papillæ projecting from its + surface.</p> + <p>Although this disposes of the wall proper, there still confronts us the question + of the development of the horny laminæ. To accurately determine this point it + is absolutely essential to examine, histologically, the feet from embryos.</p> + <p>In the foot of any young ungulate in the early stages of intra-uterine life + horizontal sections will show a covering of epidermis of varying thickness.[A] This + may be only two or three cells thick, or may consist of several layers. Lowermost we + find the cells of the rete Malpighii. As some criterion of the activity with which + these are acting, it may be noted that with the ordinary stains their nuclei take the + dye intensely. The cells of this layer rest upon a basement membrane separating the + epidermis from the corium. At this stage <i>the corium has a perfectly plane + surface</i>.</p> + <p>[Footnote A: Equine foetus, seventy-seven days old.]</p> + <br /> + <a name="a26" id="a26"></a> + <p><a href="images/image026.jpg"><img src="images/image026sm.jpg" + alt="SECTION OF FOOT OF EQUINE FOETUS, SEVENTY-SEVEN DAYS OLD" /></a></p> + <br /> + + <p>FIG. 26.—SECTION OF FOOT OF EQUINE FOETUS, SEVENTY-SEVEN DAYS OLD. The rete + Malpighii rests on a plane corium; the rent in the section is along the line of the + cells of the rete (Mettam).</p> + <br /> + <a name="a27" id="a27"></a> + <p><a href="images/image027.jpg"><img src="images/image027sm.jpg" + alt="SECTION FROM FOOT OF SHEEP EMBRYO" /></a></p> + <br /> + + <p>FIG. 27.—SECTION FROM FOOT OF SHEEP EMBRYO. It shows a pronounced epithelial + ingrowth into the corium (Mettam).</p> + <p>The next stage will demonstrate the first step in the formation of the sensitive + laminæ.[A] The plain surface of the corium has now become broken up, and what + is noticed is that the broken-up appearance is due to the epithelial cells irrupting + and advancing <i>en échelon</i> into its connective tissue. Each point of the + ingrowing lines of the <i>échelon</i> has usually one cell further advanced + into the corium than its neighbours, and may be termed the <i>apical cell</i>. The + fine basement membrane separating epithelium from corium is still clearly evident. + This epidermal irruption of the corium takes place at definite points right round the + foot. It is extremely probable, however, that it commences first at the toe and + spreads laterally.</p> + <p>[Footnote A: Sheep embryo, exact age unknown.]</p> + <p>As yet, these cellular ingrowths (which are destined to be the <i>horny</i> + laminæ, and cut up the corium into <i>sensitive</i> laminæ) are free from + irregularities or secondary laminæ. Before these are to be observed other + changes in connection with the ingrowths are to be noticed.</p> + <br /> + <a name="a28" id="a28"></a> + <p><a href="images/image028.jpg"><img src="images/image028sm.jpg" + alt="SECTION FROM CALF EMBRYO" /></a></p> + <br /> + + <p>FIG. 28.—SECTION FROM CALF EMBRYO. The epithelial ingrowths hang down from + the epidermis into the corium like the teeth of a comb (Mettam).</p> + <p>The first is merely that of elongation of the epithelial processes into the + connective tissue, until the rete Malpighii gives one the impression that it has + hanging to its underneath surface and into the corium a number of thorn-like + processes. These extend all round the front of the foot, and even in great part + behind. Accompanying this elongation of the processes is a condensation of the + epithelial cells immediately above the rete Malpighii, with a partial or total loss + of their nuclei. This is the first appearance of true horn, and its commencement is + almost coincident with the first stages of ossification of the os pedis.</p> + <br /> + <a name="a29" id="a29"></a> + <p><a href="images/image029.jpg"><img src="images/image029sm.jpg" + alt="SECTION OF AN EPITHELIAL INGROWTH FROM AN EQUINE FOETUS" /></a></p> + <br /> + + <p>FIG. 29.—SECTION OF AN EPITHELIAL INGROWTH FROM AN EQUINE FOETUS. It shows + commencing secondary laminar ridges. In the centre are epithelial cells which are + undergoing change into horny elements to form the horn core, or 'horny laminæ' + (Mettam).</p> + <p>With the appearance of horn comes difficulty of sectioning. The last specimen that + Professor Mettam was able to satisfactorily cut upon the microtome was from a foetus + between three and four months old. In this the secondary laminar ridges were clearly + indicated, and the active layer of the rete Malpighii could be traced without a break + from one ingrowing epithelial process to the next, and around this, following all the + irregularities of its outline, and covering the branches of the nascent laminæ. + The laminæ mostly show this branching as if a number of different growing + points had arisen, each to take on a function similar to the epithelial process as it + at first appeared.</p> + <p>In the centre of the processes a few nuclei may be observed, but they are scarce, + and stain only faintly; they have arisen from the cells of the rete Malpighii which + have grown into the corium. In fact, the active cells are passing their daughters + into the middle of the process, and these pass through similar stages as those + derived from the ensheathing epidermis. In other words, the daughter cells of the + constituents of the rete Malpighii which have grown into the corium pass through a + degeneration precisely similar to that undergone by cells shed at desquamation, or + those which eventually give rise by their agglutination to a hair.</p> + <p>This is the real origin of the horny laminæ, and the thickness of these is + increased merely by an increase in the area covered by the cells of the rete + Malpighii—<i>i.e</i>., by the development of secondary laminar ridges. If a + section from a foal at term be examined, the processes will be found far advanced + into the corium, and, occupying the axis of each process, will be seen a horny plate, + continuous with the horn of the wall. No line of demarcation can be observed between + the horn so formed and the intertubular material of the wall. They merge into and + blend with each other, with no indication of their different origins. The cells that + have invaded the corium have thus <i>not lost their horn-forming function</i>. There + has merely been an increase in the area for horn-producing cells. The horny processes + are continuous with the hoof proper at the point where the epithelial ingrowth first + commenced to invade the corium, and fuses here with the horn derived from the cells + of the rete Malpighii which have <i>not</i> grown inwards, and which are found + between the processes in the intact foot. From this it is clear that some + considerable portion of the horn of the wall is derived from the cells of the rete + Malpighii covering the corium of the foot. It becomes even more clear when we + remember the prompt appearance of horn in cases where a portion, or the whole, of the + wall has been removed by operation or by accident (see reported cases in Chapter + VII.).</p> + <p>The activity of the cells of the rete Malpighii of the corium covering the + remainder of the foot will be quite as necessary as the activity of the cells of the + coronary papillæ which form the horn tubes themselves. 'For,' in Professor + Mettam's own words, 'I am inclined to believe that much of the "white line" which is + found uniting the wall of the hoof to the sole has been derived from the horn formed + from the rete of the foot corium. This origin will explain the absence of pigment + from this thin uniting "line," as it does from the horn lining the interior of the + wall. The cells of the rete are free of colouring matter.'</p> + <br /> + <a name="a30" id="a30"></a> + <p><a href="images/image030.jpg"><img src="images/image030sm.jpg" + alt="SECTION THROUGH HOOF AND SOFT TISSUES OF A FOAL AT TERM" /></a></p> + <br /> + + <p>FIG. 30.—SECTION THROUGH HOOF AND SOFT TISSUES OF A FOAL AT TERM. The horn + of the wall is shown, and the horn-core ('horny laminæ') of the epithelial + ingrowth. The latter has advanced far into the corium, and is now provided with + abundant secondary laminar ridges (Mettam).</p> + <p>From the matter here given us it is easy to understand how, in a macerated foot, + the appearance is given of interlocking of the sensitive and horny laminæ. We + see that the horny laminæ are ingrowths of the rete Malpighii, ploughing into + and excavating the corium into the shape of leaves—the sensitive laminæ. + Putrefactive changes simply break into two separate portions what originally was one + whole, by destroying the cells along its weakest part. This part is the line of soft + protoplasmic cells of the rete Malpighii. Thus the more resistant parts (the horn on + the one hand, and the corium covering the foot on the other) are easily torn + asunder.</p> + <p>As a result of the evidence we have quoted, we are able to answer our original + question in the affirmative. Seeing that the horny and the sensitive laminæ are + both portions of the same thing—namely, a modified skin, in which the epidermis + is represented by the horny laminæ, and the corium by the sensitive—it is + clear to see that the cells covering the inspreading horny laminæ are dependent + for their growth and reproduction upon the cells with which they are in immediate + contact—namely, those of the sensitive laminæ—and that therefore + the sensitive laminæ are responsible for the growth of the horny.</p> + <h3>B. CHEMICAL PROPERTIES AND HISTOLOGY OF HORN.</h3> + <p>Horn is a solid, tenacious, fibrous material, and its density in the hoof varies + in different situations. It is softened by alkalies, such as caustic potash or soda + and ammonia, the parts first attacked being the commissures, then the frog, and + afterwards the sole and wall. Strong acids, such as sulphuric acid and nitric acid, + also dissolve it.</p> + <p>The chemical composition of the hoof shows it to be a modification of albumin, its + analysis yielding water, a large percentage of animal matter, and materials soluble + and insoluble in water. The proportions of these, as existing in the various parts of + the hoof, have been given by Professor Clement as follows:</p> + <table border="1" width="100%" summary="Chemical composition of the hoof"> + <tr> + <td> + </td> + <td>Wall.</td> + <td>Sole.</td> + <td>Frog.</td> + </tr> + <tr> + <td>Water</td> + <td>16.12</td> + <td>36.0</td> + <td>42.0</td> + </tr> + <tr> + <td>Fatty matter</td> + <td>0.95</td> + <td>0.25</td> + <td>0.50</td> + </tr> + <tr> + <td>Matters soluble in water</td> + <td>1.04</td> + <td>1.50</td> + <td>1.50</td> + </tr> + <tr> + <td>Insoluble salts</td> + <td>0.26</td> + <td>0.25</td> + <td>0.22</td> + </tr> + <tr> + <td>Animal matter</td> + <td>81.63</td> + <td>62.0</td> + <td>55.78</td> + </tr> + </table> + <p>Horn appears to be identical with epidermis, hair, wool, feathers, and whalebone, + in yielding 'keratin,' a substance intermediate between albumin and gelatine, and + containing from 60 to 80 per cent. of sulphur.</p> + <p>That horn is combustible everyone who has watched the fitting of a hot shoe knows. + That it is a bad conductor of heat, the absence of bad after-effects on the foot + testifies.</p> + <br /> + <a name="a31" id="a31"></a> + <p><a href="images/image031.png"><img src="images/image031sm.png" + alt="PERPENDICULAR SECTION OF HORN OF WALL." /></a></p> + <br /> + + <p>FIG. 31.—PERPENDICULAR SECTION OF HORN OF WALL.</p> + <p>In a previous page we have described the manner of growth of the horn tubules, and + noted the direction they took in the wall; also, we have noticed the existence + between them of an intertubular horn or cement.</p> + <p>Those who wish to give this subject further study will find an excellent series of + articles by Fleming in the <i>Veterinarian</i> for 1871. We shall content ourselves + here with introducing one or two diagrams and photo-micrographs, and dealing with the + histology very briefly.</p> + <p>Under the microscope the longitudinal striation of the wall is found to be due to + the direction taken by the horn tubules.</p> + <p>Fig. 31 is a magnified perpendicular section of the wall. In it the parallel dark + striæ are the horn tubules in longitudinal section. The lighter striæ + represent the intertubular material.</p> + <p>Fig. 32 gives us the wall in horizontal section. To the left of this picture we + find the horn tubules cut across, and standing out as so many concentrically ringed + circles. In the centre of the figure are seen the horny laminæ, with their + laminellæ, and the sensitive laminæ. The right portion of the figure + pictures the corium.</p> + <br /> + <a name="a32" id="a32"></a> + <p><a href="images/image032.jpg"><img src="images/image032sm.jpg" + alt="HORIZONTAL SECTION OF HORN OF WALL." /></a></p> + <br /> + + <p>FIG. 32.—HORIZONTAL SECTION OF HORN OF WALL.</p> + <p>Fig. 33 is, again, a horizontal section, cut this time at the junction of the wall + with the sole. To the left are seen, again, the horn tubules of the wall, and to the + centre the horny laminæ. In this position, however, the structures + interdigitating with the horny laminæ are not sensitive, but are themselves + horny. As the diagram shows, they contain regularly arranged horn tubules cut across + obliquely. It is this horn which forms the 'white line.' To the extreme right of the + figure are seen the horn tubules of the sole.</p> + <p>There remains now but to notice the arrangement of the horn tubules in the frog. + The peculiar, indiarubber-like toughness of this organ is well known. Histological + examination gives a reason for this.</p> + <br /> + <a name="a33" id="a33"></a> + <p><a href="images/image033.png"><img src="images/image033sm.png" + alt="HORIZONTAL SECTION OF HORN THROUGH THE JUNCTION OF THE WALL WITH THE SOLE." /> + </a></p> + <br /> + + <p>FIG. 33.—HORIZONTAL SECTION OF HORN THROUGH THE JUNCTION OF THE WALL WITH + THE SOLE. <i>a</i>, Horn tubule of the wall; <i>b</i>, horn tubule of the sole; <i>c, + d</i>, horny laminæ.</p> + <br /> + <a name="a34" id="a34"></a> + <p><a href="images/image034.jpg"><img src="images/image034sm.jpg" + alt="SECTION OF FROG THROUGH CORIUM AND HORN." /></a></p> + <br /> + + <p>FIG. 34.—SECTION OF FROG THROUGH CORIUM AND HORN. The long finger-like + projections of corium into epidermis are sections of the long papillæ from + which the horn-tubes of the sole grow. In the stainable portion of the epidermis are + to be clearly seen light and dark streaks pointing out the alternate strata-like + arrangement of cells mentioned in the text (Mettam).</p> + <p>The horn tubules of the frog are sinuous in their course. This is accounted for by + the fact that in the horn of the frog there is a large amount of intertubular + material, this having the effect of frequently turning the horn tubules from the + straight. In addition to this, the intertubular material has a peculiar arrangement + of the cells composing it. These are laid down in alternating striæ (1) of + cells with their long axes longitudinal, and (2) of cells with their long axes + horizontal. This is seen in Fig. 34, between the long papillæ of the corium, + where the lines of longitudinally arranged cells in horizontal section stand out + darker than the adjoining strata in which their arrangement is horizontal. The + tortuous direction of the horn tubules, and the almost interlocking nature of the + alternating strata of the intertubular material, together combine to give the frog + its characteristic toughness and resiliency.</p> + <h3>C. EXPANSION AND CONTRACTION OF THE HOOF.</h3> + <p>Among other questions productive of heated argument come those relating to + expansion of the horse's hoof. In the past many observers have strenuously insisted + on the fact that expansion and contraction regularly occur during progression. + Opposed to them have been others equally firm in the belief that neither took place. + Quite within recent times this question also has been settled once and for all by the + experiments of A. Lungwitz, of Dresden. His conclusions were published in an article + entitled 'Changes in Form of the Hoof under the Action of the Body-weight.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. iv., + p. 191. The whole of the matter in this article, from which we have borrowed Figs. 35 + and 36, is too long for reproduction here. It forms, however, most instructive + reading, and its careful perusal will well repay everyone interested in this most + important question (H.C.R.).]</p> + <p>In connection with this it is interesting to note how, all unconsciously, two + separate observers were simultaneously arriving by almost identical means at an + equally satisfactory answer to the question. Prior to the publication of Lungwitz's + article on the subject, Colonel F. Smith, A.V.D., had arrived at similar conclusions + by working on the same methods.</p> + <br /> + <a name="a35" id="a35"></a> + <p><a href="images/image035.png"><img src="images/image035sm.png" + alt="Electric Bell with Dry Element." /></a></p> + <br /> + + <p>Fig. 35. I. Electric Bell with Dry Element. a, Under part, with box, for the dry + element; 6, roller for winding up the conducting-wires; c, dry element, with + screw-clamp for attachment of the conducting-wires; c', conducting-wire leading to + the screw-clamp, with contact-spring in c', Fig. 2, or to the wall in Fig. 3; d, + upper part, with bell; d', conducting-wire to the shoe d' in Figs. 2 and 3; e, strap + for slinging the apparatus around the body of the assistant or rider; f, + connecting-wire between bell and dry element.</p> + <p>Fig. 35. II. Hoof Shod with Shoe provided with Toe-piece and Calkins; Wall of the + Hoof covered with Tinfoil. a, Heel angle, with b, the contact-screws; c, screw-clamp, + with contact-spring (isolated from the shoe); c' conducting-wire from the same; d, + screw-clamp, with conducting-wire (d') screwed into the edge of the shoe; e, nails + isolated by cutting a small window in the tinfoil.</p> + <p>Fig. 35. III. Hoof Shod with Plain Shoe; Horny Wall covered with Tinfoil. a, Toe + and heel angle, with b, the contact-screws; c, conducting-wire passing from the + tinfoil on the wall; d, conducting-wire passing from the shoe; c', d', ends of the + conducting-wires, which must be imagined connected with the ends c', d', passing from + the apparatus.</p> + <p>It is unnecessary for our purpose here to minutely describe the exact <i>modus + operandi</i> of these two experimenters. Briefly, the method of inquiry adopted in + each case was the 'push and contact principle' of the ordinary electric bell, and the + close attention which was paid to detail will be sufficiently gathered from Figs. 35 + and 36.</p> + <br /> + <a name="a36" id="a36"></a> + <p><a href="images/image036.png"><img src="images/image036sm.png" + alt="LEFT FORE-FOOT SHOD AND MOUNTED TO RECOGNISE THE SINKING OF THE SOLE." /> + </a></p> + <br /> + + <p>Fig. 36. I. LEFT FORE-FOOT SHOD AND MOUNTED TO RECOGNISE THE SINKING OF THE SOLE. + <i>a</i>, Iron plate covering the inner half of the horny sole; <i>b</i>, openings in + the same, with screw-holes for the reception of the contact-screw <i>c</i> (the part + of the sole under the plate is covered with tinfoil, which at <i>d</i> passes out + under the outer branch of the shoe, and becomes connected with the tinfoil of the + wall; in order to give the freshly applied tinfoil a better hold, copying-tacks are + at <i>e</i> passed through it into the horn, and one is similarly used to protect the + tinfoil at the place where the contact-screw touches the latter); <i>f</i>, holes + with screw thread for the fastening of the angle required to measure the movement of + the wall, and also for the fastening of the conducting-wire, <i>g; h</i>, + conducting-wire passing from the tinfoil; <i>i</i>, isolated nails.</p> + <p>Fig. 36. II. BAR-SHOE WITH OPENINGS. <i>a</i>, Near the inner margin and in the + longitudinal bar; <i>b</i>, for the reception of the contact-screw <i>c; d</i>, + openings for fastening the angle and the conducting-wires.</p> + <p>After numerous experiments with the depicted contact-screws, moved to the various + positions indicated in the drawings, the following conclusions were arrived at:</p> + <p>1. BEHAVIOUR OF THE CORONARY EDGE.—During uniform weighting of all four + hoofs the coronary edge shows a tendency to contraction in the anterior and lateral + regions of the hoof, and a tendency to expansion posteriorly. With heavy weighting of + the hoof, which is shown by a backward inclination of the fetlock, contraction in the + anterior and lateral regions is slight, but the expansion behind, in the region of + the heels, is distinct, commencing gradually in front, becoming stronger, and + diminishing again posteriorly. The coronary edge of the heels becomes slightly bulged + outwards. The bulbs of the heels swell up and incline a little backwards and + downwards.</p> + <p>When the fetlock is raised the expansion of the coronary edge of the heels + disappears from behind forwards, passing forwards like a fluid wave. In the lateral + and anterior regions of the coronary edge the contraction disappears; and when the + weight is thrown off the foot it passes into a gentle expansion of the coronary edge + of the toe. During the opposite movement of the fetlock, that of sinking backwards, + this change of form is executed in the converse manner.</p> + <p>In short, the coronary edge resembles a closed elastic ring, which yields to + pressure, even the most gentle, of the body-weight, in such a way that a bulging out + of any one part is manifested by an inward movement of another part.</p> + <p>In Fig. 37, <i>b</i>, the dotted line represents the changes of form in + comparatively well-formed and sound hoofs at the moment of strongest + over-extension[A] of the fetlock-joint.</p> + <p>[Footnote A: The term 'over-extension,' as employed by Lungwitz, is intended to + indicate that position assumed by the fetlock-joint when the opposite foot is raised + from the ground.]</p> + <p>2. BEHAVIOUR OF THE SOLAR EDGE.—Under the action of the body-weight this is + somewhat different from that of the coronary edge. Anteriorly, and at the sides, as + far as the wall forms an acute angle with the ground, the tendency to expansion + exists, but the change of form first becomes measurable in the region where the + lateral cartilages begin. Quite posteriorly the expansion again diminishes.</p> + <p>Fig. 37, <i>a</i>, by the dotted line represents the expansion at the moment of + over-extension of the fetlock-joint. This expansion is itself rather less than at the + coronary edge, and it shows itself distinctly <i>only when the weighted hoof is + exposed to a counter-pressure on the sole and frog</i>, no matter whether the + counter-pressure is produced naturally or artificially. Thus anything tending to the + removal of the pressure from below, such as a decayed condition of the frog or + excessive paring in the forge, will diminish the extent of expansion of the solar + edge.</p> + <p>Contraction of the solar edge of the heels occurs at the moment of greatest + over-extension of the fetlock-joint—that is, in a foot with pressure from below + absent. On the face of it, this appears impossible. Lungwitz, however, has perfectly + demonstrated it; and, when dealing with the functions of the lateral cartilages in a + later paragraph, we shall show reason for why it is but a simple and natural result + of the foot dynamics.</p> + <p>3. BEHAVIOUR OF THE SOLE.—The horny sole becomes flattened under the action + of the body-weight. This is most distinct at the solar branches, and gradually shades + off anteriorly and towards the circumference. As might be supposed, width of hoof and + thickness of the solar horn exert an influence on the extent of this movement. The + sinking of the horny sole is most marked in flat hoofs.</p> + <h3>D. THE FUNCTIONS OF THE LATERAL CARTILAGES.[A]</h3> + [Footnote A: Extracted from a paper by J.A. Gilruth, M.R.C.V.S., in the <i>Veterinary + Record</i>, vol. v., p. 358.]<br /> + <br /> + + <p>We have just referred to contraction of the heels as taking the place of a normal + expansion in those cases where ground frog-pressure was absent. We shall readily + understand this when we bear in mind the anatomy of the parts concerned, especially + that of the plantar cushion. This wedge-shaped structure we have already described as + occupying the irregular space between the two lateral cartilages, the extremity of + the perforans tendon, and the horny frog.</p> + <p>Now, when weight or pressure is exerted from above on to this organ, and the + <i>frog is in contact with the ground below</i>, it is clear from the position the + cushion occupies that, whatever change of form pressure from above will cause it to + take, it must certainly be limited in various directions.</p> + <br /> + <a name="a37" id="a37"></a> + <p><a href="images/image037.png"><img src="images/image037sm.png" + alt="expansion of the solar edge of the hoof" /></a></p> + <br /> + + <p>FIG. 37. <i>a</i>, The dotted lines in this diagram represent the expansion of the + solar edge of the hoof at the moment of over-extension of the fetlock-joint; + <i>b</i>, the dotted line represents the change in form of the coronary edge under + similar circumstances.</p> + <p>Because of the shape of the cushion its change of form cannot be forwards + (simultaneous pressure from above and below on to this wedge with its apex forwards + must tend to give it a backward change of form). Because of the pastern being + horizontal, and aiding in the downward pressure, its change of form cannot be + upwards. And because of the ground it cannot be downwards. It follows, therefore, + that the movement must be backwards and outwards, being especially directed outwards + because of its shape and the median lacuna in its posterior half—this latter, + the lacuna, accommodating as it does the frog-stay, preventing the tendency to + backward movement becoming excessive, and directing the change of form to the sides. + Where the greatest pressure is transmitted, then, is to the inner aspects of the + flexible lateral cartilages. The coronary cushion being continuous with the plantar, + the backward and outward movements of the latter will tend to pull upon and tighten + the former, especially <i>in front</i>. This will account for the contraction noted + by Lungwitz in the <i>anterior half</i> of the coronary edge of the hoof.</p> + <p>Remove the body-weight, and naturally the elastic nature of the lateral cartilages + and the coronary and plantar cushions, with, in a less degree, that of the hoof, + cause things to assume their normal position.</p> + <p>Repeat the weighting of the hoof, in this second case <i>without + frog-pressure</i>, and we shall see at once that we have done away with one of the + greatest factors in determining the outward and backward movements of the plantar + cushion—namely, the pressure from below on its wedge-shaped mass. The movement + of the plantar cushion will now be <i>downwards</i> as well as backwards; and, seeing + that it is attached to the inner aspect of each lateral cartilage, we shall expect + these latter, by the downward movement of the plantar cushion, to be drawn + <i>inwards</i>. This Lungwitz has shown to occur.</p> + <p>The chief function of the lateral cartilages, therefore, is to <i>receive the + concussion engendered by locomotion</i>, which concussion is directed backwards and + outwards by the pad-like plantar cushion.</p> + <p>In addition to this, the lateral cartilages, together with the plantar and + coronary cushions, <i>play the part of a valve to the whole of the veins of the + foot</i>.</p> + <p>It is in this way: We have only to refer to the chapter on anatomy to see that the + whole of the foot is covered with a tissue of extreme vascularity. Thus we find + papillæ—the over the coronary cushion; enlarged and modified + papillæ sensitive laminæ—covering the anterior face of the os + pedis; and numberless papillæ again covering the sole. There can be no doubt + that the quantity of fluid brought by the bloodvessels of these papillæ to the + foot acts largely as a means of hydraulic protection to the soft structures.[A] In + like manner as that delicate organ, the brain, is best protected by being floated + upon the cerebro-spinal fluid and bloodvessels (which fluids transmit waves of + concussion or pressure <i>through</i> the organ without injury to the delicate cells + forming it), so, in like manner, does the extreme vascularity of the foot protect the + cells of its softer structures from the effects of pressure and concussion.</p> + <p>[Footnote A: The <i>Veterinary Record</i>, vol. iii., p. 518.]</p> + <p>That this law of hydraulics may operate in the horse's foot to the best</p> + <p>advantage, the veins must be provided with valves, and valves of no mean strength. + These we know to be absent. It is here that the lateral cartilages and the elastic + substances of the coronary and plantar cushions step in to supply the deficiency.</p> + <p>At the time when weight is placed upon the foot (with, of course, a tendency to + drive the blood upwards in the limb), and, therefore, the time when a valvular + apparatus is needed to retain the fluid in the foot, we find the wanting conditions + supplied by the pressure outwards of the plantar cushion compressing the large + plexuses of veins on each side of the lateral cartilages, to which plexuses, it will + be remembered, the bulk of the venous blood from the foot was directed. A more + perfect valvular apparatus, automatic and powerful, it would be difficult to + imagine.</p> + <h3>E. GROWTH OF THE HOOF.</h3> + <br /> + <br /> + + <p>We will conclude this chapter with a few brief remarks on the growth of the hoof. + That the rate of growth is slow is a well-known fact to every veterinarian, and it + will serve for all practical purposes when we state that, roughly, the growth of the + wall is about 1/4 inch per month. This rate is regular all round the coronet, from + which it follows that the time taken for horn to grow from the coronary edge to the + inferior margin will vary according as the toe, the quarters, or the heels are under + consideration.</p> + <p>As might naturally be expected, the rate of growth will depend on various + influences. Any stimulus to the secreting structures of the coronet, such as a + blister, the application of the hot iron, or any other irritant, results in an + increased growth. Growth is favoured by moisture and by the animal going unshod, as + witness the effects of turning out to grass. Exercise, a state of good health, + stimulating diets—in fact, anything tending to an increased circulation of + healthy blood—all lead to increased production of horn. With the effects of + bodily disease and of ill-formed legs and feet on the wear of the hoof, and the + growth of horn, we shall be concerned in a future chapter.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER IV</h3> + <h3><a name="exam" id="exam">METHOD OF EXAMINING THE FOOT</a></h3> + <p>As a general rule, it may be taken that most diseases of the foot are + comparatively easy of diagnosis. When, however, the condition is one which commences + simply with an initial lameness, the greatest care will have to be exercised by the + practitioner.</p> + <p>What remarks follow here should rightly be confined to a treatise on lameness. + This much, however, we may state: As compared with lameness arising from abnormal + conditions in other parts of the limb, that emanating from abnormalities of the foot + is easy of detection. With a case of lameness before him, concerning which he is in + doubt, the practitioner remembers that a very large percentage may safely be referred + to the foot, and, if wise, subjects the foot to a rigorous examination.</p> + <p>Much may be gathered by first putting the animal through his paces. When at a + trot, notice the peculiarity of the 'drop,' whether any alteration in going on hard + or soft ground, and watch for any special characteristic in gait. At the same time + inquiry should be made as to the history of the case; its duration; whether pain, as + evidenced by lameness, is constant or periodic; the effect of exercise on the + lameness; and the length of time elapsed since the last shoeing.</p> + <p>This failing to reveal adequate cause for the lameness in any higher part of the + limb, one is led, by a process of negative deduction, to suspect the foot. If + 'pointing' is a symptom, its manner is noticed. The foot is compared with the other + for any deviation from the normal. In some cases the two fore or the two hind feet + may differ in size. Though this may not necessarily indicate disease, it may, + nevertheless, be taken into account if the lameness is not easily referable to any + other member. Measurement with calipers will then be of help, and a pronounced + increase in size, especially if marked in one position only, given due consideration. + The hand is used upon each foot alternately to look for change of temperature, to + detect the presence of growths small enough to escape the eye, and to discover + evidence of painful spots along the coronet.</p> + <p>At this stage the method of percussion recommends itself, and in many cases no + more useful diagnostic agent is to be found than the ordinary hammer. As a + preliminary, the foot of the sound limb should be always tapped first. This + precaution will serve to bring to light what is frequently met with—the + aversion nervous animals sometimes exhibit to this manner of manipulation of the + hoof. Unless this is done, the ordinary objection to interference is apt to be read + as evidence of pain. No aversion to the method being shown, the suspected foot is + gently tapped in various places round the wall, a keen look-out being kept for any + manifestation of tenderness. This may vary from a slight resentment to each tap, + indicated by a sudden lifting and setting down again of the foot, to a complete + removal of the foot from the ground, and a characteristic pawing of the air that + points out clearly enough the seat of pain.</p> + <p>Evidence of pain once given, the tapping is persisted in until, in some cases, the + exact position of the tender spot is definitely located.</p> + <p>Failing evidence obtained from percussion, attention should next be given to the + shoeing. We may add here that, even when difficulties have to be encountered in doing + it, it is always a wise plan to have the shoe removed.</p> + <p>The nails should be removed one by one, the course they have taken, their point of + emergence on the wall, and the condition of their broken ends all being carefully + noted as they are withdrawn.</p> + <p>The removed shoe should next be examined as to the coarseness or fineness of its + punching and the 'pitch' of its nail-holes, and close attention given to the shape of + its bearing surface.</p> + <p>From that we may pass to a consideration of the underneath surface of the foot. + The drawing-knife should be run lightly over the whole of its surface, the first + thing to be noticed being the point of entrance of the nails as compared with the + coarseness or fineness of the punching, and the staining or otherwise of the horn + immediately around. We may thus be guided towards mischief arising from tight nailing + apart from actual prick of the foot.</p> + <p>This done, more than usual care should be taken in following up any other small + prick or dark spot that may show itself upon the white surface of the cleaned sole. + In any case, a suspicious-looking speck should be followed up with the searcher until + it is either cut out or is traced to the sensitive structures.</p> + <p>While this is done, we should also have noticed the condition of the horn at the + seat of corn; should have noticed the shape of the heels, contracted or otherwise; + and the appearance of the frog, clean or discharging.</p> + <p>A point to be remembered in making this exploratory paring of the foot is the + peculiar consistency of the horn of the frog, and its tendency to hide the existence + of punctures. In like manner, as a pin pierces a piece of indiarubber, and leaves no + clearly visible trace of the hole it has made, so does a nail or other sharp object + penetrate the frog, leaving but little to show for the mischief that has been + done.</p> + <p>After all, even though we may have fully decided the foot is at fault, our case of + lameness may remain obscure so far as a cause is concerned. Nothing remains, then, + but to acknowledge the inability to discover it, to advocate poulticing, or some + other expectant palliative measure, and to bring the case up for further examination + at no distant date. Where, though we may have suspected the foot, we have not been + able to definitely assure ourselves that there the mischief is to be found, a further + method of examination presents itself—namely, subcutaneous injections of + cocaine along the course of the plantar nerves.</p> + <p>The salt of cocaine used is the hydrochlorate, 2-1/2 grains for a pony, 4 grains + for a medium-sized animal, and 6 grains for a large horse. A solution of this is made + in boiled water (about 3 drams), and injected at the seat of the lower operation of + neurectomy.</p> + <p>It is advisable to first render aseptic the seat of operation, and to sterilize + both the needle and the syringe by boiling. A suitable point to choose for the + injection is exactly over the upper border of the lateral faces of the two sesamoids, + the needle being introduced behind the cord formed by the nerve and accompanying + vessels, and parallel with it.</p> + <p>It is possible that the vein or the artery may be wounded, but such accident is of + little importance. All that is necessary in that case is to partly withdraw the + needle and again insert it. It is advisable to use a twitch.</p> + <p>When the needle is in position, the injection should be made slowly, and at the + same time the point of the needle should be made to describe a semicircular sweep, so + as to spread the solution over as wide an area as is possible.</p> + <p>Anæsthesia ensues in from six to twenty minutes, and if the cause of the + lameness is below the point of injection the animal moves sound.</p> + <p>Regarding this method of diagnosis, Professor Udriski of Bucharest, after a series + of trials, sums up as follows:</p> + <p>1. For the diagnosis of lameness cocaine injections are of very considerable + value.</p> + <p>2. These injections should be made along the course of the nerves.</p> + <p>3. Solutions heated to 40° or 50° C. produced quicker, deeper, and longer + anæsthesia than equally strong cold solutions.</p> + <p>4. In the sale of horses cocaine injections conceal fraud.</p> + <p>Cocaine being an irritant, it must be remembered that after the anæsthesia + the lameness is somewhat more marked than before.</p> + <p>To the cocaine other practitioners add morphia in the following proportions:</p> + <table border="1" width="100%" summary="Proportions of cocaine and Morphia for the anesthetic injection"> + <tr> + <td>Cocaine hydrochlorate</td> + <td>2-1/2 grains.</td> + </tr> + <tr> + <td>Morphia</td> + <td>1-1/2 "</td> + </tr> + <tr> + <td>Aqua destil</td> + <td>1-1/2 drams.</td> + </tr> + </table> + <br /> + + <p>As a diagnostic this mixture of the two is said to be far superior to either + cocaine or morphia alone.</p> + <p>In connection with this subject, Professor Hobday has published, among others, the + following cases illustrating the practical value of this method of diagnosis:[A]</p> + <p>[Footnote A: The <i>Journal of Comparative Pathology and Therapeutics</i> vol. + viii., pp. 27, 43.]</p> + <p>CASE I.—Cab gelding. Seat of lameness somewhat obscure; navicular disease + suspected. Injected 2 grains of cocaine in aqueous solution on either side of the + limb, immediately over the metacarpal nerves.</p> + <p><i>Five Minutes</i>.—Lameness perceptibly diminished.</p> + <p><i>Ten Minutes</i>.—Lameness scarcely perceptible.</p> + <p>CASE II.—Mare. Obscure lameness; foot suspected. Injected 30 minims of a 5 + per cent. solution on either side of the leg just above the fetlock.</p> + <p><i>Ten Minutes</i>.—No lameness, thus proving that the seat of lameness was + below the point of injection.</p> + <p>CASE III.—Cab gelding, aged, free clinique; Messrs. Elme's and Moffat's + case. Obscure lameness; foot suspected of navicular disease; very lame. Injected 30 + minims of a 5 per cent. solution of cocaine on either side of the leg over the + metacarpal nerves.</p> + <p><i>Six Minutes</i>.—Lameness perceptibly less; there was no response + whatever on the inside of the leg to the prick of a pin. On the outside, which had + not been injected so thoroughly, there was sensation, although not so much as in a + healthy foot.</p> + <p><i>Ten Minutes</i>.—Lameness had almost disappeared; so much so, that the + opinion as to navicular disease was confirmed, and neurectomy was performed. + Immediately after this operation there was no lameness whatever.</p> + <p>The same author also reports numerous cases among horses and cattle, dogs and + cats, pointing out the toxic properties of the drug. The symptoms following an + overdose are interesting enough to relate here, and I select the following case of + Professor Hobday's as being fairly typical:[A]</p> + <p>[Footnote A: <i>Loc. cit</i>.]</p> + <p>CASE IV.—Cart gelding. Free clinique; navicular disease. Injected + subcutaneously over the metacarpal nerves on each side 6 grains of cocaine in aqueous + solution. During the operation the animal manifested no signs of pain whatever, not + even when the nerve was cut. This animal received altogether 12 grains of cocaine (3 + grains were given on either side first, then fifteen minutes afterwards the same dose + repeated). The effect was manifested on the system in ten minutes after the second + injection by clonic spasms of the muscles of the limbs (the legs being involuntarily + jerked backwards and forwards at intervals of about twenty seconds), which materially + interfered with the performance of the operation. The animal was also continually + moving the jaws, and was very sensitive to sounds, moving the ears backwards and + forwards. This hyperæsthesia, as evinced by the movement of the ears, lasted + for some considerable time after the animal had been allowed to get up.</p> + <p>Cocaine hydrochlorate solutions, if intended to be kept for any length of time, + should have added to them when freshly made 1/200 part of boric acid in order to + preserve them. Even then they are liable to spoil, and should, for subcutaneous + injection, be made up just before needed for use.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER V</h3> + <h3><a name="operations" id="operations">GENERAL REMARKS ON OPERATIONS ON THE + FOOT</a></h3> + <h3>A. METHODS OF RESTRAINT.</h3> + <p>Many of the simple operations on the foot, such as the probing of a sinus, the + paring out of corns, or the searching of pricks, may most suitably be performed with + the animal's leg held by the operator as a smith holds it for shoeing. According to + the temperament of the animal, even the operation for the removal of a portion of the + sole, or the injection of sinuses with caustics, may be carried out with the animal + simply twitched.</p> + <p>When the operation is still a simple one, casting inconvenient or impossible, and + the animal restive, the twitch must be supplemented by some other method. The most + simple and one of the most effective is the blind, cap, or bluff (Fig. 38). With it + the most vicious animal or the most nervous is in many instances either cowed into + submission or soothed into quietness.</p> + <p>At the same time, more forcible means than the operator's own strength must be + taken to hold the animal's foot from the ground. If the foot is a fore-foot, and the + point desired to be operated on is to the outside, the pastern should be firmly + lashed to the forearm by means of a thin, short cord, or a leather strap and buckle. + Much may then be done in the way of paring and probing that would otherwise be + impossible.</p> + <br /> + <a name="a38" id="a38"></a> + <p><a href="images/image038.png"><img src="images/image038sm.png" alt="The BLIND." /> + </a></p> + <br /> + + <p>Fig. 38—The BLIND.</p> + <br /> + <a name="a39" id="a39"></a> + <p><a href="images/image039.png"><img src="images/image039sm.png" + alt="THE SIDE-LINE." /></a></p> + <br /> + + <p>Fig. 39—THE SIDE-LINE.</p> + <p>If the foot is a hind one, one of the many methods of using what is termed by + Liautard, in his 'Manual of Operative Veterinary Surgery,' the plate-longe, must be + adopted. This, in its most useful form, is a length of closely-woven cotton webbing, + from about 2 to 2-1/2 inches wide, and from 5 to 6 yards long, provided with a small + loop formed on one of its ends, and perhaps better known to English readers as a + 'side-line.' If webbing be not available, a length of soft cotton rope, or a rope + plaited and sold for the purpose, as Fig. 39, will serve equally well. One of the + most convenient methods of using the side-line for securing the hind-foot is depicted + in Figs. 40 and 41.</p> + <br /> + <a name="a40" id="a40"></a> + <p><a href="images/image040.jpg"><img src="images/image040sm.jpg" + alt="THE SIDE-LINE ADJUSTED PREPARATORY TO SECURING THE NEAR HIND-FOOT." /></a></p> + <br /> + + <p>FIG. 40.—THE SIDE-LINE ADJUSTED PREPARATORY TO SECURING THE NEAR + HIND-FOOT.</p> + <br /> + <a name="a41" id="a41"></a> + <p><a href="images/image041.jpg"><img src="images/image041sm.jpg" + alt="THE NEAR HIND-FOOT SECURED WITH THE SIDE-LINE." /></a></p> + <br /> + + <p>FIG. 41.—THE NEAR HIND-FOOT SECURED WITH THE SIDE-LINE.</p> + <p>Here the side-line has formed upon it a loop sufficiently large to form a collar. + This is placed round the animal's neck, the free end of the line run round the + pastern of the desired foot, and the foot drawn forward, as in Fig. 40.</p> + <p>The loose end of the line is then twisted once or twice round the tight portion, + and finally given to an assistant to hold (see Fig. 41). The foot is thus held from + the ground, and violent kicking movements prevented.</p> + <p>Where the operation is a major one, restraint of a distinctly more forcible nature + becomes imperative. Many of the more serious operations can most advantageously be + performed with the patient secured in some form or other of stock or trevis, and the + foot suitably fixed. It is not the good fortune of every veterinary surgeon, however, + to be the lucky possessor of one of these useful aids to successful operating. + Perforce, he must fall back on casting with the hobbles (Fig. 42).</p> + <br /> + <a name="a42" id="a42"></a> + <p><a href="images/image042.png"><img src="images/image042sm.png" + alt="CASTING HOBBLES." /></a></p> + <br /> + + <p>FIG. 42.—CASTING HOBBLES.</p> + <p>With the use of these we will assume our readers to be conversant, and will + imagine the animal to be already cast. It remains, then, but to detail the most + suitable means for firmly fixing the foot to be operated on.</p> + <p>Here the side-line is again brought into use. Care should previously have been + taken when casting to throw the animal so that the portion of the foot to be operated + on, whether inside or outside, falls uppermost, and that the buckle of the hobble on + that particular foot is placed so that it also is within easy reach when the animal + is down.</p> + <p>In the case we are illustrating the point of operation was the outside of the near + hind coronet. We will, therefore, describe the mode of fixing the near hind-foot upon + the cannon of the near fore-limb.</p> + <br /> + <a name="a43" id="a43"></a> + <p><a href="images/image043.jpg"><img src="images/image043sm.jpg" + alt="PHOTOGRAPH ILLUSTRATING METHOD OF ADJUSTING THE SIDE-LINE PREPARATORY TO FIXING THE HIND-LEG UPON THE FORE." /> + </a></p> + <br /> + + <p>FIG. 43.—PHOTOGRAPH ILLUSTRATING METHOD OF ADJUSTING THE SIDE-LINE + PREPARATORY TO FIXING THE HIND-LEG UPON THE FORE.</p> + <p>The side-line is first adjusted as follows: It is fixed upon the cannon of the + near hind-leg (A) by means of its small loop. From there it is passed under the + forearm of the same limb, over the forearm, under the rope running from A to B; from + there over and under the thigh, to be finally brought in front of the thigh, and + below the portion of rope running from arm to thigh. The loose end of the side-line + is then given to an assistant standing behind the animal's back, the buckle of the + hobble restraining the foot unloosed, and strong but steady traction brought to bear + from behind upon the line. The operator should now stand in front of the fore-limbs, + and, by placing a hand on the rope passing round the arm, prevent the line from + slipping below the knee.</p> + <p>By this means the hind-limb is pulled forward until the foot projects beyond the + cannon of the front-limb. When that position is reached, the operator grasps the hock + firmly with one hand, and, directing the side-line to be slackened, gently slides + downward the coils of rope round the arm and thigh until they encircle the cannons of + both limbs. The cannon of the hind-limb is firmly lashed to the cannon of the fore, + and the foot firmly and securely fixed in the best position for operating (see Fig. + 44).</p> + <br /> + <a name="a44" id="a44"></a> + <p><a href="images/image044.jpg"><img src="images/image044sm.jpg" + alt="PHOTOGRAPH SHOWING THE NEAR HIND-FOOT SECURED UPON THE CANNON OF THE NEAR FORE-LIMB." /> + </a></p> + <br /> + + <p>FIG. 44.—PHOTOGRAPH SHOWING THE NEAR HIND-FOOT SECURED UPON THE CANNON OF + THE NEAR FORE-LIMB.</p> + <p>Similarly, with the horse still on his off side, the off hind-limb may be fixed to + the near fore, and the near fore and the off fore to the near hind.</p> + <p>With the animal on his near side, we may fix the near hind and the off hind to the + off fore, and the off fore and near fore to the near hind.</p> + <p>The points to be remembered in fixing the limbs thus are: (1) The side-line should + always commence upon the cannon of the limb to be operated on; (2) it should next + pass under and over (or over and under, it is immaterial which) first the arm and + then the thigh, or the thigh and the arm, as the case may be; (3) in every case, + whether rounding the thigh and the arm from above or below, the piece of rope + completing the round should always finish below that portion preceding it, so that + traction upon it from behind the animal's back should tend to keep all portions of it + from slipping below the knee and the hock.</p> + <p>With the uppermost fore-limb secured to the hind-limb in the manner we have + described, we have the underneath fore-limb suitably exposed for both the higher and + lower operations of neurectomy. The position for this operation will be made better + still if the lowermost limb (the one to be operated on) is removed from the hobbles + and drawn forward by an assistant by means of a piece of rope fastened to the + pastern.</p> + <p>Taking what we have described as a general guide, other modifications of thus + securing the foot will suggest themselves to the operator to meet the special + requirements of the case with which he is dealing.</p> + <p>Regarding the administration of chloroform, no description of the method is needed + here, as it will be found fully detailed in most good works on general surgery. Where + great immobility is needed, it is one of the most valuable means of restraint we + have. Apart from that, its use in any serious operation is always to be advocated, if + only on the score of humane consideration for the dumb animal helpless under our + hands.</p> + <h3>B. INSTRUMENTS REQUIRED.</h3> + <p>In addition to those required for operations on the softer structures—such + as scalpels, forceps, artery forceps, directors, scissors, etc.—the surgery of + the foot demands instruments specially adapted for dealing with the horn.</p> + <p>A great deal will depend upon the operator as to whether these are few or many. + The average man of resource will deem a smith's rasp and one or two strong + drawing-knives amply sufficient, and on no account should they be omitted from the + list of those ready to hand.</p> + <br /> + <a name="a45" id="a45"></a> + <p><a href="images/image045.png"><img src="images/image045sm.png" + alt="THE ORDINARY DRAWING-KNIFE." /></a></p> + <br /> + + <p>FIG. 45.—THE ORDINARY DRAWING-KNIFE. The ordinary smith's drawing-knife + (Fig. 45) is well known to almost everyone, and is well suited for much of the + rougher part of the work. The careful following up of pricks, however, and some of + the more special operations demanding removal of portions of the lateral cartilages + call for instruments of a more delicate character and peculiar construction. These + are to be found in the so-called sage-knife, and the modern (French) pattern of + drawing-knife.</p> + <br /> + <a name="a46" id="a46"></a> + <p><a href="images/image046.png"><img src="images/image046sm.png" + alt="Modern forms of drawing-knife" /></a></p> + <br /> + + <p>FIG. 46. <i>a, b</i>, Modern forms of drawing-knife; <i>c, d, e</i>, sage-knives. + The modern drawing-knife differs from the smith's instrument in being attached to a + straight, instead of a curved, handle, and in usually being sharp on both edges + instead of only on one. These are made in various sizes (Fig. 46, <i>a, b</i>), and + the blades flat, curved on the flat, or curved at an angle with the edges of the + haft.</p> + <p>The sage-knife, as its name indicates, is a knife with a lanceolate-shaped blade. + These also may be obtained in varying forms and sizes (Fig. 46, <i>c, d, e</i>). Fig. + 46, <i>c</i>, is a single-edged, right-handed sage-knife. Fig. 46, <i>d</i>, is a + left-handed instrument of the same type. The double-edged sage-knife is represented + in Fig. 46, <i>e</i>.</p> + <br /> + <a name="a47" id="a47"></a> + <p><a href="images/image047.png"><img src="images/image047sm.png" + alt="SYMES'S ABSCESS-KNIFE." /></a></p> + <br /> + + <p>FIG. 47.—SYMES'S ABSCESS-KNIFE.</p> + <p>It may be mentioned too, in passing, that the ordinary Symes's abscess-knife (Fig. + 47) is a most useful instrument when performing the operation of partial excision of + the lateral cartilages, its peculiar shape lending itself admirably to the niceties + of the operation.</p> + <p>One or two good-shaped firing-irons will also be found useful. They will lighten + the labour of tediously excavating grooves with the knife, where that procedure is + necessary; and, used in certain positions to be afterwards described, will afford + just that necessary degree of stimulus to the horn-secreting structures of the foot, + which the use of the knife alone will not.</p> + <p>The man in country practice will also be well advised in carrying to every foot + case a compact outfit, such as that carried by the smith. This will consist of hammer + and pincers, drawing-knife and buffer. Much valuable time is then often saved which + would otherwise be wasted in driving round for the nearest smith.</p> + <p>There are other special operations requiring the use of specially-devised + instruments for their successful carrying out. These we shall mention when we come to + a consideration of the operations in which they are necessary.</p> + <h3>C. THE APPLICATION OF DRESSINGS.</h3> + <p>One of the most common methods of applying a dressing to the foot is poulticing. + Usually resorted to on account of its warmth-retaining properties, the poultice may + also be medicated. In fact, a poultice, strongly impregnated with perchloride of + mercury or other powerful antiseptic, is a useful dressing in a case of a punctured + foot, or a wise preliminary to an operation involving the wounding of the deeper + structures. The poultice may consist of any material that serves to retain heat for + the longest time. Meal of any kind that contains a fair percentage of oil is + suitable. Crushed linseed, linseed and bran, or linseed-cake dust are among the + best.</p> + <p>To prepare it, all that is necessary is to partly fill a bucket with the material + and pour upon it boiling water. The hot mass is emptied into a suitable bag, at the + bottom of which it is wise to first place a thin layer of straw, in order to prevent + the bag wearing through, and then secured round the foot. This is generally done by + means of a piece of stout cord, or by straps and buckles fastened round the pastern + and above the fetlock.</p> + <p>An improved method of fastening has been devised by Lieutenant-Colonel Nunn:</p> + <p>'A thin rope or stout piece of cord about 5 feet long is doubled in two, and a + knot tied at the double end so as to form a loop about 5 or 6 inches long, this + length depending on the size of the foot (as at A, Fig. 48). The poultice or other + dressing is applied to the foot, and the cloth wrapped round in the ordinary way, the + loop of the cord being placed at the back of the pastern (as in A, Fig. 49); the ends + of the cord are passed round, one on the inside and the other on the outside, towards + the front (as in B, Fig. 49). These ends are then twined together down as far as the + toe (see C in Fig. 49). The foot is now lifted up, and the ends of the cord (CC, Fig. + 49), are passed through the loop A (as at D, Fig. 49), and then drawn tight. The ends + of the cord are now separated, and carried up to the coronet (as at EE, Fig. 49), one + on the outside, the other on the inside of the foot. They are then again twisted + round each other once or twice (as at F, Fig. 50), and are passed round the pastern + once or twice on each side. They are now passed under the cord (E, Fig. 49), and then + reversed, so as to tighten up E, and are finally tied round the pastern in the usual + manner. The arrangement of the cords on the sole is shown in Fig. 51, which is a view + from the posterior part.</p> + <br /> + <table summary="Table to display images"> + <tr> + <td> + <a name="a48" id="a48"></a> + <p><a href="images/image048.png"><img src="images/image048sm.png" + alt="FIG. 48." height="100" /></a></p> + </td> + <td> + <a name="a49" id="a49"></a> + <p><a href="images/image049.png"><img src="images/image049sm.png" + alt="FIG. 49." height="100" /></a></p> + </td> + <td> + <a name="a50" id="a50"></a> + <p><a href="images/image050.png"><img src="images/image050sm.png" + alt="FIG. 50." height="100" /></a></p> + </td> + <td> + <a name="a51" id="a51"></a> + <p><a href="images/image051.png"><img src="images/image051sm.png" + alt="FIG. 51." height="100" /></a></p> + </td> + </tr> + <tr> + <td>FIG. 48.</td> + <td>FIG. 49.</td> + <td>FIG. 50.</td> + <td>FIG. 51.</td> + </tr> + </table> + <p>FIGS. 48, 49, 50, 51.—ILLUSTRATING LIEUTENANT-COLONEL NUNN'S METHOD OF + APPLYING A POULTICE TO THE FOOT.</p> + <p>'The advantages of this method of fastening have been found to be: (1) It does not + chafe the skin; (2) if properly applied it has never been known to come undone; (3) + it is the only way we know that a poultice can be satisfactorily applied to a mule's + hind-foot; (4) horses can be exercised when the poultice is on the foot, which is + almost impossible with the ordinary leather boot; (5) the sacking or canvas does not + cut through so quickly.'</p> + <br /> + <table summary="Table to display images"> + <tr> + <td> + <a name="a52" id="a52"></a> + <p><a href="images/image052.png"><img src="images/image052sm.png" + alt="FIG. 52." height="100" /></a></p> + </td> + <td> + <a name="a53" id="a53"></a> + <p><a href="images/image053.png"><img src="images/image053sm.png" + alt="FIG. 53." height="100" /></a></p> + </td> + </tr> + <tr> + <td>FIG. 52.</td> + <td>FIG. 53.</td> + </tr> + </table> + <p>FIGS. 52, 53.—TWO FORMS OF POULTICE-BOOT.</p> + <p>A further method of applying the poultice is by using one of the poultice-boots + made for that purpose (see Figs. 52 and 53).</p> + <p>These have an objection. They are apt to be allowed to get extremely dirty, and + so, by carrying infective matter from the foot of one animal to that of another, undo + the good that the warmth of the poultice is bringing about. The advantage of the + ordinary sacking or canvas is that it may be cast aside after the application of each + poultice. Where the boot is kept clean, however, it will save a great deal of time + and trouble to the attendant.</p> + <p>While on the subject of poulticing, it is well to remark that in many cases it may + be more advantageous to supply the necessary warmth and moisture to the foot by + keeping it immersed in a narrow tub of water maintained at the required temperature. + By this means the warmth is carried further up the limb (sometimes an important + point), and the water can more conveniently be medicated with whatever is required + than can the poultice. In fact, it is the author's general practice, where the + attendants can be induced to take the necessary pains, to always advise this latter + method.</p> + <br /> + <a name="a54" id="a54"></a> + <p><a href="images/image054.png"><img src="images/image054sm.png" + alt="SWAB FOR APPLYING MOISTURE TO THE FOOT." /></a></p> + <br /> + + <p>FIG. 54.—SWAB FOR APPLYING MOISTURE TO THE FOOT.</p> + <p>Where a dressing is relied upon by some practitioners on account of the warmth it + gives, others, even in identical cases, will depend upon the effects of cold. This + may be applied by means of what are called 'swabs.' In their simplest form swabs may + consist only of hay-bands or several layers of thick bandage bound round the foot and + coronet, and kept cool by having water constantly poured upon them. In many cases the + form of swab depicted in Fig. 54 will be found more convenient.</p> + <p>When only one foot is required to be dressed, and a water-supply is available, by + far the preferable method is to attach one end of a length of rubber tubing to the + water-tap, and fasten the other just above the coronet, allowing the water to trickle + slowly over the foot. In cases where a forced water-supply is unobtainable, and the + case warrants the extra trouble, much may be done with a medium-sized cask of water + placed somewhere over the animal, and the rubber tubing connected with that.</p> + <p>Where the dressing is desired to be kept applied to the sole and frog only, there + is no method more satisfactory than the shoe with plates.</p> + <br /> + <a name="a55" id="a55"></a> + <p><a href="images/image055.png"><img src="images/image055sm.png" + alt="THE SHOE WITH PLATES." /></a></p> + <br /> + + <p>FIG. 55.—THE SHOE WITH PLATES. <i>A</i>, The plates in position; <i>B</i>, + the plates separated from the shoe.</p> + <br /> + <a name="a56" id="a56"></a> + <p><a href="images/image056.png"><img src="images/image056sm.png" + alt="THE QUITTOR SYRINGE." /></a></p> + <br /> + + <p>FIG. 56.—THE QUITTOR SYRINGE.</p> + <p>The plates are of metal, preferably of thin sheet iron or zinc, and are slipped + between the upper surface of the shoe and the foot after the manner shown in Fig. 55. + The plates themselves are shaped as depicted in Fig. 55, <i>a, b, c, a</i> and + <i>b</i> curved to meet the outlines of the shoe, and <i>c</i> shaped so as to wedge + tightly over the posterior ends of the side plates, and between them and the shoe. A + distinct advantage of the plate method of dressing is that a certain amount of + pressure may be maintained on the sole and frog, a very important consideration in + connection with some of the diseases with which we shall later deal.</p> + <p>When dealing with sinuous wounds of the foot, another favourite mode of applying + dressings is by means of the syringe, and no better instrument for all cases can be + found than that known as a quittor syringe (Fig. 56).</p> + <p>A further mode of applying dressing, and one frequently practised in connection + with the foot, is known as 'plugging.' This is almost sufficiently indicated by its + name. It consists in rolling portions of the dressing into little cylinders, wrapped + round with thin paper, and introduced into a sinus or other position where considered + necessary.</p> + <h3>D. PLANTAR NEURECTOMY.</h3> + <p>As a last resort in the treatment of many diseases of the foot the operation of + neurectomy is often advised. It will be wise, therefore, to insert a description of + the operation here.</p> + <p><i>Derivation of the Word</i>.—For many years the operation was known simply + as 'nerving' or 'unnerving,' and it was not until 1823, at the suggestion of Dr. + George Pearson, that Percival introduced the word <i>neurotomy</i> to signify the + operation with which we are now about to deal. The word neurotomy, however, used + strictly, means the act or practice of dissection of nerves, and, when applied to the + operation as practised to-day, describes only a step in the procedure.</p> + <p>As the operation really consists in cutting down upon, and afterwards excising a + portion of the nerve, the modern appellation of <i>neurectomy</i>—from the + Greek <i>neuron</i>, a nerve; and <i>tome</i>, a cutting, signifying the cutting out + of a nerve or the portion of a nerve—is far more suitable.</p> + <p>According as the nerve operated on is the plantar or the median, the operation is + known as plantar or median neurectomy.</p> + <p><i>History of the Operation</i>.—It is to two English veterinarians that we + owe the introduction of the operation to the veterinary world. In 1819 Professor + Sewell announced himself as the originator of neurotomy. This claim was disputed by + Moorcraft, who appears to have successfully shown himself to be the real person + entitled to that honour, he having satisfactorily performed the operation on numerous + animals for fully eighteen years prior to Professor Sewell's announcement. It appears + that Moorcraft left this country for India in 1808, having practised the operation in + more or less obscurity for some six or seven years previous to that. After his + departure neurectomy, as introduced by him, either died away in repute, or was not + made by him sufficiently public to become a matter of general knowledge. To Professor + Sewell, therefore, although not the actual originator of the operation, belongs the + honour of making it public to the veterinary profession.</p> + <p>In 1824, five years after Sewell's introduction, we find it practised on the + Continent by Girard. We gather, however, from the writings of Percival and Liautard, + that both in this country and on the Continent the operation was for several years + largely in the stage of experiment. Unsuitable subjects were operated on; the work + afterwards given to the animal improperly adjusted to his altered condition; and the + bad after-results of the operation almost ignored by some, and greatly exaggerated by + others. In fact, some long time elapsed before veterinary surgeons allotted to the + operation that measure of credit which the results following it warranted.</p> + <p><i>The Object of the Operation</i> is to render the foot insensitive to pain, and + to give to an otherwise incurably lame animal a further period of usefulness. After + the operation, as time goes on, this object may become defeated by the reunion of the + divided ends of the nerve. In that case, neurectomy must necessarily be performed + again.</p> + <p><i>The Operation</i>.—Two forms of neurectomy are recognised—the high + operation and the low. The low operation deals with the posterior digital branch of + the plantar nerve, and the high operation with the plantar itself.</p> + <p>It is the latter operation with which we shall deal first. In our opinion it is + that most likely to be followed by satisfactory results. The area supplied by the + posterior digital is mainly the posterior portion of the digit. Thus, unless the + cause of the lameness is diagnosed with certainty to be situated somewhere in the + posterior region of the foot, section of the posterior digital alone will not give + total insensibility to pain. Added to that, we may remember this: Below the point at + which the digitals branch off from the plantar there is always more likelihood of the + part we are attempting to render insensible being supplied by another and + adventitious branch, or a branch that, as regards its direction, is abnormally + distributed. As a last consideration, we may say that the higher operation is the + easier to perform.</p> + <p>Percival, in his works on lameness, has some very sage remarks to make by way of a + preliminary, and we cannot do better than quote them here. He says:</p> + <p>'To command success in neurectomy three considerations demand attention:</p> + <p>'1. The subject must be fit and proper; in particular, the disease for which + neurectomy is performed should be suitable in kind, seat, stage, etc.</p> + <p>'2. The operation must be skilfully and effectually performed.</p> + <p>'3. The use that is made of the patient afterwards should not exceed what his + altered condition appears to have fitted him for.</p> + <p>'The veterinarian who is guided by considerations such as those will find that he + has restored to work horses who would otherwise have been utterly useless. A plain + and safe argument wherewith to meet the objections to neurectomy is simply to ask the + question what the animal is worth, or to what useful purpose he can be put, that + happens to be the subject of such an operation.</p> + <p>'If the horse can be shown to be still serviceable and valuable, then he is not a + legitimate subject for the operation. The rule of procedure I have laid down is to + operate on no other but the <i>incurably lame horse</i>; and whenever this has been + attended to, not only has success been the more brilliant, but indemnification from + blame or reproach has been assured.'</p> + <p><i>Preparation of the Subject</i>.—But little in the way of medicinal + preparation is necessary. When the animal is a gross, heavy feeder, and carries a + more than ordinary amount of cupboard, all that is needed is to withhold his usual + allowance of food for some time prior to the operation, simply to avoid risk of + rupture when casting. If considered advisable, a dose of physic may also be + administered.</p> + <p>To the seat of operation, however, careful attention should be given. On the day + previous to the operation the hair should be closely removed with the clipping + machines, and the skin thoroughly cleansed with warm water and soap. After this, a + bandage soaked in a 4 per cent, watery solution of carbolic acid should be wrapped + lightly round the limb, and allowed to remain in position until the animal is cast + and ready for the operation the following morning. On removing the bandage prior to + operating, the part should again be bathed with a cold 5 per cent. solution of + carbolic acid and swabbed dry. Attention to these details will serve to leave the + wound in that favourable condition in which it heals nicely, and with the minimum + amount of trouble.</p> + <p><i>Preliminary Steps</i>.—By some practitioners the operation is performed + with the animal standing, local anæsthesia having been first obtained by the + use of cocaine, or an ethyl chloride spray. There is no gainsaying the fact, however, + that the operation of neurectomy is a painful one, and that, with most operators, + success will be more fully guaranteed with the animal cast and the limb held in a + suitable position by an assistant.</p> + <p>The animal is thrown by the hobbles upon the side of the leg which is to be + operated on. The cannon of the upper fore-limb is then fixed to the cannon of the + upper hind, as described under the section of this chapter devoted to the methods of + restraint, and the lower limb freed from the hobbles and drawn forward by an + assistant by means of a stout piece of cord round the pastern.</p> + <p>An alternative method of holding the limb is to bind both fore-legs together above + the knee by means of the side-line run round a few times in the form of the figure 8, + and then fastened off. As in the former method, the lower foot is then removed from + the hobble, and again held forward by an assistant. By either method the inside of + the limb is operated on first.</p> + <br /> + <a name="a57" id="a57"></a> + <p><a href="images/image057.png"><img src="images/image057sm.png" + alt="THE ESMARCH RUBBER BANDAGE AND TOURNIQUET." /></a></p> + <br /> + + <p>FIG. 57.—THE ESMARCH RUBBER BANDAGE AND TOURNIQUET.</p> + <p>Although it is not absolutely necessary, it is an advantage, especially to the + inexperienced operator, to apply before operating an Esmarch's bandage and tourniquet + (Fig. 57). This expels the greater part of the blood from the limb, and renders the + operation comparatively bloodless.</p> + <br /> + <a name="a58" id="a58"></a> + <p><a href="images/image058.png"><img src="images/image058sm.png" + alt="RUBBER TOURNIQUET WITH WOODEN BLOCK." /></a></p> + <br /> + + <p>FIG. 58.—RUBBER TOURNIQUET WITH WOODEN BLOCK. The Esmarch bandage is + composed of solid rubber, and with it the limb is bandaged tightly from below + upwards. On reaching the knee the tourniquet is stretched round the limb, fastened by + means of its buckle and strap, and the bandage removed. Those who feel they can + dispense with the bandage use the tourniquet alone. For this purpose the form + depicted in Fig. 58, and the one in general use at the Royal Veterinary College, is + more suitable, on account of its wooden block, which may be placed so as to press on + the main artery of supply.</p> + <br /> + <a name="a59" id="a59"></a> + <p><a href="images/image059.png"><img src="images/image059sm.png" + alt="NEURECTOMY BISTOURY." /></a></p> + <br /> + + <p>Fig. 59. NEURECTOMY BISTOURY.</p> + <p><i>Instruments Required</i>.—These should be at hand in an earthenware or + enamelled iron tray containing just sufficient of a 5 per cent. solution of carbolic + acid to keep them covered. Those that are necessary will be a sharp scalpel, or, if + preferred, one of the many forms of bistoury devised for the purpose (see Fig. 59), a + pair of artery forceps, a needle ready threaded with silk or gut, one of the patterns + of neurectomy needle (see Fig. 60), and a pair of blunt-pointed scissors curved on + the flat. It is also an advantage, when once the incision through the skin is made, + to employ one of the forms of elastic, self-adjusting tenacula (see Fig. 61) for + keeping the edges of the wound apart while searching for the nerve.</p> + <br /> + <a name="a60" id="a60"></a> + <p><a href="images/image060.png"><img src="images/image060sm.png" + alt="NEURECTOMY NEEDLE." /></a></p> + <br /> + + <p>FIG. 60. NEURECTOMY NEEDLE.</p> + <p><i>Incision through the Skin</i>.—We remember that the plantar nerve of the + inner side is in close relation with the internal metacarpal artery, and that both, + in company with the internal metacarpal vein, run down the limb in close proximity + with the inner border of the flexor tendons. Also, we remember that the external + plantar nerve has no attendant artery, although, like its fellow, it is to be found + in close touch with the edge of the flexor tendons.</p> + <p>Bearing these landmarks in mind, we feel for the nerve in the hollow just above + the fetlock-joint by noting the pulsations of the artery, and determining the edge of + the flexor tendons. This done, a clean incision is made with the bistoury or the + scalpel in the direction of the vessels. The incision should be made firmly and + decisively, so that the skin may be cleanly penetrated with one clear cut. If + judiciously made, little else in the shape of dissection will be needed.</p> + <br /> + <a name="a61" id="a61"></a> + <p><a href="images/image061.png"><img src="images/image061sm.png" + alt="DOUBLE TENACULUM." /></a></p> + <br /> + + <p>FIG. 61.—DOUBLE TENACULUM.</p> + <p>It is now that the double tenaculum (Fig. 61) is applied. One clip is fixed to the + anterior edge of the wound, and the other carried beneath the limb and made to grasp + the posterior edge. If found desirable to keep the edges of the wound apart, and no + tenaculum to hand, the same end may be accomplished by means of a needle and silk. In + like manner as is the tenaculum, the silk is attached to one edge of the wound, + carried under the limb, and firmly secured to the other.</p> + <p>Having made the incision, the wound should be wiped free from blood by means of a + pledget of cotton-wool previously soaked in a carbolic acid solution and squeezed + dry. At the bottom of the wound will now be seen the glistening white sheath, + containing the vein, artery, and nerve. This should be picked up with the forceps, + and a further incision made with the bistoury. Care should be exercised in making + this second incision, or the artery may accidentally be opened. If an ordinary + scalpel is used, the lower end of the sheath should be picked up and the point of the + scalpel inserted through it. With the cutting edge of the scalpel turned towards the + opening of the wound, the sheath is then slit from below upwards. The second incision + satisfactorily made, the wound is again wiped dry, and the nerve seen as a piece of + white, curled string in the posterior portion of the wound.</p> + <p>At this stage it is advisable to accurately ascertain whether what we have taken + to be the nerve actually is it. This is done by taking it up with the forceps and + giving it a sharp tweeze. A sudden struggle on the part of the patient will then + leave no doubt in the operator's mind that it is the nerve he has interfered + with.</p> + <p><i>Section of the Nerve</i>.—The neurectomy needle (Fig. 60) is now taken, + and, excluding the other structures, passed under the nerve. A piece of stout silk or + ordinary string is then threaded through the eye of the needle, the needle withdrawn, + and the silk left in position under the nerve. The silk is now tied in a loop, and + the nerve by this means gently lifted from its bed. With the curved scissors or the + scalpel it is severed as high up as is possible. The lower end of the severed nerve + is then grasped firmly with the forceps, pulled downwards as far as possible, and + then cut off. At least an inch of the nerve should be excised.</p> + <p>The animal is then turned over, and the opposite side of the limb operated on in + the same manner.</p> + <p>The tourniquet is now removed, and the wound is examined for bleeding vessels. If + the hæmorrhage is only slight, the wound should be merely dabbed gently with + the antiseptic wool until it has stayed. A larger vessel may be taken up with the + artery forceps and ligatured, or the hæmorrhage stopped by torsion. On no + account, unless it it done to stay hæmorrhage that is otherwise uncontrollable, + should the wound be sutured with blood in it. With the wound once dry and clean, it + is well to insert three or four silk sutures, but care must be taken not to draw them + too tightly. This done, the patient may be allowed to get up. + <i>After-treatment</i>.—This is simple. Over each wound is placed a pledget of + antiseptic cotton-wool or tow, and the whole lightly covered with a bandage soaked in + an antiseptic solution. For the first night the animal should be tied up short to the + rack, and the following morning the bandages removed. A little boracic acid or + iodoform, or a mixture of the two combined with starch (starch and boracic acid equal + parts, iodoform 1 drachm to each ounce) should now be dusted over the wounds, the + antiseptic pledgets renewed, and the bandage readjusted over all.</p> + <p>At the end of three or four days the bandages may be dispensed with. All that is + necessary now is an occasional dusting with an antiseptic powder, and, as far as + possible, the restriction of movement. At the end of a week the sutures may be + removed, and the animal turned into a loose box or out to pasture.</p> + <h3>E. MEDIAN NEURECTOMY.</h3> + <p>As a palliative for lameness when confined to the foot, one would imagine that the + plantar operation would be all sufficient. There are operators, however, who state + that the results following section of the median nerve have been such as to cause + them to entirely abandon the lower operation in its favour. If only for that reason a + brief mention of the operation must be made here.</p> + <p>The operation was first performed in this country in October, 1895, the subject + being one of the out-patients at the Royal Veterinary College Free Clinique.</p> + <p>For five or six years following this date Professor Hobday performed the operation + some several hundred times, and was certainly instrumental in bringing the operation + into prominence. Though so recently introduced here, it appears to have been + practised for several years on the Continent, originating in Germany as early as + 1867. In that country a first public account of it was published in 1885 by Professor + Peters of Berlin, while in France it was introduced by Pellerin in 1892. In this + operation a portion of the median nerve is excised on the inside of the elbow-joint + just below the internal condyle of the humerus. Here the nerve runs behind the + artery, then crosses it, and descends in a slightly forward direction behind the + ridge formed by the radius.</p> + <p>The position of the limb most suitable for the operation is exactly that we have + described as most convenient for the plantar excision. The animal is cast, preferably + anæsthetized, and the limb removed from the hobbles, and held as far forward as + is possible by an assistant with the side-line.</p> + <p>Professor Hobday's description of the operation is as follows:</p> + <p>'A bold incision is made through the skin and aponcurotic portion of the + pectoralis transversus and panniculus muscles, about 1 to 3 inches (depending on the + size of the horse) below the internal condyle of the humerus, and immediately behind + the ridge formed by the radius. This latter, and the nerve which can be felt passing + over the elbow-joint, form the chief landmarks. The hæmorrhage which ensues is + principally venous, and is easily controlled by the artery forceps. In some cases I + have found it of advantage to put on a tourniquet below the seat of operation, but + this is not always advisable, as it distends the radial artery. We now have exposed + to view the glistening white fascia of the arm, which must be incised cautiously for + about an inch. This will reveal the median nerve itself situated upon the red fibres + of the flexor metacarpi internus muscle. If not fortunate enough to have cut + immediately over the nerve, it can be readily felt with the finger between the belly + of the flexor muscle and the radius.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. ix., + p. 181.]</p> + <p>The nerve exposed, the remainder of the operation is exactly as that described in + removing the portion of the nerve in the plantar operation. The wound is sutured and + suitably dressed, and a fair amount of exercise afterwards allowed the patient.</p> + <h3>F. LENGTH OF REST AFTER NEURECTOMY.</h3> + <p>This is placed by the majority of surgeons at about three weeks to a month. Within + that period no excessive exertion should be undergone by the patient. A certain + amount of quiet exercise, however, is beneficial, facilitating the healing of the + wounds, and accustoming the animal to the altered condition of his limb.</p> + <h3>G. SEQUELÆ OF NEURECTOMY.</h3> + <p>These we shall relate collectively, making no distinction between those following + excision of the plantar nerve and those succeeding section of the median. It must be + remembered by the surgeon, however, that the unfortunate sequelæ we are now + about to describe are likely to be far more grave when following section of the + larger nerve.</p> + <p><i>Liability of Pricked Foot going undetected</i>.—On account of the warning + they convey to the surgeon, first place among the sequelæ of neurectomy must be + given to accidents following loss of sensation. Take, for example, punctured foot. In + any case, in the sense of being unforeseen, it is accidental. In the neurectomized + foot it becomes doubly accidental, in that not only is it unforeseen, but that it is + for some time indiscoverable. With the foot deprived of sensation, a nail may be + picked up, or a prick sustained at the forge, and no intimation given to the + attendant until pus has underrun the horn, and broken out at the coronet. What + follows, then, is that the hoof as a whole, or the greater part of it, sloughs + off.</p> + <p>No neurectomy should be undertaken unless this contingency has been allowed for. + The owner should be advised of it by the surgeon, who should at the same time enjoin + on his client the absolute necessity of giving to the neurectomized foot daily and + careful attention.</p> + <p><i>Loss of Tone in the Non-sensitive Area</i>.—In addition to the mischief + resulting from a wound going undetected, it must be remembered that the loss of tone + resulting from the operation gives to every wound (however slight), in the region + supplied by the removed nerve, a sluggish and troublesome character. Difficult to + deal with as wounds about the foot ordinarily are, they are rendered more so by a + previous neurectomy.</p> + <p><i>Gelatinous Degeneration</i>. This is a condition liable to occur in cases where + the operation has been too long deferred, and when considerable structural alteration + has already taken place in the shape of diseased bone or tendon, more especially in + navicular disease. It consists in a peculiar softening of the structures of the limb, + accompanied with enlargement, due to swelling of the connective tissues, the + enlargement and softening generally making itself first apparent by a soft, pulpy + swelling in the hollow of the heel.</p> + <p>From this onwards the enlargement increases, and lameness becomes excessive, the + animal going more and more on his heels, until, finally, no portion of the solar + surface of the foot comes to the ground at all.</p> + <p>The case is hopeless, and destruction should be advised.</p> + <p><i>Reported Case</i>.—'The patient, a brown carriage gelding, was brought to + the Royal Veterinary College infirmary in a cart on December 31, the only previous + history obtainable being that it had suddenly fallen lame a month before.</p> + <p>'The symptoms presented were excessive lameness of the near fore-limb. On being + trotted, the toe was elevated each time the foot reached the ground, progression + being entirely on the heels. Separation of the hoof for about 2 inches at the hinder + part of the coronet; oedematous swelling from foot to knee, extending during the next + three days to the elbow. Great tenderness between the knee and the fetlock; below + this no sensation whatever, as a pin was inserted in several places round the coronet + without causing any symptoms of pain. On further examination, two unnerving scars + were found. No treatment was adopted, and the horse was destroyed on January 6.</p> + <p>'On dissecting the leg, the following appearances presented themselves:</p> + <p>'The limb was very much enlarged, due to thickening of the connective tissue, the + skin being removed only with difficulty. The tendons were soft and much thickened. A + rupture of the skin at the coronet, just where the skin meets the wall of the foot. + Large extravasations of blood at the back of the tendons, situated in the lower half. + <i>External</i> nerve trunk had become reunited, at the point of junction there being + a hard lump about the size of a walnut. <i>Internal</i> nerve trunk also had become + reunited, and presented a thickened portion at the point of junction, but not so + large as that of the outer side, and situated in the lower half of the tendon, about + 2 inches higher than that on the external nerve. This nerve trunk was atrophied below + the thickening, and had undergone gelatinous degeneration. Judging from the scars on + the skin, this side had evidently been unnerved a week or ten days previously to that + on the outer side. The band stretching across the back of the perforatus, between the + external and internal nerves, appeared on the inside to have become firmly fixed into + the tendon.</p> + <p>'On removing the hoof, under the sole there appeared a large quantity of very + foetid pus; the laminæ were very much inflamed in patches. There was an + enormous thickening of connective tissues in the heel. On cutting longitudinally + through the perforatus tendon, there was exposed a large blood-coloured mass, of a + gelatinous appearance, situated on the perforatus tendon, the latter being very much + thickened, and growing to the navicular bone. The underneath surface of the superior + suspensory ligament was much thickened, and firmly adherent to the bone; at the + posterior surface of the metacarpus there was a quantity of gelatinous substance. The + anterior ligament of the fetlock-joint was thickened; the navicular bone was entire, + but showed lesions of navicular disease, being ulcerated. Section through the bone + did not reveal anything further. It may be here remarked that the ulcerations were on + either side of the central ridge, and not at all on the ridge itself.</p> + <p>'Microscopic examination of the tissue joining the two ends of the nerve together + revealed a few nerve fibres; the general appearance was that of granulation tissue, + containing capillary vessels, which were fairly plentiful, and comparatively large in + size.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. iv., p. 386 (Hobday)]</p> + <p><i>Chronic Oedema of the Leg</i>.—In some cases there is a distinct swelling + of the leg some time after the operation. This exposes the limb to the infliction of + sores from striking with the opposite foot, with, of course, the difficulty in + healing we have just described.</p> + <p><i>Persistent Pruritus</i>.—This annoying sequel occurs in the neurectomized + limb, with or without gelatinous degeneration, and appears to be without a remedy. + The itching in some cases is so intense as to lead the animal to constantly gnaw at + the top of the foot. As one observer has remarked, the animal may begin literally + biting pieces out of his limb. The result of the irritation and gnawing is fatal. + Great sloughing of the parts takes place, and the animal has eventually to be + slaughtered. v<i>Fracture of the Bones</i>.—The sudden loss of sensation in a + foot may cause the animal to use violently the limb he has for months past been + carefully nursing. It may be that the lameness for which the operation has been + performed has been due to disease existing in the navicular bone, and extending, + perhaps, to the os pedis. By the disease the bone has already been made brittle, its + substance and ligamentous attachments perchance weakened and broken up by a + slow-spreading caries, and rarefaction of the remaining bone substance rendered + almost certain. In this instance, the free use of the foot, and the application to + the diseased structures of an unwonted pressure immediately after the operation + results in fracture. With the rupture of the structures we get the elevated toe and + soft swelling in the heel, as described in gelatinous degeneration. Treatment, of + course, is out of the question.</p> + <p><i>Neuroma</i>.—A further sequel is the appearance at the seat of the + operation of what is termed an 'amputational neuroma.' This is a tumour-like growth + occurring on the end of the divided nerve. It is composed of connective-tissue + elements permeated by nerve fibres which have grown out from the axis-cylinders of + the nerve stump. It may vary in size from a pea to a hazel-nut, and is frequently the + cause of much pain. This must be cut down upon and cleanly removed, taking away at + the same time as much of the nerve as is possible.</p> + <p><i>Reunion of the Divided Nerve</i>.—We may say at once that 'reunion' in + the popular sense of the word does not take place. At a varying period after section, + however, we do get a return of sensation. This is brought about in the following + manner: The axis-cylinder of the nerve, still in connection with the spinal cord, + swells somewhat, and hypertrophies. The cells of this hypertrophied portion show a + great tendency to proliferate and produce new nerve structure. This growing point + splits, and gives rise to several fibrils, which are new axis-cylinders. These + commence to grow towards the periphery, and, in so doing, grow through the + cicatricial tissue that has formed at the seat of the operation.</p> + <p>After passing through the cicatricial tissue (the amount of which tissue, of + course, controls the length of time that insensibility remains), the growing + axis-cylinders reach the degenerated portions of the nerve below the point of + section. It is along the track of the old nerve that the new growths from the stump + reproduce themselves.</p> + <p>The fact of the new growths having to pass through the fibrous tissue of the + cicatrix before they can gain the course of the old nerve, along which latter their + progress of growth is comparatively easy, affords ample illustration that as large a + portion as is possible of the nerve should be removed when operating, in order to + convey insensibility for the longest time. After reunion, of course, nothing remains + but to repeat the operation.</p> + <p><i>The Existence of an Adventitious Nerve-supply</i>.—While not exactly a + sequel of the operation, the fact that it is not discovered until after the operation + has been performed warrants us in mentioning it here. It is not an uncommon thing in + the lower operation to find that sensation and symptoms of lameness still persist + after section of the nerve. In many cases this has been traced to the existence of an + abnormal nerve branch. In the higher operation this is not so likely to be met with. + That it may occur, however, is shown by the following interesting case related by + Harold Sessions, F.R.C.V.S.:[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. xii., + p. 343.]</p> + <p>'In June of 1898 I saw a hunter suffering from navicular disease. After carefully + examining the leg, I advised the owner to have the operation of neurectomy performed + upon him. This he decided to do, and the horse was sent to me about the beginning of + July.</p> + <br /> + <a name="a62" id="a62"></a> + <p><a href="images/image062.png"><img src="images/image062sm.png" + alt="DISSECTED EXTERNAL METACARPAL NERVE AND BRANCHES." /></a></p> + <br /> + + <p>FIG. 62.—DISSECTED EXTERNAL METACARPAL NERVE AND BRANCHES. <i>a</i>, + Metacarpal; <i>b</i>, anterior plantar; <i>c</i>, extra branch (probably from the + internal metacarpal), conveying sensation after division of the external + metacarpal.</p> + <p>'The operation was performed in the ordinary way, without any difficulty whatever. + The wounds healed nicely, but the horse still continued to go lame. Careful + examination showed that there was still sensation on the outside of the foot. + Thinking that possibly there might be two external metacarpal nerves, the horse was + again cast, the operation being performed slightly lower down. Only the main branch + of the external metacarpal nerve could be found. A piece of this was taken out, and + the horse let up. On examination, sensation was still found in the posterior part of + the outside of the foot. It was very evident that there was some abnormal + distribution of the nerve, as sensation was still being conveyed to that part of the + foot.</p> + <p>'As the horse was absolutely useless, and would have to be shot unless this piece + of nerve could be found, he was again thrown, and after he had been + anæsthetized I determined to follow the course of the nerve down, until I found + where the accessory branch came from. This I found a little below the fetlock, about + 1/2 inch below the point where the anterior plantar nerve is given off from the + metacarpal nerve. It was about 1/2 inch below the spot where the anterior plantar + nerve passes between the artery and vein of the foot, and it was somewhat difficult + to get at it.</p> + <p>'Fig. 62 shows the exact size and distribution of the nerves. After the separation + of the accessory branch, sensation was taken from the foot, and the horse went + perfectly sound.'</p> + <p><i>Stumbling</i>.—In addition to the sequelæ we have mentioned, it is + urged against the operation of neurectomy that one of the first effects of depriving + the foot of the sense of touch is a tendency on the part of the animal to stumble. + From the cases we have seen we cannot regard this objection as a serious one. + Nevertheless, as veterinarians, with a knowledge of the physiology of the structures + with which we are dealing, we must treat the objection with respect, for, after all, + we are bound to allow that stumbling, and a bad form of it, would be but a natural + sequence of the operation we have just performed. The real fact remains, however, + that cases of stumbling, even immediately after the operation, are rare; and that + even when they do occur, the animal seems easily able to accommodate himself to the + altered condition, and as readily uses the comparatively inert mass at the end of his + limb as he did previously the intact foot.</p> + <h3>H. ADVANTAGES OF THE OPERATION.</h3> + <p>From the prominence we have given to the unfortunate sequelæ of the + operation it might possibly be inferred that, while not giving it our absolute + condemnation, we regard neurectomy with a certain amount of distrust. That we may + contradict any such false impression, we state here that in many cases the operation + is the only measure which will offer relief from pain, and restore to work an + otherwise useless animal. In support of that we will now quote the recognised + advantages of the operation.</p> + <p>That in many cases, when all other methods—surgical and medicinal—have + failed, there is an immediate and total freedom from pain and lameness no one will + deny. This, if it restores to active work an animal that would otherwise have had to + have been cast aside, is ample justification for giving the operation, in spite of + its many unfortunate terminations, a real place among the more highly favoured + remedial measures to our hand.</p> + <p>'For <i>Contracted Hoofs</i>, viewing them in the light of idiopathic disease, or + as being the immediate cause of the existing lameness in the uninflamed condition of + the foot, and when consequential changes of its organism have taken place which bid + defiance to therapeutic measures, <i>neurotomy</i> is a <i>warrantable resource</i>' + (Percival).</p> + <p>'For <i>Ringbone</i> neurotomy has been practised with perfect success, after + blistering and firing had both failed, notwithstanding the work the animal had to + perform afterwards was of the most trying nature' (<i>ibid</i>.).</p> + <p>For <i>Navicular Disease</i>, when that malady is diagnosed, the earlier + neurectomy is performed the better. The greater work given to the diseased bursa and + bone, and the return of the contracted heels to the normal, brought about by the + greater freedom with which the foot is used, are claimed by many to effect a + cure.</p> + <p>Writing of navicular disease, and mentioning his belief in the possibility of the + diseased bone effecting its own repair after the operation, Harold Leeney, + M.R.C.V.S., says:</p> + <p>'The expansion of the heel, and rapid development of the frog (in this and many + other cases) immediately after the operation, has not, I venture to think, attracted + so much attention as it deserves, and may have something to do with those cases which + appear to be actually <i>cured</i>, not merely made to go sound by absence of + pain.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xi., p. 297.]</p> + <p>Speaking of the median operation before a meeting of the Central Veterinary + Medical Society, Professor Hobday says:[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xiii., p. 427.]</p> + <p>'For old-standing lamenesses, when due to splints, exostoses, chronically + sprained, thickened, and painful perforans and perforatus tendons, or cases of that + kind which cause pain by pressing on the adjacent nerve structures, after all other + known methods have failed, median neurectomy is the operation which will be most + likely to give the animal a new lease of life and usefulness.'</p> + <p>'Of the <i>Humanity and Utility of Neurectomy</i> there can be no question + whatever, and provided the cases are well selected, and the operation is efficiently + performed, the advantages to be derived from it are most striking as well as + enduring. But the disadvantages attending the loss of sensation in the foot have been + brought forward on many occasions as an argument against neurectomy, and no one can + deny that the foot with sensation is better than one without that faculty. But in a + long experience of the operation I have never found these disadvantages outweigh the + great advantages which have immediately followed it.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. ix., p. 178 (Fleming).]</p> + <p>Beyond these, the direct advantages of neurectomy, are other and more indirect + advantages which claim attention.</p> + <p>The most astonishing among them is the fact noted by many writers of repute that + exostoses (ringbones, side-bones, splints, etc.) rapidly diminish in size. This is + vouched for by such well-known authorities as Zundel and Nocard.</p> + <p>Percival, too, mentions at some length the effect of the removal of pain on the + oestral and generative functions, quoting a case of a brood cart-mare by reason of + bony deposits being stayed from breeding for some years. Two months after the + operation she went to work, and moved sound, her altered condition leading her to + breed several healthy foals.</p> + <h3>I. THE USE OF THE HORSE THAT HAS UNDERGONE NEURECTOMY.</h3> + <p>No operation is of any considerable value to the veterinary surgeon unless he is + able to show that after it he has left his patient workable. The alleviation of pain + alone, commendable as it is from a humanitarian standpoint, is of no interest to the + average owner of horse-flesh, unless with it he sees his animal capable of justifying + his existence by the amount of labour performed.</p> + <p>Criticised in this way, is the operation of neurectomy justifiable? Upon that + point the opinions of many practitioners, even at the present day, differ. We have + already partly answered the objections likely to be raised on this score by stating + that the work afterwards allotted the animal should be fixed to suit his altered + condition. It may be taken as a general rule that in all cases where the animal's + usefulness depends upon his delicacy of touch, as, for example, animals used solely + for hacking or hunting, his future usefulness in that special sphere of work will be + done away with.</p> + <p>Percival himself, always a strong advocate for the operation, fully recognises + this. 'Does the neurotomized horse maintain the same step as before?' he asks. 'To + this important question,' he replies, 'I unhesitatingly answer no; he does not. There + can be no doubt but that the horse <i>feels</i> the ground upon which he is treading, + and that he regulates his action in consonance with such feeling, so as to render his + step the least jarring and fatiguing to himself, and therefore the easiest and + pleasantest to his rider.... Such impressions'—those of touch—'being in + the neurotomized subject, so far as regards the feeling of the foot, altogether + wanting, a bold, fearless projection of the limb in action will be the consequence, + followed by a putting down of the hoof flat upon the ground, as though it were a + block, creating a sensation alike unpleasant both to horse and rider.'</p> + <p>Emphatic as Percival is upon this point, there are, nevertheless, others who + maintain with equal stoutness that the unnerved animal is positively as safe, if not + safer, than the animal who has not been so treated.</p> + <p>'That the tactile sense in the horse's foot is useful, it would be idle to deny; + but that it is absolutely essential, even to safe progression, no one who has paid + attention to the results of plantar neurectomy will maintain. On several occasions + for years I have hunted, hacked, and driven horses which have been deprived of + sensation in their fore-feet, and never had an accident with them. Their action has + not been impaired by the operation; on the contrary, it has been vastly improved + compared with what it had been previous to it. And my opinion has not been single in + this respect, as many competent horsemen can give like evidence after long and severe + trials of neurotomized horses. The opponents of neurotomy were, probably, not aware + that there is in progression a <i>muscular</i> as well as a <i>tactile + sense</i>.'</p> + <p>This latter contention is supported by numerous cases, reported at the time when + the operation of neurectomy was at the heyday of its popularity. Two I select from + writings of a later period:</p> + <p><i>Recorded Cases</i>.—1. 'Two of the finest among the many fine horses in + the Second Life Guards were so lame from navicular disease, when I joined the + regiment, that they were unsafe and unsightly to ride, and were therefore entered on + the list to be cast off and sold. One was so crippled that it could scarcely be moved + out of its stable. Peeling sorry at having to get rid of such good horses, and + anxious to give another blow to the mistaken theory that unnerved animals were + unsafe, I obtained the consent of my commanding officer, who patronizes practical + conclusions, to perform neurotomy. This was carried out on both horses about eighteen + months ago. Within a fortnight they were at their duty, absolutely free from + lameness, and with first-rate action, and one of them, from being troublesome and + unsteady in the ranks—probably from the pain in its feet—had become quite + steady and tractable. Instead of being lame, blundering, and unsafe, both were sound, + free in movement, and secure, and, the pain being abolished, they looked improved in + condition.</p> + <p>'During the month of July the regiment attended the summer drills at Aldershot, + and five days every week for a month these horses carried a weight of about 22 stones + each over the roughest and most dangerous ground, nearly always at a fast pace, and + for four, five, or six hours each day; and yet they never fell or blundered, and the + troopers who rode them had unbounded confidence in their sure-footedness. They + returned to Windsor, at the end of the month's severe test, as sound in their paces + as when they left, and certainly now offer no indication whatever that they are less + safe to ride than any other horse in the regiment. The effects of the relief from + pain are also most marked, not only in the altered gait out of doors, but also in the + stable.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal, vol</i>. ix., p. 178 (George Fleming, + F.B.C.V.S.).]</p> + <p>2. 'Some years ago I operated upon a valuable hunter, the property of a gentleman + in Kildare, the animal having shown unmistakable symptoms of navicular disease for + some months previously, and which had been unsuccessfully combated by the milder + forms of treatment for the disease without any benefit. Although the horse went + sound, the owner feared to ride him, and sent him to be sold in Dublin, where he was + disposed of for a small price, and I then lost sight of him. The following + Punchestown Races, to my surprise, amongst a group of horses walking round the + paddock previous to saddling for an important race, I recognised my old patient, + bandaged, clothed, and trained, ready to take his part in the cross-country contest, + and surrounded by a host of admirers willing to back him at any price.</p> + <p>'Having satisfied myself that it was no other than the same animal, my first + impulse was at once to find out the jockey who was to ride him, and warn him of his + danger by telling him his mount was devoid of feeling in both fore-feet; but the + saddling-bell had already rung, and in a few moments more the jockey emerged from the + weighing-room and the next view of the horse was his tearing up the course in the + preliminary, and "pulling double." I was sorry for the jockey if he felt as I did at + that moment, for if he did I fear he and his horse would have parted company at the + first fence, as I was certain there would be a smash before the end of the long and + difficult three miles of the Kildare Hunt Cup course. It was not until I saw him + again in the front rank passing the stand, in the first round, that I breathed + freely, and even then I felt very guilty, and, had he come to grief badly, I don't + think I should ever have operated on another horse except in such a way as would have + left unmistakable traces after it.</p> + <p>'"The old horse wins!" screamed a thousand voices as the competitors safely + cleared the last bank (now taken away for a gorse fence) the last time round, and + from that moment the operation went up in my estimation a hundredfold, and I almost + lost all interest in the finish (and it was a close one, with my patient a good + third), resolving I would operate for the future on every animal, young and old, + which showed symptoms of navicular disease.</p> + <p>'Neither owner nor jockey knew the horse had been operated on, and he was soon + after, on the strength of his performance, sold for a good price to come to England. + It is idle to think that all cases are as successful as this was, as experience soon + told me; but I consider that, in careful hands, the advantages well outweigh the + disadvantages of the operation, and I have selected this instance merely as a + practical example.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. iii., p. 254 (W. Pallin, + M.B.C.V.S.).]</p> + <p>It is solely with the object of ventilating both sides of the question that we + quote the last two cases. In our opinion, the colours in which the results of the + operation are there painted are far too rosy. The practitioner who has before him the + task of satisfying a client as to what will or what will not be the results of an + operation he has suggested will do well to weigh each side of the argument carefully, + and endeavour in his explanation to strike the happy mean.</p> + <p>We hold, further, that the animal who has previously been accustomed to fast work, + and to work entailing a large call upon the sense of touch when passing over rough + and uneven ground, will be far more likely, in his neurectomized condition, to give + satisfaction to his owner if put to a slower and a more suitable means of earning his + living.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER VI</h3> + <h3><a name="conform" id="conform">FAULTY CONFORMATION</a></h3> + <p>Under this heading we shall deal with such formations of the feet as depart + sufficiently from the normal to render them serious. Faulty conformation may be + either congenital or acquired, and acquired gradually as the result of slowly + operating causes, or suddenly as the sequel to previous acute disease. Whether + congenital or acquired, serious in its nature or comparatively of no account, the + veterinary surgeon will often find that the matter of conformation is one which will + have a direct bearing on many of his 'foot' cases, and, furthermore, that it is one + upon which he will often be called to give advice.</p> + <h3>A. WEAK HEELS.</h3> + <p><i>Definition</i>.—That condition of the wall in which, owing to the + softness of the horn and the oblique direction of the horn fibres, the heels are + unable properly to bear the body-weight, and, as a consequence, curve in beneath the + sole. We give the condition first mention, not because of its greater importance, but + for the reason that it is frequently the forerunner of the condition to be next + described—namely, contracted feet.</p> + <p><i>Symptoms</i>.—The extreme point of the heel is not affected unless the + foot has been greatly neglected, and the condition allowed to develop. Where, + however, the foot has been uncared for, curving in of the wall takes place to an + alarming degree, and the heels curl underneath the foot to such an extent as to grow + over the sole and the bars. By the pressure they exert on the sole corns result, and + the animal is lamed.</p> + <p><i>Causes</i>.—In the main this defect is hereditary. It is seen commonly in + connection with flat-foot, and where the horn of the wall is thin and shelly.</p> + <p><i>Treatment</i>.—In the case of weak or 'turned in' heels no suitable + bearing is offered for the shoe in the posterior half of the foot. Any attempt to + induce the heels to bear weight is immediately followed by their bending in. It + follows from this that the best shoe to be used here is one in which the bearing is + confined to the anterior half of the wall, the heels being relieved by being + sufficiently pared. As might be expected, this bearing on the anterior half only of + the foot is insufficient; pressure must be given the frog. This latter end is best + gained by a bar shoe (Fig. 68). With it the anterior portions of the wall, the whole + of the bars, and the whole of the frog may be in contact, and the heels only so pared + as to take no bearing at all. A few such shoeings sees the defect remedied. In every + instance paring of the sole should be discouraged, as it serves but to increase the + deformity.</p> + <h3>B. CONTRACTED FOOT.</h3> + <p><i>(a)</i> GENERAL CONTRACTION—CONTRACTED HEELS.</p> + <p><i>Definition</i>. By the term contracted foot, otherwise known as hoof-bound, is + indicated a condition in which the foot, more especially the posterior half of it, + is, or becomes, narrower from side to side than is normal.</p> + <p>It must be borne in mind, however, that certain breeds of horses have normally a + foot which nearer approaches the oval than the circular in form, and that a narrow + foot is not necessarily a contracted foot.</p> + <p>The contraction may be bilateral when affecting both heels of the same foot and + extending to the quarters, or unilateral when the inside or outside heel only is + affected.</p> + <p>In some cases contraction is confined to one foot, while in others it may be + noticed equally bad in both. It is a matter of common knowledge that contraction is + usually seen in the fore-feet, while the hind seldom or never suffer from it, a fact + which, to our minds, seems difficult of adequate explanation. Zundel explains this by + stating that contraction is principally <i>observed</i> in the fore-feet, by reason + of the fact that when lameness arises from it alteration in action will more readily + be detected in front than behind. Percival, on the other hand, suggests that the + greater expansive powers of the hind-foot, by reason of the impetus of its action, is + able to overcome any influence operating towards contraction. It may be, however, + that given a cause for contraction, such as the removal of the frog's + counter-pressure with the ground by faulty shoeing or excessive paring, the + fore-feet, by reason of their being called upon to bear the greater part of the + body-weight, are the first to suffer.</p> + <p>Flat feet with weak heels are those most frequently affected, and, as we have + already intimated, the condition may exist with or without other disease of the + foot.</p> + <p>Depending upon its degree, contracted foot may vary from a simple abnormality, + non-inflammatory and painless, to a condition in which it becomes a veritable + disease, giving rise to a bad form of lameness, and bringing about a withered and + sometimes discharging and cankerous affection of the frog.</p> + <p><i>Symptoms</i>.—In its early stages contraction is difficult of detection, + and where both feet are affected may for some time go unsuspected. With only one foot + undergoing change, the early stages may the more readily be marked, for in this case + comparison with the other and sound foot will at once reveal the alteration in shape. + If lameness in the suspected foot is present, then any lingering doubt will be + quickly dispelled.</p> + <p>When far advanced, contraction offers signs that cannot well be missed. The + converging of the heels narrows the V-shaped indentation in the sole for the + reception of the frog. As a consequence of this, the frog itself becomes atrophied by + reason of the <i>continual</i> pressure exerted upon it by the ingrowing horn of the + wall and the bars. The median and lateral lacunæ of this organ, from being + fairly broad and open channels, become pressed into mere crack-like openings (see the + commencing of this condition in Fig. 80, and a badly wasted frog in Fig. 74A). As the + case goes on, the lateral branches of the frog entirely disappear, and all that is + left of the organ is a remnant of its body or cushion, now wedged in tightly between + the bars. Following upon the disappearance of the frog, we find that the bars are in + contact, or, in some cases, actually overlapping each other at their posterior + extremities.</p> + <p>At this stage, perhaps, the whole condition has become aggravated by a foul + discharge from the place originally occupied by the frog, and the foot, especially in + the region of the heels, has become hot and tender—really a form of local and + subacute laminitis.</p> + <p>The long-continued inflammation, although only of a low type, renders the horn of + the hoof hard and dry, and only with difficulty will the ordinary foot instruments + cut it. This in its turn leads to cracks and fissures in various places, but more + especially in the bars and what is left of the frog. Often, too, cracks will appear + in the horn of the quarters, and a troublesome and incurable form of sand-crack + results.</p> + <p>An animal with contraction advanced as far as this, especially if confined to one + foot, goes unmistakably lame. With both feet affected, he ordinarily starts out from + the stable in a manner that is commonly called 'groggy.' In other words, the gait is + uncertain, and feeling; and stumbling is frequent. Anyone who has had the misfortune + to drive an animal with feet in this condition knows full well that every little + irregularity in the road at once makes itself felt to the feet, and that the animal, + as time goes on, learns to carefully avoid any suspicious-looking group of stones he + may see. To drive an animal like this is to keep one's self continually on + tenter-hooks, for, sooner or later, the inevitable happens, and the animal comes + down.</p> + <p>Up to now we have described the changes of form in the hoof as seen when the + contracted foot is viewed from the solar surface. With those changes as evident as we + have depicted them, there will be no difficulty in detecting the alterations in the + form of the wall.</p> + <p>In addition to a narrowing from side to side there will be noticed an abnormal + straightness of the quarters, with a turning in, more or less sudden, of the heels. + This effect is given in these cases by the smith maintaining the shoe of a length and + width that should normally fit a foot of that particular animal's size and substance. + This is probably done with the idea of deceiving anyone examining the solar surface. + Viewed from this position, the width of the shoe at the heels gives the impression + that it is attached to a foot of normal breadth. This deception is heightened if at + the same time has been practised the process of 'opening up the heels.' That + expression indicates that the bars have been removed, and the lateral lacunæ of + the frog made to continue the concavity of the sole. The arch of the latter is thus + made to appear of much greater extent than it really is, and the heels, by reason of + their being abruptly cut off when removing the bars, also convey the false impression + of being wide apart.</p> + <p>The practitioner unversed in the tricks of the forge will best guard against this + by viewing the foot, while on the ground, from behind. From that position he will be + able to detect the lowness of the quarters, and the projecting portion of the shoe, + that the hoof, by reason of its sudden bending inwards, does not touch.</p> + <p>The 'feeling' manner of the gait before alluded to, together with the + disinclination to put the foot firmly and squarely forward, will sometimes lead the + examiner to over-look the contraction, and diagnose his case as one of shoulder + lameness. In many cases, too, such consequent conditions as 'thrushy frogs' and + 'suppurating corns' are often treated with utter disregard of the contraction that + has really brought them about. But above all, the disease most likely to be + confounded with simple contraction is navicular disease. More than probable it is + that many cases of so-called 'navicular' have in reality been nothing more than + contraction brought about by one or other of the causes we shall afterwards + enumerate—cases where a due attention to the prime cause of the mischief would, + in all likelihood, have remedied the lameness.</p> + <p><i>Changes in the Internal Structures</i>.—It follows as a matter of course + that the changes we have described in the form of the hoof itself carry with them + alterations in the bones and sensitive structures beneath it. The tissues, as a + whole, become atrophied. The os pedis becomes deformed, loses its circular shape, and + gradually becomes more or less oval in contour. At the same time, its structure + becomes more compact, the cribriform appearance of its anterior and lateral faces + more or less destroyed, and the few remaining openings apparently increased in size. + This atrophy of the os pedis is best noted at the wings.</p> + <p>In the plantar cushion the effects of the atrophy are noted in the smallness of + the organ, in its becoming whiter in colour than normal, and more resistant to + pressure.</p> + <p>The coronary cushion is also affected in the same way, where the changes are noted + most in its posterior portions.</p> + <p>A further effect of the narrowing of the heels, and their consequent tendency to + drop downwards, is the exertion of a continual pressure on the sensitive sole. In + course of time, and especially in flat feet, this leads to the appearance of + corns.</p> + <p>The navicular bone and bursa and the tendon of the perforans also suffer from the + effects of compression. The movement of the tendon is restricted, and arterial supply + to the adjacent structures rendered deficient. The tissues of the bone and bursa are + insufficiently nourished, and the secretion of synovia lessened. In this way it is + conceivable that navicular disease may follow the condition of simple contracted + heels.</p> + <p>In common with the other structures, the lateral cartilages also suffer from the + continual pressure. Their blood-supply is lessened, their functions interfered with, + and side-bones result.</p> + <p><i>Causes</i>.—Upon the causation of contraction a very great deal has been + written, both by early veterinarians and by those of the present day. Many and widely + differing opinions have been advanced, but a careful résumé of only a + few will lead one to certain fixed conclusions.</p> + <p>We may consider the causes of contraction under two headings—predisposing + and exciting.</p> + <p><i>Predisposing Causes of Contraction</i>.—Among these we will first mention + heredity, although it is possible it should not be deemed of so great account as it + is by some. That the shape of certain feet, especially those with low heels and + abnormally sloping walls, predisposes to contraction no one will deny. So long, + however, as the animal goes unshod, so long does the foot maintain a normal condition + of the heels. In other words, it is not until the tendency to contraction already + there is aggravated by careless shoeing and the effects of work that it operates to + any noticeable extent.</p> + <p>The degree of contraction will also be very largely governed by the amount of the + development of the frog. With a frog of good size, low down, and taking part in the + pressure of the foot on the ground, contraction will be prevented. On the other hand, + an ill-developed frog, one wasted by long-continued and spreading thrush, or one + robbed of its normal function by excessive paring in the forge, is a common + starting-point of the condition we are considering. We have already referred to this + in Chapter III., when considering the experiments of Lungwitz in this connection. + What we have to bear in mind in these experiments is that the application of a pad to + the frog, in such a manner that effective ground-pressure is obtained, results always + in a marked expansion of the heels, and that, with counter-pressure with the ground + absent, expansion occurs to little or no extent. This is proof positive of the + enormous part the frog plays in maintaining an open and elastic condition of the + heels—a fact so insisted on by Coleman.</p> + <p>It is worthy of mention, however, that loss of the frog's function does not + operate to nearly so serious an extent in horses with high, upright heels as in those + with the heels low and excessively sloping.</p> + <p>In illustrating this, Mr. Dollar, in his work on shoeing, mentions the case of a + pair of trotting horses of similar age, size, and weight, each having weak + fore-heels. In one case the hoofs were flat, in the other upright. The horse with the + flat hoofs suffered from contraction, while the other did not.</p> + <p>The reason appears to be that in the animal with upright hoofs the proportion of + body-weight borne by the heels is considerably less than in those with the hoofs flat + and sloping.</p> + <p>Certain conditions of the horn-producing membranes also predispose to contraction. + For example, in horses reared on marshy soils, and afterwards transferred to standing + in town stables, we find that a dry and brittle condition of the horn supervenes. + This we may regard as a low form of laminitis, brought about by the heat of the + material upon which the animal is standing, and the congestion of the feet engendered + by his enforced standing for long periods in one position, as opposed to the more or + less continuous exercise when at pasture. With the hoof in this condition it loses by + evaporation the moisture that normally it should contain, and, as we might expect, a + certain degree of contraction of its structure is the inevitable result.</p> + <p>We thus see that contraction brought about in this way is not so much caused by + the heat of the stable, as it is by the decreased ability of the horn to retain its + own moisture.</p> + <p>On the other hand, it cannot be denied that excessive warmth and dryness combined + tend also to an undue abstraction of moisture, even from the horn of the healthy + foot; and this explains in great measure how it is that lameness, as a rule, and + especially that proceeding from contracted heels, is far more frequent and of greater + intensity in the hot, dry months of summer, than in the cooler and more humid + atmosphere of winter. It is interesting to note, too, that an alternation of humidity + and dryness is far more liable to injure the quality of the horn and tend to its + contraction than the long-continued effects of dryness alone. A common illustration + of this is to be found in the effects of the ordinary poultice. Everyone knows that + when, after a few days' application, they are discontinued, we get as a result an + abnormally dry and brittle state of the horn. This is doubtless due to the poultice + removing the thin, varnish-like, and protective pellicle known as the periople, and + thereby allowing the process of evaporation to act on the water normally contained in + the hoof.</p> + <p><i>Exciting Causes of Contraction</i>.—Among these, first place must + undoubtedly be given to shoeing. This does not necessarily imply shoeing more than + ordinarily faulty, nor a faulty preparation of the foot, but shoeing as it is + generally practised. No ordinary shoe, except a few devised for the purpose, such as + the Charlier or the tip, allows the frog to come in contact with the ground. This we + take to be the main factor in the causation of contracted heels, especially with a + predisposition already present in the foot itself. In the words of Lungwitz: + 'Regarded from this point of view, there is no greater evil than shoeing. It + abolishes the necessary counter-pressure, and thus interferes with expansion. Bars, + sole, and frog cannot perform the functions that naturally belong to them as they + would do without the shoe.'</p> + <p>In addition to the evil of the shoe itself, errors of practice in the forge + contribute to the causation of contraction. Taking first the preparation of the foot, + we find that often the heels are lowered far too much, and the toe allowed to remain + too long. This can have but one effect—that of throwing a greater proportion of + the animal's weight upon the heels than properly they should bear, with, what we now + know to be the consequence of that, a corresponding pushing inwards and downwards of + the horn; in other words, contraction.</p> + <p>Excessive paring of the bars, to which we have already partly alluded, is also an + active agent in bringing about an inward growth of the horn of the heels and + quarters. The bar, or inflexion of the wall at the heel, by means of its close + contact with the frog, communicates the outward movements of that organ to the wall + of the hoof. With the bar removed, the outward movements of the frog under pressure + are naturally rendered of no account, and a proper and intermittent expansion of the + wall denied it. The same evil follows, though to a less extent, excessive paring of + the sole.</p> + <p>The shape of the bearing surface of the shoe is often to be blamed. Where this is + concave—'seated'—and the 'seating' is carried back to the heels, it is + easy to see that, when weight is on the foot, there is an ever-present tendency for + the bearing edge of the wall to slide down towards the inner edge of the shoe. This + tendency, operating on both the inner and outer wall simultaneously, must strongly + favour contraction.</p> + <p>A further wrong practice is that of continuing the nailing too far towards the + heels. In our opinion this is not now often met with. When it occurs its effect is, + of course, to prevent those movements of expansion of the wall which we now know to + be normal and most marked at the heels.</p> + <p>It may be remarked of the build of the shoe, or of errors in the preparation of + the foot, that neither are of much moment. Neither are they. But when one stays to + consider that errors of this description are practised not only once, but each time + the horse goes to the forge, and that with some of them—those relating to the + build of the shoe—the injury thereby brought about is inflicted not only once, + but every day that particular shoe is worn, then it is not to be wondered at that, + sooner or later, ill consequences more or less grave result.</p> + <p><i>Prognosis</i>.—This will depend to a very large extent upon the + conformation of the limb, and upon the previous duration of the contraction. + Contraction of long standing, where atrophy of the sub-lying, soft structures and the + pedal bone may be expected, will prove obstinate to treatment. Especially will this + be so if the lateral cartilages have become ossified. Neither may we look for much + benefit from treatment if the contraction has occurred in animals with an oblique + foot axis and flat hoofs.</p> + <p>On the other hand, if the case is comparatively recent, if the limb is straight + and the form of the hoof is upright, and if matters are uncomplicated by side-bones, + or other serious alteration in the internal structures, then treatment may be + rewarded with some measure of success.</p> + <br /> + <a name="a63" id="a63"></a> + <p><a href="images/image063.png"><img src="images/image063sm.png" alt="TIP SHOE." /> + </a></p> + <br /> + + <p>FIG. 63.—TIP SHOE. The dotted portions represent the length of the branches + removed.</p> + <p><i>Treatment</i>.—The greater part of the treatment of contracted foot will + almost suggest itself as a corollary of the causes we have enumerated. The normal + width of the heels may be renewed, and development of the wasted frog brought about + by one of three methods:</p> + <p>1. By restoring the pressure from below to the frog.</p> + <p>2. By the use of an expansion shoe.</p> + <p>3. By operative measures upon the horn of the wall.</p> + <p>1. <i>By Restoring the Pressure from Below to the Frog</i>.</p> + <p>This may be accomplished as follows:</p> + <p><i>(a) By Shoeing with Tips</i>.—This method is advocated by Percival, by + A.A. Holcombe, D.V.S., Inspector. Bureau of Animal Industry, U.S.A., by Dollar in his + work on horseshoeing, and by many others.</p> + <p>Though requiring more care than in fitting the ordinary shoe, the application of a + tip is simple. In reality, the tip is just an ordinary shoe shortened by truncating + the heels.</p> + <p>Before applying the tip, the horn of the wall at the toe should be shortened + sufficiently to prevent any undue obliquity of the hoof, and the foot should be so + prepared as to allow the heels of the tip to sink flush with the bearing edge of the + wall behind it.</p> + <p>When the foot does not allow of the removal of much horn at the toe, what is + termed a 'thinned' tip is to be preferred. Its shape is sufficiently shown by the + accompanying figure (Fig. 65).</p> + <p>With the tip the posterior half of the foot is allowed to come into contact with + the ground, and the object we are striving for—namely, frog pressure, and + greater facilities for alternate expansion and contraction of the heels—is thus + brought about.</p> + <br /> + <a name="a64" id="a64"></a> + <p><a href="images/image064.png"><img src="images/image064sm.png" + alt="THE TIP SHOE LET IN THE FOOT." /></a></p> + <br /> + + <p>FIG. 64.—THE TIP SHOE LET IN THE FOOT.</p> + <br /> + <a name="a65" id="a65"></a> + <p><a href="images/image065.png"><img src="images/image065sm.png" + alt="THE THINNED TIP." /></a></p> + <br /> + + <p>FIG. 65.—THE THINNED TIP.</p> + <p><i>(b) By Shoeing with the Charlier</i>.—The results brought about by the + use of a tip may be arrived at by the application of a Charlier or preplantar shoe, + or by a modified Charlier or Charlier tip.</p> + <p>Briefly described, a Charlier is a shoe that allows the sole and the frog to come + to the ground exactly as in the unshod foot. This is accomplished by running a groove + round the inferior edge of the hoof by removing a portion of the bearing edge of the + wall with a specially devised drawing-knife. Into this groove is fitted a narrow and + somewhat deep shoe, made, preferably, of a mixture of iron and steel, and forged in + such a manner that its front or outer surface follows the outer slope of the + wall.</p> + <p>The Charlier should have the inner edge of its upper surface very slightly + bevelled, in order to prevent any pressure on the sensitive sole, and should be + provided with from four to six nail-holes. These latter should be small in size and + conical in shape. The nails themselves should be small, and have a conical head and + neck, to fit into the nail-hole of the shoe.</p> + <br /> + <a name="a66" id="a66"></a> + <p><a href="images/image066.png"><img src="images/image066sm.png" + alt="THE SPECIAL DRAWING-KNIFE (FLEMING'S) FOR PREPARING THE FOOT FOR THE CHARLIER SHOE." /> + </a></p> + <br /> + + <p>FIG. 66.—THE SPECIAL DRAWING-KNIFE (FLEMING'S) FOR PREPARING THE FOOT FOR + THE CHARLIER SHOE.</p> + <p>The modified Charlier, or Charlier tip, perhaps the better of the two for the + purpose we are describing, is really a shortened Charlier, and bears the same + relation to the Charlier proper as the tip does to the ordinary shoe. It is let into + the solar surface of the foot in exactly the same manner as its larger fellow, but it + does not extend backwards beyond the commencement of the quarters. By its use greater + opportunity for expansion is given to the heels than is done by the Charlier with + heels of full length.</p> + <br /> + <a name="a67" id="a67"></a> + <p><a href="images/image067.png"><img src="images/image067sm.png" + alt="FOOT PREPARED FOR THE CHARLIER SHOE." /></a></p> + <br /> + + <p>FIG. 67.—FOOT PREPARED FOR THE CHARLIER SHOE.</p> + <p>We do not here intend to deal at any length with the arguments for and against the + Charlier as regards its adoption for general use. These will be found fully set out + in any good work on shoeing.</p> + <p>The point that it is correct in theory it would be idle to attempt to evade; but + that it is generally practicable, or that it offers any very pronounced advantages, + as compared with the disadvantages urged against it, over the shoes in ordinary use, + the limited favour it has drawn to itself, since its introduction in 1865, seems + sufficiently to deny.</p> + <p><i>(c) By the Use of a Bar Shoe</i>.—Where the frog is not excessively + wasted benefit will be derived from the use of a bar shoe.</p> + <br /> + <a name="a68" id="a68"></a> + <p><a href="images/image068.png"><img src="images/image068sm.png" alt="BAR SHOE." /> + </a></p> + <br /> + + <p>FIG. 68.—BAR SHOE.</p> + <p>The transverse portion at the back, termed the 'bar,' and which gives the shoe its + name, is instrumental in bringing about from below that counter-pressure on the frog + that we now know to be so necessary a factor in remedying contraction. When the frog, + by wasting or disease, is so deficient as to be unable to reach the 'bar,' this shoe + must be supplemented by a leather or rubber sole.</p> + <p>In the event of corn or sand-crack existing with the contraction, the shoe known + as a 'three-quarter bar' is preferable (see Fig. 103). The break here made in the + contour of the shoe allows of dressing the corn, and, in the case of sand-crack, + removes the bearing from that portion of the wall. <i>(d) By the Use of a Bar Pad and + a Heelless or 'Half' Shoe</i>.—The bar pad consists of a shape of rubber + composition firmly fixed to a leather foundation, which shape of rubber takes the + place of the 'bar' of the bar shoe.</p> + <br /> + <a name="a69" id="a69"></a> + <p><a href="images/image069.png"><img src="images/image069sm.png" + alt="RUBBER BAR PAD ON LEATHER." /></a></p> + <br /> + + <p>FIG. 69.—RUBBER BAR PAD ON LEATHER.</p> + <br /> + <a name="a70" id="a70"></a> + <p><a href="images/image070.png"><img src="images/image070sm.png" + alt="THE BAR, PAD APPLIED WITH A HALF-SHOE." /></a></p> + <br /> + + <p>FIG. 70.—THE BAR, PAD APPLIED WITH A HALF-SHOE.</p> + <p>For habitual use in such cases as prove obstinate to treatment, or where a + complete cure was never from the commencement expected, the bar pad is undoubtedly + one of the most useful inventions to our hand. The animal's 'going' is improved, the + tender frog is protected from injury by loose stones, and greater comfort given to + both the horse and the driver.</p> + <br /> + <a name="a71" id="a71"></a> + <p><a href="images/image071.png"><img src="images/image071sm.png" alt="FROG PAD." /> + </a></p> + <br /> + + <p>FIG. 71.—FROG PAD.</p> + <br /> + <a name="a72" id="a72"></a> + <p><a href="images/image072.png"><img src="images/image072sm.png" + alt="FROG PAD APPLIED." /></a></p> + <br /> + + <p>FIG. 72.—FROG PAD APPLIED.</p> + <p><i>(e) By the Use of a Frog Pad and a Shoe of Ordinary Shape</i>.—The shape + of rubber on this pad is designed to cover the frog only. Its shape and mode of + application is sufficiently shown in the accompanying illustrations.</p> + <p><i>(f) By turning out to Grass</i>.—Where the expense of keep is no object, + a return of contracted feet to the normal may be brought about by removing the shoes + and turning the animal out to pasture, thus giving the feet the advantages to be + derived from a more or less continuous operation of the normal movements of expansion + and contraction. In this case the treatment must extend from three to four, or + possibly six months.</p> + <p>2. <i>By the Use of Some Form of Expansion Shoe</i>.</p> + <br /> + <a name="a73" id="a73"></a> + <p><a href="images/image073.png"><img src="images/image073sm.png" + alt="SMITH'S EXPANSION SHOE SEEN FROM ITS GROUND SURFACE AND FROM THE SIDE." /> + </a></p> + <br /> + + <p>FIG. 73.—SMITH'S EXPANSION SHOE SEEN FROM ITS GROUND SURFACE AND FROM THE + SIDE. <i>a</i>, The screw, with a fine-cut thread; <i>b</i>, nut which travels along + it; <i>c</i>, a hollow thimble into which the screw passes at one end, the other + being cut out V-shaped to catch into a slot (<i>d</i>) on the shoe; <i>e, e</i>, the + grip[A] for the bars, the length and direction of which depend upon the shape of the + foot; <i>f, f</i>, the counter-sunk rivets forming the hinge (<i>f</i>'); <i>g</i>, + the counter-sunk rivet of the expanding piece.</p> + <p>[Footnote A: The inventor of this shoe uses the word 'grip' to denote what, in + describing other expansion shoes, we term the 'clip' (H.C.R.).]</p> + <p><i>(a) Smith's</i>.—For many years past continental writers have been + practising this method. So far as we know, however, Lieutenant-Colonel Fred Smith was + the first English veterinarian to use a shoe of his own devising, and to report on + its effects. This shoe we will, therefore, give first mention.</p> + <p>The above figure, with its accompanying letterpress, sufficiently explains the + nature of the shoe. In fitting the shoe, care must be taken to have the hinges (<i>f, + f</i>) far enough back, or the shoe will have a tendency to spring at the heels, and + the grips <i>(e, e)</i>, which catch on the bars, will have a difficulty in biting. + This trouble will be avoided by having the hinges about 1-1/2 to 2 inches from the + heels.</p> + <p>After the shoe has been firmly nailed to the foot, the travelling nut <i>b</i> is + driven forward on the screw <i>a</i> so as to cause the grips to just catch on the + inside of the bars of the foot. According to the inventor, the amount of pressure to + be exerted must be learned by experience, and he says:</p> + <p>'I screw up very gradually until I see the cleft of the frog just beginning to + open. I now trot the horse up, and if he goes sound it is certain that the pressure I + have exercised will not give rise to trouble. The animal is sent to work to assist in + the expansion of the foot. On examining the shoe next day, the grip is found to be + quite loose, the foot has enlarged, and the nut is turned once more until the grip on + the bars is tightened, the horse being again trotted to ascertain that no injurious + pressure is exerted.</p> + <p>'Every day or two I repeat this process, making measurements in all cases before + widening the heels. The increase in width of the foot which results is astonishing, + 1/4 to 3/8 inch during the first week may be safely predicted, and in a month to six + weeks it is impossible to recognise in the large healthy frog and wide heels, the + shrivelled-up organ of a short time before.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. v., p. + 98.]</p> + <p>It is pointed out by the writer of the above (and his observations, doubtless, + apply to the use of all other expansion shoes in which the bars are gripped and + forcibly expanded) that the whole secret of success lies in avoiding injurious + pressure by exerting too great an expansion at one operation. After each manipulation + of the expanding apparatus the horse should trot sound and the frog remain cool. + Should the foot become hot, and lameness supervene, then tension should at once be + relaxed.</p> + <p><i>Recorded Cases of the Use of the Shoe</i>.—The inventor of the shoe + relates two cases of contracted foot treated by these means in which the heels of + one, after thirty-nine days' treatment, had increased in width to the extent of 1 + inch, and the heels of the other, after twenty-four days', had enlarged 5/8 inch. Of + the first case he gives the drawings in Fig. 74.</p> + <p>A represents the foot before treatment; B the same foot after nine days' + treatment, when the heels had widened 3/4 inch; and C the same foot at the end of the + thirty-nine days' treatment, at which date the frog was an excellent-looking one, and + the foot had increased an inch in width.[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. v., p. + 100]</p> + <br /> + <a name="a74" id="a74"></a> + <p><a href="images/image074.png"><img src="images/image074sm.png" + alt="THE CHANGES IN FORM OF A CONTRACTED FOOT TREATED WITH SMITH'S EXPANSION SHOE" /> + </a></p> + <br /> + + <p>FIG. 74.—THE CHANGES IN FORM OF A CONTRACTED FOOT TREATED WITH SMITH'S + EXPANSION SHOE</p> + <p>In 1893, at a meeting of the Midland Counties Veterinary Medical Association, the + late Mr. Olver said he had applied this shoe to a valuable hunter that had gone so + lame that he could scarcely put his foot to the ground. After a fortnight's + application, and by the assistance of the double screw in the shoe, the heel was + forced out. Then the horse was put to work with the shoe on, and he had hunted the + whole of the last season in a perfectly sound condition.[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. vi., p. 143]</p> + <p>F.D. McLaren, M.R.C.V.S., writes:[A] 'I resolved to try one of Captain Smith's + shoes in a case where the hoof was badly contracted, and where the frog had entirely + disappeared, there being also slight lameness. The roof rapidly expanded, and every + other day the nut was moved on a bit to keep the cross-piece tight. I then had the + cross-piece bent downwards a little <i>to prevent the nut pressing on the + rapidly-growing frog</i>.[B] After another fortnight or so, I had a shoe made with + clips resting against the inside of the bars,[C] and the next time he was shod these + were also dispensed with. It is now a year ago since the animal recovered his frog, + and he still has the largest frog in the stable, and the hoof shows no sign of + contraction.'</p> + <p>[Footnote A: <i>Ibid</i>., vol. vi., p. 183]</p> + <p>[Footnote B: The italics are mine (H.C.R.).]</p> + <p>[Footnote C: The expanding shoe itself was here evidently dispensed with, and an + ordinary shoe with bar-clips used in its stead (H.C.R.).]</p> + <p><i>(b) De Fay's</i>.—Among other shoes of the expansion class may be + mentioned that of De Fay. Like the preceding, it is a shoe with a flat bearing + surface, and provided with bar-clips. It is, however, <i>un</i> hinged. The requisite + degree of periodic expansion is in this case arrived at by a forcible widening of the + heels of the shoe, accomplished by bending the substance of which it is made, and for + this purpose the instrument illustrated in Fig. 75 is employed.</p> + <p>The foot is first properly trimmed by levelling the heels and thinning the sole on + each side of the frog. The shoe is then fixed by nails in the ordinary manner, taking + care that the last nails come not too far back, and that the clips rest evenly and + firmly on the inside of the bars.</p> + <p>The dilator, hoof-spreader, or vice, as it is variously called, is then applied, + its two jaws (<i>a</i> and <i>b</i>) fitting against the inner edge of the shoe at + the heels. Careful note is taken of the width of the hoof as measured on the + graduated scale (<i>e</i>, <i>e</i>), and the double screw (<i>g</i>, <i>h</i>) + revolved by means of the wrench (k), until the opening of the jaws thus obtained + registers an expansion of 1/12 to 1/8 inch.</p> + <p>The dilatation is repeated at intervals of from eight to ten days, until, at the + expiration of a month or six weeks, the amount of total expansion of the heels + registers nearly an inch. That the method requires the greatest care may be gathered + from the reports of continental writers. They state that frequently the pain and + consequent lameness keep the patient confined to the stable for several days.</p> + <p>Numerous and but slightly differing forms of the dilator are on the market. As in + principle they are all essentially the same, and are to be found illustrated in any + reliable instrument catalogue, they need no description here.</p> + <br /> + <a name="a75" id="a75"></a> + <p><a href="images/image075.png"><img src="images/image075sm.png" + alt="DE FAY'S VICE." /></a></p> + <br /> + + <p>FIG. 75.—DE FAY'S VICE.</p> + <p><i>(c) Hartmann's</i>.—A further useful expansion shoe is that of Hartmann's + (Fig. 76), in that it may be adapted for either unilateral or bilateral contraction. + This shoe is also provided with bar-clips, and forcibly expanded at the heels by + means of a dilator. The expansion is governed by saw-cuts through the inner margin of + the shoe directed towards its outer margin, and running only partially through the + inner half of the web (see Fig. 76).</p> + <p>According as the contraction is confined to the inner or outer heel, the saw-cuts, + one or two in number, are placed to the inner or outer side of the toe-clip. When the + contraction is bilateral, the saw-cuts, one or more in number, are placed on each + side of the toe-clip.</p> + <p><i>(d) Broué's</i>.—This is one of the forms of so-called 'slipper' + shoes (see Fig. 77). We have already indicated that the shape of the bearing surface + of the ordinary shoe—by its 'seating' or sloping from outside to + inside—is sometimes a cause of contraction. In the 'slipper' of Broué + this bearing is reversed, and the slope is from inside to outside. In the original + form of this shoe the slope to the outside was continued completely round the shoe. + Experience taught that the strain this enforced upon the junction of the wall with + the sole was injurious, and that the 'reversed seating,' if we may so term it, was + best confined to the hinder portions of the shoe's branches.</p> + <br /> + <a name="a76" id="a76"></a> + <p><a href="images/image076.png"><img src="images/image076sm.png" + alt="Hartmann expanding shoe." /></a></p> + <br /> + + <p>FIG. 76. This figure illustrates the principle of the Hartmann expanding shoe. + <i>a, a</i>, The clips to catch the inside of the bars; <i>b, c</i>, saw-cuts.</p> + <p>The amount of slope should not be excessive. If it is, too rapid and too forcible + an expansion takes place, and pain and severe lameness results. Dollar gives the + requisite degree of incline by saying that the outer margin of the bearing surface of + the shoe should be from 1/12 to 1/8 inch lower than the inner.</p> + <p>In the case of the Broué slipper, it is the animal's own weight that brings + about the widening of the heels, the slope or outward incline of the slipper simply + causing the inferior edge of the wall at the heels to spread itself outwards instead + of sliding inwards on the bearing surface of the shoe.</p> + <br /> + <a name="a77" id="a77"></a> + <p><a href="images/image077.png"><img src="images/image077sm.png" + alt="THE SLIPPER SHOE OF BROUÉ." /></a></p> + <br /> + + <p>FIG. 77.—THE SLIPPER SHOE OF BROUÉ.</p> + <p><i>(e) Einsiedel's</i>.—Like the 'slipper' of Broué, the Einsiedel + shoe depends for its effects upon the slope of the bearing surface.</p> + <p>It differs from the Broué in being provided with a 'bar-clip.' This, in + addition to gripping the bars like the bar-clips of other expanding shoes, also + assists, under the body-weight, in expanding the heels by the pronounced slope given + to its upper surface. The expanding force exerted by the body-weight falls thus, + through the medium of the bar-clip, clip, <i>partly</i> upon the bars, instead of, as + in the Broué, solely upon the wall. We say <i>partly</i> advisedly, for, in + addition to the slope upon the outer side of the bar-clips, the bearing surface of + the heels of the shoe is <i>slightly</i> sloped outwards also. The good office served + by the bar-clip is the lessening of any tendency to strain upon the white line.</p> + <br /> + <a name="a78" id="a78"></a> + <p><a href="images/image078.png"><img src="images/image078sm.png" + alt="THE SLIPPER AND BAR-CLIP SHOE OF EINSIEDEL." /></a></p> + <br /> + + <p>FIG. 78.—THE SLIPPER AND BAR-CLIP SHOE OF EINSIEDEL.</p> + <p>Those we have described by no means exhaust the number of expansion shoes that + have been devised. There are numerous others, many of which are composed of + three-hinged portions, the two hindermost of which are gradually separated by a + toothed arrangement of their inner margins and a travelling bar, the disadvantage of + which is that it is liable to work loose. In the majority of this class of shoe the + hinges are placed far forward, one on each side of the toe. They there become exposed + to excessive wear. In fact, against the bulk of this form of shoe it may be urged + that they cannot be worn by the animal at work, that they are expensive, difficult to + make, and easily put out of order.</p> + <p>3. <i>By Operations on the Horn of the Wall</i>.</p> + <p><i>(a) Thinning the Wall in the Region of the Quarters</i>.—This is best + done by means of an ordinary farrier's rasp. The thinning should lessen gradually + from the heel for 2-1/2 to 3 inches in a forward direction. That portion of the wall + next to the coronary border, about 1/2 inch in breadth, should not be touched. At + this point the thinning should commence, should be at its greatest, and lessen + gradually downwards until at the inferior margin of the wall the normal thickness of + horn is left. The animal is then shod with a bar shoe and the hoof bound with a + bandage soaked in a mixture of tar and grease, in order to keep the thinned portion + of the wall from cracking. In this condition the animal may remain at light + labour.</p> + <p>When possible, however, it is better to combine the thinning process thus + described with turning out to grass. In this case the ordinary shoe is first removed, + and the foot poulticed for twenty-four hours to render the horn soft. The foot is + then prepared by slightly lowering the heels—leaving the frog + untouched—and thinning the quarters in exactly the manner described above.</p> + <p>After this is done, the animal is shod with an ordinary tip, a sharp cantharides + blister applied to the coronet, and then turned out in a damp pasture. In this case + the object of the tip is to throw the weight on to the heels and quarters. The + thinned horn yields to the pressure thus applied, and a hoof with heels of a wider + pattern commences to grow down from the coronet. Two to three months' rest is + necessary before the animal can again he put to work.[A]</p> + <p>[Footnote A: This is the treatment strongly advocated by A.A. Holcombe, D.V.S., + Inspector, Bureau of Animal Industry, U.S.A.]</p> + <p><i>(b) Thinning the Wall in the Region of the Toe</i>.—This is done with the + idea that the tendency of the heels to expand under pressure of the body-weight is + helped by the thinned portion at the toe allowing the heels to more readily open + behind. Seeing that in the case of toe sand-crack the converse is argued—that + contraction of the heels readily takes place and forces the sand-crack wider + open—it is doubtful whether this method is of any utility in treating + contracted heels.</p> + <p><i>(c) Grooving the Wall Vertically or Horizontally, and Shoeing with a Bar + Shoe</i>.—Marking the wall with a series of grooves, each running in a more or + less vertical direction, was suggested to English veterinarians by Smith's operation + for side-bones.</p> + <p>The manner of making the grooves, and the instruments necessary, will be found + fully described in Section C of Chapter X.</p> + <p>That the method is followed by satisfactory results the undermentioned case will + show:</p> + <p>'A mare, which I have had in my possession since she was a foal, has always had + contracted feet, which were also unnaturally small.... Lately the mare has been going + very "short," and at length her action was quite crippled. At times she was decidedly + lame on the off fore-foot. At no time have I been able to detect any sign of + structural disease. I thereupon concluded that the lameness was due to mechanical + pressure on the sensitive structures, and I determined to try the effects of the + above treatment. As this was my first experience of the process, I was careful to + carry it out in all its details, as described by Professor Smith. After the bar shoes + had been put on, the mare was very lame. I allowed her two days' rest, then commenced + regular walking exercise, and she daily improved. After fourteen days there was no + lameness, but still short action. I thereupon gave the mare another week's walking + exercise, at the expiration of which I drove her a short turn of five miles, which + she did quite well, and free from lameness. For three months I kept the saw-cuts open + to the coronet, and continued the bar shoes, keeping the mare at exercise, and giving + her occasionally a drive. She never liked the bar shoes, and I was glad when I could + discontinue them, which I did in the fourth month. When shod with the usual shoes the + complete success of the treatment was shown. I have now had her going with the + ordinary shoes for the past two or three months, and the improvement in the shape of + the feet is very marked; there is no lameness; the mare is free in movement, fast, + and spirited, whereas previously she was quite the reverse, and almost unfit to + drive.'[A]</p> + <p>[Footnote A: W.S. Adams, M.R.C.V.S., <i>Veterinary Journal</i>, vol. xxx., p. + 19.]</p> + <p>This method, though but recently introduced to the English veterinary surgeon, is + by no means new. According to Zundel, it was recently made known on the Continent by + Weber, but was previously known and mentioned by Lagueriniere, Brognier, and Hurtrel + d'Arboval.</p> + <p>When the grooving is in a horizontal direction, a single incision is sufficient. + This is made 3/4 inch below the coronary margin of the wall, and parallel with it, + extending from the point of the heel for 2 or 3 inches in a forward direction. As in + the previous method, a bar shoe is applied, and the animal daily exercised. Thus + separated from the fixed and contracted portion of the wall below, the more elastic + coronet under pressure of the body-weight commences to bulge. The bulging is of such + an extent as to cause the new growing hoof from the top to considerably overhang the + contracted portion below, and cure of the condition results from the newly-expanded + wall above growing down in a normal direction.</p> + <p>This consideration of contracted heels may be concluded by drawing attention to + the advisability of always maintaining the horn of the wall in as soft and supple a + condition as is natural by the application of suitable hoof dressings.</p> + <p>A useful one for the purpose is that made with lard, to which has been added a + small quantity of wax or turpentine.</p> + <p>Especially should a dressing like this be used when the hoof is inclined to be + hard and brittle, and where tendency to contraction has already been noticed.</p> + <p>The application of a hoof ointment is also particularly indicated where the foot + is much exposed to dampness, where the animal is compelled to stand for long periods + upon a dry bedding, or where the bedding is of a substance calculated to have a + deleterious effect upon the horn.</p> + <p>This, in conjunction with correct shoeing, will probably serve to avoid the + necessity for more drastic measures at a later time.</p> + <p><i>(b)</i> LOCAL OR CORONARY CONTRACTION.</p> + <p><i>Definition</i>.—Contraction at the heels, confined to the horn + immediately succeeding that occupied by the coronary cushion. Really, the condition + is but a somewhat arbitrary subdivision of contracted hoof, as we have just described + it in general. For that reason we shall give it but very brief mention.</p> + <p><i>Symptoms</i>.—In this case the horn of the heels, instead of running down + in a straight line from the coronary margin to the bearing surface of the wall, + presents a more or less distinct concavity (See Fig. 79, <i>a</i>, <i>a</i>).</p> + <p>As is the case with contraction considered as a whole, this deformity may affect + one or both heels; and during its first appearance, which is after the first few + shoeings, the animal may go distinctly lame.</p> + <p><i>Causes</i>.—Coronary contraction may occur in hoofs of normal shape + immediately shoeing is commenced, and frog pressure with the ground removed. It is + far more likely to ensue, however, if the hoof is flat, with the heels low, and the + wall sloping. And with those predisposing circumstances it is that the horse goes + lame, and not with the hoof of normal shape.</p> + <p>Seeing, then, that this condition is largely dependent upon the shape of the foot, + we may, to some extent, regard it as hereditary. Seeing further, however, that it + only appears when shoeing is commenced, we may in a greater degree also regard it as + acquired. The lesson, therefore, that this and other forms of contraction should + teach us is the carefulness with which the shoeing should be superintended in a large + stud, or in any case where the animal is of more than ordinary value.</p> + <br /> + <a name="a79" id="a79"></a> + <p><a href="images/image079.png"><img src="images/image079sm.png" + alt="HOOF WITH LOCAL OR CORONARY CONTRACTION (AS INDICATED AT THE POINTS" /></a></p> + <br /> + + <p>FIG. 79.—HOOF WITH LOCAL OR CORONARY CONTRACTION (AS INDICATED AT THE POINTS + <i>a, a</i>).</p> + <p>The explanation of the restricted nature of this form of contraction is simple + enough. We have only to refer to the lessons taught by the experiments of Lungwitz, + described in Chapter III., and the condition almost explains itself. We remember + that, briefly, the coronary margin of the wall resembles a closed elastic ring, which + yields and expands to local pressure, no matter how slight. We remember also that + removal of the counter-pressure of the frog with the ground tended to contraction of + the wall's solar edge when weight was applied. Connect these two facts with the + experience that this form of contraction more often than not occurs in hoofs with + sloping heels, and we arrive at the following:</p> + <p>1. The excessive slope of the heels tends to throw a more than usual part of the + body-weight upon the posterior portion of the coronary margin of the wall, with a + consequent expansion of that part of the coronary margin implicated.</p> + <p>2. That the shoeing, in removing the counter-pressure of the frog with the ground, + is at the same time tending to bring about contraction of the lower portions of the + wall at the heels and quarters.</p> + <p>3. That this tendency to contraction will at first appear in the thinner portion + of the area of wall named—namely, in that immediately below the bulging + coronary margin.</p> + <p>We thus get the appearance depicted in Fig. 79—a contraction <i>(a, a)</i> + of the heels in the horn below the coronary margin, with the coronary margin itself + bulging above, and a hoof of apparently normal width below.</p> + <p>We say 'apparently' with a purpose, for, as actual measurements will show, the + wall near the solar edge is really contracting, for reasons which we have just + described connected with shoeing. Its 'appearance' of normal width is accounted for + thus: The contraction at <i>a, a</i> is caused by the dragging inwards of the + coronary cushion brought about by the sinking downwards of the plantar cushion, with + which body it will be remembered the coronary cushion is continuous. With the + constant dragging in and down of the coronary cushion there is given, to the + horn-secreting papillæ, studding both the lower third of its outer face and its + lowermost surface, a distinct 'cant' outwards. Below the lowermost limit of the + coronary cushion, then, by reason of the cant outwards of the coronary papillæ + in the situations mentioned, the horn of the wall takes a more outward direction than + normal, a fact which lessens in effect the contraction as a whole really going on. It + is interesting, too, to note that by this outward cant of the wall below, and the + bulging of the coronary margin above it, the contraction (<i>a, a</i>) is heightened + in effect, and caused to appear greater than really it is.</p> + <p>From what we have said it follows that contraction of the heels, excepting the + extreme coronary margin, is existent generally, and not confined solely to <i>a, + a</i>.</p> + <p>We have, then, in this condition, as we indicated at the commencement, but a phase + in the evolution of ordinary contracted heels, for, with the progress of the + contraction already existing at <i>a, a</i>, and below those points, it is only fair + to assume that with it falling in of the at present bulging coronary margin must + sooner or later occur, that, though expanded when compared with the wall below it, it + will be really contracted as compared with what it was once in that same foot.</p> + <p>We may therefore conclude this section by remarking that factors tending to + contraction of the heels in general are equally potent in the causation of contracted + coronet alone.</p> + <p><i>Treatment</i>.—Exactly that described for contracted heels. Bearing in + mind that contracted coronary margin is but the onset of contracted heels, and that + its first exciting cause is that of removal of the ground-pressure upon the frog, the + most careful attention must be paid to the shoeing. The use of bar shoes, ordinary + frog pads, or heelless shoes and bar pads, are especially indicated, together with + abundant exercise. By these means the normal movements of expansion will be brought + into play, and the condition quickly remedied.</p> + <h3>C. FLAT-FOOT.</h3> + <p><i>Definition</i>.—By this term is indicated a condition of the foot where + the natural concavity of the sole is absent.</p> + <p><i>Symptoms</i>.—In the flat-foot the inferior edge of the wall, the sole, + and the frog, all lie more or less in the same plane. It is a condition observed far + more frequently in fore than in hind limbs, and is seen in connection with low heels, + more or less obliquity of the wall, and a tendency to contraction. The action of the + animal with flat feet is heavy, a result partly of the build of the foot, and partly + of the tenderness that soon comes on through the liability of the sole to constant + bruising.</p> + <br /> + <a name="a80" id="a80"></a> + <p><a href="images/image080.png"><img src="images/image080sm.png" + alt="lower surface of a typical flat-foot." /></a></p> + <br /> + + <p>FIG. 80. This figure represents the lower surface of a typical flat-foot. It + illustrates, too, the commencement of a condition we referred to in Section B of this + chapter—namely, the compression of the frog by the ingrowing heels (b) and bars + (a).</p> + <p><i>Causes</i>.—Flat-foot is undoubtedly a congenital defect, and is seen + commonly in horses of a heavy, lymphatic type, and especially in those bred and + reared on low, marshy lands. It is thus a common condition of the fore-feet of the + Lincolnshire shire.</p> + <p>As might be expected, a foot of this description is far more prone to suffer from + the effects of shoeing than is the foot of normal shape, and regarded in this light + shoeing may be looked upon as, if not an actual cause, certainly a means of + aggravating the condition. Directly the shoe—or at any rate the ordinary + shoe—is applied, mischief commences. The frog is raised from the ground, and + the whole of the weight thrown on to the wall. The heels, already weak and inclined + to turn in, are unable to bear the strain. They <i>turn in</i>, and contraction + commences. This 'turning in' of the heels is favoured by the undue obliquity of the + wall. At the same time, the sole being archless, a certain amount of elasticity is + lost. The weight is thrown more on to the heels, and the os pedis slightly descends, + rendering the flatness of the sole even more marked than before. With the loss of + elasticity of the sole concussion makes itself more felt. The animal is easily lamed, + bruised sole becomes frequent, and corns sooner or later make their appearance.</p> + <p><i>Treatment</i>.—Flat-foot is incurable. All that can be done is to pay + careful attention to the shoeing, and so prevent the condition from being aggravated. + In trimming the foot the sole should not be touched; the frog, too, should be left + alone, and the wall pared only so far as regards broken and jagged pieces.</p> + <p>The most suitable shoe is one <i>moderately</i> seated. If the seating is + excessive, and bearing allowed only on the wall, there is a tendency for the wall to + be pushed outwards, and for the sole to drop still further. On the other hand, if the + seating is insufficient, or the web of the shoe too wide, and too great a bearing + thus given to the sole, then we get, first, an undue pressure upon the last-named + portion of the foot a bruise, and, finally, lameness. The correct bearing should take + in the whole of the wall and the whole of the white line, and should <i>just + impinge</i> upon the sole. Above all, the heels of the shoe should be of full length, + otherwise, if the shoe is worn just a little too long, its heels are carried under + the sole of the foot, and by pressure there produce a corn.</p> + <p>If, with these precautions in shoeing flat-foot, tenderness still persists, a sole + of leather or gutta-percha must be used with the shoe.</p> + <h3>D. PUMICED-FOOT, DROPPED SOLE, OR CONVEX SOLE.</h3> + <p><i>Definition</i>.—This term is applied to the foot when the shape of the + sole is comparable to the bottom of a saucer. When least marked it is really an + aggravated form of flat-foot.</p> + <p><i>Symptoms</i>.—In pumiced-foot the sole projects beyond the level of the + wall. The obliquity of the latter is more marked than in the previous condition, and + progression, to a large extent, takes place upon the heels. In addition to its + deformity, the horn is greatly altered in quality, and, as the name 'pumice' + indicates, is more or less porous in appearance, bulging, and brittle.</p> + <p><i>Causes</i>.—As a general rule, it may be taken that pumiced-foot is a + sequel of previous disease, although in its least pronounced form it may occur as the + result of accidental or other causes, such as those described in the causation of + flat-foot.</p> + <p>Occurring in its most marked form, there is no gainsaying the fact that + pumiced-foot is a sequel of either acute or subacute laminitis. As we shall see when + we come to study that disease, the dropping of the sole is brought about by distinct + and easily-understood morbid processes affecting the sensitive structures. Briefly, + these morbid processes in laminitis may be described thus: The accumulated + inflammatory exudate, and in some cases pus, weakens and destroys the union between + the sensitive and insensitive laminæ. This separation, for reasons afterwards + to be explained, is greatest in the region of the toe. The os pedis, loosened from + its intimate attachment with the horny box, is dropped upon the sole, and the sole, + unable to bear the weight, commences to bulge below.</p> + <p>The altered character of the horn is accounted for by the inflammatory changes in + the sensitive laminæ and the papillæ of the keratogenous membrane + generally, for it follows as a matter of course that these tissues, themselves in a + diseased condition, must naturally produce a horn of a greatly altered and inferior + quality.</p> + <p>When following the <i>subacute</i> form of laminitis, the changes characterizing + pumiced-foot are slow in making their appearance. The animal at first goes short, and + the lameness thus indicated gradually becomes more severe, until the animal is no + longer able to work. The feet become hot and dry, the hoof loses its circular form, + and the growth of horn at the heels becomes excessive. At this stage the appearance + of bulging at the sole begins to make itself seen. Later, the outer surface of the + wall becomes 'ringed' or 'ribbed,' the rings being somewhat closely approximated in + the region of the toe, and the distance between them gradually widening towards the + heels. The wall too, especially in the region of the toe, instead of running in a + straight line from the coronary margin to the shoe, becomes concave. It is this + change, together with the appearance of the rings, that indicates the loosening of + the attachment of the os pedis to the wall, and its afterwards backward and downward + direction (see Fig. 124).</p> + <br /> + <a name="a81" id="a81"></a> + <p><a href="images/image081.jpg"><img src="images/image081sm.jpg" + alt="HOOF WITH THE RIBS OR RINGS CAUSED BY CHRONIC LAMINITIS." /></a></p> + <br /> + + <p>FIG. 81.—HOOF WITH THE RIBS OR RINGS CAUSED BY CHRONIC LAMINITIS.</p> + <p>As a sequel of <i>acute</i> laminitis, these changes make their appearance with + more or less suddenness, and are generally complicated in that they owe their + occurrence to the formation of pus within the horny box.</p> + <p><i>Treatment</i>.—Pumiced-foot is always a serious condition. The animal is + useless for work upon hard roads or town pavings, and is of only limited utility for + slow work upon soft lands. The more serious form, that following acute laminitis, and + complicated by the presence of pus, we may regard as beyond hope of treatment.</p> + <p>With the more simple form of the condition, we may do much to render greater the + animal's usefulness. The same principles as were applied to the shoeing of flat feet + will have to be observed here. Trimming or paring of any kind, save 'straightening + up' of the wall, must be severely discountenanced. A broad-webbed shoe, one that will + give a certain amount of cover to the sole, is indicated. As in the treatment of + flat-foot, however, direct pressure upon the sole must be avoided, and the shoe + 'seated.' The 'seating,' however, should not commence from the absolute outer margin + of the shoe's upper surface. A <i>flat</i> bearing should be given to the wall and + the white line, and the seating commenced at the sole.</p> + <p>We have already remarked on the increased growth of horn at the heels. It is in + this position, then, that will be found the greatest bearing surface for the shoe, + and it is wise, in this case, to have the heels of the shoe kept flat. In other + words, the 'seating' is not to be continued to the hindermost portion of the branches + of the shoe. By this means there may be obtained at each heel a good solid bearing of + from 2 to 3 inches, which would otherwise be lost.</p> + <p>Where the accompanying condition of the horn is bad enough to indicate it, a + leather sole should be used, beneath which has been packed a compress of tow and + grease, rendered more or less antiseptic by being mixed with tar.</p> + <p>Where the sole is exceedingly thin, and inclined to be easily wounded, and where + the hoof, by its brittleness, has become chipped and ragged at the lower margin of + the wall, it may perhaps be more advantageous to use, in place of the compress of + tow, the <i>huflederkitt</i> of Rotten. This is a leather-like, dark brown paste. + When warmed in hot water, or by itself, it becomes soft and plastic, and may readily + be pressed to the lower surface of the foot, so as to fill in all little cracks and + irregularities, and furnish a complete covering to the sole and frog, and to the + bearing surface of the wall. When cold it hardens, without losing the shape given to + it, into a hard, leather-like substance.</p> + <p>Treated in this way, the animal with pumiced feet may yet be capable of earning + his living at light labour or upon a farm.</p> + <h3>E. 'RINGED' OR 'RIBBED' HOOF.</h3> + <p><i>Definition</i>.—A condition of the hoof in which the wall is marked by a + series of well-defined ridges in the horn, each ridge running parallel with the + coronary margin. They are known commonly as 'grass rings,' and may be easily + distinguished from the more grave condition we have alluded to as following + laminitis, by the mere fact that they do not, as do the laminitic rings, approximate + each other in the region of the toe, but that they run round the foot, as we have + already said, <i>parallel with each other</i>.</p> + <br /> + <a name="a82" id="a82"></a> + <p><a href="images/image082.jpg"><img src="images/image082sm.jpg" + alt="HOOF SHOWING THE RINGS IN THE HORN BROUGHT ABOUT BY PHYSIOLOGICAL CAUSES." /> + </a></p> + <br /> + + <p>FIG. 82.—HOOF SHOWING THE RINGS IN THE HORN BROUGHT ABOUT BY PHYSIOLOGICAL + CAUSES.</p> + <p><i>Causes</i>.—This condition is purely a physiological, and not a + pathological one, and the words of its more common name, 'grass rings,' sufficiently + indicate one of the most common causes. Anything tending to an alternate increase and + decrease in the secretion of horn from the coronet will bring it about. Thus, in an + animal at grass, with, according to the weather conditions, an alternate moistness + and dryness of the pasture, with its consequent influence on the horn secretion, + these rings nearly always appear. The effects of repeated blisters to the coronet + make themselves apparent in the same way, and testify to the efficacy of blisters in + this region in any case where an increased growth of horn is deemed necessary. From + this it is clear that the condition depends primarily upon the amount and condition + of the blood supplied to the coronary cushion. Thus, fluctuations in temperature + during a long-continued fever, or the effects of alternate heat and cold, or of + healthy exercise alternated with comparative idleness, will each rib the foot in much + the same manner.</p> + <p><i>Treatment</i>.—The condition is so simple that we may almost regard it as + normal. Consequently, treatment of any kind is superfluous. Where constitutional + disturbance is exerting an influence upon either the quality or quantity of the blood + directed to the part, then, of course, attention must be paid to the disease from + which it is arising.</p> + <h3>F. THE HOOF WITH BAD HORN.</h3> + (<i>a</i>) THE BRITTLE HOOF. + <p><i>Definition</i>.—As the name indicates, we have in this condition an + abnormally dry state of the horn.</p> + <p><i>Symptoms</i>.—These are obvious. The horn is hard, and when cut by the + farrier's tools gives the impression of being baked hard and stony, the natural + polish of the external layer is wanting, and there is present, usually, a tendency to + contracted heels. With the dryness is a liability to fracture, especially at points + where the shoe is attached by the nails. As a consequence, the shoes are easily cast, + leading to splits in the direction of the horn fibres. These run dangerously near the + sensitive structures, giving rise in many cases to lameness. Even where pronounced + lameness is absent the action becomes short and 'groggy,' and the utmost care is + required in the shoeing to keep the animal at work.</p> + <p><i>Causes</i>.—To a very great extent the condition is hereditary, and is + observed frequently in animals of the short, 'cobby' type. In ponies bred in the + Welsh and New Forest droves the condition is not uncommon, especially in the smaller + animals. Animals who have had their feet much in water—as, for instance, those + bred and reared on marshy soils—and afterwards transferred to the constant + dryness of stable bedding, are also particularly liable to this condition. It is + noticed, too, following the excessive use of unsuitable hoof-dressings, more + especially in cases where coat after coat of the dressing is applied without + occasionally removing the previous applications.</p> + <p><i>Treatment</i>.—As a prophylactic, a good hoof-dressing is indicated. It + should not consist solely of grease, but should have mixed with it either wax, + turpentine, or tar.</p> + <p>Above all, careful shoeing should be insisted on, and the owner of an animal with + feet such as these will be well advised if he is recommended to have the shoeing + superintended by one well competent to direct it rightly. The foot should be trimmed + but lightly, always remembering that in a foot of this description the horn, in + addition to being brittle, is generally abnormally thin. Jagged or partly broken + pieces should be removed, and the bearing surface rendered as level as possible. The + foot should be carefully examined before punching the nail-holes in the shoe, and the + nail-holes afterwards placed so as to come opposite the soundest portions of horn. + The nails themselves should be as thin as is consistent with durability, and should + be driven as high up as possible.</p> + <p>On the least sign of undue wear the shoes should be removed, never, as is too + often done, allowing them to remain on so long that a portion breaks away. If, with + the laudable idea of not interfering with the horn more than is possible, this is + practised, the portion of the shoe breaking off is bound to tear away with it more or + less of the brittle horn to which it is attached.</p> + <p>Where the breaks in the horn are so large as to prevent a level bearing for the + shoe being obtained, the interstices should be filled up with one or other of the + preparations made for this purpose. One of the most suitable is that discovered by M. + Defay. By its means sand-cracks or other fractures of the horn may be durably + cemented up.</p> + <p>'Even pieces of iron may be securely joined together by its means. The only + precaution for its successful application is the careful removal of all grease by + spirits of sal-ammoniac, sulphide of carbon, or ether. M. Defay makes no secret of + its composition, which is as follows: Take 1 part of coarsely-powdered gum-ammoniac, + and 2 parts of gutta-percha, in pieces the size of a hazel-nut. Put them in a + tin-lined vessel over a slow fire, and stir constantly until thoroughly mixed. Before + the thick, resinous mass gets cold mould it into sticks like sealing-wax. The cement + will keep for years, and when required for use it is only necessary to cut off a + sufficient quantity, and remelt it immediately before application. We have frequently + used this cement for the repair of seriously broken hoofs. It is so tenacious that it + will retain the nails by which the shoe is attached without tearing away from the + hoof.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. iii., p.71.]</p> + <p>Failing this, the bearing surface may be made level, and fractures repaired by + using the <i>huflederkitt</i> described in the treatment of pumiced sole.</p> + <p>(<i>b</i>) THE SPONGY HOOF.</p> + <p><i>Definition</i>.—This is the opposite condition to the one we have just + described, and is characterized by the soft and non-resistant qualities of the + horn.</p> + <p><i>Symptoms</i>.—Spongy hoof is quite common in animals that have large, + flat, and spreading feet—in fact, the two appear to run very much together. It + is a common defect in animals reared in marshy districts, and of a heavy, lymphatic + type. The Lincolnshire Shire, for instance, has often feet of this description, and, + the causative factors being in this case long-continued, render the feet extremely + predisposed to canker. The horn is distinctly soft to the knife, and has an + appearance more or less greasy. Animals with spongy feet are unfit for long journeys + on hard roads. When compelled to travel thus, the feet become hot and tender, and + lameness results. A mild form of laminitis, extending over a period of three or four + days, often follows on this enforced travelling on a hard road, more especially in + cases where the animal is 'heavy topped,' and the usual food of a highly stimulating + nature. In fact, it has been the author's experience to meet with this condition + several times in the case of shire stallions doing a long walk daily upon hard roads, + with the weather hot and dry.</p> + <p><i>Treatment</i>.—When a horse with spongy feet is shod for the first time, + care must be taken to avoid excessive paring of the sole, for already the natural + wear of the foot has been sufficient to keep the soft horn in a state of thinness. + For the same reason hot fitting of the shoe must not be indulged in for too long a + time. That common malpractice of the forge, 'opening up the heels,' must, in this + case, be especially guarded against, or the excessive paring of the frog and partial + removal of the bars that this operation consists in will lay the foot open to risk of + contraction. To begin with, the heels are naturally weak, and, once the bars are + removed, there is nothing to prevent them rapidly caving in towards the frog. Even + when carefully shod, a foot of this class is readily prone to contract directly the + animal is brought into the stable, and the horn commences to dry to excess. An + ordinary light shoe should be used, and the nails should be light and thin. They + should be driven carefully home, and the 'clinching' made as tight and secure as + possible.</p> + <h3>G. CLUB-FOOT.</h3> + <p><i>Definition</i>.—Under this name we indicate all cases in which the horn + of the wall become straightened from above to below. It will, therefore, include all + conformations varying from the so-called 'upright hoof,' in which the toe forms an + angle of more than 60 degrees with the ground, to the badly 'clubbed' foot, in which + the horn at the toe forms a right angle with the ground, or is even directed + obliquely backwards and downwards, so that the coronary margin overhangs the solar + edge of the wall.</p> + <br /> + <a name="a83" id="a83"></a> + <p><a href="images/image083.png"><img src="images/image083sm.png" + alt="THE CLUB-FOOT." /></a></p> + <br /> + + <p>FIG. 83.—THE CLUB-FOOT.</p> + <p><i>Symptoms</i>.—Even in its least pronounced form the condition is apparent + at a glance, the alteration in the angle formed by the hoof with the ground striking + the eye at once, and the heels, as compared with the toe, appearing much too high. + When the condition is slight, the wall of the toe is about twice as high as that of + the heels, while in the most marked form the toe and the heels may in height be + nearly equal (see Fig. 83). When congenital, but little interference with the action + is noticed. Such animals, by reason of their 'stiltiness,' are unfit for the saddle, + but at ordinary work will perform their duties equally well with the animal of + normal-shaped feet. When acquired as the result of overwork, of contracted tendons, + or other causes, however, the gait becomes stumbling and uncertain. The body-weight + is transferred from the heels to the anterior parts of the foot, and the shoe shows + undue signs of wear at the toe.</p> + <p><i>Causes</i>.—Upright hoof is undoubtedly hereditary, and is even seen as a + natural conformation in the feet of asses and mules. When hereditary in the horse, + however, it is certainly a defect, and is associated commonly with an upright limb, + and a short, upright pastern (see Fig. 83).</p> + <p>Among other causes, we may enumerate sprains or wounds of the flexor tendons, or + any disease of the limbs for a long time preventing extension of the fetlock-joint, + such as sprains or injuries of the posterior ligaments of the limb, splints or + ringbones so placed as to interfere with the movements of the flexor tendons, or, in + the hind-limb, spavin, keeping for some months the fetlock in a state of flexion. In + the very young animal the condition may be induced by an improper paring of the + foot—cutting away too much at the toe, and allowing the heels to remain.</p> + <p><i>Treatment</i>.—When the condition is congenital, no treatment at all is + indicated. It might, in fact, be said that interference would tend rather to minimize + than enhance the animal's usefulness; for, in this case, the club-shaped feet are in + all probability due to faulty conformation above. In other words, the upright hoof is + in this instance but a natural result of the animal's build, with which useful + interference is impossible.</p> + <p>Where the upright hoof is a consequence of excessive paring of the toe, or + insufficient removal of the heels, the condition may be remedied by directing + attention to those particulars, and preventing their continuance. At the same time, a + greater obliquity of the limb axis may be given by the use of a suitable shoe. The + shoe indicated is a short one, with thin heels and a thick toe. In some cases the + abnormality may be remedied by the use of a tip. Whatever method is adopted, care + must be taken not to attempt too positive a change in the direction of the limb at + one operation. The process must be gradual.</p> + <p>In cases where the abnormality has been brought about by wounds to the flexor + tendons, the alteration in the direction of the limb is often so great as to produce + 'knuckling over' of the fetlock. This, to a very great extent, may be remedied by the + use of a shoe with calkins and an extended toe-piece (see Fig. 84).</p> + <br /> + <a name="a84" id="a84"></a> + <p><a href="images/image084.png"><img src="images/image084sm.png" + alt="THE SHOE WITH EXTENDED TOE-PIECE AND HIGH CALKINS." /></a></p> + <br /> + + <p>FIG. 84.—THE SHOE WITH EXTENDED TOE-PIECE AND HIGH CALKINS.</p> + <p>With this shoe a certain amount of forced exercise is advisable, and at intervals + of about two weeks the calkins should be somewhat lowered, until the heels are + brought as close to the ground as is possible. In giving directions for this shoe to + be made the veterinary surgeon must, when referring to the length of the toe-piece, + be guided entirely by the condition of the case. Ordinarily, a suitable length is + from 3 to 4 inches. It is necessary also to warn the owner that, by reason of the + length projecting, the shoe is liable to be torn off.</p> + <p>Should the 'knuckling over' have become complicated by bony deposits round the + seat of the original injury, then a favourable modification of the condition is not + so likely to result.</p> + <p>The benefit to be derived from the shoe with an extended toe-piece in a case of + excessive knuckling is admirably shown in a brief report of a case, under the title + of 'Hooked Foot,' in vol. xiv. of the <i>Veterinary Record</i>, p. 716:</p> + <p>'An eighteen months' old filly showed a deformity of the third phalanx, resulting + in her walking with the front face of the hoof on the ground. The flexors were + apparently all right, and the bending back seemed to be due to contraction of the + ligaments of the joint and the sheath of the perforans.</p> + <p>'On the ground of absence of contraction of the flexors, or atrophy and paralysis + of the extensors, the surgeon considered the lesion curable by simple + orthopædic measures. By means of an elongated toe-piece to the shoe and + calkins, which were shortened every fifteen days, the filly was completely cured in + seventy days.'</p> + <h3>H. THE CROOKED FOOT.</h3> + <p>(<i>a</i>) THE FOOT WITH UNEQUAL SIDES.</p> + <p><i>Definition</i>.—The foot thus affected has one side of the wall higher + than the other.</p> + <p><i>Symptoms</i>.—This deformity is the better recognised when the foot on + the floor is viewed from behind. In addition to the difference between the height of + the inner and outer heel is seen at once a deviation in the normal direction of the + horn. That of the higher side is distinctly more upright than that of the lower, and + runs from above downwards and inwards towards the axis of the foot, while the horn of + the lower side maintains its normal direction of downwards and outwards.</p> + <p>From what we have said before on contracted foot, this bending in of the wall of + the upright side will at once be recognised as a form of contraction. It is, in fact, + contraction confined to one-half of the foot only, and, as a result, the upright side + of the crooked foot is prone to the troubles arising from that condition. Corns are + frequent, and atrophy of that half of the frog on the affected side supervenes. With + the inflammatory changes accompanying these conditions we find the horn of the + affected side deteriorating in quality. It becomes dry and brittle, and extremely + liable to sand-crack. At the same time, thrush of the contracted frog begins to make + its appearance.</p> + <p><i>Causes</i>.—More often than not this condition is a result of the + conformation of the limb. According as the build above inclines the animal to 'turned + in' or 'turned out' toes, so shall we have feet with a wall crooked inwards or + crooked outwards; and it may be mentioned here that the evil results inflicted on the + foot by ill-shaped limbs above will make themselves the more readily noticed when the + animal comes to be shod for any length of time. So long as a natural wear of the foot + is allowed, so long does it accommodate itself to the form of limb above. So soon, + however, as the shoe is applied, and a more or less equal (and in this case harmful) + wear by that means insisted on, so soon does this abnormal change in the height and + direction of the horn fibres begin to make itself seen.</p> + <p>While arising in the majority of instances from faulty conformation of the limb, + crooked feet may also be brought about by bad shoeing, or by unequal paring of the + foot, and, in a few cases, from unequal wear of the foot in a state of nature.</p> + <p><i>Treatment</i>.—Although it may be taken as a rule that lowering of the + higher wall, even if persisted in at every shoeing, will do nothing towards remedying + the primary cause (viz., the evil conformation of the limb), yet it will serve to + keep the condition within reasonable limits. In this case, while removing so much of + the wall as is deemed necessary, care must be taken to leave uncut the sole and the + bar. Leaving these intact gives us two natural and very potent protections against + the contraction already mentioned as impending.</p> + <p>Where, by reason of the thinness of the horn or other causes, sufficient paring to + equalize the tread cannot be practised, then the same end may be arrived at by the + use of special shoes. That branch of the shoe applied to the half of the foot with + the lower wall should be thickened from above downwards. Or, on the same branch, may + be turned up a calkin of sufficient height for the purpose. Of the two methods the + first is preferable.</p> + <p>In any case, whether depending upon paring, or upon the use of a special shoe, the + animal should be sent to the forge quite often, for it is only by a well-directed, + and therefore constant, application of the principles here laid down that improvement + may be brought about.</p> + <p>When marked contraction of one-half of the foot is present, it will be best + treated with the expanding shoe of Hartmann, already described in the section of this + chapter dealing with contracted heels (see Fig. 76).</p> + <p>(<i>b</i>) THE CURVED HOOF.</p> + <p><i>Definition</i>.—The hoof with the wall of one side convex, and that of + the opposite side concave. Fig. 85, showing the foot in section from side to side, + gives an exact idea of this malformation.</p> + <p><i>Causes</i>.—As was the case with the condition previously described, this + abnormality finds its primary cause in an unequal distribution of weight due to vice + of conformation in the limb above, causing one side of the hoof to be higher than the + other. As a result of this, the wall that is inordinately increasing in height + commences to bulge outwardly (Fig. 85, <i>a</i>), while the opposite (Fig. 85, + <i>b</i>) becomes concave.</p> + <p>The same state of affairs may be occasioned in the forge by leaving one side of + the foot too high, and subjecting the other to excessive paring for several + consecutive shoeings.</p> + <p><i>Treatment</i>.—In the main this condition may be regarded as a + long-standing and aggravated form of the foot with unequal sides. We may say at once, + therefore, that it is not so easily remedied as that simpler defect; that, although + identical principles will be followed in its treatment, cure must be a matter of some + considerable time.</p> + <br /> + <a name="a85" id="a85"></a> + <p><a href="images/image085.png"><img src="images/image085sm.png" + alt="SECTION THROUGH A CROOKED FOOT" /></a></p> + <br /> + + <p>FIG. 85.—SECTION THROUGH A CROOKED FOOT. <i>a</i>, The higher and convex + side of the wall; <i>b</i>, the lower and concave side of the wall</p> + <p>Again, we must look to successive parings of the wall of the higher side to bring + about a gradual return to the normal. At the same time, the tendency to contraction + of that side is counteracted by shoeing wide, and, if necessary, giving to the upper + surface of that branch of the shoe what we have termed elsewhere a 'reversed + seating'—viz., an incline of its upper surface from within outwards.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER VII</h3> + <h3><a name="diseases" id="diseases">DISEASES ARISING FROM FAULTY + CONFORMATION</a></h3> + <h3>A. SAND-CRACK.</h3> + <p><i>Definition</i>.—A solution of continuity of the horn of the foot, + occurring usually in the wall, and following the direction of the horn fibres.</p> + <p><i>Classification</i>.—It is usual to classify sand-cracks according + to—</p> + <p>(<i>a</i>) <i>Their Position</i>.—<i>Toe-crack</i> when occurring in the + middle line of the horn of the toe, and <i>quarter-crack</i> when occurring in the + horn of the quarters.</p> + <p>Sand-crack of the frog and sand-crack of the sole may also each be met with. They + are, however, of rare occurrence, and are seldom serious enough to merit special + attention.</p> + <p>The toe-crack is met with more often in the hind-foot than in the fore, while the + quarter-crack more often than not makes its appearance in the fore-foot, and is + there, as a rule, confined to the inner side. The reasons for these positions being + so affected we shall deal with when treating of the causes of sand-crack in general. + It is interesting to note that the portions of wall known as inside and outside toe + are seldom affected.</p> + <p>(<i>b</i>) <i>Their Length</i>.—<i>Complete</i> when they extend from the + coronary margin of the wall to its wearing edge; <i>Incomplete</i> when not so + extensive.</p> + <p>(<i>c</i>) <i>Their Severity</i>.—<i>Simple</i> when they occur in the horn + only, and do not implicate the sensitive structures beneath; <i>Complicated</i> when + deep enough to allow of laceration and subsequent inflammation of the keratogenous + membrane. Such complications may vary from a simple inflammation set up by laceration + and irritation of the sensitive structures by particles of dirt and grit that have + gained entrance through the crack, to other and more serious changes in the shape of + the formation of pus, hæmorrhage from the laminal vessels, caries of the os pedis, or + the development of a tumour-like growth of horn on the inner surface of the wall + known as a keraphyllocele.</p> + <p>(<i>d</i>) <i>Their Duration</i>.—<i>Recent</i> when newly formed; + <i>old</i> when of long standing.</p> + <p>(<i>e</i>) <i>Their Starting-point</i>.—This last distinction we make + ourselves, and, referring to cracks of the wall, term them <i>high</i> when + commencing from the coronary margin, <i>low</i> when starting from the bearing + surface.</p> + <p><i>Causes</i>.—We have already classified sand-crack as a disease arising + from faulty conformation. Thus, in just so far as a predisposing build of body may be + handed down from parent to offspring, we may regard sand-crack as hereditary. If we + do so, however, we must afterwards make up our minds to sharply distinguish between + the sand-crack plainly brought about by accidental cause, and that occurring as a + result of hereditary evil conformation.</p> + <p>With regard to the latter, we need hardly say that feet with abnormally brittle + horn are extremely liable. But with this, as with many other affections of the feet, + we shall find it necessary to consider several causes acting in cooperation. In this + case, for instance, given the brittle horn, it becomes necessary to further look for + exciting causes of its fracture.</p> + <p>We will take conformation first. In the animal with turned-out toes a more than + fair share of the body-weight is imposed on the horn of the inner quarter. Here, + then, three causes exert their influence together: The horn is brittle; the wall of + the inner quarter is thinner than that of the outer; additional weight is imposed + upon it. Fracture results.</p> + <p>Take, again, the vice of contracted heels. Here, in the first place, we have a + variety of causes tending to bring about the contraction. With the contraction, and + its consequent pressure upon the sensitive structures in the region of the quarters + and the frog, has arisen a low type of inflammation. The horn of the part has become + dry and brittle. The exciting cause of its fracture is found in an excessive day's + work upon a hard, dry road, with, perhaps, a suddenly-imposed improper distribution + of weight, due to treading upon a loose stone, or a succession of such evil transfers + of weight due to travelling upon a road that is rough in its whole extent.</p> + <p>In their turn, too, such defects of the feet as we have mentioned in the last + chapter—as, for example, the foot with the pumiced horn, the foot with + abnormally upright heels, or that which is upright on one side only, or + crooked—each offers a condition which is predisposing to the formation of a + sand-crack. In each case it wants but the uneven distribution of the body-weight, + which, as a matter of fact, some of these conditions themselves give, to bring about + a fracture.</p> + <p>Apart from the predisposition conferred by conformation, must be remembered the + simpler predisposing causes leading to brittleness of the hoof. We refer to the + after-effects of poulticing, the moving from pasture to stable, the emigration from a + damp to a dry climate, or the alternate changes from damp to dry in a temperate + region. Each may have a deteriorating influence upon the horn, rendering it liable to + the condition we are describing. Excessive dampness alone, especially when the animal + is called upon to labour at the drawing of heavy loads upon a rough road, is not + infrequently a cause. In this case the wet, together with the constant friction of + the sharp materials of which the road is made, serves to destroy the varnish-like + periople. The wet gains access to the inner structures of the wall, the agglutination + of the horn fibres is weakened, and fissures begin to appear.</p> + <p>Other causes of sand-crack are purely accidental. An animal at fast work + over-reaches. The secretion of horn at the injured coronet is interfered with, a + diminished supply at an isolated spot being the result. From this point grows down a + fissure in the wall.</p> + <p>An injury of the same character may also be sustained in various other + ways—treads from other animals when working in pairs, accidental wounding with + the stable-fork, blows of any kind, or a self-inflicted tread with the calkin of an + opposite foot—each with the same result.</p> + <p>So far as causation is concerned, toe-crack stands in a class almost by itself. It + is met with nearly always in a heavy animal in the hind-foot, and is directly + attributable to the force exerted in starting a heavy load.</p> + <p>Unskilful shoeing also plays a part in the causation of sand-crack. Removal of the + periople by excessive rasping of the wall is most certainly a predisposing cause. + Cracks, or their starting-points, may also be caused by using too wide a shoe, or by + the use of nails too large in the shank. Also, they may arise from unskilful fitting + of the toe-clip, especially in the hind-foot of a heavy animal. It must be admitted, + however, that the part shoeing plays in the causation of sand-crack is not a large + one; far more depends upon the state of the horn and the animal's conformation than + upon the exciting cause.</p> + <p>So far, our observations on the causes of sand-crack have referred to that form + occurring in the wall. Sand-crack of the sole or frog we have already said is but + seldom met with, and then it is always in connection with some exceptionally + deteriorated quality of the horn, as in the case of badly pumiced feet, or occurs as + a result of direct injury. Extensive slit-like cuts in this region, when deep enough + to lacerate the keratogenous membrane, are sometimes followed by the growth of a + fissure in the horn, and what might almost be termed a permanent sand-crack results. + Such cuts may be occasioned by sharp flints, broken glass, or other sharp objects + picked up on the road, or may result from the animal treading on the toe-clip of a + partially cast shoe.</p> + <p><i>Symptoms</i>.—In every case the fissure, or evidence of its commencement, + is a diagnostic symptom. It is well to remember, however, that this may be easily + overlooked, especially when the crack is one commencing at the coronary margin. The + reason is this: Sand-cracks in this position often commence in the wall proper, and + not in the periople. They may, in fact, be first observed as a fine separation of the + horn fibres immediately beneath the perioplic covering. A crack of this description + may even show hæmorrhage, and have been in existence for some time, without the + periople itself showing any lesion whatever. Thus, unless lameness is present, or a + more than specially keen search is directed to the parts in question, the sand-crack + goes undiscovered, until of greater dimensions.</p> + <p>Further, the fissure may be hidden, either accidentally or of set purpose. It may + be covered by the hair, filled in and covered over with mud, or intentionally + concealed by being 'stopped' with an artificial horn, with wax, or with gutta-percha, + or, as is more common, be hidden by the lavish application of a greasy + hoof-dressing.</p> + <p>In this latter connection it is well to warn the veterinary surgeon, especially + the beginner, when examining for soundness, to be keenly critical before passing an + animal who is presented with feet smothered with tar and grease or any other + dressing. More especially should this warning be heeded when examining any of the + heavier breeds of animal with an abundance of hair about the coronet.</p> + <p>Referring again to the search for the crack, it is well to know that with + toe-crack the fissure is the more readily seen when the foot is lifted from the + ground. With quarter-crack, on the other hand, the fissure is wider, and consequently + the easier detected with the foot bearing weight.</p> + <p>Although commencing in the insidious manner we have described, the lesion is not + thus often seen by the veterinary surgeon. Usually, the animal with sand-crack is + brought for his inspection when lameness has arisen from it. In this case the cause + for the lameness will reveal itself in the crack, which is now too large to escape + observation. The coronet is hot and tender to the touch, and a sensation of warmth is + sometimes conveyed to the hand by the horn of the surrounding parts of the wall. It + is hardly necessary to say that, with accompanying conditions such as these, the + sand-crack is a <i>deep</i> one.</p> + <p>Where the lameness is but slight, we may attribute it almost solely to the pain + occasioned by the mere wounding of the keratogenous membrane, and to no very + extensive inflammatory changes therein. By some authorities this is said to be due to + the pinching of the sensitive structures between the edges of the fissure in the + horny covering. In our opinion, however, pinching does not occur unless inflammatory + exudation into the sensitive structures adjoining the crack has led to sufficient + swelling to cause them to protrude. In other words, the movements of the horny box, + communicating themselves to the structures beneath, and so occasioning movement in + the wounded keratogenous membrane, are quite sufficient to give rise to the lameness + without actual pinching of the structures implicated.</p> + <p>The severity of the lameness will vary with the rapidity of the gait, and with the + character of the road upon which the animal is made to travel. For instance, many + animals in which the lameness is imperceptible at a walk become 'dead' lame at a fast + trot. It is sufficiently explained when one remembers the greater movements of + expansion and contraction of the posterior parts of the wall brought about by the + increase in the rate of progression. The same animal, too, will go distinctly more + lame upon a hard than upon a soft surface.</p> + <p>In like manner the lameness from toe-crack also varies in degree with the rate of + progression and the character of the travelling, though not to such a noticeable + extent as in the lameness from quarter-crack. A greater variation may in this case be + brought about by moving the animal on ascending and descending ground. Descending an + incline, with a more than ordinary share of the body-weight thus thrown upon the + heels, the lameness is most marked. The reason would appear to be that the greater + expansion of the wall of the heels thus brought about leads to a proportionate + contraction of the wall at the toe, especially at the edges of the crack, thus + causing undue pressure upon the exact spot of the wound in the sensitive structures. + Ascending—the weight in this case transferred from the posterior to the + anterior portion of the foot—the expansion of the heels becomes a contraction, + with a corresponding lessening of the contraction at the toe and a distinct decrease + in the lameness.</p> + <p>In the case of a deep but recent crack there is always more or less + hæmorrhage. This favours risk of infection of the lesion with pus-forming + organisms, and so leads to a more or less pronounced lameness, a degree of swelling, + heat and tenderness in the coronet above, and a certain amount of surgical fever.</p> + <p>The acute symptoms subdued, but the fissure still remaining, gives us the crack we + have classified as 'old.' This may in every case be distinguished from a more recent + lesion by the amount of thickening of the overhanging coronet, and the presence of an + increased quantity of sub-coronary horn in the region immediately about the crack. The + previous inflammatory changes in the adjoining sensitive structures have here led to + an increased secretion of horn, and a greater or less deposition of inflammatory + connective tissue in the wounded coronary cushion.</p> + <p>Sand-crack of the toe always follows the direction of the horn fibres. That of the + quarter, however, may on occasion run a course that is somewhat zigzag, first + following the direction of the horn fibres for a short distance, then travelling in a + horizontal direction, and finally continuing its course again in a line with the horn + fibres, commonly at a point posterior to that at which it commenced.</p> + <p>In a quarter-crack that is old, and when contraction of the heels exists (which in + this case it usually does), then will often be found overlapping of the edges of the + crack. The expansion of the wall brought about when the body-weight is on the heels, + cannot, by reason of the break in it, continue itself anterior to the crack. As a + consequence, repeated expansion of the wall posterior to the crack, with the portions + anterior to it in a state of enforced quiescence, leads in time to the posterior edge + of the crack coming to lie over that of the anterior.</p> + <p><i>Complications</i>.—The first complication likely to arise in a case of + sand-crack is that attending simple laceration of the sensitive structures in a + <i>deep</i> lesion. With the laceration all the phenomena of a repairing inflammation + make their appearance. As a result, there is more or less heat according to the + degree of inflammatory hyperæmia, swelling according to the amount of + inflammatory exudate, and pain according to the amount of pressure the two foregoing + bring to bear on the nerves in the inflamed area.</p> + <p>A second and more serious complication is the greater inflammation set up by the + introduction into the crack of foreign substances. Small portions of gravel and + flint, both by the irritation set up by their friction and by the infection they + carry in with the dirt surrounding them, are responsible for the mischief.</p> + <p>When, from direct communication with the blood-stream, due to extensive + hæmorrhage, bacteria from the outside gain entrance, this simple inflammation + is further complicated by the formation of pus, or a limited gangrene of the + keratogenous membrane.</p> + <p>In cases of great severity the gangrene of the keratogenous membrane spreads until + the deeper structures are involved. We then get a necrosis (in the case of toe-crack) + of the extensor pedis, and sometimes caries of the os pedis.</p> + <p>In like manner the necrotic changes occurring under these circumstances may invade + the deeper structures in the region of quarter-crack. As a result of this, we may + have the starting-point of suppurating corn, or necrosis of the lateral + cartilage—in other words, cartilaginous quittor.</p> + <p>Commonly accompanying quarter-crack is the condition of contracted heels and + atrophied frog. Sometimes described as a complication of sand-crack, it appears to us + more rational to rather regard the sand-crack as a result or complication of the vice + of contraction.</p> + <p>The overlapping of the edges of the crack before referred to occasionally gives + rise to the condition known as false quittor. A probe or a director passed beneath + the overhanging ledge of horn reveals sometimes a fissure of 1 inch or considerably + more in depth, and quittor is diagnosed. A careful paring away of the overhanging + horn, however, reveals the true state of affairs, and exposes to view the original + cause of the mischief—a simple fissure in the wall.</p> + <p>A serious complication—one fortunately met with but rarely—is that of + keraphyllocele. This is a tumour-like growth of horn, varying in size from the + thickness of an ordinary quill pen to that of one's middle finger, growing down from + the coronary cushion, and attached to the inner side of the wall of the hoof. With + this lameness is always present, and more or less deformity of the hoof results. This + condition will be found described at greater length in Chapter IX.</p> + <p><i>Prognosis</i>.—In the case of sand-crack this should always be guarded. + It may be taken as a general rule that cracks commencing from the coronary margin are + more troublesome to deal with than those originating below. The reason is not far to + seek. They here affect the wall just where the bevel in it for the accommodation of + the coronary cushion has rendered it weakest. Not only is it weakest, but being more + resilient than the portions below it, it suffers more from the alternate movements of + expansion and contraction of the foot than does the horn below.</p> + <p>Although in many cases a cure of the existing crack may be easily accomplished, + regard should be paid to the possibility of its recurrence, either in the same + position or elsewhere. Really, in offering an opinion as to the future usefulness of + an animal so affected, a greater attention should be directed to the animal's + conformation than to the crack itself. Where the vice of conformation giving rise to + it (as, for example, contracted heels or upright hoof) gives hope of being remedied, + then naturally it may be safely said that the liability to sand-crack goes with + it.</p> + <p>A like favourable prognosis may be given in the case of cracks occasioned by + purely accidental causes.</p> + <p>Ordinarily, however, cracks once commenced tend rather to increase than decrease + in size and severity. From being superficial and incomplete, they become complete and + deep, with every unfavourable circumstance that an increase in size and depth brings + with it.</p> + <p>This much, however, may be promised to the owner. A simple crack, even though + originating from the coronary margin, is, in the vast majority of cases, curable. + Under a rational treatment its increase in size may be prevented, and a sound wall + caused to grow down from the coronet.</p> + <p><i>Treatment</i>.—The principles governing the treatment of sand-crack are + simple enough in themselves, if not always followed by success.</p> + <p>1. <i>Preventive</i>.</p> + <p>This, as a rule, does not suggest itself until a crack of greater or less extent + has made its appearance. Then, simultaneously with the treatment proper of the + lesion, preventive measures should be adopted, to aid both in the healing of the + fissure already present, and to ward off the occurrence of others that might be + likely to form. The hoof, if abnormally brittle, should be regularly dressed with a + suitable ointment (one containing glycerine for preference), and its horn kept as + nearly as possible in a normal condition. When the condition of the horn predisposing + to its fracture is brought about by excessive wet, then the appropriate preventive + measures to be adopted suggest themselves.</p> + <p>With regard to the lesion itself, we may term 'preventive treatment' all those + measures having for their object the prevention of increase in the size of the crack. + They are as follows:</p> + <p><i>(a) Blistering the Coronet</i>.—In a simple case, where the crack is + superficial and close under the coronary margin of the wall, a sharp cantharides + blister to the coronet immediately above it will have the desired effect. An + increased secretion of horn is brought about, and by this simple means the crack + prevented from becoming longer. Very often this is all that is necessary. In fact, we + may say here that, no matter what other treatment is adopted, the simultaneous + application of a blister to the coronet is always beneficial. To derive full + advantages therefrom, the blistering should be repeated several times at intervals of + about a fortnight.</p> + <p><i>(b) Clamping the Crack</i>.—When the services of a skilled smith are at + hand, one of the readiest methods of performing this is to draw the edges of the + crack together with an ordinary horse-nail.</p> + <p>On each side of the crack a small horizontal furrow is burned or cut into the + wall, leaving the horn for about 1/4 inch on each side of the crack intact. This + provides a groove for the ends of the clamping-nail to rest in, and brings them flush + with the outer surface of the wall. The nail is then driven carefully home through + the crack, and the pointed end grasped by the farrier's pincers. The edges of the + crack are then drawn tightly together, and the nail firmly clenched.</p> + <br /> + <a name="a86" id="a86"></a> + <p><a href="images/image086.png"><img src="images/image086sm.png" + alt="THE SAND-CRACK FIRING-IRON." /></a></p> + <br /> + + <p>FIG. 86.—THE SAND-CRACK FIRING-IRON.</p> + <p>'The horse-nails are prepared in the ordinary way as for driving, with the + exception that each is pointed on the reverse side, to prevent puncturing the + sensitive structures. Before being used the nails are put in a vice, and the head + hammered to form a shoulder, to prevent their being driven too far into the wall, and + breaking out the hold.'[A]</p> + <p>[Footnote A: <i>Veterinarian</i>, vol. xlviii., p. 100.]</p> + <p>Before driving the nail some operators burn or bore a hole for it. Opinion seems + to differ as to whether this is at all necessary.</p> + <p>A method of clamping which, on account of its simplicity, has become greatly + popular, is that of Vachette. For this operation is needed the outfit depicted in + Figs. 86 and 87.</p> + <br /> + <a name="a87" id="a87"></a> + <p><a href="images/image087.png"><img src="images/image087sm.png" + alt="THE SAND-CRACK FORCEPS AND CLAMP." /></a></p> + <br /> + + <p>FIG. 87.—THE SAND-CRACK FORCEPS AND CLAMP.</p> + <p>With the special firing-iron (Fig. 86) an indentation, sufficiently large to admit + the points of the clamp (Fig. 87), is made on each side of the crack. The clamp is + then adjusted, and pressed home tight by means of the sand-crack forceps (Fig. 87). + According to the length of the crack, one, two, or three clamps may be necessary. + Another useful clamp, though far more complicated in its structure, is that of + Professor McGill (Fig. 88).</p> + <br /> + <a name="a88" id="a88"></a> + <p><a href="images/image088.png"><img src="images/image088sm.png" + alt="MCGILL's SAND-CRACK CLAMP." /></a></p> + <br /> + + <p>FIG. 88.—MCGILL's SAND-CRACK CLAMP.</p> + <p>'The object of this invention is to arrange on a spindle, which is screw-threaded + at one end with a right-hand thread and at the other with a left-hand thread, two + clips or clamps, free to travel on the thread, there being a nut between the two + which can be turned by a spanner. The clips are placed on the hoof, one on each side + of the sand-crack, the hoof being prepared to receive the instrument by filing a + groove or notch for the clamps to fit into, and by turning the nut on the screw the + clamps are brought towards each other, and the crack thus prevented from + spreading.'[A]</p> + <p>[Footnote A: <i>Veterinarian</i>, vol. lxi., p. 141.]</p> + <p>Still a further useful clamp is that of Koster. This is considerably broader than + the clamp of Vachette, and its gripping edges are provided with teeth (see Fig. + 89).</p> + <p>As with the clamp of Vachette so with this, a groove is burned into the wall on + each side of the crack for the accommodation of the jaws of the instrument, and the + clamp itself pressed home by means of a special pair of forceps. This form of clamp + holds well, and has the advantage of securing a wider area of horn than that of + Vachette or McGill.</p> + <br /> + <a name="a89" id="a89"></a> + <p><a href="images/image089.png"><img src="images/image089sm.png" + alt="KOSTER'S SAND-CRACK CLAMP." /></a></p> + <br /> + + <p>FIG. 89.—KOSTER'S SAND-CRACK CLAMP.</p> + <p>Clamping by any method should be advised or undertaken only under certain + conditions. The horn should be moderately strong, and the wall should be thick. This + practically restricts the use of the clamp to cracks of the toe, and it is there, as + a fact, they are found of most benefit. While burning the grooves for the clamp, and + while tightening the clamp itself, the animal's foot should be on the ground and + bearing weight at the heels, thus insuring the greatest possible approximation of the + edges of the crack.</p> + <p>With all methods of clamping an untoward result is sometimes the formation of a + fresh crack at the point of insertion of the clamps.</p> + <p>(c) <i>By the Use of Thin Metal Plates</i>.—These are of use when the horn + of the wall is too thin to allow of clamping, and are therefore of especial use in + cracks of the quarters. The plates are made so as to cover the greater part of the + length of the lesion, and are fastened to the wall by two or more screws on either + side of the crack. It is an advantage to slightly let the plate into the wall by + means of fitting it hot. In a complicated crack the plate serves the further useful + purpose of holding in position antiseptic pledgets, and so keeping the lesion free + from dirt and grit.</p> + <p><i>(d) By Various Methods of bandaging the whole Circumference of the + Wall</i>.—In our opinion this method of attempting to secure immobility of the + crack, and so prevent its extension, is not often followed by success. The main + objection to the method is that it subjects the whole of the wall to the same + pressure, and does not restrict the operation to the point at which it is required. + As in the case of the metal plate, however, this method has the advantage that + antiseptic dressings may be kept in position in the case of a complicated crack.</p> + <br /> + <a name="a90" id="a90"></a> + <p><a href="images/image090.png"><img src="images/image090sm.png" + alt="SAND-CRACK BELT." /></a></p> + <br /> + + <p>FIG. 90.—SAND-CRACK BELT.</p> + <p>The binding of the wall may be accomplished in two ways. The simpler of the two is + to merely apply the sand-crack belt depicted in Fig. 90. Beneath this should be + applied a compress of tar and tow or other material, and the whole tightened up and + kept in position by means of the buckle and strap. This method of binding admits of + after-tightening should it unfortunately work loose.</p> + <p>The older method of binding the wall, and one now often practised by the smith, is + to use a quantity of so-called 'tar-band' or other stout cord. With this the foot is + neatly bound after the manner of a cricket-bat handle, and all movement of the crack + apparently restricted. There is always a tendency, however, for such a dressing to + work loose, and in the case of a complicated crack it has the disadvantage of + permanently hiding from view the changes taking place in the discharge from the + fissure.</p> + <p><i>(e) By wedging the Crack</i>.—This is the exact opposite of clamping. + Whereas in clamping we obtain immobility of the crack by keeping it fixed in the + position of greatest approximation of its edges, in wedging, the crack is rendered + free from movement by maintaining it in that position where its edges are most widely + separated. In this case the edges of the crack are pared smooth, the cavity + thoroughly cleansed, and a wedge of hard wood firmly driven in so as to fit exactly + the fissure.</p> + <p>On the face of it it appears that this procedure would really tend to force open + and so lengthen the crack, especially at its coronary extremity. What one should + really remember, however, is that the crack <i>is not made wider</i> than before, but + that it is simply maintained in a position occurring with every contraction of the + heels of the foot, when it is normally at its widest. Movement of the edges is + thereby stopped, the immediately surrounding structures are rested, and a new growth + of horn, free from crack, induced to grow down from the coronet.</p> + <p>This method of treatment only serves to emphasize the fact that, with a sand-crack + once formed, it is the constant movement of the parts that tends most to keep it in + existence, and not any particularly marked exertion of force.</p> + <p>Some practitioners, with the wedge, apply also a clamp, thus assuring additional + firmness and solidity to that portion of the wall under treatment.</p> + <p>The method of wedging is undoubtedly successful, if neatly performed.</p> + <p><i>(f) By Surgical Shoeing</i>.—A partial rest is given to the affected + parts by easing the bearing of the shoe at the point required. This may be done + either by removal of part of the wall at the spot indicated, or by thinning the web + of the shoe in the same position. The former is the method usually practised. + Cessation of movement given in this way is, as we have already said, only partial; + for, while the effects of pressure and concussion from below are minimized, the crack + is still able to suffer from the movements of expansion and contraction of the foot. + Still, as an auxiliary to other treatments, 'easing' of the wall under the affected + part should always be practised.</p> + <br /> + <a name="a91" id="a91"></a> + <p><a href="images/image091.png"><img src="images/image091sm.png" + alt="THE BEARING 'EASED' BY REMOVAL OF THE WALL." /></a></p> + <br /> + + <p>FIG. 91.—THE BEARING 'EASED' BY REMOVAL OF THE WALL.</p> + <br /> + <a name="a92" id="a92"></a> + <p><a href="images/image092.png"><img src="images/image092sm.png" + alt="THE BEARING 'EASED' BY THINNING THE WEB OF THE SHOE." /></a></p> + <br /> + + <p>FIG. 92.—THE BEARING 'EASED' BY THINNING THE WEB OF THE SHOE.</p> + <p>Figs. 91 and 92 show respectively the manner of 'easing' by removal of the wall, + and by thinning the web of the shoe. In this connection it is necessary to point out + that on no account should 'springing' of the heels of the shoe be allowed. Fig. 93 + illustrates the ill-practice.</p> + <p>In this case, when the entire weight is thrown on to the heels, the portion of + wall posterior to the crack is bound to participate unduly in the downward movement, + and so tend to widening of the crack at its highest point.</p> + <br /> + <a name="a93" id="a93"></a> + <p><a href="images/image093.png"><img src="images/image093sm.png" + alt="THE BEARING 'EASED' BY 'SPRINGING' THE HEEL OF THE SHOE." /></a></p> + <br /> + + <p>FIG. 93.—THE BEARING 'EASED' BY 'SPRINGING' THE HEEL OF THE SHOE.</p> + <p>We have already referred to the matter of 'clips.' In no case, whether the crack + be at the toe or in the quarters, should a clip be placed immediately below it. If + the crack is at the toe, the usual clip should be dispensed with, and a clip at each + side made to take its place. At the same time care should be taken to avoid throwing + the weight far forward. For that reason a shoe with calkins or with very high heels + should be removed, and a shoe with an ordinary flat web substituted.</p> + <p>In the case of quarter-crack, where the constant movement of the parts under + expansion and contraction of the foot makes itself most felt, it is wise to apply a + shoe with clips fitting moderately tight against the inside of the bars. By this + means movement will to a very large extent be curtailed.</p> + <p>Where a marked tendency to contraction is found, as is often the case with + quarter-crack, then the shoe with the clips may be rendered more marked in its + operation by giving to the outer face of each clip—that face applied to the + bar—a slope from above downwards and outwards. In other words, a slipper shoe + should be applied and the contraction given equally as much attention as the + sand-crack itself.</p> + <p>Where the crack is situated far back in the quarter, and easing of the bearing + cannot be accomplished without tending to spring the heels, then the most suitable + shoe is a bar shoe. With it the bearing may, of course, be eased in exactly the + position required, and the heels still allowed to take their fair share in bearing + the body-weight, and thus assist in closing the crack. The bar shoe, if properly + fitted, gives us also a bearing on the frog, and aids greatly in counteracting + contraction.</p> + <p>2. <i>Curative</i>.</p> + <p><i>(a) The Application of Dressings to the Lesion</i>.—In the case of a + recent crack, deep, and attended with hæmorrhage, the foot should be thoroughly + cleansed. Where possible, a constant flow of cold water from a hose-pipe should be + allowed to run over the foot. By this means the inflammatory symptoms will be held in + check and pain prevented. Later the shoe may be eased at the required place, and a + blister applied to the coronet. This, with rest, will sometimes prove all that is + needed.</p> + <p>Should a crack be of old standing, and complicated by the presence of pus, a + course of hot poulticing will often prove of benefit. The poultice should be + medicated with any reliable disinfectant, and should be renewed, or at any rate + reheated, two or three times daily. The crack itself should be thoroughly cleaned + after the removal of each poultice, and a concentrated antiseptic solution—such + as Tuson's spts. hydrarg. perchlor., carbolic acid, and water, (1 in 10) or liquor + zinci chlor.—poured into it. On discontinuing the poulticing, the strength of + the antiseptic solutions may be decreased, the parts rested by correct shoeing, and a + blister applied to the coronet as before.</p> + <p>If these measures alone should prove insufficient, then the surgeon will either + fall back on those we have just related, or proceed to methods next to be + described.</p> + <p><i>(b) Immobilizing the Crack by Means of grooving the Wall</i>.—To our + minds, this is as ready and withal as successful a method of dealing with sand-crack + as has yet been devised. It may be done in a variety of ways: (1) By two grooves + arranged about the crack in the form of a V, as Fig. 94; (2) by a perpendicular + groove on either side of the crack, about 1 inch in distance from it, and parallel + with the horn fibres, as Fig. 95; (3) by a single horizontal groove at the extreme + upper limit of the crack; (4) by drawing two horizontal grooves, one at its upper and + one at its lower end (see Fig. 96).</p> + <br /> + <table summary="Table to display images"> + <tr> + <td> + <a name="a94" id="a94"></a> + <p><a href="images/image094.png"><img src="images/image094sm.png" + alt="FIG. 94" /></a></p> + </td> + <td> + <a name="a95" id="a95"></a> + <p><a href="images/image095.png"><img src="images/image095sm.png" + alt="FIG. 95" /></a></p> + </td> + <td> + <a name="a96" id="a96"></a> + <p><a href="images/image096.png"><img src="images/image096sm.png" + alt="FIG. 96" /></a></p> + </td> + </tr> + <tr> + <td>FIG. 94</td> + <td>FIG. 95</td> + <td>FIG. 96</td> + </tr> + </table> + <p>In Figs. 94, 95, and 96 the thick black lines illustrate the positions of the + various grooves made with the firing-iron for the purpose of immobilizing a quarter + sand-crack.</p> + <p>The points to be observed in carrying out this line of treatment are simple + enough. In all cases see that the crack is rendered as clean as possible by the use + of suitable dressings, and if an excess of horn is present immediately around it, as + in the case of a long-standing and complicated lesion, have it thinned down by + rasping.</p> + <p>All that is then needed is one or two moderately sharp, flat firing-irons. The + groove is then burned into the horn in the positions indicated, and that portion of + the wall containing the sand-crack thus prevented from participating in the movements + of the foot. For our own part, we consider the V-shaped incision, or either of the + horizontal methods of grooving, preferable to lines running in the direction of the + horn fibres. With the latter there is certainly a greater tendency to the formation + of new cracks than with either of those we advocate. The V-shaped incision we + consider most suitable of all, for the reason that by its means a greater degree of + immobility is conferred upon the necessary portion of the wall.</p> + <p>Whichever method is adopted, care should be taken to carry the grooves deep enough + into the horn, taking them down as near as possible to the sensitive structures. At + the same time, especial care should be exercised in not carrying them too deep at + their extreme upper limit, or in that case the liability to the formation of fresh + cracks in those positions will be greatly increased. vAfter grooving, a sharp blister + should be applied to the coronet every three or four weeks, and the animal, if free + from lameness, put to work.</p> + <p><i>(c) By stripping away a V-shaped Portion of the Wall around the + Crack</i>.—This method is only indicated when the crack is greatly complicated + by the presence of pus, or by the growth of adventitious horn on the inner surface of + the wall. A radical cure is thus obtained, but the animal for a longer time + incapacitated from work.</p> + <p>The operation is best performed by first grooving a line to connect the points + <i>a</i> and <i>c</i> (Fig. 97). This should run immediately under the coronary + margin of the wall, and should stop short of injuring the coronary cushion beneath. + Grooves forming the sides <i>ab</i> and <i>bc</i> of the triangular piece of horn are + next made, and the horn contained within the lines <i>ab, bc</i>, and <i>ca</i>, + carefully removed. The grooves are the easiest made by a cautious use of the + firing-iron. The greater thickness of the horn may thus be penetrated, and the + grooves afterwards carried to their full and requisite depth by the use of the + drawing-knife.</p> + <p>With the removal of the horn the diseased structures are exposed to view. All such + should be removed by a free use of the scalpel, and a suitable dressing afterwards + applied. A necessary factor in the treatment is the employment of pledgets of + antiseptic tow. With these the exposed tissues are covered, and the successive turns + of a bandage run tightly over them, so as to exert a moderate degree of pressure. + When hæmorrhage has accompanied the operation, this dressing should be removed + on the following day, the wound dressed, and the pledgets of tow and the bandage + renewed. Any after-dressing need only then be practised at intervals of a week. + Repair after this operation is rapid, and takes place both from the exposed + podophyllus membrane and from the coronary cushion.</p> + <br /> + <a name="a97" id="a97"></a> + <p><a href="images/image097.png"><img src="images/image097sm.png" + alt="treatment of complicated toe-crack." /></a></p> + <br /> + + <p>FIG. 97. The dotted lines outline the V-shaped portion of wall to be removed in + the treatment of complicated toe-crack.</p> + <br /> + <a name="a98" id="a98"></a> + <p><a href="images/image098.png"><img src="images/image098sm.png" + alt="operation for complicated toe-crack." /></a></p> + <br /> + + <p>Fig. 98. The dotted lines indicate the portion of wall to be removed in the + complete operation for complicated toe-crack.</p> + <p><i>(d) By stripping the Wall from the Coronary Margin to its wearing Edge on + Either Side of the Crack</i>.—This is merely a more extensive application of + the method just described, and is only indicated in a <i>complete</i> and + <i>complicated</i> crack that has refused to yield to other modes of treatment (see + Fig. 98).</p> + <p>As in the previous case, a groove is run from <i>a</i> to <i>c</i>. The grooves + <i>ab</i> and <i>de</i> are then continued to the lowermost edge of the wall, and the + whole of the wall within these points removed. To facilitate removal, the white line + should be grooved between the points <i>b</i> and <i>d</i>. After-treatment is + exactly the same as that just referred to.</p> + <h3>B. CORNS.</h3> + <p><i>Definition</i>.—In veterinary surgery the term 'corn' is used to indicate + the changes following upon a bruise to that portion of the sensitive sole between the + wall and the bar. Usually they occur in the fore-feet, and are there found more often + in the inner than in the outer heel.</p> + <p>The changes are those depending upon the amount of hæmorrhage and the + accompanying inflammatory phenomena occasioned by the injury.</p> + <p>Thus, with the hæmorrhage we get ecchymosis, and consequent red staining of + the surrounding structures. As is the case with extravasations of blood elsewhere, + the hæmoglobin of the escaped corpuscles later undergoes a series of changes, + giving rise to a succession of brown, blue, greenish and yellowish coloration.</p> + <p>With the inflammation thereby set up we get swelling of the surrounding + bloodvessels, pain from the compression of the swollen structures within the + non-yielding hoof, and moistness as a result of the inflammatory exudate.</p> + <p>In a severe case the inflammation is complicated by the presence of pus.</p> + <p><i>Classification</i>.—Putting on one side the classification of Lafosse + <i>(natural</i> and <i>accidental</i>), as perhaps wanting in correctness, seeing + that all are accidental, and disregarding the suggested divisions of Zundel + <i>(corn</i> of the <i>sole</i> and <i>corn</i> of the <i>wall</i>) as serving no + practical use, we believe, with Girard, that it is better to classify corns according + to the changes just described.</p> + <p>Following his system, we shall recognise three forms: (1) <i>Dry</i>, (2) + <i>moist</i>, (3) <i>suppurating</i>.</p> + <p>The <i>dry</i> corn is one in which the injury has fortunately been unattended + with excessive inflammatory changes, and where nothing but the coloration imparted to + the horn by the extravasated blood remains to indicate what has happened.</p> + <p>The <i>moist</i> corn is that in which a great amount of inflammatory exudate is + the most prominent symptom. It indicates an injury of comparatively recent + infliction.</p> + <p>The <i>suppurating</i> corn, as the name indicates, is a corn in which the + inflammatory changes are complicated by the presence of pus.</p> + <p><i>Causes</i>.—The causes of corns we may consider under two + headings—namely, <i>predisposing</i> and <i>exciting</i>.</p> + <p><i>Predisposing Causes</i>.—By the heading of this chapter we have already + intimated that corns are due to faulty conformation of the foot. It is, therefore, + merely a description of such shapes of foot as favour their formation that will need + mention here.</p> + <p>The wide, flat foot, with low heels, may be first considered. Here the posterior + portions of the sole, those portions between the wall and the bars, fall very largely + in the same plane as the wearing surface of the bars and the wall. As a consequence, + these portions of the sole are more prone to receive injury from stones and rough + roads and from the pressure of the shoe.</p> + <p>The low heels, too, favour a more than due proportion of the body-weight being + thrown on to the posterior parts of the foot. Two evils, both inclining to the + production of corn, result from this. In the first place, the sensitive structures of + the posterior portions of the foot are subjected to undue pressure from above; + secondly, the posterior half of the foot, by reason of the extra weight thrown upon + it, is exposed also to greater effects of concussion than normally it should meet. + Added to this we find that the abnormally flat condition of the sole has resulted in + a great loss of resiliency. With undue pressure above, and a loss of resiliency and + added effects of concussion below, the sensitive structures included between the + opposing pedal-bone and the horny sole are bound to suffer more or less bruising each + time the foot comes to the ground, especially if the animal is moved at a rapid + pace.</p> + <p>Writing here of the effects of pressure and concussion affords a fitting occasion + to mention the fact that corns occurring in feet affected with side-bones are always + worse than in feet with normal elastic cartilages. The explanation of this is simple, + for there can be no doubt that the loss of resiliency in the diseased cartilage is + only another aid to undue pressure and concussion. The sensitive structures are + pinched between unyielding bone above and practically unyielding horn below.</p> + <p>Feet with high and contracted heels are also predisposed to corn. The contraction + in this case interferes with the downward movements of the os pedis during + progression, while in a state of rest there is a more or less constant pressure upon + the sensitive structures, due to the correct downward displacement of the pedal-bone + being opposed by the amount of contraction present. In the contracted foot, too, the + nutrition of the vessels supplying the secretory apparatus of the horn is largely + interfered with. The horn loses its natural elasticity, fails to respond to the + normal movements of the parts within, and aids in the compression and laceration of + the sensitive structures.</p> + <p>Weak feet, with horn too thin to withstand the expansive movements continually + going on—in other words, feet with weak, spreading heels—are also prone + to suffer from corns. In this case the flatness induced by the spreading, and the + insufficient protection afforded by the thin horn, both combine to lay the sole open + to the effects of concussion and direct injury.</p> + <p>Brittle feet—feet with horn of undue dryness, by reason of the contraction + thus brought about—are, again, particularly subject to corn.</p> + <p>So also with long feet. Whether occurring as a natural deformity, or as the result + of insufficient paring, bruises of the sole in feet thus shaped are common. The + reason for this will be better understood when we come to deal with the shoeing.</p> + <p>Other and minor predisposing causes are those mainly referring to an unnatural + dryness of the hoof when animals reared in the country are put to work in large + towns. We here really get several predisposing causes combining. A sudden change is + made from a more or less moist condition underfoot to one excessively dry. The + character of the travelling is wholly altered from occasional work upon soft lands to + continual labour upon hard-paved roads. The horn is often exposed to the vicious + influences of unsuitable litter, the application of unsuitable dressings, and the + deleterious effects of the street mud of our cities. All these play their part in + determining a condition of the horn, rendering it open to receive the effects of the + more exciting causes which we shall next consider.</p> + <p><i>Exciting Causes</i>.—Than the shoeing, no more frequent and exciting + cause of corn exists. Whatever the predisposing influences may be, it is the shoeing + that in nearly every case completes the list, and finally inflicts the injury.</p> + <p>The evils in this connection we shall consider under two headings—viz., (1) + the manner in which the foot is pared; (2) the make and fitting of the shoe.</p> + <p>First among the faulty preparations of the foot comes that of excessive thinning + of the sole, especially in the regions subject to corn. The farrier addicted to this + is not as a rule content to confine his operations to the sole alone. In addition, + the frog and the bars also suffer from the too lavish use of his knife. His main + object is doubtless that of giving a broad and open appearance to the foot. It + follows from this that his operations are confined more to the posterior than the + anterior parts of the foot, and that the toe is therefore left too long. This gives + us a combination of causes leading to pressure and bruises upon the sensitive + structures at the seat of corn.</p> + <p>By this unequal paring of the toe and the heels greater weight is thrown upon the + posterior half of the foot. What then happens to the structures thinned as we have + described is this: the pared frog, lessened in volume, does not meet the ground. It + therefore fails to expand laterally with weight, and cannot assist, as normally it + should, in aiding the heels generally in their movements of expansion. The weakened + bars and the thinned sole, meeting with no opposition from the frog, give downwards + and inwards with the body-weight at the precise moment these movements should be + directed mainly outwards. As a further result of non-resistance on the part of the + frog, this time in a lateral direction, the bars, the sole, and the wall at the heels + all contract at the exact time they should expand. The end result must mean abnormal + pressure and bruising of the sensitive structures in that particular region. + Naturally, also, the excessive thinning of the horn renders direct injury to the sole + from stones or other objects in the road far more probable.</p> + <p>For this one reason alone—the manner in which it favours the production of + corn—too great a condemnation cannot be placed upon excessive paring of the + sole, the bars, and the frog.</p> + <p>When corns are already present, as they may be from other causes, the same remarks + will again apply to excessive paring. It is the custom with many smiths to carefully + pare down the discoloured horn in every case of corn they meet with, and at the same + time to again weaken the bars and even part of the wall at the heels, with the + laudable idea of relieving pressure on the part diseased. After what has gone before, + we need hardly say that their well-meant efforts have a precisely opposite effect to + the one they intend.</p> + <p>The fitting of the shoe is, perhaps, to a greater extent responsible for the + causation of corn than is the paring we have just described.</p> + <p>A few of the evils connected with the shoe may, however, be justly described as + unavoidable. We <i>must</i> shoe; we cannot shoe and leave a normal foot!</p> + <p>A shoe excessively seated, especially from the last nail-hole backwards, may be + regarded as dangerous. In this case, with every application of the body-weight, there + is given to the foot a tendency to contract, especially at its lower margin. Result: + undue pressure upon the tissues around and the production of corn.</p> + <p>On the other hand, varying with the form of foot, the seating may be insufficient. + In the case of flat-foot, or dropped sole, for instance, insufficient seating will + lead to undue pressure of the web of the shoe upon the sole, and in that way bring + about bruising of the sensitive sole beneath.</p> + <p>Shoes with heels or calks too high, by destroying the counter-pressure of the frog + with the ground, serve to bring about a series of changes we have described under + contraction, and again result in pinching and bruising of the sensitive + structures.</p> + <p>The opposite excess—a shoe thick at the toe and thin at the heels—is + blamed by Zundel for causing a like injury. In our opinion, the reason this author + gives—namely, that the throwing of greater weight upon the heels leads to + bruising of the sensitive structures—can only correctly apply to a + <i>wrongly-applied</i> shoe of this type, and not to the shoe itself. True, a shoe + with a thick toe and thinned heels will throw an undue proportion of the body-weight + upon the heels if the foot is not properly prepared for it. A wise man, however, will + most certainly so cut down the toe for the reception of this shoe that, with the shoe + in position, there will still be maintained a tread that is normal. To our minds harm + is far more likely to arise from a shoe of this class through the thinned iron heels + of the shoe becoming attenuated under wear to the point of bending, and so inflicting + an injury upon the adjoining sole.</p> + <p>Similarly, this last remark with regard to the thinning of the heels of the shoe + will apply to a shoe with too broad a web. As the thinning of the shoe proceeds with + wear, the inner portion of the thinned branch is bent up on to the sole, and again + inflicts the injury.</p> + <p>The matter of bearing is also of importance when considering the causation of + corn. In a previous chapter we have already described the correct bearing as that + which includes the whole of the lower margin of the wall and the white line, and just + impinges on the sole. Any marked deviation from that will, if long continued, be + followed by injury to the foot.</p> + <p>With the bearing surface of the shoe too narrow—in contact with the wall + solely, or perhaps only a portion of it—it is evident that a large proportion + of the foot that should properly bear weight is thrown out of action. A heavy strain + is imposed on the white line, and undue descent of the sole and contraction of the + heels brought about. Again the result of this is compression and bruising of the + tissues around the seat of corn.</p> + <p>With its bearing surface too wide, the shoe immediately exerts direct pressure + upon the sole with every movement of the animal. The sole normally is not made to + receive this, and harm is bound to result.</p> + <p>Among other ill-fitting shoes we may mention the one with branches too short, and + the one with the extremities of the branches too pointed. In the first case, as wear + of the shoe proceeds, the thinned end is far more likely to turn in under the seat of + corn than is a shoe with branches of ordinarily correct length. It is evident in the + second case that the pointed branch, when thinned, is a more dangerous agent than the + branch which is nearer the square at its end.</p> + <p>The matter contained in the first half of the foregoing paragraph explains in a + large measure the rarity of corns in the hind-feet. Here there is nothing to prevent + a shoe with branches of full length being used. The correct bearing is thus + maintained, even with a shoe excessively thinned with wear, and the liability to + injury from it decreased. An exception is to be found in the case of a feather-edged + shoe, such as is used to prevent cutting or brushing. The thinning by wear from above + to below of the branch already purposely thinned from side to side leads to the + formation of a thin and narrow piece of iron admirably calculated to bend over and + injure the sole.</p> + <p>Even with a shoe of correct length, with a flat-bearing surface at the heels, and + other conditions favourable to correct application, evil may still result from the + shoe itself being made too narrow. As a result of this, the branch of <i>each</i> + side is set too far under the foot, with consequent injury to the sole. This is, of + course, sheer carelessness on the part of the smith. When practised, however, it is + not easy of detection, as in all cases the foot is rasped down to cover what has been + done. In other words, the foot is made to fit the shoe and not the shoe the foot.</p> + <p>Recognising this close fitting of the shoe as a cause, we are able to explain in + some measure how it is that corns should occur with greater frequency in the inner + than in the outer heel. There is no doubt that the inner branch of the shoe is nearly + always fitted closer than is the outer. In the fore-foot it is also often shorter. + Take these two evils and add to them the fact that the inner heel is called upon to + bear more of the body-weight than is the outer, and the frequency of corns in the + inner heel will no longer be wondered at.</p> + <p>Indirectly, the shoe may still be a cause of corn by reason of the irritation set + up by gravel and small pieces of flint becoming firmly fixed between the sole and the + web of the shoe. In nearly every case of this description the part to be injured is + the white line.</p> + <p>Corns may also result from the animal picking up a stone. The stone becomes firmly + wedged in between the inner border of the branch of the shoe and the bar or the frog. + With every step the animal takes it becomes wedged more tightly into position. + Projecting below the level of the lower surface of the shoe, it imparts the + concussion it thus obtains directly to the sole. A bruise—and a bad + bruise—is the result.</p> + <p>Finally, it cannot be denied that the work the horse is put to is largely + responsible for the causation of corn. In country animals corns are comparatively + rare, while in animals in town, almost constantly upon hard paving, they are common. + This seems to point strongly to the fact that concussion through constant work upon + unyielding roads is a great factor in their production.</p> + <p><i>Symptoms</i>.—Unless the discoloration of the horn is accidentally + discovered by the smith, the simple, dry corn may go undetected. The disturbance + excited by it is so small, and the pain occasioned so slight, that the patient may + offer no indication of its existence.</p> + <p>Ordinarily, however, the first symptom is that of pain. The animal goes feelingly + with one or both feet, in some cases even showing decided lameness. The lameness, + however, is in no way diagnostic, and the lesion itself must be discovered before an + exact opinion can be pronounced.</p> + <p>As an aside, it is well to observe in this connection that a negative opinion as + to the existence of corn should never be given unless the superficial layers of horn + have first been removed with the knife.</p> + <p>When standing at rest the animal exhibits signs more or less common to all foot + lamenesses. He 'points' the foot—in other words, the limb is slightly advanced, + the fetlock partly flexed, and the heels from off the ground. When both feet are + affected they are pointed alternately, and the animal often manifests his uneasiness + by repeated pawing movements, and by scraping his bedding behind him.</p> + <p>Should the injury run on to suppuration, the lameness becomes most acute. The + pawing movements become more pronounced, and there is evident disinclination on the + part of the animal to place the foot squarely on the ground. One is then led to + manipulate the foot. The hoof is hot to the touch. Percussion causes the animal to + flinch, and to flinch particularly when that portion of the wall adjoining the corn + is struck. Finally, exploration with the knife reveals the serious extent to which + the injury has developed. In a neglected case of this description it is even possible + to detect the presence of pus by the amount of swelling and fluctuating condition of + the coronet. The suppurative process has advanced in the direction of least + resistance, and is on the point of breaking through the tissues immediately above the + horn.</p> + <p>Lameness due to corn is oftentimes intermittent. With a simple corn, dry or moist, + this intermission is largely dependent on the degree of dryness of the hoof or the + road, and also on the character of the road surface. With a neglected, suppurating + corn, on the other hand, variation in the degree of lameness, in addition to + depending on circumstances such as these, is dependent to a larger extent upon the + changes occurring with the suppuration. In this case the time of greatest lameness is + immediately before the pus gains outlet. Immediately after its exit at the coronet + the animal will go almost sound. Soundness continues so long as the opening at the + coronet remains clear. The tendency, however, is for the opening thus made to quickly + close again. Pus again accumulates, lameness arises as before, and disappears again + with the second discharge of the contents of the sinus now formed.</p> + <p><i>Pathological Anatomy</i>.—When dealing with their classification we gave + in outline the main pathological changes to be met with in corns. It now only remains + to give the same matter in slightly greater detail.</p> + <p><i>In dry corn</i> the changes we meet with are those accompanying blood + extravasation. From excessive compression of the parts, or from the effects of direct + injury, a portion of the sensitive sole has become lacerated. The escaping blood + stains the surrounding soft tissues after the manner of blood extravasation + elsewhere. If the escape of blood is sufficiently large, the horn fibres in the + immediate vicinity also are stained. It is this stain in the horn that is the direct + evidence of the injury, and is itself popularly known as the corn. It may vary in + size from quite a small spot to a broad patch as large as half a crown, while its + colour may be a uniform red, or a mottled red and white. The microscopic changes in + this connection are illustrated in Fig. 99.</p> + <br /> + <a name="a99" id="a99"></a> + <p><a href="images/image099.jpg"><img src="images/image099sm.jpg" + alt="HORIZONTAL SECTION OF A CORN." /></a></p> + <br /> + + <p>FIG. 99.—HORIZONTAL SECTION OF A CORN. The section cut at about the base of + the papillæ of the sensitive sole. <i>a</i>, papillæ, with horn-cells + surrounding them; <i>b</i>, interpapillary or intertubular horn; <i>c</i>, hollow + spaces in the intertubular material filled with blood; <i>d</i>, a papilla and its + surrounding horn-cells filled with blood.</p> + <p>Ordinarily, this ecchymosis of the horny sole is due to injury of the sensitive + sole <i>immediately beneath</i> it. It may, however, proceed from injury to the + vessels of the laminæ either of the bars or of the wall. In this case the + ecchymosis of the horny sole may be explained by the fact that the escaped blood + tends to <i>gravitate</i> to that position.</p> + <p>When the corn is of long standing, or is due to <i>repeated</i> injuries on the + same spot, the horn adjacent to the lesion becomes hard and dry, and often abnormally + brittle, simply on account of the inflammatory changes thus kept in continuation. + This is often seen when attempts are made to <i>pare out</i> the corn with the + knife.</p> + <p>Should the injury be seated in the sensitive laminæ, then the brittle nature + of the horn secreted by the injured tissues makes itself apparent by the appearance + of cracks in the wall of the quarter. Why this should occur will be readily + understood by a reference to Fig. 100.</p> + <br /> + <a name="a100" id="a100"></a> + <p><a href="images/image100.jpg"><img src="images/image100sm.jpg" + alt="INNER SURFACE OF THE WALL OF THE QUARTER, SHOWING CHANGES IN THE HORNY LAMINÆ BROUGHT ABOUT BY CHRONIC CORN." /> + </a></p> + <br /> + + <p>FIG. 100.—INNER SURFACE OF THE WALL OF THE QUARTER, SHOWING CHANGES IN THE + HORNY LAMINÆ BROUGHT ABOUT BY CHRONIC CORN.</p> + <p>It will here be seen that the injury to the keratogenous membrane has led to great + interference with the secretion of horn from the sensitive laminæ. As a result, + the regularly leaf-like arrangement of the horny laminæ has been largely broken + up. Certain of the laminæ are altogether wanting, while others are broken in + their length and rendered incomplete. With this condition there is always more or + less contraction of the quarter.</p> + <p>Microscopic examination of the structures involved in such a case reveals the fact + that with the contraction is an alteration in the normal direction of the horny and + sensitive laminæ.</p> + <p>They become bent backward, and, instead of the regular and normal arrangement + depicted in Fig. 32, show the distorted appearance given in Fig. 101.</p> + <p>From the appearances and characters of the blood-stain in the horny sole we are + able to deduce evidence relative to the duration and nature of the injury.</p> + <br /> + <a name="a101" id="a101"></a> + <p><a href="images/image101.jpg"><img src="images/image101sm.jpg" + alt="PERPENDICULAR SECTION OF THE WALL OF A CONTRACTED QUARTER IN A CASE OF CHRONIC CORN." /> + </a></p> + <br /> + + <p>FIG. 101.—PERPENDICULAR SECTION OF THE WALL OF A CONTRACTED QUARTER IN A + CASE OF CHRONIC CORN. Both the sensitive and horny laminæ are bent backwards, + and hæmorrhages have taken place at the base of the sensitive laminæ.</p> + <p>When, for instance, the stain is not to be found in the superficial layers of the + sole, but is only discoverable by deep paring, then the injury is a recent one.</p> + <p>Where the stain <i>is</i> met with in the superficial layers of horn, and is + quickly pared out, then the injury has been inflicted some time before, and has not + been repeated. When, as is sometimes the case, layers of horn that are stained are + found alternated with layers that are healthy, then we have evidence that the cause + of the corn, whatever it may be, is not in constant operation.</p> + <p>Similar indication of the age of the injury is also afforded by the colour of the + lesion.</p> + <p>A stain that is deep red is proof that the injury is comparatively recent.</p> + <p>A distinct yellow or greenish tinge, on the other hand, is evidence that the + injury is an old one.</p> + <p><i>In the Moist Corn</i> we have, in addition to the blood extravasation, the + outpouring of the inflammatory exudate. In the most superficial layer of the horn + this may not be noticeable. As one cuts deeper into the sole with the knife, however, + it will be found that the lower layers of horn are more or less infiltrated with the + discharge. This gives to the horn a soft consistence, a yellow appearance, and a + touch that is moist to the fingers.</p> + <p>With the accompanying inflammation the cells in the neighbourhood of the injury + are enfeebled and their normal functions interfered with. We may thus expect a + corresponding interference with the growth of horn. This is exactly what happens, and + as one cuts deeper still into the horn a point is finally reached when a well-marked + cavity is encountered. A pale yellow and usually watery exudate fills it. This cavity + points out the exact spot where the force of the injury has been greatest, where + death of certain cells of the keratogenous membrane has resulted, and where the + natural formation of horn has for a time been suspended.</p> + <p><i>In the Suppurating Corn</i>, as in moist corn, we have pathological changes due + to the tissue reaction to the injury, <i>plus</i> the addition of pus organisms. + Confined within the horny box we have a discharge that, by reason of the living and + constantly multiplying elements it contains—the pus organisms—is always + increasing in bulk. This must be at the expense of the softer structures of the foot. + Accordingly, as the formation of pus increases, we get pressure upon and final + gangrene of the sensitive sole and of the sensitive laminæ of the bars and the + wall. With no outlet below, the pus formation increases until finally it finds its + way out of the hoof by emerging at the coronet.</p> + <p>This in some instances it may do by confining its necrotic influences solely to + the sensitive laminæ of the wall, in which case, if a dependent orifice is + quickly made at the sole, the injury to the laminæ is soon repaired by the + healthy tissue remaining.</p> + <p>In other cases, however, the necrosis has spread deeper. Caries of the os pedis, + of the lateral ligaments of the pedal-joint, or of the lateral cartilages, is a + result. When this occurs the exuding discharge from the coronet becomes thinner and + more putrescent, and its feel, when rubbed between the fingers, sometimes gritty with + minute fragments of broken-up bone. Here, unless operative measures prevent it, + necrosis soon spreads deeper still. The deeper portions of the os pedis become + affected. The capsular ligament of the joint is penetrated by the suppurative + process, and a condition of septic arthritis results. The cavity of the joint becomes + more or less tensely distended, according to the amount of drainage present, which in + this case is almost nil, with matter in a state of putrescence. As a consequence, the + surrounding ligaments become softened and yield, and the articular surfaces + displaced. The articular cartilages also suffer, become necrotic in patches, and + frequently wholly destroyed. The end result is one of anchylosis of the joint and + permanent lameness.</p> + <p><i>Prognosis</i>.—With the ordinary dry corn a return to the normal may + nearly always be looked for. Similarly, with moist corn, and even with careful + treatment of the suppurating variety, the same favourable termination may be looked + for and promised.</p> + <p>What cannot so safely be assured is that a relapse will not occur. In other words, + the extent of the injury, no matter how serious, does not often offer anything that + cannot be overcome by Nature and careful surgery; but the conformation of the animal + does. A vicious predisposing conformation once there is there always, and although + the injury resulting from it may easily give way to correct treatment, the same + injury is bound to re-occur when the animal is again put to work.</p> + <p>Although with care suppurating corn, like other cases of suppuration within the + hoof, may yield to treatment, the owner of the animal should, nevertheless, be warned + that the condition is a serious one, especially should the joint become affected. It + may so happen, as sometimes in fact it does, that the animal may die as a result of + the infective fever so set up. From no surface in the body can absorption take place + quicker than from the synovial membrane of a joint. So soon, therefore, as this + membrane comes in contact with septic material, so soon does a severe septic fever + make its appearance. The septic matter has gained the blood-stream, and the patient + succumbs to septic poisoning.</p> + <p>Apart from death occurring naturally, the changes taking place in the joint in the + shape of bony growths or of actual anchylosis may be so severe as to render the + animal useless, and slaughter may have to be advised.</p> + <p><i>Treatment</i>.—We have already said that by far the most active cause in + the production of corn is the shoe. It follows from this that it is to the shoeing we + must largely look for a successful means of their prevention, and that the treatment + of corn in its most simple form is really a matter for the smith, and not for the + veterinary surgeon.</p> + <p>The faults in connection with the shoeing we have mentioned fully when treating of + the <i>causes</i> of corn. From those we learn that a shoe with a flat-bearing + surface, or one moderately seated but flat at the heels, is the correct shoe for + nearly all feet. The heels of the shoe should not be too high, should not be too + short, and should be wide enough apart from each other to insure the wall of the foot + obtaining a fair share of the bearing. Finally, even with the present method of + shoeing, whenever it is possible to allow the frog to come to the ground, it should + be encouraged to do so, and excessive paring either of the latter organ or of the + bars or the sole should be strictly discountenanced. Where the sole is thin, or the + frog wasted, use a leather sole or a rubber pad. With these precautions, corns may be + prevented from occuring even in a foot with a predisposing conformation.</p> + <p>When corn is present, the first treatment usually adopted is that of 'paring it + out.' This is advocated by Percival and by many other writers. We cannot say, + however, that we agree with it—at any rate, not in the case of simple dry + corn.</p> + <p>'Paring it out,' and by that we mean thinning down the sole until close on the + sensitive structures, can only be advised in the case of suppurating corn, or in + cases where doubt exists as to whether pus is present or not. In the latter case + paring becomes necessary as an exploratory means to diagnosis.</p> + <p>When it appears fairly certain, even in the case of a moist corn, that pus does + not exist, then paring is to be discountenanced, for the reason that it only tends to + weakening of the parts and to assist largely in the corn's recurrence.</p> + <p>Those who advocate it do so for the reason that it relieves pressure on the + injured parts.</p> + <p>That it does so directly from below cannot be denied; but that it also favours + contraction and compression from side to side is equally certain.</p> + <p>A moderate paring may, however, be indulged in, say, to about one-half the + estimated thickness of the sole. Softening of the horn and consequent lessening of + pressure may then be brought about by the use of oil, oil and glycerine, tincture of + creasote, or by poulticing.</p> + <p>In the case of a moist corn the paring should be stopped immediately the true + nature of the injury has made itself apparent. Warm poultices or hot baths should + then be used in order to soften the surrounding parts, lessen the pressure, and ease + the pain. After a day or two day's poulticing, should pain still continue with any + symptom of severity, the formation of pus may be expected, and it is then time for + the paring to be carried further, until the question 'pus or no pus?' is definitely + settled.</p> + <p>Should the moisture be due simply to the presence of the inflammatory exudate, + then poulticing alone will have the desired effect, and the pain will be lessened. + With the decrease in pain the poulticing may be discontinued, and the horn over the + seat of the injury dressed with some antiseptic and hardening solution. Sulphate of + zinc, a mixture of sulphate of zinc and lead acetate, sulphate of copper, or the + mixture known as Villate's solution,[A] may either of them be used. Suitably shod, + and with a leather sole for preference, the animal may then again be put to work.</p> + <p>[Footnote A: The composition of the escharotic liquid bearing his name was + published by M. Villate in 1829 as under:</p> + <table border="0" width="100%" summary="The composition of the escharotic liquid"> + <tr> + <td>Subacetate of lead liquid</td> + <td> + </td> + <td>128 grammes</td> + </tr> + <tr> + <td>Sulphate of zinc</td> + <td>[=a=a]</td> + <td>64 grammes</td> + </tr> + <tr> + <td>Sulphate of copper</td> + <td>[=a=a]</td> + <td>64 grammes</td> + </tr> + <tr> + <td>Acetic acid</td> + <td> + </td> + <td>1/2 litre</td> + </tr> + </table> + <p>Dissolve the salts in the acid, add little by little the subacetate of lead, and + well shake the mixture.]</p> + <p>When dealing with suppurating corn, then, a considerable paring away of the horn + of the sole becomes a matter of necessity. The freest possible exit should be given + to the pus, and this even when an opening has already occurred at the coronet. Unless + this is done, and done promptly, the putrescent matter still contained within the + hoof will make further inroads upon the soft structures therein, and later upon the + ligaments, and even bone itself.</p> + <p>Having given drainage to the lesion by the dependent orifice in the sole, + poulticing should again be resorted to and maintained for at least three or four + days. The poulticing may then be discontinued, and the openings in the sole injected + with a weak solution of Tuson's spts. hydrarg. perchlor., a 1 in 20 solution of + carbolic acid, a solution of copper sulphate, with Villate's solution, or with any + other combined antiseptic and astringent. The success of the treatment is soon seen + in the cessation of pain and in the decreased amount of discharge from the opening in + the sole.</p> + <p>Should pain unfortunately continue, the discharge remain, and a state of fever + reveal itself, then it may be understood that the suppurative process has not been + checked, that a portion of necrosed ligament, cartilage, or bone still remains, + which, surrounded as it is by pus organisms and putrefactive germs, is sufficient to + excite a constant irritation and maintain the internal structures in a state of + infection. In other words, we have what is known as a quittor.</p> + <p>This will call for deeper operation. The horn of the wall must be removed, and the + diseased structures, whether gangrenous keratogenous membrane, necrosed ligament, or + carious bone, carefully excised or curetted. This will be better understood by a + reference to the chapter on Quittor, where the means for carrying out the necessary + operative measures will be found described in detail.</p> + <p><i>Surgical Shoeing for Corn</i>.—In the case of an ordinary dry corn, where + the injury has been definitely ascertained to be accidental, no alteration in the + shoeing will be necessary. Where, however, the corn is attended with a more than + ordinary degree of inflammation, or where for some reason or other excessive paring + has been practised, then it will become needful to shoe with a special shoe. The + object to be attained is the removal of pressure from that portion of the wall next + to the seat of corn.</p> + <p>The most simple shoe for effecting this is the ordinary three-quarter shoe. The + only way in which this differs from the ordinary shoe is that about an inch and a + half of that branch of the shoe adjoining the corn is cut off (Fig. 102). If at the + same time contraction of the heels exists, then, perhaps, a better shoe is that known + as the three-quarter bar (Fig. 103).</p> + <p>Or, if preferred, a complete bar shoe such as that described for sand-crack may be + used, and the upper portion of the web in contact with the foot at the seat of corn + thinned out so as to avoid pressure on the wall at this point. With this shoe we + shall at the same time supply a certain amount of pressure to the frog, and aid in + the healthy development of the part indirectly involved in the disease.</p> + <p>The same pressure may also be given to the frog, and protection afforded the sole, + by the use of a leather sole, or rubber pad on leather, as described when dealing + with contracted feet.</p> + <p>A further method of relieving pressure on this portion of the wall, without + removing the wall itself (a practice which should never be advised) is to make + certain alterations in the web of the shoe. This may be done in one of two ways.</p> + <br /> + <a name="a102" id="a102"></a> + <p><a href="images/image102.png"><img src="images/image102sm.png" + alt="THREE-QUARTER SHOE." /></a></p> + <br /> + + <p>FIG. 102.—THREE-QUARTER SHOE.</p> + <br /> + <a name="a103" id="a103"></a> + <p><a href="images/image103.png"><img src="images/image103sm.png" + alt="THREE-QUARTER BAR SHOE." /></a></p> + <br /> + + <p>FIG. 103.—THREE-QUARTER BAR SHOE.</p> + <p>In the first, that portion of the bearing surface of the heel of the shoe is + 'dropped' about 1/8 inch from the plane of the remainder, so that the shoe at this + position does not come into contact with the foot at all (see Fig. 104).</p> + <p>In the second case the shoe is what is termed 'set' at the heel. Here it is the + plane of the <i>wearing</i> surface of the shoe that is altered. The hinder portion + of the required heel is thinned so that its lower surface does not come into contact + with the ground. By this means the wall is freed from concussion and pressure. At the + same time the upper surface of the shoe is in contact with the wall of the foot (see + Fig. 105).</p> + <p>This 'setting' of the shoe is preferable to the method first described. It affords + a greater protection to the foot, and does not allow of fragments of stone and flint + getting in between the foot and the shoe, and so giving rise to further mischief.</p> + <p>The 'set' portion should be fitted full and long. It is obvious, too, that the + animal should not be allowed to carry the shoe too long; otherwise, as the other + portion of the shoe wears down to the level of the 'set' heel, pressure on the tender + part of the foot will again result.</p> + <br /> + <a name="a104" id="a104"></a> + <p><a href="images/image104.png"><img src="images/image104sm.png" + alt="SHOE WITH A 'DROPPED' HEEL." /></a></p> + <br /> + + <p>FIG. 104.—SHOE WITH A 'DROPPED' HEEL.</p> + <br /> + <a name="a105" id="a105"></a> + <p><a href="images/image105.png"><img src="images/image105sm.png" + alt="SHOE WITH A 'SET' HEEL." /></a></p> + <br /> + + <p>FIG. 105.—SHOE WITH A 'SET' HEEL.</p> + <p>In applying surgical shoes for corn of long standing, it must be remembered that + the protection so afforded must be continued for some time. It is not sufficient to + see the lesion itself disappear. In addition to that there is also, in the majority + of cases, a certain amount of contraction to be overcome. This can only be done by + continuing the use of a leather sole or some form of frog or bar-pad as recommended + for the relief of that condition.</p> + <h3>C. CHRONIC BRUISED SOLE.</h3> + <p>A similar condition to that of corn may be met with in other positions on the + sole. It is described by Rogerson as sand-crack of the sole[A], and is invariably met + with around that portion of the sole in contact with the shoe.</p> + <p>[Footnote A: <i>Veterinarian</i>, vol. lxiii., p. 51.]</p> + <p>The animal is lame, and the shoe is removed in order to ascertain the cause. + Nothing at first is noticeable except that the animal flinches when pressure is + applied to the spot with the pincers, or the sole is tapped with the hammer.</p> + <p>On removing the sole with the knife, however, a distinct black mark is discovered, + which, when followed up by careful paring, is often found to have pus at the + bottom.</p> + <p>In this case the injury has resulted, as we have already intimated elsewhere, from + causing the animal to wear for too long a time a shoe with too broad a web or + insufficiently seated. Or it may have originated with the irritation set up by + foreign and hard substances between the web of the shoe and the foot.</p> + <p>In his description of this condition Mr. Rogerson draws attention to the fact that + the pus found should not be wrongly attributed to accidental pricking of the foot. He + says:</p> + <p>'Considering that the cracks or splits are always found in the immediate vicinity + of the nail-holes, a certain amount of discretionary skill is required in order that + the lameness may be attributed to its proper cause. This is an instance in which the + presence of the veterinary surgeon is imperative, in order to prevent undue blame + being attached to the shoeing-smith. Misconception in these cases might very easily + arise when parties concerned are disposed to accept an unskilled opinion, sometimes + resulting in danger to the proprietor of the forge, not only of losing a shoeing + contract, but also of being involved in other ways which would probably prove even + more disastrous.</p> + <p>'Horses that stand on sawdust or moss litter are sometimes found with extensive + discoloration of the horny sole in front of the frog. Their bedding material collects + in the shoe as snow does, and forms a mass, which keeps a continued and uneven + pressure upon the sole. A sound foot is not injuriously affected, but a very thin + sole is, and so also is a sole which has been bruised by a picked up stone. Even a + slight bruise becomes serious if pressure is allowed to remain active over the + injured part. Lameness increases, serous fluid is effused between the horn and + sensitive part, or even hæmorrhage may take place.'[A]</p> + <p>[Footnote A: Hunting, <i>Veterinary Record</i>, vol. xiv., p. 593.]</p> + <p><i>The Treatment of Chronic Bruised Sole</i> offers no special difficulty. Removal + of the cause (in nearly every case incorrect bearing of the shoe) is the first + consideration. That done, the lesion may be searched for and treated in the ordinary + manner as described for corn. When pus is present it must, of course, be given exit, + and an antiseptic solution applied to the wound. Should the sensitive structures be + laid bare when allowing the pus to escape, then the wound so made should afterwards + be protected with a leather sole and antiseptic stopping.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER VIII</h3> + <h3><a name="wounds" id="wounds">WOUNDS OF THE KERATOGENOUS MEMBRANE</a></h3> + <h3>A. NAIL-BOUND—BIND OR TIGHT-NAILING.</h3> + <p><i>Definition</i>.—By the term 'nail-bound' is indicated that accident + occurring in the forge in which the nail of the shoe is driven too near the sensitive + structures. Although involving no actual wound, it is important to consider the + condition under the heading of this chapter, in order that it may be distinguished + from the graver accident of a 'prick.'</p> + <p><i>Causes</i>.—Very largely the whole matter of causation turns on the + correct fitting of the shoe. The points especially to be noticed in this connection + are (1) the position of the nail-holes in the web of the shoe, (2) the 'pitch' of the + nail-holes.</p> + <p>Regarding the position of the nails, it goes without saying that the first + consideration when 'holing' the shoe should be to punch the holes opposite to sound + horn. This remark applies especially to shelly and brittle feet, the type of feet in + which tight-nailing most often occurs. The next consideration in this connection is + that of punching the holes so that the nail emerges from the upper surface of the web + at exactly its correct point of entrance on the bearing surface of the foot. This + should be on the white line immediately where it joins the wall. From this position + any marked deviation inwards ('fine-nailing,' as it is termed) is bound to give to + the nail a direction dangerously near the sensitive structures.</p> + <p>The 'pitch' of the nail-holes should be such that the nail is guided more or less + nearly to follow the line of inclination of the wall. Accordingly, the nail-holes at + the toe should be 'pitched' distinctly inwards, the inward pitch lessening as the + quarters are reached, until the hindermost nail-hole or two is pitched in a direction + that is almost perpendicular.</p> + <p>Too great an inward inclination of the nail will, however, give rise to a + bind.</p> + <p>It is probable that 'tight-nailing' results more often from fine punching of the + shoe than from any fault in the pitch of the hole. Inattention to either detail, + however, is apt to bring the mischief about.</p> + <p>Even with a correctly fitted shoe, and with a normal foot, tight-nailing may occur + as a result of sheer carelessness on the part of the smith.</p> + <p><i>Symptoms</i>.—Possibly the animal returns from the forge sound. It is on + the following day, as a rule, that evidence of the injury is given by the animal + coming out from the stable lame. In a well-marked case the foot is warmer to the hand + than its fellow, and percussion over the wall will sometimes reveal the particular + nail that is the cause of the trouble. Should the shoe be removed, then the fact that + the hole the nail has made is far too close to the sole often points out at once the + seat of the mischief.</p> + <p><i>Treatment</i>. As to whether or not the shoe should be removed is very much a + matter for careful discretion on the part of the veterinary surgeon. Where the foot + is shelly and brittle even a good smith sometimes finds himself unable to firmly + attach the shoe without verging closely on causing the condition we are now + describing. The author has known cases where animals with feet of this description + have almost invariably returned from the forge, or rather been found the next day, + with a suspicion of tenderness. After the lapse of a day or two this has quite often + disappeared, and nothing in the meantime been done with the foot. Seeing, therefore, + that removal and refitting of the shoe is in this case attended with risk of breaking + away portions of the brittle horn, and so rendering the foot in an even worse + condition than it was before, it is policy to decline to have the shoes removed + unless worse symptoms make their appearance.</p> + <p>In coming to this decision the veterinary surgeon must be guided by noting in the + wall the points of exit of the nails. Should the nail adjoining the position already + pronounced to be tender have come out at a higher point than the others, it may be + assumed that at a lower position in its course through the horn it has gone near the + sensitive structures without actually penetrating the horny box, and that in the + course of a day or two the sensitive structures involved will accommodate themselves + to the pressure thus inflicted.</p> + <p>If, on the other hand, symptoms of tight-nailing show themselves in an animal with + good sound feet, then there is no objection to be raised against having the shoe at + once removed. Should the offending nail be definitely detected, then the shoe may + again be put on, and that particular nail omitted from the set.</p> + <h3>B. PUNCTURED FOOT.</h3> + <p>(<i>Pricked Foot</i>—<i>Nail-tread</i>—<i>Gathered Nail</i>.)</p> + <p><i>Definition</i>.—Under this heading we propose describing wounds of the + foot occurring in the sole or in the frog, and penetrating the sensitive structures + beneath.</p> + <p><i>Causes</i>.—These we shall consider under two headings:</p> + <p>1. Wounds resulting from the animal himself 'picking-up' or 'treading' on the + offending object.</p> + <p>2. Cases of pricking in the forge.</p> + <p>Those occurring under the first heading are, of course, purely accidental. In the + majority of cases, the object picked up is a nail; but similar injury may result from + the animal treading on sharp pieces of wood or iron, on pieces of umbrella wire, on + pointed pieces of bones, broken-off stable-fork points, sharp pieces of flint, etc. + The same accident may also occur in the forge as a result of the animal treading on + the stumps of nails, from treading on an upturned shoe with the stumps of nails <i>in + situ</i>, or from treading on an upturned toe-clip. It may also occur from an + accidental prick with the stable-fork when 'bedding up,' or from casting part of a + shoe when on the road and treading on the nails, in this case left sometimes partly + in and partly out of the horn.</p> + <p>'Serious wounds of this description are also met with in animals engaged in + carting timber from plantations in which brushwood has recently been cut down. This + is, of course, from treading on the stake-like points that are left close to the + ground. Hunters also meet with the same class of injury when passing through + plantations or over hedge banks, where the hedge has just been laid low or cut + down.</p> + <p>'Agricultural horses also meet with severe wounds of this class from treading on + an upturned harrow.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. iv., + p. 2.]</p> + <p>It has been remarked how strange it is that nails should so readily penetrate the + comparatively hard covering of the foot. The matter, however, admits of explanation. + One knows from common observation how easy it is to tilt a nail with its point + upwards by exerting a pressure in a more or less slanting direction upon its head. + This is exactly the form of pressure that is no doubt put upon the nail if the animal + treads upon it when moving at any pace out of a walk. The foot in its movement + forward tilts the nail up, and almost simultaneously puts weight upon it. The great + weight of the animal is then quite sufficient to account for its ready + penetration.</p> + <p>In purely country districts cases of punctured foot are of far less frequent + occurrence than in large towns. In the latter, animals labouring in yards where a + quantity of packing is done, or engaged in carting refuse containing such objects as + we have mentioned, or broken pieces of earthenware or glass bottles, meet with it + constantly.</p> + <p>For the manner of causation of those wounds to the foot occurring in the forge the + reader may be referred to the matter under the heading of 'nail-bound.' As in that + case so in this the nail may be wrongly directed by improper fitting of the shoe, by + the 'pitch' of the hole, or by the position of the hole. The nails may also be + wrongly directed as a result of faulty pointing, or by meeting with the stump of a + nail that has carelessly been allowed to remain in the substance of the horn.</p> + <p>Often pricking is a result of carelessness engendered by a rush of work. Often it + is almost unavoidable on account of the character of the foot that is brought to be + shod. Feet with thin horn, especially a thin sole, feet with horn shelly and brittle, + each in their way are difficult to shoe.</p> + <p>Sometimes pricking is purely accidental, as in the case of a 'split' nail. The + nail as it is driven splits at its point, and continues to split down its centre, one + half emerging at the correct spot on the wall, the other half bending inwards, and + penetrating the sensitive structures.</p> + <p><i>Common Situations of the Wound</i>.—In a case of picked-up nail the + common seat of puncture is about the point of the frog, either in one of the lateral + lacunæ, in the median lacuna, or the apex of the frog itself. In comparison + with this puncture of the sole is rare.</p> + <p>Prick sustained at the hands of the smith may, of course, run in either of the + following directions: (1) Directly into the position where the horny and sensitive + laminæ interleave; (2) between the sensitive laminæ and the os pedis; (3) + into the os pedis itself; (4) the nail may bend excessively immediately after + entering the horn, and so pass either between the horny and sensitive sole; or (5) + between the sensitive sole and the bone.</p> + <p><i>Classification</i>.—Punctured wounds of the foot may be classified as + follows:</p> + <p><i>Simple or superficial</i> when penetrating no structure of great importance. + For instance, a prick that penetrates to the sensitive sole and is not driven with + sufficient force to seriously injure the os pedis we may regard as simple. In the + same manner a prick to the frog that, although deep, is mainly concerned with + penetrating the plantar cushion may also be classed as simple.</p> + <p><i>Deep or penetrating</i> when driven with sufficient force or in such a + direction as to injure structures whose penetration is calculated to give rise either + to serious constitutional disturbance or to permanent lameness. In this category we + may place injuries to the terminal portion of the perforans, puncture of the + navicular bursa, fracture of the navicular bone and penetration of the pedal + articulation, and splintering of the os pedis.</p> + <p><i>Symptoms and Diagnosis</i>.—While discussing the symptoms and diagnosis, + we will still continue to consider our subject under the two headings of (1) + accidental 'gathering' of some foreign body, and (2) pricks inflicted in the + forge.</p> + <p>In a few cases belonging to the former class the veterinary surgeon is fortunate + in obtaining a direct history of the injury. The driver has seen the animal go + suddenly lame, and has examined the foot for the cause. Either the nail has been + found embedded in the horn, or the puncture it has made detected, and the matter has + been reported. The foot is then explored and the full extent of the injury + ascertained.</p> + <p>In many cases, however, it so happens that no evidence of the infliction of the + injury is forthcoming. The momentary lameness occurring at the time of the prick is + unreported at the time by the attendant, and the horse for a time goes sound. It is + not until the changes set up by the subsequent inflammatory phenomena make their + appearance, and lameness results, that attention is called to the foot. When this + happens there has, as a rule, been time for pus to form around the seat of + puncture—a matter of about forty-eight hours.</p> + <p>The horse is now brought out for the veterinary surgeon's examination, going + distinctly lame. If the case is well marked there may then be noted by the man of + experience many little signs pointing to the foot as the seat of the lameness. These, + though well enough known to the practitioner, are nevertheless difficult to describe. + It is, in fact, hard to say exactly in what they really consist, appearing to be as + much a matter of intuition as of actual observation.</p> + <p>There is a peculiar 'feeling' characteristic in the gait. The affected foot is put + forward fearlessly enough, but is not nearly so rapidly put to the ground. When at + rest the foot is almost immediately pointed, and the pain at intervals manifested by + pawing movements. It is this extreme liberty of the rest of the limb, as evinced + during the pawing movements, that really strikes one. Shoulder, elbow, knee, and + fetlock are all easily and painlessly flexed and extended. There is nothing wrong + with them; it must be the foot. The short manipulation necessary to test the + lameness—viz., the walk and slow trot—is sufficient to raise the animal's + pulse and quicken the breathing.</p> + <p>All this is enough, and more than enough, to lead the veterinary surgeon to + examine the foot. It is hot to the touch, and at the coronet tender to pressure, + possibly in a neglected case fluctuating at the heel. Pain is evinced by the animal + withdrawing his foot when percussion takes place over the affected spot. In a bad + case one gentle tap is all that is needed. The animal at once snatches away his foot, + holds it high from the ground, and makes pawing movements in the air. At that moment, + too, his countenance is highly expressive of the pain he is suffering. Again the foot + is explored, the injury found, and the pus liberated.</p> + <p>Regarding the manner of exploration of the foot we will take first that case in + which the veterinary surgeon is called in early, and in which pus has not yet had + time to form. Sometimes the merest cleaning up of the inferior surface of the foot + then reveals a distinct stab either in the sole or the frog.</p> + <p>If the accident be recent only a little blood will be found, either liquid, or + coagulated about the wound. Later there exudes from the stab a flow of yellow, serous + fluid. The opening thus found should be carefully probed, and its depth and situation + noted.</p> + <p>At other times the prick is not so readily apparent. The nail or other object has + penetrated and afterwards withdrawn itself. The natural elasticity of the horn, + especially that of the frog, causes it to contract upon the puncture, and to largely + obliterate the hole made. What, therefore, may look to be but a simple injury to the + horn alone may in reality be the only evidence of a stab complicating the sensitive + structures. It thus behoves the veterinary surgeon to follow up and carefully cut out + any unnatural-looking mark in the horn, more especially if the horn is discoloured, + or if blood is extravasated into its fibres, or there is moisture exuding from the + part.</p> + <p>In some cases of this description the knife in the act of paring comes into + contact with the cause of the trouble. Sometimes this is a nail, sometimes a sharp + and small piece of flint, so deeply penetrated as to have become quite buried. When + met with in this manner, however, the foreign body is more often than not a splinter + of wood deeply embedded in the cleft of the frog or in the frog itself.</p> + <p>The fact that multiple punctures may occur should here be remembered, and the + remainder of the inferior surface of the foot thinly pared.</p> + <p>On withdrawal of the foreign object blood may immediately follow. Should the + former have been fixed in position for some time, however, pus is nearly always found + at the bottom of the wound. As a rule, its removal is comparatively easy, but one + case recalls itself to the author's mind in which the extraction was a matter of + considerable difficulty. The offending object was a large, flat-headed nail, some 2 + inches long. This was driven fast into the os pedis, and necessitated the employment + of a pair of pincers and the exertion of some amount of force to move it from its + position.</p> + <p>In this connection it must be remembered that the penetrating object sometimes + breaks off after entering the foot. The fact that this occasionally happens only + serves to give point to the advice we have previously rendered—that every stab + should be carefully probed, and its exact condition and depth ascertained.</p> + <p>In those cases where percussion has led to the positive opinion that pus really + exists, then the exploration must be most searching. There may, or may not, be a + suspicious-looking mark to work on. In the latter case, the veterinary surgeon must + not be content with confining his paring operations to one spot. The sole should be + carefully thinned all round, and the thinning cautiously proceeded with until either + small, pin-point hæmorrhages denote that healthy sensitive structures have been + reached, or a sudden flow of pus indicates that the injury has been definitely + located.</p> + <p>While the symptoms remain much about the same, the diagnosis of pricks received in + the forge, as compared with those occurring in the natural manner, is easy. The + animal starts to the forge quite sound, and returns, perhaps, with a slight limp. The + slight limp in two days' time becomes a decided lameness, and no doubt remains as to + what has occurred. The mere fact of the lameness arising immediately after a visit to + the forge should be sufficient in the majority of cases to lead one to a correct + diagnosis.</p> + <p>Where the opinion has been formed that a prick has been received, then the shoe + should be removed.</p> + <p>This operation should always be superintended by the veterinary surgeon himself. + After the removal of the clinches, the nails should be drawn one at a time with the + pincers, and carefully examined. Often the offending nail may thus be picked out by + observing upon it blood-stains, or the moisture from inflammatory exudate or from + pus. Further inflammation will also be gathered by occasionally meeting with a nail + that has split.</p> + <p>At this stage, too, the veterinary surgeon should have noticed whether or not the + smith has previously sent the animal home with what is known as a 'draw back.' He has + discovered, immediately after he has done it, that he has pricked the animal. He has + then withdrawn the nail, and either sent the animal back with that nail altogether + missing from the set in the shoe, or with the hole filled up with a stump.</p> + <p>The shoe once off, the holes made by the nails in the horn should be minutely + examined for the presence of hæmorrhage, inflammatory fluid, or pus exuding + from them, and also for evidence of their correct placing in the foot. Should fluid + matter issue from any one of them, or should it be deemed that one has approached too + near the inner margin of the white line, more especially if tenderness exists around + it, that hole should be followed up with a 'searcher' or small drawing-knife until + diagnosis is certain.</p> + <p><i>Complications</i>.—Before proceeding to discuss the complications that + may arise in the case of pricked foot, we may call to mind that the anatomy of the + parts teaches us that the most serious position in which a punctured wound can occur + is at the centre of the foot. Here the plantar aponeurosis, the navicular bursa, the + navicular bone itself, or the pedal articulation may be injured.</p> + <p>Anterior to this position the most serious mischief that can ordinarily result is + stabbing of the os pedis.</p> + <p>Posterior to the position we have named, the only structure to be injured is the + plantar cushion.</p> + <p>Anatomically, then, the inferior surface of the foot may be divided into three + zones, as follows:</p> + <p><i>A. Anterior</i>, extending from the toe to the point of the frog.</p> + <p><i>B. Middle</i>, extending from the point of the frog to the commencement of its + median lacuna.</p> + <p><i>C. Posterior</i>, including everything posterior to the middle zone. This + division of the inferior surface of the foot into zones will be somewhat of a guide + also when describing the complications next to follow:</p> + <p>(<i>a</i>) <i>Suppuration</i>.—This is the common complication of most + wounds of the foot. When detected, it calls for immediate surgical interference in + the shape of removal of the horn of the sole or the frog, as the case may be. This we + shall consider further under the treatment.</p> + <p>(<i>b</i>) <i>Separation of the Horny Frog</i>.—This is a sequel to pus + formation in the sensitive structures immediately beneath it, and the condition makes + itself apparent by a line of separation between the horn and the skin of the heel of + the injured side.</p> + <p>(<i>c</i>) <i>Wounding of the Plantar Aponeurosis</i>.—This occurs when a + moderately-deep penetration of the horn of the middle zone has taken place. It is + always most painful, especially when complicated by necrosis. The heel is then + persistently elevated, and lameness is extreme, in some cases so severe as to cause + the leg to be carried altogether.</p> + <p>In favourable cases the necrosed piece of tendon is sloughed off by the process of + suppuration, and escapes with the discharges from the wound. There is then an + abatement in the symptoms, and recovery is rapid.</p> + <p>Commonly, however, on account of the non-vascularity of the structure of the + tendon, the necrotic spot in it tends to spread. The wound is thus led to become + fistulous in character, and the pus forming within it prevented from escaping from + the original opening. As a result, lameness and fever persist. There is a gradual + increase in the severity of the symptoms, and later fistulous openings appear in the + hollow of the heel.</p> + <p>(<i>d</i>) <i>Puncture of the Navicular Bursa</i>.—This results from a prick + in exactly the same position as that last described, and means that the penetrating + object has gone deeper, It may be distinguished from puncture of the plantar + aponeurosis alone by the fact that there is an excessive discharge of synovia from + the wound. This, as it escapes, is at first clear and straw-coloured. Later it + becomes cloudy and flaked with pus, and shows a tendency to coagulate in yellowish + clots.</p> + <p>Pain and accompanying fever is most marked, much more so than when the plantar + aponeurosis alone is injured.</p> + <p>Should the original wound be insufficiently enlarged, or should its opening become + occluded by the solid matters of the discharge, then this condition, like the last, + ends in the formation of fistulous openings in the heel. These make their appearance + as hot, painful, and fluctuating swellings in that position. Later they break, + discharge their contents, and leave a fistulous track behind.</p> + <p>(<i>e</i>) <i>Fracture of the Navicular Bone</i>.—Penetration of the + substance of the navicular bone, <i>without</i> its fracture, adds nothing to the + symptoms we have described under puncture of the bursa. That the bone has been + reached by the penetrating object may be detected by probing. This, however, must be + performed with care, especially if a flow of synovia is absent. Otherwise, the wound, + as yet, perhaps, superficial enough to avoid penetrating even the bursa, is made a + penetrating one by the probe itself.</p> + <p>Fracture of the navicular bone is fortunately rare.</p> + <p>(<i>f</i>) <i>Penetration of the Pedal Articulation and Arthritis</i>.—This + we shall consider in greater detail in Chapter XII. It is sufficient here to state + that the condition may be suspected when a hot and painful swelling of the whole + coronet makes its appearance. There is at the same time a diffused oedema of the + fetlock and the region of the cannon, sometimes extending upwards to the whole of the + limb.</p> + <p>Of all the complications to be met with in punctured foot this is the one most to + be dreaded. The intense pain and the high fever render the animal weak and thin in + the extreme. The appetite becomes impaired, sometimes altogether lost, and the + patient in many cases appears to die from sheer exhaustion. Added to this is always + the extreme probability of the wound becoming purulent, and later the dread of + general septic infection of the blood-stream ensuing, and death resulting from that. + Even with the happier ending of resolution, anchylosis of the joint and incurable + lameness is more often than not left behind. (See Suppurative or Purulent Arthritis, + Chapter XII.)</p> + <p>(<i>g</i>) <i>Ostitis and Caries of the Os Pedis</i>.—Injuries to the os + pedis are met with in the anterior zone of the foot. Evidence that the bone has been + injured is not usually forthcoming until after the lapse of some days. One is led to + suspect it by the fact that there is no indication of the suppurative process + extending further upwards, coupled with the facts that great pain, high fever, and + extreme lameness persist, and that there is a continuous discharge from the wound of + a copious blood-stained and foetid pus. Used now, the probe reveals the fact that the + bone is bared, and conveys to the hand that is holding it a sensation of crumbling + fragility.</p> + <p>(<i>h</i>) <i>Wounding of the Lateral Cartilage and Quittor</i>.—This occurs + as the result of a deep stab in the posterior zone. Ordinarily, wounds in this + position are unattended with serious consequences, and the prick has to be a deep and + a severe one before the cartilage is reached. What then happens is that a spot of + necrosis is formed round the seat of puncture in the cartilage. This, unless met with + surgical interference, is sufficient to maintain the wound in a septic condition; it + takes on a fistulous character, and a quittor is formed. (See Chapter X.)</p> + <p>(<i>i</i>) <i>Septic Infection of the Limb</i>.—This we have already once or + twice referred to. It simply means that the septic matters from the wound have gained + the lymphatics, and finally the blood-vessels of the limb, and set up local lesions + elsewhere than in the foot. Although dismissed here with these few words, the + condition is a most serious one. Usually, it has resulted from penetration of the + pedal articulation and septic infection of the joint. In the vast majority of these + cases slaughter is both humane and economical.</p> + <p><i>Prognosis</i>.—The first consideration in giving a prognosis in punctured + foot should be the position of the wound. When occurring in the middle zone, the + surgeon's statements should be most guarded, and the dangers attending a wound in + that particular position fully explained to the owner. A wound in the anterior + position is, as we have said, far less serious, and one in the posterior region of + the foot even less serious still.</p> + <p>Whenever possible, the nail or other object causing the prick should be examined. + Much of the prognosis may be based upon the estimated depth of the wound, and this, + in many cases, it is far safer to calculate from the length of the offending body + than from the use of the probe. We need hardly say that in the middle zone the deeper + the prick, the more serious the case, and the less favourable the prognosis. As in + succession the sensitive sole, the plantar aponeurosis, the navicular bursa, the + navicular bone, or the pedal articulation is injured, so with each step deeper of the + prick is the severity of the case increased.</p> + <p>The shape of the penetrating object may also be considered. One excessively blunt, + and calculated to bruise and crush the tissues, will inflict a more serious wound + than one of equal length that is pointed and sharp.</p> + <p>The conformation of the foot should also be regarded. Wounds in well-shaped feet + are less serious than in feet with soles that are flat or convex, or in which the + horn is pumiced or otherwise deteriorated in quality.</p> + <p>Although unaffecting the prognosis so far as the actual termination of the case is + concerned, it may be mentioned that punctured foot is far more serious in a nag than + in a heavy draught animal. With an equal degree of lameness resulting in each case, + the former will be well-nigh useless, but the latter still capable of performing much + of his usual labour.</p> + <p>The temperament and condition of the patient will also in many cases largely + influence the prognosis. An animal of excitable and nervous disposition is far more + likely to succumb to the effects of pain and exhaustion than the horse of a more + lymphatic type. In the case of a patient suffering from a prick to a hind-foot while + heavily pregnant, the attempted forecast of the termination should be cautious. More + especially does this apply to the case of a heavy cart-mare. Ordinarily, the heavier + the breed, the greater the tendency to lymphatic swelling of the hind-limbs. With + pregnancy this tendency is enormously increased, and it is no uncommon thing to find + a cart-mare in this condition, with legs, as the owner terms it, 'as thick as + gate-posts.' A prick to the foot, with the lymphatics of the limb in this state, is + extremely likely to end in septic infection of the leg, for there appears to be no + doubt but that invasion of the lymphatics with septic matter is favoured by a + sluggish stream. Also, in the case of a patient in the advanced stages of pregnancy, + it must be remembered that, no matter how great may be the need, one is debarred, for + obvious reasons, from using the slings.</p> + <p><i>Treatment</i>.—<i>In a simple</i> case—and by 'simple' here we mean + the case in which the injury is discovered early, and pus has not yet commenced to + form—our first duties are to give the wound free drainage, and to maintain it + in an aseptic condition. The first of these objects is to be arrived at by paring + down the horn in a funnel-shaped fashion over the seat of the prick. It is, perhaps, + even better to thin the horn down to the sensitive structures for some little + distance round the injury. By this latter method pressure from inflammatory exudate + is lessened, and the after-formation of pus, if unfortunate enough to occur, the more + readily detected, and the less likely to spread upwards. The matter of asepsis may + then be attended to.</p> + <p>When the puncture is sufficiently large to admit of it, the antiseptic dressing is + best applied by means of the probe. This instrument is thinly wrapped with tow, or + other absorbent material, so as to form a small swab. Dipped in a suitable solution + (as, for example, Zinc Chloride, Spts. Hydrarg. Perchlor., Carbolic Acid, or any + other that suggests itself), the swab is inserted into the prick, and the wound + conveniently mopped clean. A further portion of the medicated tow is then pushed + partially into the wound, and allowed to remain in position. The foot is subsequently + wrapped in a clean bag, and kept free from dirt. This dressing should be repeated + twice daily.</p> + <p>If the prick is in a dangerous position, and deep enough to occasion alarm, our + precautions to prevent the formation of septic matters within it may be more + elaborate. The thinning of the horn and the swabbing of the wound may, as before, be + proceeded with. In addition, the whole foot may then be immersed for some hours daily + in a cold bath, which bath should be strongly impregnated with one or other of the + following salts: Iron Sulphate, Zinc Sulphate, Copper Sulphate, Aluminium Sulphate, + Lead Acetate, or Sodium Chloride—better still, a mixture of the various + sulphates here mentioned. If preferred, one of the more commonly accepted + antiseptics—such as Carbolic Acid, Lysol, Boracic Acid, or Perchloride of + Mercury—may be substituted.</p> + <p>By the cold of the bath inflammatory phenomena are held in check, while its added + antiseptic prevents the formation of septic discharges. The lameness gradually + diminishes, and resolution is rapid. In this way deep and serious, wounds are + sometimes easily and successfully treated.</p> + <p><i>When suppuration has occurred</i>—and this, by-the-by, is by far the most + frequent condition in which we find punctured foot—treatment must be prompt and + decided. Careful search must at once be made by thinning down the sole, and carefully + trimming the frog. On no account should the veterinary attendant rest content with + 'digging' in one place, and upon that basing a negative opinion as to the existence + of pus. The paring should be carried on, until either pus or hæmorrhage shows + itself, in at least three positions—namely, at the most anterior portion of the + sole, and in the sole at each side of the frog. In addition to this, the frog itself + should be minutely examined for evidence of puncture, or for leaking of pus at the + spot where the horn of the heels joins the skin.</p> + <p>In many of our cases, however, this careful search is not so necessary. The + accompanying symptoms are so decided as to leave no doubt as to the condition of the + case. In such instances paring may often be commenced over the exact position of + suppuration as previously ascertained by percussion.</p> + <p>When met with, the track formed by the suppurative process should be followed up + in whichever direction it has spread. This will often necessitate the removal of the + greater part, if not the whole, of the horny sole.</p> + <p>Having given vent to the pus, and opened up the cavity made by its formation, the + foot should be placed in a hot poultice or, preferably, in a hot antiseptic + bath.[A]</p> + <p>[Footnote A: At the time of writing this, a certain amount of discussion is going + on in our veterinary journals as to whether a hot or a cold bath is the one + indicated. It is urged against the application of heat that it favours organismal + growth and reproduction, and tends rather to induce the spread of the suppurative + process than to overcome it. Those who hold this opinion urge in support of it that + cold applications are inimical to the life of the pus organism. At the same time, it + must be remembered that in just so far as cold inhibits the growth of the invading + germ, so in just the same degree does it adversely influence the functions of the + tissues that are to fight against it. To our minds the question thus set up must + always remain more or less a moot-point, and while we fully agree that cold + undoubtedly checks the growth of septic material, we just as fully believe that + warmth serves to place the healthy surrounding structures in a far better condition + to maintain a vigorous phagocytosis against it. We thus continue to advise a hot + antiseptic poultice, or, better still, a bath.—THE AUTHOR.]</p> + <p>At the end of the third or fourth day the poultice or the bath may be + discontinued, and the opening in the sole dressed with any suitable astringent and + antiseptic.</p> + <p>The most serious complication arising from this method of treatment is one of + excessive granulation of the sensitive sole. This we find to be successfully held in + check by a daily application of undiluted Spts. Hydrarg. Perchlor. (Tuson). Should + the granulations become very exuberant, then the knife must be called to our aid, and + the wound so made afterwards dressed with an astringent.</p> + <p>When the suppuration has under-run the horny frog there should be no hesitation in + at once removing all the horn that is visibly separated from the sensitive structures + beneath.</p> + <p><i>When the os pedis is splintered and carious</i>, a portion of the sole round + the wound is removed, and the bone exposed. The diseased portion is scraped away + either with a curette or with the point of the drawing-knife. In this case the only + after-treatment called for is the application of suitable antiseptic dressings.</p> + <p><i>When necrosis of the plantar aponeurosis has occurred</i>. We have already + pointed out the tendency there is in this case for the wound to maintain a fistulous + character, and lead to the formation of abscesses in the hollow of the heel. With a + wound in this position, as with a wound in any other, the only method of avoiding + this termination consists in removing all that is visibly diseased, whether it be + soft structures, bone, ligament, or tendon, and giving the wound free drainage.</p> + <p>This can only be done by removing the horny sole and frog, and cutting boldly down + upon the structures beneath. The operation is known as resection of the plantar + aponeurosis, or the complete operation for gathered nail.</p> + <p>Practised for some years on the Continent, this operation, on account of its + gravity, has been avoided by English veterinarians. From reported cases, however, it + appears often to be followed by success. That there is a large element of risk in the + operation is quite evident, if only from the two facts mentioned beneath:</p> + <p>1. That the close attachment of the plantar aponeurosis to the navicular bursa, + and the nearness of both to the pedal articulation, render penetration of a synovial + sac or a joint cavity extremely likely.</p> + <p>2. That there is always great difficulty in maintaining strict asepsis of the + foot, more especially if it is a hind one.</p> + <p>On the other hand, it may be argued that equal risk to the patient is run in + allowing him to remain with a disease (and that disease a progressive one) of the + structures so closely antiguous to the navicular bursa and the pedal + articulation.</p> + <p>If only for that reason we give the operation brief mention here.</p> + <p>The animal is prepared in the usual way for the operating bed; the foot soaked for + a day or two previously in a strong antiseptic solution, the patient cast and + chloroformed, and the operation proceeded with.</p> + <br /> + <a name="a106" id="a106"></a> + <p><a href="images/image106.jpg"><img src="images/image106sm.png" + alt="'CURETTE,' OR VOLKMANN'S SPOON." /></a></p> + <br /> + + <p>FIG. 106.—'CURETTE,' OR VOLKMANN'S SPOON.</p> + <p>An Esmarch's bandage should be first applied, and a tourniquet afterwards placed + higher up on the limb. The foot is then secured as described in an earlier chapter, + and the whole of the horny structures of the lower surface of the foot (the sole, the + frog, and the bars) pared until quite near the sensitive structures, or, if under-run + with pus, stripped off entirely. An incision is then made in each lateral lacuna of + the frog, the two meeting at the frog's point. Each incision thus made should be + carried deep enough to cut through the substance of the plantar cushion. A tape is + then passed through the point of the frog, tied in a loop, and given to an assistant + to draw backwards. The plantar cushion itself is then incised in a direction from + before backwards, and pulled on by the assistant, so as to expose the plantar + aponeurosis.</p> + <p>Should this be found at all necrotic, it may be taken that purulent inflammation + of the navicular bursa and of the navicular bone itself exists. The operator must + then proceed to resection of the tendon in order to treat the deeper structures thus + affected. At its point of insertion into the semilunar crest the tendon is severed + and afterwards reflected. This exposes the inferior face of the navicular bone. + Instead of the glistening and clear appearance it ordinarily presents, its glenoid + cartilage is found to be showing hæmorrhagic or even purulent spots of + necrosis. The terminal portion of the tendon must then be excised.</p> + <p>To effect this a clean transverse incision is made at the extreme upper border of + the navicular bone. Here we are in close contact with the pedal articulation, and + great care is necessary in making this last incision, in order that the synovial sac + may not be penetrated.</p> + <p>All structures showing spots of necrosis should now be carefully removed, either + with the knife or with the curette. The knives most suitable for the last stages of + this operation are those depicted in Fig. 45 (<i>c</i>, <i>d</i>, and <i>e</i>). The + curette, or Volkmann's spoon, we show in Fig. 106.</p> + <br /> + <a name="a107" id="a107"></a> + <p><a href="images/image107.jpg"><img src="images/image107sm.jpg" + alt="RESECTION OF TERMINAL PORTION OF THE PERFORANS." /></a></p> + <br /> + + <p>FIG. 107.—RESECTION OF TERMINAL PORTION OF THE PERFORANS. The horny sole and + the horny frog stripped from off the sensitive structures. <i>a</i>, The plantar + cushion; <i>b, b</i>, the plantar aponeurosis, or terminal portion of perforans; + <i>c</i>, the navicular bone; <i>d</i>, interosseous ligaments of the pedal + articulation; <i>e, e</i>, semilunar crest of the os pedis; <i>f</i>, inferior + surface of os pedis; <i>g, g</i>, the sensitive laminæ of the bars; <i>h, + h</i>, bearing surface of the wall; <i>i, i</i>, the sensitive sole; <i>k</i>, the + sensitive frog.</p> + <p>When at all diseased the glenoidal surface of the navicular bone should be + curetted, even to the extent of the removal of the whole of the cartilage. A healthy, + granulating surface is thus insured.</p> + <p>The above figure from Gutenacker's 'Hufkrankheiten' explains shortly the position + of the operation wound and the structures involved, rendering further description + unnecessary here.</p> + <p>The operation ended, the dressing follows. Upon this depends very largely the + ultimate recovery of the patient, for it is only by careful attention and suitable + dressings that effectual repair of the injured structures may be brought about.</p> + <p>A light shoe is first tacked on to the foot, and those portions of the horny sole + that have been allowed to remain dressed with Venice turpentine, tar, or other + thickly-adherent antiseptic.</p> + <p>The exposed soft tissues are then dressed with pledgets of tow[A] soaked in + alcohol and carbolic acid. This dressing must be allowed to remain in position, and + is kept there by means of a bandage, or the shoe with plates (Fig. 55) and a bandage + over it. No pressure is needed; consequently, the pledgets of tow must not be too + thick.</p> + <p>[Footnote A: When using tow in the form of a pad, it is well to remember that many + small balls of the material rolled lightly in the palm of the hand and afterwards + massed together are far better than one large pad of the tow taken without this + preparation. The irregularities of the wound are better fitted, and the whole + dressing easier remains <i>in situ</i> (H.C.R.).]</p> + <p>In the after-dressing of the wound careful attention must be paid to the + granulating surface. Where tending to become too vigorous in growth it should be held + in check by suitable caustic dressings. At the same time it must be remembered that + the granulating process of repair is always more rapid upon the plantar cushion and + fleshy sole than upon the bone, or upon tendinous or cartilaginous structures. As a + result of this we have a wound showing various aspects of cicatrization. Healthy + granulation may be profuse in one spot, while in another it may be checked either by + a flow of synovia from the still open bursa, or by fragments of bone or of tendon + still acting as foreign bodies in the wound. These latter may be readily detected by + their standing out as dark and uncovered spots in the healthy granulation around, and + should be at once removed.</p> + <p>The time that an operation wound of this description takes to heal—and that + without complication—is from one to two or three months. Continuation of pain + and intensity of lameness are not to be taken as indications of failure. The + reparative inflammation in the synovial membrane is quite sufficient to induce pain + severe enough to prevent the animal from placing his foot to the ground for some + weeks, even though the progress of the case, all unknown, may be all that is desired. + So long as a great amount of pain is absent, and so long as appetite remains and + swellings in the hollow of the heel fail to make their appearance, so long may the + progress of the case be deemed satisfactory.</p> + <p><i>Recorded Case of the Treatment</i>.—A cart-horse, aged six years, was + sent to the Alfort School by a veterinary surgeon for having picked up a nail in the + hind-foot. Professor Cadiot, judging the necessity for the complete operation, + performed it on January 14, and spared the plantar cushion as much as possible. In + consequence of the plantar aponeurosis being extensively necrosed, it was advisable + to scrape the navicular bone and a part of the semilunar crest. The wound having been + washed with a 1 per cent. solution of perchloride of mercury, it was dusted with + iodoform and packed with gauze, and covered with a cotton-wool dressing, kept in + position by means of a suitable shoe.</p> + <p>On January 16 there was no snatching up of the limb when the horse was made to put + weight upon it; he ate his food well, and his condition improved every day. On + January 21 the dressing was removed; the wound appeared pinky and granular, and there + was no suppuration. The clot remaining from the hæmorrhage after the operation + was removed, the wound was irrigated with a hot solution of sublimate, and then + dusted with iodoform and covered with a dressing of iodoform gauze and absorbent + wool. At this date the horse could stand on the injured limb. On January 31 a second + dressing was made, and the animal almost walked sound. On February 7 the wound had + almost closed up, save in its central part, where there was a small cavity, and the + lameness had disappeared. On February 15 the wound had completely healed, and its + borders were covered by a layer of thin horn. As the animal was sound it was sent to + work.</p> + <p>The author directs attention to the rapidity with which a large and complete wound + cicatrizes after the operation for gathered nail.[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. XV., p. 226 (Jourdan).]</p> + <p><i>In the case of Penetrated Navicular Bursa</i>, unaccompanied by the formation + of any large quantity of pus, and uncomplicated by necrosis of the aponeurosis, our + aim must be to maintain the wound in that happy condition. This is doubtless best + done by keeping the foot continually in a cold bath, rendered strongly antiseptic by + the addition of sulphate of copper and perchloride of mercury. Should there be + intervals when the bath must be neglected, the foot in the meantime must be kept + clean by antiseptic packing and bandaging, and a clean bag over all. This treatment + should be continued so long as the character of the discharge denotes that synovia is + running. If, in spite of our precautions, the discharge becomes purulent, then the + track made by the penetrating object should be syringed twice daily with a 1 in 1,000 + solution of perchloride of mercury.</p> + <p>During the treatment it will be wise to shoe the animal with a high-heeled shoe. + We do not know as yet the full extent of the injury. The navicular bone may be + tending to caries; or necrosis of the plantar aponeurosis, all unknown, gradually + becoming pronounced. This calls for a relief of tension on the perforans, and is only + to be brought about by the high-heeled shoe.</p> + <p>The result of the inflammatory changes in the tendon, aided possibly by the use of + the high-heeled shoe, is to afterwards bring about contraction. Where this has + occurred, and the animal walks continuously on his toe, the shoe with the projecting + toe-piece (Fig. 84) must be applied. When the continual use of the toe-piece appears + inadvisable, the shoe devised by Colonel Nunn may be used in its stead (see Fig. + 108).</p> + <p>The toe-piece is screwed into the toe of the shoe when the horse is about to be + exercised, and forms a powerful point of leverage with which to stretch the + contracted tendon, and the shoe, being thin at the heels, admits of this. The + advantage of this form of toe-piece over the ordinary form of fixed toe-lever is that + it can be removed when the horse is in the stable; while the curved point diminishes + the danger of the horse hurting itself—a danger always present if it is on a + hind-foot. (See also Treatment of Purulent Arthritis in Chapter XII.)</p> + <br /> + <a name="a108" id="a108"></a> + <p><a href="images/image108.png"><img src="images/image108sm.png" + alt="COLONEL NUNN'S SHOE WITH DETACHABLE TOE EXTENSION." /></a></p> + <br /> + + <p>FIG. 108.—COLONEL NUNN'S SHOE WITH DETACHABLE TOE EXTENSION.</p> + <p><i>Should a Sinuous Wound remain in the region of the Lateral Cartilage</i>, it + should be explored, and its depth and likely number of branches ascertained. Should + this exploration denote that the cartilage itself is diseased, or that the wound is + not able to be sufficiently drained from the sole, then we know that we have on our + hands a case of quittor. The treatment necessary in such a case will be found + described in Chapter X.</p> + <p><i>When the Complication of Purulent Arthritis has arisen</i>, the surgeon has to + admit to himself, reluctantly no doubt, that the case is often beyond hope of aid + from him. Nothing can be done save to order continuous antiseptic baths and + antiseptic irrigation of the wounds with a quittor syringe, and to attend to the + general health and condition of the patient. At the best it is but a sorry look-out + both for the veterinary attendant and the owner of the animal. Even with resolution + incurable lameness results, and the animal is afterwards more or less a walking + exhibition of the limitations of surgery, while the owner, unless the animal is + valuable for the purpose of breeding, finds himself encumbered with a life that is + practically useless. (See Treatment of Purulent Arthritis, Chapter XII.)</p> + <p><i>In the case of Lameness Persisting after the healing of all appreciable + lesions</i>, then neurectomy is followed by good results. The animal, apparently + recovered, is for a long time useless. Lameness persists for several months, as if + the nail had at the moment of its penetration caused lesions, which doubtless it + sometimes does, similar to those of navicular disease. Examination of the foot in + this case reveals no lesion, and the pain has evidently a deep origin. The lameness + caused by it is subject to variation. Frequently it becomes lessened during rest, and + increased by hard work, while sometimes it is very much more pronounced at starting + than after exercise.</p> + <p>It is here that neurectomy is called for. The operation does nothing to impede the + work of healing going on, and allows free movement of the foot and pastern to take + place. At the same time suffering and emaciation cease, and the animal is rendered + workable.[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. ii., p. 371.]</p> + <h3>C. CORONITIS (SIMPLE). TREAD, OVERREACH, ETC.</h3> + <p>1. <i>Acute</i>.</p> + <p><i>Definition</i>.—Under the heading of simple coronitis in its acute form + we intend to describe those inflammatory conditions of the skin and underlying + structures of the coronet occurring without specific cause. Specific coronitis will + be found described in Chapter IX.</p> + <p><i>Causes</i>.—This condition is almost invariably set up by an + injury—either a bruise or an actual wound—to the coronet. By far the most + common among such injuries are those inflicted by the animal himself by means of the + shoes.</p> + <p>That known as 'tread' is caused by the shoe on the opposite foot, and may happen + in a variety of ways. More often than not it is met with in the feet of heavy draught + animals, and is there caused by the calkin, either when being violently backed or + suddenly turned round. It may also occur in horses with itchy legs, as a result of + the animal rubbing the leg with the shoe of the opposite limb. The irritation in this + case is nearly always due to parasitic infection (<i>Symbiotes equi</i>), and becomes + sometimes so unbearable as to render the animal unmindful of the injury he may be + inflicting so long as he experiences the relief obtained by the rubbing.</p> + <p>Self-inflicted tread is also sometimes met with when horses are worked abreast at + plough. The animal in the furrow, with one foot sometimes in and sometimes out of the + hollow, is caused to make a false step, and so brings the injury about.</p> + <p>Animals worked in pairs are further liable to receive a tread from the foot of + their companion. This is commonly seen in heavy animals at agricultural labour in + fields, where the walking is uneven, and abrupt turning constant. It is not uncommon + either in animals at work in vans in town, and is occasionally met with in the feet + of carriage-horses.</p> + <p>'Overreach' is the term used to indicate the injury inflicted on the coronary + portion of the heel of the fore-foot by the shoe of the hind. Ordinarily, overreach + occurs when the animal is at a gallop, and is thus met with in its severest form in + hunters and steeplechasers. It can only occur when the fore-foot is raised from the + ground and the hind-foot of the same side reached right forward. When the feet + separate the injury takes place. In its movement backwards the inner border of the + shoe of the hind-foot catches the coronet of the fore, and tears it backwards with + it. Quite frequently a portion of the skin is removed entirely, but often it hangs as + a triangular flap. The flap in such a case is always attached by its hindermost edge, + and indicates plainly enough that the direction of the blow that cut it must have + been from before backwards.</p> + <p>Although ordinarily inflicted at the gallop, the same injury may, nevertheless, be + caused by allowing a fast trotter, and one with extreme freedom of action behind, to + push forward at the utmost limit of his pace. The outside heel is the one most + subject to the injury.</p> + <p>While the common form of injury to the coronet is, as we have described, that + occasioned by the animal's own shoe, or that of a companion, it is evident that the + foot is also open to similar injuries from quite outside sources. Falls of the shafts + when unyoking animals from a heavy cart, blows or wounds from the stable fork, wounds + resulting from the foot becoming fixed in a gate or a fence, either may equally well + set up the mischief.</p> + <p>Apart from severe injury, a particularly troublesome form of coronitis may arise + from the condition of the roads. We refer to the conditions attendant on a thaw after + snow. The animal is called upon to labour in, or perhaps stand for long periods in, a + mixture of snow and water, or snow and mud. That this must have a prejudicial effect + upon the structure of the coronet is plain. The circulation of the part, already + predisposed to sluggishness by reason of its distance from the heart, is farther + impeded by the action of the cold. Small abrasions of the skin, so small as to scarce + be noticeable, are in this case freely open to infection with the septic matter the + mud contains. Necrosis and consequent sloughing of the skin is bound to follow, and + an extensive ulcerous wound, or a spreading suppuration of the coronary cushion is + the result.</p> + <p><i>Symptoms</i>.—We will take first the case in which no actual wound is + observable. Here the first indication of the trouble is the appearance of an + inflammatory swelling, confined usually to one side, but extending sometimes to the + whole of the coronet. Always the part is hot and tender, and with it the patient is + lame—so much so, in many cases, as to be unable to put the foot to the ground, + the toe alone being used.</p> + <p>In a mild case, uncomplicated by septic infection, these symptoms rapidly subside, + and resolution occurs.</p> + <p>Always, however, the presence of septic infection must be suspected and looked + for. When this has occurred, the inflammatory swelling becomes larger and more + diffuse, and the animal fevered. This is then followed by a slough of the injured + part. A portion of the skin first becomes gray, or even black, in appearance, and + around it oozes an inflammatory exudate, or even pus. The skin immediately adjoining + the spot of necrosis is swollen and hyperæmic, and extremely painful and + sensitive. Later, the necrosed portion becomes cast off, and an open wound remains. + This as a rule marks the turning-point in the case. The pain and other symptoms + rapidly abate, and the wound, with proper attention, is not more than ordinarily + difficult to treat.</p> + <p>In the case of an actual wound the symptoms are probably less severe. The injury + is, in this instance, the sooner detected, and remedial measures put into operation. + In this manner the formation of septic material is often checked, and nothing but the + treatment of a simple wound demands attention.</p> + <p>There are, however, complications.</p> + <p><i>Complications—(a) Diffuse Purulent Inflammation of the Sub-coronary + Tissue</i>.—This condition is brought about by the spread into the loose tissue + of the coronary cushion of the septic material introduced by the tread. The whole + coronet in this instance becomes excessively swollen, hot, and painful, and the + dangerous nature of the complication is evident enough when the structure and + situation of the parts involved is considered. The amount of tendinous and + ligamentous material in the neighbourhood offers a strong predisposition to necrosis, + and the necrosis, with its attendant formation of pus, offers a further danger when + the close proximity of the pedal articulation and the unyielding character of the + horny box is considered with it.</p> + <p>The pus formed in this condition may remain confined to the coronet and break + through the skin as an ordinary abscess, or it may, before so doing, burrow beneath + the wall, and invade the sensitive laminæ. In this case, whenever portions of + the secreting layer of the keratogenous membrane are destroyed, or perhaps only + temporarily prevented from fulfilling their horn-producing functions, then + corresponding cavities in the horn are the result (see Fig. 109).</p> + <p><i>(b) Purulent Arthritis</i>.—Only too readily the pus so formed tends to + penetration of the articulation and the causation of an incurable arthritis (see + Chapter XII.).</p> + <br /> + <a name="a109" id="a109"></a> + <p><a href="images/image109.jpg"><img src="images/image109sm.jpg" + alt="MESIAL SECTION OF A HOOF ILLUSTRATING THE CONDITIONS FOLLOWING UPON CORONITIS." /> + </a></p> + <br /> + + <p>FIG. 109.—MESIAL SECTION OF A HOOF ILLUSTRATING THE CONDITIONS FOLLOWING + UPON CORONITIS. <i>a</i>, Cavity in the horn of the wall; <i>b</i>, enlargement of + the coronet and the horn of the wall following sub-coronary suppuration; <i>c</i>, + cavity in the wall following purulent inflammation of the sensitive laminæ; + <i>d</i>, hollow in the horn of the sole consequent upon suppuration of the sensitive + sole.</p> + <p><i>(c) Necrosis of the Extensor Pedis</i>.—This may arise either as a result + of spreading purulent infection of the coronary cushion, or as a result of direct + injury immediately over it. The close relation of the terminal portion of this tendon + with the pedal articulation, and the incomplete protection from outside injuries here + afforded to the joint by the horny box, sufficiently points out the gravity of the + condition.</p> + <p><i>(d) Penetration of the Articulation</i>.—This also may be a result either + of the inroads made by pus, or of an actual wound. When occurring from the latter, it + is seen more often than not in the hind-foot, being there caused by the calkin of the + opposite foot. Where a wound in this position is characterized by an excessive flow + of synovia, the condition should be suspected, and, if the wound be large enough, the + little finger should be introduced in order to ascertain. Needless to say, the injury + is a grave one.</p> + <p><i>(e) Sand-crack</i>.—Sand-crack is likely to result from tread when an + injury is inflicted in the region of the quarter by a severe overreach. Treads, too, + especially with the calkin of the hind-shoe, are especially apt to end in this way. + In this latter instance the sand-crack usually has its origin in a nasty jagged tear + at the top of the wall of the toe.</p> + <p><i>(f) Quittor</i>.—In one respect any suppurating wound at the coronet may + be deemed a quittor. By indicating quittor as a complication of coronitis, however, + we denote the more serious form of this disease, in which the wound has taken on a + sinuous character, and conducted pus to invasion of the lateral cartilage. It is one + of the worst complications we are likely to meet with in this condition, and will be + found fully described in Chapter X.</p> + <p><i>(g) False Quarter</i>.—This complication of coronitis occurs when the + injury or after-effect of the formation of pus has been severe enough to destroy + outright a comparatively large portion of the papillary layer of the coronary + cushion. To this condition we devote Section D of this chapter.</p> + <p><i>Prognosis</i>.—In giving a prognosis in a case of coronitis, attention + should be paid to the manner in which the condition originated, and the extent, when + present, of the wound.</p> + <p>When the inflammatory swelling has arisen from bruising alone, without actual + division of the skin, when the weather is that of winter, and the swelling showing a + marked tendency to spread, then the prognosis must be guarded. As we have seen, this + state of affairs is probably ushering in a condition of spreading suppuration of the + coronary cushion, and considerable gangrene and sloughing of the skin. We have here + no intimation as yet of how far the suppurative process may run, nor what important + structures it may involve. Consequently, the guarded prognosis we have mentioned is + imperative.</p> + <p>Where an actual wound is to be seen, and where advice is sought early, then a more + favourable opinion may be advanced. In this case antiseptic measures, commenced early + and persisted in, may prevent the rise of further mischief.</p> + <p>It goes without saying that, should there arise any other of the complications we + have mentioned (viz., Arthritis, Necrosis of the Extensor Pedis, Sand-crack, Quittor, + and False Quarter), the fact should be pointed out to the owner, and the prognosis + regulated thereby.</p> + <p><i>Treatment—Preventive</i>.—Seeing that at any rate the majority of + cases of coronitis result from injuries inflicted by the shoes, we may look at once + to that particular for a means of prevention.</p> + <p>Take first the case of 'treads'. There is no doubt that they are most common in + animals shod with heavy shoes and with high and sharp calkins. This suggests at once + that a preventive is to be found in substituting a calkin that is low and square.</p> + <p>Where the injury is an overreach, and where, on account of the animal's pace and + manner of gait it is in risk of being constantly inflicted, the shoeing should be + seen to at once.</p> + <p>We have already pointed out that it is the inner border of the lower surface of + the toe of the hind-shoe which, in the act of being drawn backwards, inflicts the + injury. (See Fig. 110).</p> + <p>In this case prevention may be brought about either by shoeing with a shoe whose + ground surface is wholly concave, or by bevelling off the sharp border (see Fig. 110, + <i>a</i>, p. 236). When the tendency to overreach is not excessive, prevention may in + many cases be effected by simply placing the shoe of the hind-foot a trifle further + backwards than would ordinarily be correct, thus allowing the horn of the toe to + project beyond the shoe. This at the same time does away with the annoyance of + 'forging' or 'clacking,' which, as a rule, accompanies this condition.</p> + <p>While recognising the value of shoeing in these cases, we must not forget that a + great deal may be brought about by careful horsemanship. The animal should be held + together and kept well up to the bit, but should <i>not</i> be allowed to push + forward at the top of his pace. With many animals of fast pace and free action + overreach is more an indiscretion of youth than any defect in action or conformation, + and his powers should therefore be husbanded by the driver until the animal has + settled down into a convenient and steady manner of going.</p> + <br /> + <a name="a110" id="a110"></a> + <p><a href="images/image110.png"><img src="images/image110sm.png" + alt="UNDER SURFACE OF THE TOE OF A HIND-SHOE." /></a></p> + <br /> + + <p>FIG. 110.—UNDER SURFACE OF THE TOE OF A HIND-SHOE. <i>a</i>, Marks the + portion of the inner margin that inflicts overreach.</p> + <br /> + <a name="a111" id="a111"></a> + <p><a href="images/image111.png"><img src="images/image111sm.png" + alt="THE INNER MARGIN OF THE INFERIOR SURFACE OF THE HIND-SHOE BEVELLED TO PREVENT OVERREACH." /> + </a></p> + <br /> + + <p>FIG. 111.—THE INNER MARGIN OF THE INFERIOR SURFACE OF THE HIND-SHOE BEVELLED + TO PREVENT OVERREACH.</p> + <p><i>Curative</i>.—Although in some cases it is so small as to go undetected, + we may take it that in all cases of coronitis there is a wound, with consequent + danger of septic infection of the surrounding parts. Therefore, after attention to + the shoeing and removal of the cause, the first indication in the treatment will be + to render the parts aseptic. This is best done by removing the hair from the coronet + and soaking the whole foot in a cold antiseptic solution. After removal from the + bath, the coronet may be dressed with a moderately strong solution of carbolic acid + or perchloride of mercury. When the injury is slight and recent, such is sufficient + to effect resolution.</p> + <p>When marked swelling persists, however, and the increase in heat and tenderness + denotes the formation of pus, recovery is not so easily obtained. In this case the + application of hot poultices or hot baths is called for. By these means suppuration + is promoted and induced to early break through in the most favourable + position—namely, the softened skin of the coronet. The pus so escaping is + always more or less blood-stained, and contains both large and small pieces of broken + down and decomposed tissue. After discharge of the pus, the cavity remaining should + be mopped out with an antiseptic solution, and a pledget of antiseptic tow or other + material left in position. All that is then needed is constant dressing in a suitable + manner. We prefer in this instance washing some three or four times a day with hot + water until a perfectly clean wound is obtained, and, after the washing, painting the + raw surface with a strong solution (1 in 200, or 1 in 100) of perchloride of + mercury.</p> + <p>When the abscess we have described as forming is extremely large, or where it is + more than ordinarily slow in 'pointing,' the likelihood of its having burrowed for + some distance below the upper margin of the wall must be suspected. Here it is + sometimes wise to thin the wall with the rasp immediately below the point of greatest + swelling of the coronet. This will serve to lessen pressure on the sensitive + structures beneath.</p> + <p>Immediately the abscess contents have found exit at the coronet, the cavity + formerly occupied by the pus should be explored. If to any extent it is found then to + have 'pocketed' beneath the upper border of the wall, a counter-opening should be + made where the horn of the wall has been thinned with the rasp.</p> + <p>When it so happens, either from extensive bruising or from the action of excessive + cold, that we have or suspect the condition of sloughing, then the first indication + is to aid the live tissues to throw off the necrosed portion. In spite of what is + sometimes urged to the contrary, a hot poultice is, perhaps, the best means of + bringing this about. Directly the necrosed piece is shed, a wound remains which, so + far as treatment is concerned, may be regarded exactly as that left by the formation + of pus. Hot water applications, some three or four times daily, will serve both to + cleanse the wound and also to maintain vitality in the tissues immediately + surrounding it. After each washing, the use of a strong antiseptic solution to the + wound is again beneficial.</p> + <p>In the case of an actual wound, whether, as in overreach, affecting the coronet + alone or involving destruction of part of the wall, or, as in the case of toe-tread, + penetrating the pedal articulation, the treatment to be followed is simple enough, in + theory, if not always easy to carry out. It consists solely in maintaining a rigid + asepsis of the parts until healing is well advanced or complete. The whole foot, + including the coronet, should first be thoroughly washed in warm water. At the same + time there should be used some agent that will tend to remove the natural grease of + the parts. In this manner cleansing will be rendered more thorough, and penetration + of the antiseptic solution to be afterwards applied made the more certain. The most + ready way of effecting this is to use the ordinary stable 'water'-brush, and plenty + of a freely-lathering soap.</p> + <p>This done, the foot should be rinsed in cold water, and afterwards constantly + soaked in a cold antiseptic bath. Where it is inconvenient or impossible to have the + constant bathing carried out, a dry antiseptic dressing may be tried in its stead. In + this case the foot should first be thoroughly washed and dressed as before. + Afterwards an antiseptic powder in the shape of a mixture of iodoform 1 part, boracic + acid 10 parts, should be freely dusted on the wound, a pledget of carbolized tow or + cotton-wool placed over it, and the whole maintained in position with a bandage + previously soaked in a 1 in 500 solution of perchloride of mercury. Once on, this + dressing should be allowed to remain until healing is complete. Should the animal + manifest pain, however, by constantly pawing, or should swelling and heat of the + parts be suspected, the bandage should be removed, and the condition of the wound + ascertained.</p> + <p>An excellent example of the value of this method of treatment is that given + below:</p> + <p>'I call to mind a valuable hunter in my practice a few seasons since, who, whilst + hunting, we suppose, struck himself in the way we suggest. He not only removed the + superior portion of the inner heel, but tore about 3 inches of the hoof from the top + nearly to the bottom. This was clapped back by the owner, tied with a handkerchief, + and the horse removed home. When the handkerchief was removed, I confess I did not + think the horse looked at all like hunting again. The heel was fairly pulled down, + the portion of the hoof that was hanging to it I could easily have wrenched off. The + parts were fomented, however, with warm water which was slightly carbolized. I then + removed a great portion of the heel and the lateral cartilage, which was split; + placed the portion of hoof again on the laminæ, smothered the wound with + iodoform pulv., covered it with cotton-wool packing, and all the boracic acid I could + get it to hold. A piece of linen bandage was then tightly wrapped a few times round, + and the lot enclosed in a plaster-of-Paris bandage. I did not undo it for a + fortnight, when, to my great pleasure, the heel and hoof presented a highly + satisfactory appearance. I did it up in much the same way for another ten days, then + put the sand-crack clamps into the hoof and fixed it to the sound part. The hoof + remained in position while the new horn grew from the top, and the horse hunted again + the same season.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. ix., p. 501 (Bower).]</p> + <p><i>Sequels</i>.—Either of the complications we have mentioned—as, for + instance, Arthritis, Sand-crack, or Quittor—may persist and remain as sequels + to the case. In addition to these, there may be left behind a cavity in the horn of + the wall (see Fig. 109), or a loss of the horn-substance of the wall proper, as that + depicted in Fig. 112, or described under the heading of False Quarter.</p> + <br /> + <a name="a112" id="a112"></a> + <p><a href="images/image112.jpg"><img src="images/image112sm.jpg" + alt="HOOF WITH A CAVITY IN THE SUBSTANCE OF THE WALL FOLLOWING UPON 'TREAD' TO THE CORONET." /> + </a></p> + <br /> + + <p>Fig. 112.—HOOF WITH A CAVITY IN THE SUBSTANCE OF THE WALL FOLLOWING UPON + 'TREAD' TO THE CORONET.</p> + <p>The treatment of Arthritis, Sand-crack, Quittor, False Quarter, and Seedy-toe, + will be found in the chapters devoted to their consideration.</p> + <p>2. <i>Chronic</i>.</p> + <p><i>Definition</i>.—Coronitis in which, owing to the persistence of the + cause, inflammatory phenomena continue, resulting in the growth of large fibrous + tumours about the coronet.</p> + <p><i>Causes</i>.—In many cases it is possible, of course, that abnormal large + growths in this position may have an origin similar to that of neoplasms + elsewhere—that is to say, an origin as yet undiscovered. There is no doubt, + however, that the majority of the huge enlargements about the coronet have their + starting-point in one or other of the diseases to which the foot is liable, in which + the cause remains, and a low type of inflammation persists.</p> + <p>In chronic and neglected suppurating corn, in untreated quittor, and in + long-standing complicated sand-crack, for instance, we have conditions in which pus + and other septic matters find ready entrance into the sub-coronary tissues. Should + either of these be neglected, or should the pus formation from the onset take on a + slow but gradually spreading form (in other words, should either of these cases run a + chronic rather than an acute course) then, with the persistence of the inflammatory + phenomena so caused, is bound to result a steady and increasing growth of + inflammatory fibrous connective tissue. This, as it grows, becomes in its turn + penetrated by the ever-invading pus, and, under the stimulus thus caused, itself + throws out new tissue. And so, constantly excited, the tumour-like mass tends to + steady increase in size, until enlargements are formed which one may sometimes truly + term enormous.</p> + <p><i>Symptoms</i>.—The appearance of the growth is, of course, immediately + evident. Usually these swellings are slow in forming, so that the size of the + enlargement depends entirely upon its age. We may thus meet with growths of this + description, varying in weight from 4 or 5 pounds to the almost incredible size of + 33-1/2 pounds. In the majority of cases a discharging sore is to be found upon + it—in some cases several. Explored, these sores reveal their true nature. Their + lip-like openings, and the ready manner in which they may be searched by the probe, + show them to be sinuses.</p> + <p>In a few cases, however, the outer surface of these tumours is intact. When this + is the case, it is possible that the growth is a true fibroma—that is to say, a + non-inflammatory new growth of fibrous connective tissue. On the other hand, it may + have resulted from one or other of the causes we have enumerated, and its exact + diagnosis have been impossible until operative measures had been proceeded with. In + this case, small and encysted foci of inspissated pus scattered more or less + throughout the growth indicate its true nature.</p> + <p>Pain as a rule is absent, and, unless the growth, on account of its size, + interferes with progress, the animal walks perfectly sound. Here the patient may, + without offending the dictates of humanity, be put to slow work.</p> + <p><i>Treatment</i>.—In very many cases, possibly on account of the decreased + circulation and vitality of the parts, these growths occur in aged animals. Here + treatment is not economic, and may for that reason be put out of the question. + Further, the growths are more common in heavy cart animals of a lymphatic type than + in those of a lighter breed. Couple this with the fact that the tumour is often + unattended with pain, and we see that the animal is still able to perform his + accustomed labour. Here, again, treatment is contra-indicated.</p> + <p>For still another reason surgical treatment, which is the only treatment likely to + be of benefit, must not be undertaken rashly. A large and open wound is bound to be + left behind. So large is it in many cases that the complete covering of the exposed + surface with epidermal growths from the circumference cannot possibly be looked for. + There is then left a large and horny-looking scar, which is an even worse eyesore + than was the original enlargement.</p> + <p>When the patient is a young and otherwise valuable animal, however, and when the + case, judged either by the size of the swelling or its outside appearance, promises a + fair measure of success, operative measures may be determined on.</p> + <p>In this case the author's practice has been, after casting the animal, to apply a + tourniquet to the limb and proceed to excision. A lozenge-shaped incision, extending + to near but not quite the circumference of the swelling, should be made with a large + knife right through the skin and deeply into the growth. The whole is then removed, + proceeding in an excavating manner under the thickened skin at the margin. + Hæmorrhage, though proceeding from several apparently large vessels in the + structure of the tumour, and oozing generally over the whole of the outer surface, is + rarely profuse enough to interfere with the operation, and is easily controlled by + cold water douches and the application of the artery forceps to one or more of the + larger vessels. The operation completed, the larger bleeding-points should be secured + by exerting torsion with the artery forceps, and the surface oozing stayed by + frequent dashing with cold water.</p> + <p>When the hæmorrhage has sufficiently ceased, an ordinary flat firing-iron + should be passed over the whole of the cut surface, and an effectual eschar + formed.</p> + <p>Following this, and <i>before removing the tourniquet</i>, the wound should be + filled with pledgets of carbolized tow, and the whole tightly secured by a stout and + broad linen bandage of not less than 6 yards in length.</p> + <p><i>Reported Case</i>.—'The patient, a middle-aged cart mare, had a pair of + fore-feet the like of which I never saw. As the result of long-standing and + imperfectly-treated quittor all over the seat of side-bone on the outer side of each + fore-foot, beginning pretty far forward, and extending to the heel on the inner side, + filling up the hollow and reaching nearly to the fetlock, was a big, bulging, hard, + calloused enlargement or tumour standing out 3 or 4 inches all round, covered with + thick horny skin and stubby hair, and having on its surface the small openings of + several sinuses leading deeply down to the ossified and diseased cartilage + underneath. And yet with all this diseased undergrowth the mare, strangely enough, + walked and trotted sound. I was told that this mare had been troubled with + suppurating corns and quittor, that many unsuccessful attempts had been made at cure, + but that, getting worse instead of better, these tumours had formed.</p> + <p>'After casting and anæsthetizing, a strong rubber tourniquet was placed + above the knee and the operation commenced. With a surgeon's amputating knife all the + big fibrous mass which I could safely remove was cut and sliced off, and the coronet + and pastern reduced as nearly as possible to its natural dimensions. The diseased + cartilage, or side-bone, gave some trouble, a considerable portion having to be cut + and scraped, and the sinus in it gouged out; but its complete removal did not appear + to be called for.</p> + <p>'There was little if any hæmorrhage until release of the tourniquet, when + the whole broad surface became deluged with blood, three or four small arteries + spurting and veins flowing in all directions, so much so that I was glad to refix the + clasp, and with the firing-iron seal up the vessels, searing gently all over the + surface.</p> + <br /> + <a name="a113" id="a113"></a> + <p><a href="images/image113.jpg"><img src="images/image113sm.jpg" + alt="CHRONIC CORONITIS FOLLOWING 'TREAD.'" /></a></p> + <br /> + + <p>FIG. 113.—CHRONIC CORONITIS FOLLOWING 'TREAD.'</p> + <p>'A good dusting with antiseptic powder, a thick pad of carbolized wool, and two + long calico bandages wound tightly round, completed the work.</p> + <p>'The other, the near-leg, was then dealt with in the same way.</p> + <p>'The mass removed weighed a little over 9-1/2 pounds—5 pounds from the + off-foot and 4-1/2 pounds from the near. Its structure was fibrous tissue, almost as + firm and hard as cartilage, and with no appearance of malignancy.</p> + <p>'The after-treatment consisted simply of fresh dry dressings—copper, + sulphate, zinc sulphate, and calamine, equal parts—applied every third or + fourth day, after first bathing the feet in a shallow tub of warm antiseptic + water.</p> + <p>'At the end of eight or ten weeks a fairly presentable appearance existed. The + greater part of what had been raw surface was covered with healthy skin, and the + remainder had become dry and horny.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xiv., p. 201 (C. Cunningham, + M.R.C.V.S.).]</p> + <p>A further form of chronic coronitis is that shown in Fig. 113.</p> + <p>This condition is commonly the result of a severe and jagged tread with the + calkin, and takes the form of an ulcerous and excessively granulating wound. As time + goes on the granulations become hard and horny-looking, and their fibrous tissue as + hard and unyielding as tendon or cartilage.</p> + <p>These if treated in the early stages with repeated dressings of caustic, or, if + very exuberant, the use of the knife, usually yield to treatment. If neglected until + the condition depicted in the figure is arrived at, then treatment, as a rule, is of + no avail. Neither is treatment of any use if any great loss of the coronary cushion + has occurred.</p> + <h3>D. FALSE QUARTER.</h3> + <p><i>Definition</i>.—False quarter is the term applied to that condition of + the horn of the quarter in which, owing to disease or injury of the coronet, the wall + is grown in a manner that is incomplete.</p> + <p><i>Symptoms</i>.—This condition of the foot appears as a gap or shallow + indentation, narrow or wide, in the thickness of the wall, with its length in the + direction of the horn fibres. By this we do not mean that the sensitive laminæ + are bared and exposed. Horn of a sort there is, and with this the sensitive + structures are covered. Running down the centre of the incomplete horn is usually a + narrow fissure marking the line of separation in the papillary layer of the coronary + cushion, which, as we shall later see, is responsible for the malformation.</p> + <p>On either side of the indentation, as if wishing to aid further than ordinarily it + should in bearing the body-weight, the horn takes on an increased growth, and stands + above the level of the horn surrounding it. It may, as perhaps it really is, be + regarded as a form of hypertrophy, brought about by the increased work that the loss + of substance in the region of the false quarter puts upon it.</p> + <p>So long as the sensitive structures are protected the animal remains sound. + Sometimes, however, from the effects of concussion or of the body-weight, a fissure + appears in the narrow veneer of horn that covers them. Into this, which, of course, + is but a form of sand-crack, gravel and dirt penetrate, and so set up inflammatory + changes in the keratogenous membrane. As a result suppuration ensues, and the animal + is lame.</p> + <p><i>Causes</i>.—False quarter may result from any disease of the foot that + involves destruction of a portion of the coronary cushion. As we may see from a + reference to Chapter III., it is from the papillæ of this body that the horn + tubules of the wall are secreted. Destruction of any portion of it necessarily + results in a corresponding loss of horn in that position. The disease occasioning + this more often than any other is perhaps quittor. It may also result from + suppurating corn, from a severe tread or overreach, or from the effects of a slowly + progressing suppurating coronitis.</p> + <p><i>Treatment</i>.—A radical treatment of false quarter is not to be found. + Once destruction of the secreting layer of the coronary cushion has occurred, the + appearance of the fissure in the wall will always have to be reckoned with. A false + quarter, therefore, not only renders the horse liable to occasional lameness, but + also renders weaker that side of the hoof in which it occurs.</p> + <p>The only method of treatment that can be practised, therefore, is that of + palliation. Seeing that the trouble the veterinary attendant will have to deal with + is loss of a portion of the weight-bearing surface, his attention is immediately + directed to the shoeing. As with sand-crack, so with false quarter, the frog and the + bars must be called upon to take more of the body-weight than commonly they do with + the ordinary shoe. The indication, then, is a bar shoe. At the same time, the bearing + of the wall on the shoe on either side of the fissure should be eased by slightly + paring it, and the hypertrophied horn on the outer surface of the wall removed with + the rasp.</p> + <p>In cases where penetration of the sensitive structures has occurred, complicated + with the formation of pus, the same treatment as for complicated crack is to be + followed. The foot should be poulticed for several days with hot antiseptic + dressings, and thorough cleansing of the infected parted brought about. Afterwards + strong solutions of suitable antiseptics should be applied daily until such time as + the horny covering has renewed itself. This done and the bar shoe applied, the + fissure may be plugged with any effectual stopping. Either a mixture, such as + Percival's, of pitch 2 parts, tar 1 part, and resin 1 part, melted and mixed + together, or one of the artificial hoof-horns may either be used with advantage.</p> + <h3>E. ACCIDENTAL TEARING OFF OF THE ENTIRE HOOF.</h3> + <p><i>Causes</i>.—Seeing that this accident to, and consequent severe wounding + of, the keratogenous membrane nearly always occurs in but one way, it is worthy of + special mention. So far as we are able to ascertain, it is an accident peculiar to + horses continually engaged in shunting operations either in pits or station-yards. At + the moment the animal is released from the waggon he has been pulling, and should + turn to the right or the left in order to allow it to pass him, the shoe either + becomes wedged in between two converging rails, or is trapped by the wheel of the + waggon. Either the approaching waggon with the added weight its impetus gives it then + pushes the animal suddenly away, leaving a part of his foot still fixed to the rails, + or the animal himself, feeling securely held, makes a sudden effort to release + himself, and draws his foot cleanly out of the imprisoned horny box.</p> + <p>The author calls to mind a case in which entire removal of the horn of the foot of + an ox occurred through the passing over it of the wheel of a heavily-laden cart. It + is therefore quite conceivable that the same accident might occur to the horse. As a + matter of fact, we find one case on record where one-half of the horny box was thus + removed.[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xiii., p. 129.]</p> + <p>So far as we are able to gather, it is more a result of imprisonment of the shoe + than of the foot. It appears, further, to be always a result of the animal being + newly shod, and the clinches firmly secured; so much so that it would be probable, + with imperfectly secured clinches, that the animal would draw the hoof from the + clinches and the shoe rather than the foot from its horny covering.</p> + <p>Therefore, as the author of one of the cases we shall afterwards relate suggests, + it should be proposed as a preventive that the shoe-nails of animals regularly + engaged in work on the metals should not be clinched in the regulation manner, but + should have their points merely screwed off, and the nails afterwards rasped level + with the wall.</p> + <p>These cases are particularly interesting as illustrating the rapid manner in which + a new hoof is afterwards formed, and the way in which the exposed sensitive + laminæ take their share in adding to, though not forming the bulk of, the horn + of the wall.</p> + <p>From the cases we are able to record it will be seen that this accident need not + be looked upon as fatal, nor the injury itself beyond hope of repair. Dependent + largely upon the temperament of the animal, the amount of pain that is caused, and + the way in which the animal bears it, recovery may be looked for. Even from the very + commencement of the accident, however, the pain may be so acute and the animal so + violent with it that slaughter becomes necessary.</p> + <p><i>Treatment</i>.—This consists in applying an antiseptic and sedative + dressing to the injured parts (for example, Carbolized Oil and Tincture of Opium, + equal parts) and afterwards bandaging.</p> + <p>From the only data we are able to work on, it appears that this dressing should be + repeated daily, the bandage being removed, each time, the foot well bathed in warm + water, and the dressing and bandage afterwards replaced. On first sight, it would + appear that once cleansed and bandaged the dressings might be left <i>in situ</i> for + several days. Seeing, however, that suppuration, if once set up, would add further to + the intense pain the animal is already suffering, and considering the always constant + exposure of the foot to infection, it is perhaps wise to persist in daily changing of + the dressings.</p> + <p>At the same time, the general health of the animal should be attended to. Suitable + febrifuges should be administered, either in the shape of a dose of physic, or + salines and liq. ammonia. acetatis; and the pain, if appearing unbearable, allayed by + doses of choral and hypodermic injections of morphia.</p> + <p><i>Recorded Cases</i>.—1. 'A short time ago I was called to see a horse + which had had his hoof torn off in a railway "point." When I arrived at the stable + the injury had been done two hours, and the horse had been led from the railway to a + loose-box nearly half-a-mile off. On going to this box I was surprised and horrified + to find the poor animal mad with pain, rolling and dashing himself about. When on his + back he would struggle and kick the walls with the injured foot, as though + unconscious of pain. Not one moment was he still, and as I could see that the + sensitive structures were much damaged by his violence, I obtained a gun and put him + out of his pain.</p> + <p>'The accident happened in this way. The horse was employed in shunting + coal-waggons, and had just drawn four loaded trucks up to a point at which they + diverged to the left, and the horse, being unhooked, ought to have turned to the + right. Here, unfortunately, the near fore-foot became wedged in between two + converging railway plates, one of which formed a part of the waggon-way, on which the + trucks were running. The horse was a big animal, and freshly shod with heavy shoes, + on which a toe-piece and calkins were used. The shoe was roughly but strongly nailed + on with eight nails, the clinches of which were all firm. This shoe was fitted wide + at the heels, and when the foot was fixed in the points (toe downwards) it protruded + over the face of the rail. When the trucks reached it they pressed it down, and, the + horse leaning forward, the hoof was drawn off like a glove. The hoof was almost as + clean inside as if taken off by maceration—only towards the toe was a small + portion of the coffin-bone and some torn laminæ left inside the hoof.</p> + <p>'As soon as possible after the accident, so I was told, the foot was bound up with + tow and a bandage; then a sack was cut up and placed over all, and the horse slowly + led to his loose-box. He "carried" the leg all the way, limping along on the three + sound ones. Almost immediately after reaching the box he lay down, but only for a + short time. The standing position was not long maintained—profuse perspiration + set in, and the alternations of position became more rapid and violent, till plunging + and rolling were added to the other signs of excruciating pain. I was also told that + the groaning of the poor animal was almost constant, and at times so loud and + prolonged as to amount to a shriek.</p> + <p>'I have no experience of a similar case, and I should not have supposed that this + accident would have caused such acute suffering and violent symptoms. I think I have + heard of such cases making a complete recovery; but I feel sure that, in this case, I + only anticipated death by, at most, a few hours.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. iv., p. 127.]</p> + <p>2. 'The case I am about to give you an account of, being one of rare occurrence, I + thought would not prove uninteresting to the members of the Veterinary Medical + Association. It is an instance of complete removal of the hoof by mechanical + force.</p> + <p>'Our patient was a brown mare, five years old, the property of Messrs. Crawshaw + and Co., railway contractors on the Sheffield and Manchester line.</p> + <p>'On June 20 the mare was, as usual, working on the line, drawing one of the + waggons for the removal of soil from one place to another, and, as was the custom, + the pace is generally increased at about the distance of from sixty to eighty yards + from where the unloading takes place, in order to add to the velocity, so that the + contents of the waggons might roll down so great a precipice. It was at this + increased action, when the mare was being removed from the waggon, that she stepped + between the ends of two iron rails, sufficiently apart to admit the foot only, when + one end of the rail inserted itself between the sole and toe of the shoe, the other + at the top and in front of the crust.</p> + <p>'The mare, finding herself fixed, endeavoured to disengage herself, and, in doing + so, got in front of the waggon, which, coming at a great pace, forced her down into + the pit, leaving behind the off fore-hoof, which was only removed from its situation + between the two rails by a large hammer, it being so firmly wedged in. The shoe and + hoof were bent in a very peculiar manner, as the accompanying cuts will show, the + inside heel being completely raised from above the level of the frog, not one of the + nails being unclenched, or in the slightest degree having given way to so large an + amount of force imposed upon them, although the toe of the shoe was raised from the + sole by the rail being immediately under it (see Fig. 114). The mare had been shod + the day before, and, having a good sound foot, the shoe was firmly put on.</p> + <p>'Being a mile from home, she was with some difficulty made to travel that + distance. On her arrival, my preceptor, Mr. Taylor, was immediately sent for, who + found her, as I have before stated, with the off fore-foot hoofless.</p> + <p>'Proceeding to examine the foot, he ascertained that it had bled considerably, + which, however, was stopped by bandages to the foot and a ligature round the coronet. + The laminæ on one side and a small portion of the sensitive sole, though not to + any great extent, were lacerated. The coffin-bone was not at all injured. The + bleeding having nearly ceased, she was put into slings, the foot carefully washed + with warm water, and immediately bound up with pledgets of tow saturated with the + simple tincture of myrrh and tincture of opium, of each equal parts.</p> + <br /> + <a name="a114" id="a114"></a> + <p><a href="images/image114.png"><img src="images/image114sm.png" + alt="HOOF TORN FROM THE FOOT BY ACCIDENT." /></a></p> + <br /> + + <p>FIG. 114.—HOOF TORN FROM THE FOOT BY ACCIDENT.</p> + <p>'The dressing was ordered to be allowed to remain on all night, and on the + following morning to be removed. The foot was then bathed, as before, in warm water, + and the application of the tinctures repeated night and morning. The medicine + internally given was castor oil, with tinct. opium, and this, in a diminished dose, + was ordered the next morning. Blood was also abstracted from the jugular vein, to the + amount of 6 quarts, so as to allay the inflammatory fever set up. The food consisted + of bran and linseed, with small portions of hay and water. The mare being in a highly + excited state, and suffering such severe pain, the opinion Mr. Taylor gave was that, + should she get over the first four days (which appeared quite uncertain), he had no + doubt of her ultimately getting well, and also that she would have a perfect hoof + formed. It was now left for the owners' consideration, whether they thought the mare + worth her keep till such took place, the time mentioned by Mr. Taylor being four or + five months. She was seen again the fourth day after the accident, and was then found + to be perfectly tranquil and feeding well; her pulse, which at the first visit could + not be counted, was now not more than 65 beats in the minute. On removing the + dressings, the foot presented a very favourable appearance, the treatment therefore + varied only in the application of a linseed-meal poultice over the former dressings + of tinctures of opium and myrrh, confining the whole in a soft leather boot. Diet as + before, in addition to which give a few oats. Should the bowels become constipated, + repeat the castor oil without the opium.</p> + <p>'<i>June</i> 28.—The animal was again seen, and appeared to be going on very + favourably. The poultices were directed to be discontinued, and the parts dressed + every other day with sol. sulph. cupri, as the granulations were getting rather + luxuriant.</p> + <p>'<i>July</i> 6.—To-day she was found to have gone on so well, having two + days before been removed from the slings, that it was thought justifiable to turn her + out, protecting the foot with a boot, and ordering the dressings to be repeated.</p> + <p>'<i>July</i> 23.—She was seen by me in the field, where I had the boot + removed, and so much had she improved, that not less than 2 inches of crust, + proceeding from the coronary ring, had been formed, and the foot looked remarkably + healthy.</p> + <p>'It will be seen that the accident occurred on June 20, a fortnight after which + time I observed the horny crust to be forming from the coronet, and the insensitive + laminæ at the same time, in which on every visit an increase of growth was + perceptible, and it soon attained a thickness exceeding that of the other hoof, but + which at the same time presented a more upright appearance. It was not until three + weeks after our first visit that any formation of new sole or frog was to be seen. Of + the two the sole was the first, being secreted by the sensitive sole, the growth + proceeding from the heels. In like manner the insensitive frog was being produced by + the sensitive.</p> + <br /> + <a name="a115" id="a115"></a> + <p><a href="images/image115.jpg"><img src="images/image115sm.jpg" + alt="HOOF TORN FROM THE FOOT BY ACCIDENT." /></a></p> + <br /> + + <p>FIG. 115.—HOOF TORN FROM THE FOOT BY ACCIDENT.</p> + <p>'During the last week in October the mare, having her foot protected with a bar + shoe plated at the bottom, and so formed as to open without necessity of removing the + shoe, in order to facilitate the applications of the tinctures, was put to light + work, which has since been gradually increased, and she now performs her usual labour + equal to any other horse.</p> + <p>'The growth of the wall or crust and insensitive laminæ is not yet quite + complete, nor is the sole, there being wanting about an inch of the horny substance + of it, the entire completion of which I should rather doubt, as I mentioned in my + former communication that the sensitive laminæ and a small portion of the sole + were lacerated, and it is in these parts that the imperfections exist.</p> + <p>'The yet imperfectly-formed wall not admitting of the insertion of nails all + around it, the shoe is held on partly by nails and partly by a strap attached to it + bound round the coronet.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. iv., p. 182 (B. Cartledge).]</p> + <p>3. 'This case is related by Mr. A. Rogerson, F.R.C.V.S. It occurred to an animal + regularly engaged in shunting, and happened through the corner of the shoe becoming + "trapped" between a line of metal and the wheel of a truck. It is particularly + interesting on account of the photograph accompanying it, and which we here reproduce + in Fig. 115.</p> + <p>'The photograph shows plainly the manner in which the holding of the "clinches" on + the left side of the hoof has resulted in drawing it off from the foot. Had these + clinches, as Mr. Rogerson suggests, been left unfastened, then the accident in all + probability would not have occurred. The animal was destroyed.'[A]</p> + <p>[Footnote A: <i>Ibid</i>., vol. xiii., p. 2.]</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER IX</h3> + <h3><a name="inflam" id="inflam">INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS + APPARATUS</a></h3> + <h3>A. ACUTE. ACUTE LAMINITIS.</h3> + <p><i>Definition</i>.—The term 'laminitis' is used to indicate a spontaneous + and diffuse inflammation of the whole of the sensitive structures of the foot, more + particularly the sensitive laminæ. Usually it occurs in the two front feet, + often in all four, and occasionally in the hind alone.</p> + <p><i>Causes</i>.—In dealing with the causes of laminitis, we will first + dispose of those coming under the heading of <i>traumatic</i>. Correctly speaking, + however, lesions of the laminæ thus occurring do not present the same symptoms, + nor run an identical course with the disease we now purpose describing, and for which + we would prefer to entirely reserve the term 'laminitis.' The fact, however, that + traumatic causes are detailed in other works on the same subject compels us to give + them mention here.</p> + <p>Strictly traumatic causes giving rise to a limited inflammation of the sensitive + laminæ are violent blows upon the foot, either purely accidental, or + self-inflicted by violent kicking.</p> + <p>A similar limited laminitis is to be found in the conditions we have described + under 'Nail-bound and Punctured Foot.' It is met with also in the injuries resulting + from tread and overreach, and in the tissue-changes accompanying corn.</p> + <p>The tenderness following upon excessive hammering in the forge, or of too long an + application of the shoe in hot-fitting has also been described as laminitis.</p> + <p>With either of the conditions we have mentioned, it goes without saying that there + is either a simple congestion or an actual inflammation, localized or general, of the + laminæ of the injured foot. In neither case, however, can the resulting + mischief be closely compared with the lesions attending an attack of laminitis + proper, a disease which appears to have an almost specific cause, and to run a course + peculiarly its own.</p> + <p>The specific cause we have indicated as existing can, in the present state of our + knowledge, be only vaguely described as a poisoned state of the blood-stream. This, + as clinical evidence teaches us, may result from a variety of causes.</p> + <p>Among these, by far the most common is that state of the circulation induced by + excessive feeding with too stimulating or too irritating a diet. In any case, where + the use of old oats as a staple diet is departed from, and where the quantity and + manner of using the substitute is left to the discretion of careless or unskilled + attendants, trouble is likely to ensue. The food more prone, perhaps, than any other + to bring about an attack is wheat improperly prepared—that is, uncooked or + unground. So much so is this the case that one full meal of this provender to an + animal unused to it is sufficient to lead to a train of symptoms often ending + fatally.</p> + <p>Beans, peas, barley, rye, new maize, or even new oats, are all liable, if + carelessly used, to have the same effect.</p> + <p>It is the laminitis following feeding on new oats that has caused us to apply to + the food the adjective 'irritating.' Here, more often than not, the peristaltic + action of the bowels is found to be abnormally in evidence, and the excessive use of + the diet is always accompanied by a more or less fluid discharge of the intestinal + contents.</p> + <p>In addition to the foods we have mentioned, many others might be enumerated, more + especially the numerous 'made-up' feeding materials now on the market. Many are + composed of substances that may be regarded as absolutely opposed to the correct + feeding of a horse, and their use can only be followed by this and other evil + results.</p> + <p>Another most fruitful cause of laminitis is a severe and continued inflammatory + condition of the system elsewhere. It is the laminitis known to veterinary surgeons + as 'metastatic,' and perhaps the two most notable examples of it are the laminitis + following a prolonged attack of pneumonia, and the 'Parturient Laminitis' occurring + as a concomitant of septic metritis.</p> + <p>Parturient laminitis it is that offers us the most striking illustration of the + truth that a poisoned state of the blood-stream is a sure factor in the causation of + an attack. From the direct evidence of our senses (namely, manual exploration of the + infected womb, and the stench of the exuding discharge) we know that we have in the + interior of the womb matter in a state of putrescence. From the experience of + previous post-mortems we know, further, that the putrescent matter thus originating + often gains the blood-stream, and forms foci of septic lesions elsewhere—liver + or lung. When, therefore, during an attack of septic metritis a condition of + laminitis supervenes, we are justified in attributing it to the escape of septic + matter from the already infected uterus.</p> + <p>In the same category of laminitis from metastasis may also be placed the laminitis + occurring as a result of an overdose of aloes. The enteritis thus set up is often + followed by laminitis, and that of a serious type.</p> + <p>Prolonged and excessive work upon a hard road is also apt to induce an attack. + When this occurs it in many cases resolves itself into a case of cruelty. (See + reported case, No. 1, p. 279.)</p> + <p>Laminitis from this cause was frequent among coach and carriage horses in the + pre-railroad period, and resulted from attempting to obtain from the animal a faster + pace and a greater number of miles than he was physically capable of giving.</p> + <p>In our day, however, it is more often a result of gross feeding, combined with + only that amount of work which the horse, if ordinarily fed, would be easily able to + perform. An excellent example of this is the laminitis occurring in the Shire + stallion when commencing his rounds of service in the spring and early summer. At + this season these animals are constantly supplied with a more than sufficient supply + of a highly stimulating and nutritious diet. In this case the blood is already in + that state in which it is predisposed to the disease. Add to this the unwonted + exercise—for during all the winter the animals are idle—and congestion of + the venous apparatus of the extremities is not to be wondered at.</p> + <p>Passing from these, the more common, we may consider other and less frequent + causes of the disease. Congestion of the laminal blood-vessels and consequent + laminitis occurs when animals are made to maintain a standing position for prolonged + periods, as, for instance, when making sea voyages. A long and painful disease of one + foot, necessitating the whole of the weight being borne by the other, ends often in + laminitis of the second member. It may thus occur as a sequel to quittor, complicated + sand-crack, suppurating corn, and punctured wounds of the feet.</p> + <p>Laminitis has also been known to occur as a result of septic infection of the + blood-stream consequent on the operation of castration. (See recorded case, No. 2, p. + 281.)</p> + <p>A sudden lowering of the surface circulation at a time when the animal is + excessively perspiring is also said to favour an attack, as also is the giving to + drink of cold water to an animal just in from a long and tiring journey. Also, + according to Zundel, 'the influence of the season cannot be denied, and it is during + the summer months that laminitis is more frequent, while it is rare in winter, as + well as in the spring and autumn.'</p> + <p>Further, laminitis has been described as occurring when the animal is at grass, + and when all causes—at any rate, active ones—have appeared to be absent. + (See reported case, No. 3, p. 282.)</p> + <p>Regarding heredity, we may safely say that, as a cause of laminitis, it may be + almost totally disregarded. That a bad form of foot, either a flat-foot or a foot + with heels contracted, and already thus affected with a mild type of inflammation, + did not offer a certain predisposition, we should not like to assert. There must, + however, be an exciting cause—namely, a poisoned condition of the blood-stream. + This latter cannot, of course, be in any way regarded as hereditary.</p> + <p>In short, the dietetic cause is by far the most common, and, in prosecuting + inquiries as to the starting-point of an attack, the veterinarian's attention should + be directed in the main to that particular.</p> + <p><i>Symptoms</i>.—Laminitis is always ushered in by a set of symptoms + indicative of a high state of fever. The pulse is raised from the normal to as many + as 80 or 90 a minute, muscular tremors are in evidence, the respirations are short + and hurried, and the temperature rises to 105°, 106°, or 107° F. The + visible mucous membranes are injected, that of the eye, in addition to the + hyperæmia, often tinged a dirty yellow. The mouth is dry and hot, the urine + scanty, and the bowels frequently torpid. As yet, however, the walk is sound.</p> + <p>Called in during this early stage, the veterinarian is often puzzled as to the + exact significance of the symptoms. Enteritis, lymphangitis, or pneumonia he knows to + be often heralded in the same manner. In this connection, Zundel says: 'Laminitis, in + most instances, is preceded by certain general symptoms, such as are premonitory of + the invasions of ordinary inflammatory diseases, but of an uncertain + significance.'</p> + <p>So far we agree with him, but to what we have already said we would add that, even + in this early stage, there is an additional symptom, unmentioned by Zundel, which + often leads one to an exact diagnosis. The feet are in turn lifted a short distance + from the ground, and almost immediately replaced. This movement ('paddling,' we may + term it) is constant, the animal appearing to obtain ease in no one position for more + than a few moments at a time.</p> + <p>Seen but a few hours later, when the swelling caused by the hyperæmia and + outpouring of the inflammatory exudate has led to compression of the sensitive + structures within the horny box, the symptoms presented admit of no misreading, save + by the most casual and careless observer. The patient now stands as though fixed to + the ground. The pulse is hard and frequent, the respirations tremendously increased + in number, the body wet with a patchy perspiration, and the countenance indicative of + the most acute suffering. Only with difficulty, and often only at the instigation of + the whip, can the animal be induced to move. This he does by throwing his weight, so + far as he is able, on to the heels of the feet affected, and putting the feet slowly + forward in a shuffling and feeling manner. The feet themselves give to the hand a + sensation of abnormal heat, percussion upon them with the hammer is followed by + painful attempts at withdrawal, while any effort we may make to remove one foot from + the ground is useless, so great an aversion does the animal show to placing a greater + weight upon the opposite foot.</p> + <p>According as the front-feet alone, the hind-feet alone, or all four feet are + affected, the symptoms will vary.</p> + <p>With all four feet diseased, the animal stands with the two front-feet extended in + front of him, while the hind-limbs are at the same time propped as far beneath him as + is possible. The horse is, in fact, standing upon the extreme hindermost portions of + the feet.</p> + <p>Why the animal should thus distribute his weight is easily explained. Standing in + the normal position, the body-weight is borne by the sensitive laminæ, the + sole, of course, sharing in the burden, but the laminæ taking by far the + greater part of the pressure thus exerted. With the vessels of the laminæ + gorged with blood, and the laminal connective tissue infiltrated with a profuse + inflammatory exudate, the most excruciating pain is bound to result by reason of the + compression of the diseased tissues within the non-yielding structures. In some + little measure the suffering animal may afford himself relief by partly removing + pressure from the fore-parts of the hoof. When placing the body-weight behind, the + pressure, instead of falling upon the highly sensitive laminæ, is directed to + the follicular and fatty tissues of the plantar cushion: from there, with only a + small portion of the sensitive sole intervening, to the horny frog, and from thence + to the ground.</p> + <p>The same distribution of weight also places the foot in a position of greatest + expansion, thus, by giving greater room to the diseased parts, again affording relief + of pressure on the inflamed lamina, while it at the same time relieves of weight the + foremost portions of the sensitive sole.</p> + <p>With the fore-feet alone attacked, the animal affects exactly the same position of + standing as that just described. The fore-feet are again extended, and the hind + propped far beneath him. The fore extended, in order to obtain the relief occasioned + by standing on the heels; the hind in this case carried forward in order to take a + greater share of the body-weight, and thus relieve the congested members in + front.</p> + <p>With the hind only attacked, then the fore and the hind feet are more closely + approximated than in the normal position. The reason, of course, is that the + hind-feet are carried forward in order to be placed upon the heels, while the fore + are taken backwards to relieve the hind of the body-weight.</p> + <p>In like manner the movements of the animal will vary with the feet affected. With + only the front-feet diseased the animal is, comparatively speaking, comfortable. The + hind-feet take the weight, and the animal stands for long periods together, resting + alternately first one fore-foot and then the other, moving often in a circle of which + his body is the radius, and his hind-limbs the centre. If urged to move forward, then + immediately his countenance and movements manifest the pain to which he is put. Only + with reluctance does he cause the fore-feet to take weight. They are shuffled forward + quickly one after the other, so that weight may not be placed upon them for one + instant longer than is necessary, and the hind-limbs immediately brought again with + two short, awkward movements beneath the body. Progress thus takes place in a + succession of movements 'half hobble,' 'half jump.'</p> + <p>Painful though this may appear, progress is still more difficult when the + hind-feet alone are diseased. Afraid that, in placing his fore-members freely + forward, he will add to the pain in his hind, the walk takes place in a series of + extremely short steps, with the feet more or less closely approximated. The gait is + thus rendered extremely awkward, and Zundel, by saying that 'the animal appears as if + treading on sharp needles,' most fitly describes it.</p> + <p>Movement with all four feet affected, though less awkward in appearance, is + doubtless more painful than in either of the other conditions. Here the animal can + hardly be induced to shift his position at all. Only by flogging, and that severe, + can he be made to go forward. When so induced to move, the agonizing pain to which + the patient is subjected may be gathered by noting his countenance and manner of + progression.</p> + <p>With each movement forward, muscular tremors affect the limbs; each step is short, + jerky, and convulsive; the respirations and pulse are almost immediately greatly + quickened, and the lower lip is hung pendulous, and moved almost unconsciously up and + down with a flapping noise against the upper. A patchy perspiration breaks out about + the body and quarters, and the tail is outstretched and quivering. At the same time + the lines of the face become drawn, the commissures of the lips pulled upwards, the + eyes staring and haggard, the eyelids puckered, the nostrils extended, and the whole + expression indicative of the intense and agonizing pain of the disease.</p> + <p>One can perhaps better give one's client some vague idea of the patient's + suffering by likening the pain to the throbbing sensation of a festered finger-nail. + Tell him that each hoof of the horse is similarly, or, if anything, more delicately, + constructed, that in each foot the same process of 'festering' is going on, and that + upon them the animal has perforce to stand.</p> + <p>As one might expect, the position of greatest ease is the decumbent. Strange to + say, though, in many cases of laminitis the animal persists in maintaining a standing + posture. Once down, however, one has sometimes the greatest difficulty in persuading + him again to rise. The lying position is so long maintained that bedsores begin to + make their appearance, and the animal rapidly loses flesh, not only by reason of the + fever and the pain, but by giving to rest the time he should normally give to + feeding.</p> + <p>Difficulty in rising is greatest when all four feet are affected; is <i>nearly</i> + as great when the hind-limbs only are in trouble, but is least when the disease + exists alone in the two fore-feet.</p> + <p>THE COURSE OF THE DISEASE AND ITS PATHOLOGICAL ANATOMY.—As with most + inflammations of any severity, so with this we may consider the pathological changes + taking place in the foot under three headings: (a) The period of Congestion; (b) the + period of Exudation; (c) the period of Suppuration.</p> + <p>(a) <i>Congestion</i>.—In the early stages of laminitis there is a state of + engorgement of the vessels of the keratogenous apparatus generally, but more + particularly the laminal portion of it. With the hoof removed at this stage the + sensitive laminæ are found to be swollen, dark red in colour, and affording a + distinct feeling of increased thickness when pressed between the fingers, Incised, + there escapes from the cut surface a large flow of dark venous-looking blood. At this + stage hæmorrhages of the laminal vessels occur. The escaping blood infiltrates + the surrounding connective tissue, and in many cases destroys the union between the + horny and sensitive laminæ. This change is most noticeable in the region of the + toe and the commencement of the quarters, the os pedis appearing as though pushed + backwards by the escaping fluid collected between the wall and the bone. In severe + cases, fortunately but rarely seen, the blood so escaping continues to infiltrate, + and separate the tissues until it is seen to be freely oozing at the region of the + coronet. (See reported case, No. 1, p. 279.)</p> + <p>(b) <i>Exudation</i>.—The period of exudation marks the outpouring of the + inflammatory fluid. This, even more than the hæmorrhages attending the stage of + congestion, tends to destroy the intimacy between the sensitive and the horny + laminæ, leading finally to their complete separation at the region of the toe. + Fig. 116 illustrates this state of affairs after laminitis has existed for a week. + The sensitive and horny laminæ are here shown to be distinctly separated from + each other, a well-marked cavity existing between them, which cavity is greatest in + extent at the toe of the os pedis. With the sensitive structures thus detached from + the wall, it is evident that very much that formerly held the os pedis in normal + position has been destroyed. What then happens is that the whole of the body-weight + is placed upon the sole. Never intended to bear the strain thus imposed, it naturally + sinks. With the sinking is a corresponding 'dropping' of the pedal bone—in + fact, of the whole of the bony column. Seeing that the structures <i>above</i> the + hoof are still normally adherent to the bones, it follows that they must, as the os + pedis sinks, be carried with it. As a consequence we get a marked depression at the + coronet (see Fig. 117, <i>a</i>), which depression may be often noticed after the + second or third week of a severe attack of the disease.</p> + <br /> + <a name="a116" id="a116"></a> + <p><a href="images/image116.jpg"><img src="images/image116sm.jpg" + alt="LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF EIGHT DAYS' STANDING." /> + </a></p> + <br /> + + <p>FIG. 116.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF EIGHT DAYS' + STANDING. The separation between the sensitive structures and the hoof is indicated + by a dark line. The cavity is filled with exudate. It will be noted that as yet there + is little change in the position of the os pedis.</p> + <p>Here, again, though to a greater extent than that caused by the hæmorrhage + alone, the os pedis appears to be pushed backwards, the space at the toe between the + bone and the horny box being closely filled with the yellow, slightly blood-stained + exudate. This condition is well depicted in Fig. 117.</p> + <br /> + <a name="a117" id="a117"></a> + <p><a href="images/image117.jpg"><img src="images/image117sm.jpg" + alt="LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF FOURTEEN DAYS' STANDING." /> + </a></p> + <br /> + + <p>FIG. 117.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF FOURTEEN DAYS' + STANDING. <i>a</i>, The depression at the coronet caused by the dropping of the bony + column within the horny-box: <i>b</i>, a portion of the sensitive sole pushed + downwards and forwards by the descending os pedis.</p> + <p>With the descent of the os pedis we get in many cases a penetration of the horny + sole (see Fig. 117), leading always to serious displacement of the sensitive sole + (see Fig. 117, <i>b</i>), and often to caries of the exposed bone.</p> + <p>The backward displacement of the os pedis may be accounted for in two ways. + Firstly, the greater vascularity of the membrane covering its front leads to a + greater outpouring of inflammatory fluid in that particular position. Here, + therefore, loss of adhesion with the wall is greatest, while into the cavity so + formed is poured a large quantity of a fluid that is practically incompressible. The + os pedis <i>must</i> be pushed backwards. Secondly, the manner in which the animal + distributes his weight—namely, upon the heels—is calculated to aid in the + bone's backward movement, for with his feet in this position tension upon the + extensor pedis is relaxed, while that upon the flexor perforans is greatly + increased.</p> + <p>(c) <i>Suppuration</i>.—Should the animal survive the pain and exhausting + calls made upon his system by the accompanying fever of the foregoing conditions, the + case ends either in resolution or suppuration. When suppuration occurs it is found, + as a rule, at the sole, leading to almost entire separation of the sensitive and + horny structures. The pain, if possible, is even worse than in either of the + foregoing stages, and relief for the suffering patient is only obtainable by the + natural exit of the pus at the coronet, or by giving it escape with the knife at the + sole. As a rule, suppuration in laminitis is rare, and then only occurs when the + disease has been of some several days' duration. It has been the author's experience, + however, to meet with it in a case but three days' old. This particular animal had + laminitis restricted to the hind-feet. The condition was diagnosed and pus liberated + at the sole of one foot during the third day of the lameness. The animal was cast on + the fourth day, and pus obtained from the sole of the opposite foot.</p> + <p><i>Complications</i>.—In a moderate case, carefully treated, laminitis + terminates at the end of three or four days in resolution. The general symptoms of + fever gradually subside, the appetite returns, and the walk becomes easier. Cases + thus terminating fortunately leave behind them no change of serious importance, + either in the sensitive tissues or in the horny envelope. Should resolution, however, + be longer delayed, then the case, although eventually terminating successfully so far + as soundness in gait is concerned, leaves more or less evidence behind in the shape + of rings about the wall and alterations in the build of the sole.</p> + <p>When the happy ending of rapid resolution is denied us, then, in addition to the + condition we have described as suppuration, we may meet with one or other of the + following complications:</p> + <p>(<i>a</i>) <i>Metastatic Pneumonia</i>.—This complication is not uncommon, + and, when occurring, more often than not ends fatally. It may be accounted for + indirectly by the greater work the lungs are called upon to perform in carrying out + the increased number of respirations occasioned by the general fever and pain, and + directly by the poisonous materials circulating in the blood-stream.</p> + <p>(<i>b</i>) <i>Metastatic Colic</i>.—This may be either a subacute + obstruction of the bowel or an enteritis accompanied by an offensive purge.</p> + <p>A striking case of the former is related in the <i>Veterinary Journal</i> (vol. + xvi., p. 180) by H. Thompson, of Aspatria. Here no evacuation of the bowels occurred + for three days, and the pains of laminitis were added to by the usual pains of + intestinal obstruction.</p> + <p>The colic of enteritis is in some cases caused by the nature of the food, giving + rise to laminitis. In our opinion, however, it is more often occasioned by the + drastic action of the aloes nearly always resorted to in the treatment of the + disorder. As does the pneumonia, the enteritis thus brought about nearly always has a + fatal termination.</p> + <p>(<i>c</i>) <i>Gangrene of the Structures within the Hoof</i>.—This + complication is the one most to be dreaded. It occurs as a result of the great + pressure exerted by an excessive exudation, and doubtless affects first the + laminæ and softer structures. Once commenced, however, it rapidly extends to + death of the other structures (ligament, tendon, and even bone), and gives a fatal + ending to the case.</p> + <p>That gangrene of the tissues ("mortification" as our older writers called it) has + occurred is soon made evident to the veterinarian by the symptoms shown by the + patient. The agonizingly acute pains suddenly subside, the feet are placed firmly and + squarely to the ground, and the animal walks with ease. Perhaps but the night before + the patient is seen racked with excruciating pain; the morning sees the astounding + change of apparent absolute recovery. Too well, however, the eye of the experienced + veterinary surgeon sees that such is not the case. Even before proceeding to take a + record of the other symptoms, he knows that it is but the commencement of the end. + Methodically, however, he notes the other conditions. The pulse he finds small and + imperceptible, save at the radial. The thermometer registers a subnormal temperature, + the extremities are cold, and cold sweats bedew the body. To the same experienced eye + the countenance of the animal is almost suggestive of what has occurred. The drawn + and haggard expression, to which we have previously referred, becomes more marked, + and the angles of the lips are drawn back in what has been described by some writers + as a 'sardonic' grin.</p> + <p>We can best express what the whole look of the animal's countenance indicates to + us by saying that it gives us the impression that the animal himself knows that some + serious change, and a change fatally inimical to his chances of life, has taken place + in his feet.</p> + <p>It may be that in some odd cases, although it has not yet been our lot to meet + with them, gangrene may terminate in the casting off of one or more hoofs. Needless + to say, there can still be but one termination to the case.</p> + <p>(<i>d</i>) <i>Periostitis and Ostitis</i>.—This complication is referred to + by other writers under the term of 'Peditis.' It signifies, of course, that the + periosteum and the bone have become invaded by the inflammatory process. It is our + opinion that these two conditions, even including an actual arthritis, always exist, + even in an attack of laminitis that ends favourably. We do not claim, however, to be + able to relate any means, save that of post-mortem examination, by which it may be + singled out from the other changes occurring in the foot. The high fever and pain + occasioned by the inroads of the inflammation into the other sensitive structures + serves to effectually mask whatever evidence of it we might otherwise obtain. It may + be sometimes only small in degree, but we feel confident that inflammation, at any + rate of the <i>outer</i> layer of the periosteum, is in laminitis constant even, we + repeat, in a mild case.</p> + <br /> + <a name="a118" id="a118"></a> + <p><a href="images/image118.jpg"><img src="images/image118sm.jpg" + alt="SHOWING CHANGES IN THE OS PEDIS WITH LAMINITIS OF LONG STANDING," /></a></p> + <br /> + + <p>FIG. 118.—SHOWING CHANGES IN THE OS PEDIS WITH LAMINITIS OF LONG STANDING, + (<i>a</i>, Viewed from the front; <i>b</i>, viewed from the side.) The porous + condition of the bone, which is here shown, is a result of a rarefying or rarefactive + ostitis. This specimen also illustrated (what the photograph cannot show) an + accompanying condition of condensation of bone, or osteoplastic ostitis. (For a + fuller description of the changes occurring in these forms of ostitis, see Chapter + XI.)</p> + <p>When the case is a serious one we have ample evidence to show that ostitis exists, + and exists in a severe form. The bones become vastly altered in shape, a process of + absorption leads to the formation of large, irregular cavities within their + substance, and what of the bone is left is rendered hard and ivory-like (condensed) + near what was the original centre, while the edges and other portions show often a + tendency to become brittle and porous.</p> + <p>Fig. 118 illustrates the effects of a severe ostitis in pedal bones removed from + hoofs with laminitis of several weeks' standing.</p> + <p>(<i>e</i>) <i>Chronic Laminitis</i>.—The most common complication—or, + perhaps, rather we should term it 'sequel'—to acute laminitis is the chronic + form of the disease. For this condition we have reserved a separate section of our + work. It will be found described in Section B 1 of this chapter.</p> + <p><i>Diagnosis and Prognosis</i>.—One is almost tempted to state that the + diagnosis of laminitis offers no difficulty. In the very early stages, however, it + may, as we have already indicated, be mistaken for the oncoming of Enteritis, + Lymphangitis, or even Pneumonia. The paddling of the feet may help us. If this is + absent, however, nothing but a most careful examination, or, if necessary, the + withholding of our opinion until the following visit will prevent a blunder being + made.</p> + <p>Even when well established, laminitis has been mistaken for paralysis, for + tetanus, for rheumatic affections of the loins, or even for some undiscovered + affection of the muscles of the arms and chest. This latter is no doubt suggested to + the uninitiated by the reluctance the animal shows to move the muscles + <i>apparently</i> of that region, and led the older writers to give to the disease + its name of 'Chest-founder.' It is only fair to add, however, that these blunders in + diagnosis are nearly always committed by persons without a veterinary training.</p> + <p>Thus warned, the veterinary surgeon of average ability should have no difficulty + in establishing a distinction between the diseases we have enumerated as likely to be + confounded with it, and the one this chapter is describing.</p> + <p>The prognosis in laminitis should, in our opinion, always be guarded. No advice + given in a work of this description can be of any real use, for every case must be + judged entirely on its merits. The severity of the symptoms, the cause of the attack, + the complications, and the idiosyncrasies of the patient, have all to be taken into + account. These the veterinarian must be left to judge for himself.</p> + <p><i>Treatment</i>.—The treatment of acute laminitis in its early stage must + be based upon the fact that we have to deal with a congested state of the circulatory + apparatus of the whole of the keratogenous membrane. This fact was well enough known + to the older veterinarians. It is not surprising, therefore, to learn that jugular + phlebotomy was at once resorted to as the readiest means of relieving the overcharged + vessels of their blood. As a matter of fact, bleeding from the jugular is still + advocated by modern authorities. We cannot say, however, that we unhesitatingly + recommend it. Mechanically, of course, the removal of a large quantity of blood is + bound to result in a lowering of the pressure in the vessels. The effect, however, is + but transient. Blood removed in this way is again quickly returned to the vessels so + far as its fluid matter is concerned, and the pressure, removed for a time, is again + as great as before. With the other and more vital constituents of the + blood-stream—namely, the corpuscles—restoration is not so rapid. We have, + in fact, a weakened state of the system, in which it is probable it will not so + successfully combat the adverse conditions the disease may induce.</p> + <p>With these prefatory remarks, we may advise bleeding under certain conditions. The + quantity removed must be moderate (7 to 8 pints), and the pulse and other conditions + must show no signs of weakness or collapse.</p> + <p>Local bleeding, either from the toe or the coronet, is also advised. In the former + situation the sole is thinned down until a sufficient flow is obtained, while at the + coronet scarification is the method adopted. Bleeding locally, however, is far less + effectual than the jugular operation. Neither must it be forgotten that wounds in + these situations, more particularly at the toe, are extremely liable, especially with + the existing poisoned state of the blood-current, to take on a septic character. What + might possibly have remained a comparatively simple inflammation is induced by the + operation itself to terminate in the more complicated and serious condition of + suppuration.</p> + <p>Other means of combating the congested state of the membrane are principally those + of local applications. With many veterinary surgeons warm poulticing is still largely + advocated and practised. We do not believe in it. Warmth, as a means of removing + local congestion, can only be successful when applied <i>widely</i> round the + congested area, and so dilating surrounding bloodvessels and lymphatics. Applied to + the congested area itself, and to that alone, it is almost worse than useless.</p> + <p>With the foot, both around and below it, a surrounding area is denied us. The only + vessels we are able to dilate with the warmth, and so enable them to carry off the + fluid from the congested foot, are those in the limb above. That poulticing cannot be + successfully there applied is self-evident. Apart from that, it is an open question + whether poultices may not do actual harm in inducing suppuration in cases where, + probably, it would not otherwise occur.</p> + <p>For these reasons we hold to the opinion that when a local application is + determined on it should be a cold one. Various methods of applying cold are in vogue. + Cold swabs are perhaps most in favour. They must, however, be <i>kept</i> cold. When + a suitable water-course, pond, or other expanse of shallow water is at hand, then the + animal may be kept standing therein, or preferably walked about in it. When suitable + apparatus is obtainable, a constant stream over each foot from a rubber hosepipe is + most beneficial.</p> + <p>Astringent baths, containing solutions of alum, of copper sulphate, of iron + sulphate, or of common salt, or composed of a mixture of two or more of the salts + mentioned, may also be used with advantage. In addition to the fact that such + solutions are for a time below the temperature of simple water, we have the advantage + that they have also a more or less antiseptic property.</p> + <p>While on the subject of the relief of the congestion, we must not forget to + mention a treatment which we ourselves have practised with considerable + success—namely, that of forced exercise. It appears to have been first brought + into prominence by Mr. Broad, of Bath, and the two terms 'Forced Exercise and Rocker + Shoes' and 'Broad's Treatment' have come to be synonymous.</p> + <p>The Broad shoe is a shoe with a web of quite twice the thickness of the animal's + ordinary shoe, and has this web gradually thinned from the toe backwards until at the + heels the shoe is at its thinnest (see Fig. 119).</p> + <p>The excessive thickness of the shoe serves two purposes. It allows of the + requisite amount of slope being given to the web, and so enables the animal readily + to throw himself back on to his heels, a position in which, as we have already + indicated, he obtains the greatest ease. It also minimizes to some extent the effects + of concussion.</p> + <br /> + <a name="a119" id="a119"></a> + <p><a href="images/image119.png"><img src="images/image119sm.png" + alt="SEATED ROCKER BAR SHOE (BROAD'S) FOR TREATMENT OF LAMINITIS." /></a></p> + <br /> + + <p>FIG. 119.—SEATED ROCKER BAR SHOE (BROAD'S) FOR TREATMENT OF LAMINITIS.</p> + <p>With forced exercise, as practised by Mr. Broad, this shoe is first applied, and + the animal afterwards made to walk upon soft ground, or even upon the roadway, for a + half an hour to an hour and a half three times a day.</p> + <p>For our own part, we consider the shoe to be almost if not quite superfluous, so + far as its influence upon the progress of the disease is concerned. We therefore + dispense with it, and have the animal exercised in his ordinary shoes. To do this, + the patient has sometimes to be severely flogged into taking the first few steps. + After that progress gradually becomes easier.</p> + <p>It has been said to be cruel. In so far as we knowingly, and of set purpose, + occasion the animal pain, cruel it undoubtedly is; but it is cruelty with an aim that + is truly benevolent, and the object of our benevolence is the animal upon whom the + cruelty is practised.</p> + <p>One word of advice is needed. The forced exercise must be commenced early. In the + later stages, when the stage of congestion has passed from that to the acuter stages + of the inflammation and the outpouring of the inflammatory exudate, then forced + exercise cannot be safely commenced. The loss of adhesion between the pedal bone and + the horny box, which we know to be then existent, negatives its advisability.</p> + <p>By many it is advised to always remove the shoes. From what we have already said, + it will be seen that this is not our practice. But one argument in favour of so doing + appears to us to carry weight, and that is that 'dropping' of the sole is probably + prevented from becoming so marked. That condition, however, is entirely dependent + upon the changes occurring within the horny box. It is bound to occur with the animal + shod or unshod, and to reach a stage when only contact with the ground prevents its + further descent. The complication then sometimes following—namely, penetration + of the sole by the bone, is not prevented by having the shoes removed. It may, in + fact, be thus rendered more likely.</p> + <p>Internal treatment consists in the exhibition of suitable febrifuges and the + administration of a dose of aloes.</p> + <p>With regard to the wisdom of the latter proceeding, opinion seems to be divided. + Personally, we hold an open mind concerning it. This much is certain: in many cases + of laminitis—those cases which have their origin in overfeeding with an + irritating food—there is already a strong predisposition to enteritis. The + administration of aloes in this case is extremely apt to induce a fatal + super-purgation. Aloes is, again, contra-indicated when the laminitis is a result of + excessively long journeys, and the patient is already greatly exhausted. Neither can + it be advocated in the laminitis occurring as a sequel to septic metritis or to + pneumonia.</p> + <p>On the other hand, when the disease has occurred as a result of long standing in + the stable and an overloaded condition of the bowels, or where one full meal of some + constipating food, such as whole wheat, pea or bean meal, wheat or barley meal, has + occasioned the attack, then a dose of aloes at the commencement of the treatment is + productive of good.</p> + <p>Suitable febrifuges are found in potassium nitrate, potassium chlorate, sodium + sulphate, or magnesium sulphate, either of which or a mixture of two or more of them, + the animal will readily take in his drinking-water.</p> + <p>The administration of sedatives is also indicated. In this connection aconite will + be found most useful. More especially in the early stages of the disease, when pain + is excessive and the temperature high, will its good effects be noticed. This also + the animal will often take in his drinking-water. We have been in the habit of so + prescribing the B.P. tincture in 1/2-dram doses three times daily. By its use the + temperature is rapidly lowered, the pulse reduced in number and in fulness, and the + pain in some instances perceptibly diminished. With others hypodermic injections of + morphia and atropine have given equally satisfactory results.</p> + <p>Needless to say, good nursing is a <i>sine quâ non</i>. During the first + stages of the fever a light and easily digested diet should be + allowed—bran-mashes, roots and grass when obtainable, and a carefully regulated + supply of water. The animal should be warmly clothed and the box well ventilated, + even to the opening of the doors and windows. Only in this way is pneumonia as a + sequel sometimes prevented. The patient's comfort should be attended to in providing + him with a suitable bed. Anything in the shape of long litter should be avoided. When + nothing else is at hand, litter that has already been broken and shortened by + previous use is best. With this the box floor should be thickly covered, and matting + of the material prevented by constant turning. A good bed for the horse with + laminitis is peat-moss mixed with short straw. This, without being dragged into + irregular heaps, remains springy and elastic with but little attention. Better than + all, however, especially with good weather, is an open crewyard. Here the animal has + an abundance of fresh air, has a bed that is always soft, and has plenty of room in + which to get up and down with some degree of ease.</p> + <p>Leaving the dietetic and medicinal, we may consider other treatments of laminitis + that come more particularly under the heading of operative.</p> + <p>The first matter that here demands our attention is that of allowing the exudate + to escape at the sole. If after the expiration of three or four days pain and other + symptoms of distress continue, then it may be judged that the inflammatory exudate + has made its appearance. Operative measures allowing of its escape, though not giving + absolute ease, do undoubtedly relieve the more marked expressions of suffering, and + should be at once determined on. To do this completely it is necessary to cast the + animal. The sole is then thinned at the toe with the drawing-knife until the + sensitive structures are reached. A flow of yellow and sometimes blood-stained + discharge is immediately obtained, and the sole itself found to be underrun to a + considerable extent. An opening sufficiently large to admit of free drainage (about + the size of a half a crown-piece) is made, the wounds antiseptically dressed, and the + hobbles removed.</p> + <p>If showing an inclination to do so, the animal should then be allowed to remain + and rest. In one instance in which we so operated (a case of laminitis in the + hind-feet alone), the relief given was at once manifested. For three days previously + the animal had remained standing in agonizing pain. On the fourth he was cast, and + the discharge—partly inflammatory exudate, and partly a sanious foetid + pus—liberated. The hobbles were removed, and the animal allowed to remain down + while our attention was drawn to another case. This attended to, we walked back to + the field where, our first patient was lying. His breathing, but a short time before + distressedly short and catching, was now so slow and deeply regular that for one + brief moment the thought flashed across our mind that he was dead. He was in a + <i>profound</i> sleep.</p> + <p>Other operators sometimes give the exudate escape while making the grooves in what + is now known as 'Smith's Operation.'</p> + <p>In this operation the hoof is so grooved as to allow of its expansion, so + relieving the pressure on the sensitive structures within it. Incidentally, the + inflammatory exudate is given exit.</p> + <br /> + <a name="a120" id="a120"></a> + <p><a href="images/image120.png"><img src="images/image120sm.png" + alt="DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE GROOVES MADE IN THE TREATMENT OF LAMINITIS." /> + </a></p> + <br /> + + <p>FIG. 120.—DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE GROOVES MADE IN + THE TREATMENT OF LAMINITIS.</p> + <p>The animal is cast, the shoes removed, and three vertical grooves made in the + wall. The first is cut down the centre of toe, extending from the coronet to the + ground surface. The second is made to the right of this, and the third to the left, + each following the direction of the horn fibres, and each distant about 2 inches from + the first (see 1, 2, and 3, Fig. 120).</p> + <p>Each of the grooves must run completely from the coronary margin to the ground + surface, and each should be carried through the substance of the horn until the horny + laminæ are reached. This done, the underneath surface of the foot is grooved at + the white line (see curved groove 4, Fig. 121) in such a manner as to entirely + isolate the two pieces of horn <i>a</i> and <i>b</i> from the remainder of the + hoof.</p> + <p>Expansion of the horny box is thus brought about, while at the same time the + semicircular groove at the toe is made deep enough to allow of the escape of the + exudate.</p> + <p>If thought wise by the operator, the two pieces of horn <i>a</i> and <i>b</i> may + be isolated, and the exudate given exit by making the fourth groove in the position + of the dotted lines in Fig. 120—that is to say, at the lowermost portion of the + sensitive structures. By this means the sole will be left intact.</p> + <br /> + <a name="a121" id="a121"></a> + <p><a href="images/image121.png"><img src="images/image121sm.png" + alt="LOWER SURFACE OF FOOT SHOWING POSITION OF THE GROOVES MADE IN THE TREATMENT OF LAMINITIS." /> + </a></p> + <br /> + + <p>FIG. 121.—LOWER SURFACE OF FOOT SHOWING POSITION OF THE GROOVES MADE IN THE + TREATMENT OF LAMINITIS.</p> + <p>Fuller instruction for making the grooves and the instruments required will be + found described in Section C of Chapter X.</p> + <p>The animal should be afterwards shod, and the bearing on the portions <i>a</i> and + <i>b</i> of the wall removed. Almost immediate relief is afforded the patient.</p> + <p><i>Recorded Cases</i>.—1. 'On the evening of September 28 last, I was called + rather hurriedly to attend a posting-horse which had just arrived from a twenty-one + miles' journey, and was said to be "very ill." I lost no time in proceeding to the + spot, and found my patient "very ill" indeed. No need for long consideration as to + diagnosis; the symptoms showed at once that I had an uncommonly severe case of acute + founder before me. On examination I found the pulse was 120, the respirations 100, + and the thermometer 106° F. The poor brute could not move, the fore-legs were + well out before, and the hind-legs thrown back behind; in fact, he was, as one might + say, propping himself up with his four legs!</p> + <p>'On examining his feet, I discovered what I had never either seen or heard of + before—namely, <i>blood freely oozing out</i> at the coronet of all four feet; + if anything, the hind-feet were the worst, and, showing that this bloody discharge at + coronets had commenced during progression and before he was stabled, the inside of + the thighs were all shotted over with blood, which had been thrown up by his feet + while he was trotting or walking. He was completely soaked all over with + perspiration.</p> + <p>'My prognosis could not well be otherwise than unsatisfactory. I resolved, + however, to do all I could to relieve the poor suffering brute. As a matter of + course, jugular phlebotomy was utterly impracticable; so, to relieve the pressure in + the feet, I had him (after, with extreme difficulty, removing the shoes) bled, or + rather opened, at all four toes, and hot poultices applied. On opening the off-side + toe, in both hind and fore feet, I found an escape of very dark-coloured blood, with + a great many bubbles of gas, thus showing that the destructive process was fairly + established in the two bony extremities mentioned. The near fore and near hind feet + showed no signs of gas-bubbles on being opened at the toe.</p> + <p>'I gave a laxative in combination with a diffusible stimulant, and ordered doses + of aconite and potassium iodide; I also applied strong sinapisms to each side, + immediately behind the shoulders. After three hours I found my patient rather easier; + respiration about 90, and temperature 104°; willing to take a little water, and + even attempted to take some hay. Ordered continued applications of hot water to the + poultices at feet, and clothed him up for the night. Next morning there was little + improvement; respirations over 80, and temperature 103.5°. Continue same + treatment. Second morning, horse apparently easier; temperature 102.5°, but very + difficult respiration; laxative had operated during the night; ordered diffusible + stimulants. About two hours and a half after my last visit, the horse turned round in + his stall and dropped down dead!</p> + <p>'<i>History of the Horse</i>.—He belonged to an extensive horse-hiring + establishment; was purchased a short time before for £60—a long price for + a post-horse—had recently suffered and been off work from some "severe cold"; + was taken out, and did forty-seven miles of a journey the day <i>before</i> I saw + him; on forenoon of the day on which he was attacked he did two or three short turns, + and then twenty-one miles of a journey in the afternoon, during which he became so + ill as scarcely to be able to conclude the twenty-one miles; this was the last turn + he was to do. He was a grand stepper, and no doubt was pushed a little during this + final journey, as the driver intended, after a short rest, to finish off with the + twenty-six miles between this and home. With the short turns on the second forenoon, + this would have been over 100 miles in less than two days, with a horse just out of a + <i>severe cold</i>.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. xvii., p. 314 (A.E. + Macgillivray).]</p> + <p>2. 'Whilst attending a patient on a farm on September 5 last my attention was + called to a cart-horse, five years of age, that had been castrated in the standing + position by a travelling castrator about ten days previously.</p> + <p>'I found the animal presenting the following symptoms: Head down, blowing hard, + very dull, and disinclined to move, temperature 105° F., hard, rapid, slightly + irregular pulse, membranes injected, appetite lost; scrotum, sheath, and penis + tremendously swollen, castration wounds unhealthy, and exuding a thin, reddish-brown + discharge of a most foetid odour.</p> + <p>'The next day well-marked symptoms of laminitis were present. I finally ceased + attending him about the middle of October, and at the end of that month he was turned + out for the winter.'[A]</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xiv., p. 649 (Charles A. Powell).]</p> + <p>3. 'On July 8 an interesting case of laminitis came under my notice. The subject + was a mare, eight years old, which had been running on the common here for some + months, and was taken up on the night of July 2 by a boy, who did not observe + anything amiss with her. The following morning, on the owner going to the stable, he + found the animal in great pain, and at once sent for me. I discovered her to be + suffering from laminitis, and saw her again in the evening, when she was much worse. + The attack proved to be a most severe one.</p> + <p>'The owner informed me that she had not been allowed any corn for two months, and + that she had no distance to travel on the road from the common.</p> + <p>'Though on such a poor pasture, the mare was very fat; she had never been unwell + before this attack.</p> + <p>'This is the first case I have seen of laminitis occurring when the animal was on + grass.'[A]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. ix., p. 176 (W. Stanley + Carless).]</p> + <h3>B. CHRONIC.</h3> + <p>1. CHRONIC LAMINITIS.</p> + <p><i>Definition</i>.—A low and persisting type of inflammation of the + sensitive structures of the foot, characterized by changes in the form of the hoof, + and incurable pathological alterations within it.</p> + <p><i>Causes</i>.—Chronic laminitis more often than not is a sequel to the + acute form we have just described. With an attack of acute laminitis that defies + treatment, and does not end in resolution in from ten days to a fortnight, then the + chronic form may be expected.</p> + <p>The brittle horn, convex sole, and other changes we have described under Pumiced + Foot may, however, be regarded as a chronic laminitis, and this condition, as we have + already indicated in Chapter VI., may run a course slow and insidious from the + onset.</p> + <p><i>Symptoms</i>.—When the disease arises without previous acute symptoms, + the first thing noticeable is an alteration in the gait. The animal begins to go + feelingly, especially when first moved out from the stable. Our opinion is asked as + to the cause of the lameness, and an inspection is made. With the changes in the form + of the hoof as yet wanting, we have nothing to guide us, and other causes for the + lameness suggest themselves, probably corns. Evidence of these is not forthcoming, + and we in all probability withhold our opinion until a later visit. On the second or + a subsequent call we are perhaps lucky enough to find our patient down. Diagnosis is + then rendered easier. Made to rise, the animal stands in the attitude we have + described as indicative of laminitis. We have him walked and trotted out. The + symptoms of tenderness disappear, and the animal soon goes fairly sound. He is, in + fact, workable—that is, by anyone who is careless as to the comfort of his + beast.</p> + <p>When following an acute attack, we have the most marked symptoms of pain and + distress, somewhat abating after the second or third week. The walk, however, is + still painful, and, for a short time after rising from the ground, even + difficult.</p> + <p>In short, in both cases we have the horse going on his heels, with a walk that is + painful, and with symptoms of pain that are most apparent when moved on after a + rest.</p> + <p>Later, the changes in the form of the hoof begin to appear. It seems to have lost + its elasticity, and is seen to be dry and chippy, and to have become denuded of its + varnish-like outer covering.</p> + <p>In addition, it is of largely altered shape. The toe, by reason of the animal + walking on his heels, and by reason of an increased growth of horn, becomes elevated, + so that the front of the wall, instead of forming an obtuse angle with the ground, + comes to run very nearly horizontal with it. The horn of the heels, as compared with + that of the toe, takes on an increased growth. The same thing we have already + indicated as happening at the toe, though in lesser degree. Taken together, this + increased growth of horn at the toe and at the heels has the result of lengthening + the diameter of the foot from before backwards, the transverse diameter remaining + more or less normal. The hoof thus loses its circular build, and comes to approach + nearer an elongated oval.</p> + <br /> + <a name="a122" id="a122"></a> + <p><a href="images/image122.png"><img src="images/image122sm.png" + alt="FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS." /></a></p> + <br /> + + <p>[FIG. 122.—FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS. At this + stage, too, the pathological 'ribbing' of the hoof is observable. The outer surface + of the wall becomes marked with a series of ridges encircling the hoof from heel to + heel (see Fig. 81, which illustrates a moderate deformity of the hoof occurring after + laminitis). In the badly laminitic hoof, however, this deformity is largely + increased, until in some cases the shapeless mass can hardly be likened to a foot at + all (see Fig. 122).</p> + <p>The inferior or solar surface of the foot also offers certain changes for our + consideration. The first thing that strikes one is the convexity of the sole. This, + as we have already pointed out, is due to descent of the os pedis, and the highest + point of the convex portion is that immediately in front of the apex of the frog. + Here the horn is sometimes found to be quite yielding to the finger, is excessively + thin, and is more or less granular and inclined to break up under manipulation. As a + consequence, any rough use of the drawing-knife, or an accidental wounding with sharp + flints or stones, leads to exposure of the sensitive structures and local + gangrene.</p> + <p>With the horn of the sole thus deteriorated by reason of excessive and continued + pressure upon the parts secreting it, it is not surprising to find that, in many + cases, actual penetration of it with the os pedis occurs. It is the anterior portion + of the inferior margin of the bone that makes its appearance, and shows itself as a + small semicircular white or dark gray line on the sole.</p> + <br /> + <a name="a123" id="a123"></a> + <p><a href="images/image123.png"><img src="images/image123sm.png" + alt="SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS," /></a></p> + <br /> + + <p>FIG. 123.—SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS, SHOWING ITS ABNORMAL + OVAL SHAPE FROM BEFORE BACKWARDS, AND THE EXCESS OF HORN GROWING FROM THE WHITE LINE + IN THE REGION OF THE TOE.</p> + <p>Exposure of the bone is soon followed by its necrosis, in which case the wound + takes on an ulcerating character. From it there is a discharge of pus, black in + colour and offensive in smell, and, protruding from the opening, are excessive + granulations of the remains of the sensitive sole.</p> + <p>The 'white line,' so apparent when a normal foot is cleaned with the knife, can no + longer be sharply distinguished from the surrounding horn, while in some cases the + horn composing it takes on an abnormal growth at the toe (see Fig. 123). This adds + still further to the abnormal lengthening of the antero-posterior diameter of the + foot already mentioned.</p> + <p>In other cases horn in this position is altogether wanting, and in its place is a + well-defined cavity, into which the blade of a knife can be readily passed. This + cavity is bounded in front by the original wall of the hoof, and is here lined by a + degenerated and hypertrophied growth of the horny laminæ. Posteriorly the + cavity is bounded by the front of the os pedis, and is lined by a thin growth of horn + secreted by the keratogenous membrane covering the bone. Superiorly the cavity is + quite narrow, and extends to near the lower surface of the coronary cushion, while + inferiorly, at its open portion, it is often 1/2 inch to 1 inch wide. Laterally it + extends on each side of the toe to the commencement of the quarters.</p> + <br /> + <a name="a124" id="a124"></a> + <p><a href="images/image124.png"><img src="images/image124sm.png" + alt="LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF THREE WEEKS' STANDING." /> + </a></p> + <br /> + + <p>FIG. 124.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF THREE WEEKS' + STANDING. On the anterior face of the cavity, in front of the os pedis, are thickened + horny laminæ. Due to the sinking of the bony column, the os pedis has + perforated the horny sole.</p> + <p>Exploration with a director, or with the blade of a scalpel, removes from the + opening a dry detritus. This is composed of the solid constituents of the escaped + blood, the dried remains of the inflammatory exudate, and broken-down fragments of + cheesy-looking horn. The size to which the cavity may sometimes extend is illustrated + in Fig. 124. The thickened horny laminæ forming the anterior boundary of the + cavity are here depicted, together with commencing perforation of the horny sole by + the os pedis. It is this cavity which, when opened at the bottom and discharging its + mealy-looking contents, is known as seedy-toe, for a further description of which see + p. 293.</p> + <p>The lameness occurring with chronic laminitis does not always persist. As time + goes on the sensitive structures accommodate themselves to the altered form and + conditions of the horny box. In certain situations—namely, where pressure is + greatest—the softer structures become atrophied, and sometimes even wholly + destroyed; while in other positions the changes in form of the hoof tend to increase + in size of its interior, with a consequent diminution of pressure upon, and increased + growth of the structures within it.</p> + <p><i>Pathological Anatomy</i>.—In detailing the changes to be observed in + chronic laminitis, we take up the description where we left it when dealing with the + pathological anatomy of the acute form. The alterations to be met with are best + observed by taking a foot so diseased and making of it two sections—one + longitudinal, from before backwards; the other horizontal, and in such a position as + to cut the os pedis through at its centre.</p> + <p>These sections will expose to view the cavity formed by the pouring out of the + exudate, and its full extent may be noticed by examining the sections alternately. + Taking the horizontal section first, it will be seen that the hollow space extends + wholly round the toe, and as far back as the commencement of the quarters. In the + latter position one is able to observe laminæ still in their normal positions + and condition. At the toe, however, the horny and secretive laminæ are widely + separated, and the space between them filled with a yellow, semi-solid material, the + remains of the inflammatory exudate and new horn secreted by the keratogenous + membrane. The laminæ, both horny and sensitive, are greatly enlarged. This is a + hypertrophy, resulting from the continued effects of the inflammation, and leads in + time to the formation of laminæ quite three or four times their normal size. It + is this hypertrophy of the laminæ and the pressure of the exudate that causes + the bulging and increased growth of the horn at the toe (see Fig. 125), and + contributes towards the oval formation of the foot we have mentioned before.</p> + <br /> + <a name="a125" id="a125"></a> + <p><a href="images/image125.jpg"><img src="images/image125sm.jpg" + alt="LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF SEVERAL YEARS' DURATION." /> + </a></p> + <br /> + + <p>FIG. 125.—LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF SEVERAL YEARS' + DURATION.</p> + <p>In the longitudinal section the first thing noticeable is the change in position + of the bones, more especially in that of the os pedis. The circumstances we have + mentioned before—pressure of the exudate upon it in front and tension of the + perforans on it behind—have caused it to assume a more upright position than is + normal, so much so that in a bad case the front of the bone becomes quite vertical. + This vicious direction the other bones of the digit follow (see Fig. 125).</p> + <p>Consequent upon the displacement of the bone, the plantar cushion, by reason of + the continued pressure thus put upon it, becomes atrophied, while its hinder half is, + as it were, squeezed into taking up a position more posterior and higher in the digit + than normally it should. The horn-secreting papillæ covering its inferior face + thus become directed backwards sooner than downwards, in which way we account in some + measure for the noticeable increase of horn at the heels.</p> + <p><i>Treatment</i>.—Chronic laminitis is incurable. Treatment must therefore + be directed towards the palliation of such conditions as are present, with the object + of rendering the the animal better able to perform work. When perforation of the sole + has occurred, with the attendant formation of pus and necrosis of the os pedis, it is + doubtful whether treatment of any kind is advisable. There are on record cases of + this description, where careful curetting of the exposed and necrotic portions and + the after application of antiseptic dressings, held in position by a plate shoe or a + leather sole, has been followed by good results, and the animal restored for a time + to labour. In our opinion, however, early slaughter is the most economical course to + adopt, and certainly the wisest advice to give to the ordinary client.</p> + <p>When perforation of the sole is absent, and when serious alteration in the shape + of the horny box has not occurred, then the most simple treatment is to put the + animal straight away to slow work, with the feet protected by suitable shoes.</p> + <p>Here, again, the most useful shoe is the Rocker Bar (Fig. 119). The broad web and + deep seating gives ample protection to the convex sole, and with the ease in + distributing his weight that this shoe affords the animal is able to perform slow + work on soft lands with some degree of comfort.</p> + <p>Should the growth of the horn at the toe and at the heels be unduly excessive, + then our attention may be directed towards reducing it to some approach to the + normal. This is accomplished by removing with the rasp and the knife those portions + indicated by the dotted lines in Fig. 127. Here it will be seen that the bulk of the + horn removed is that protruding at the toe. After this the animal should again be + suitably shod. In this connection it should be noted that the fact of the animal + walking largely on the heels tends to a forward displacement of the shoe. This must + be prevented by providing each heel of the shoe with a clip, after the manner shown + in Fig. 128; or, in the case of a bar shoe, supplying it with a clip at the centre of + the bar.</p> + <br /> + <a name="a126" id="a126"></a> + <p><a href="images/image126.png"><img src="images/image126sm.png" + alt="DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS." /> + </a></p> + <br /> + + <p>FIG. 126.—DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN AT THE TOE AND + HEELS OF THE FOOT WITH CHRONIC LAMINITIS.</p> + <br /> + <a name="a127" id="a127"></a> + <p><a href="images/image127.png"><img src="images/image127sm.png" + alt="THE SAME FOOT AS IN FIG. 126." /></a></p> + <br /> + + <p>FIG. 127.—THE SAME FOOT AS IN FIG. 126. The dotted lines show the excess of + horn removed preparatory to shoeing.</p> + <p>Among other treatments to be noted we may mention one or two to be found chiefly + in Continental works on this subject.</p> + <p>The method of Gross consists in thinning down with a rasp about 1-1/2 inches of + the horn of the wall immediately below the coronet, the thinned portion extending + from heel to heel. The groove made is filled with basilicon ointment,[A] and the + coronet stimulated with a cantharides ointment, In this way there is induced to grow + from the coronet a new wall of nearly normal dimensions.</p> + <p>[Footnote A: Basilicon ointment is made by heating together resin 8 parts, beeswax + 8 parts, olive oil 8 parts, and lard 6 parts. Allow to cool without stirring.]</p> + <p>By other operators (Bayer, Imminger, Meyer, and Gunther) this treatment has been + modified by enlarging upon it and removing the whole of the adventitious horn.</p> + <br /> + <a name="a128" id="a128"></a> + <p><a href="images/image128.png"><img src="images/image128sm.png" + alt="THE SHOE WITH HEEL-CLIP." /></a></p> + <br /> + + <p>FIG. 128.—THE SHOE WITH HEEL-CLIP.</p> + <p>This is done by means of the drawing-knife and the rasp, the ugly-looking pumiced + foot being carefully cut and trimmed until, so far as outward appearances are + concerned, it is perfectly normal. This done, the whole foot is treated with a + suitable hoof ointment, and a shoe applied that affords protection to the sole + without imposing pressure upon it. The shoe indicated is either an ordinary shoe with + an unusually broad and well-seated web, or the seated Rocker Bar of Broad. With + either it is well to additionally protect the sole by means of a leather or rubber + pad and tar stopping, or by using the Huflederkitt described on p. 148. In every case + the nails must be kept well back in order to avoid the weakened and degenerated horn + at the toe, and to take advantage of the greater growth of horn at the heels.</p> + <p>The wisdom of thus removing the whole of the adventitious horn may be questioned. + Although a foot of a nearly normal shape is obtained, it must be remembered that the + grave alterations within it are unchanged, and that in certain positions the + operation must have carried us nearer the sensitive structures than is advisable.</p> + <p>All other treatments failing, the operation of neurectomy has been advised. This + we do not think wise. One would imagine that, with degenerative processes already + going on in the foot, the tendency to gelatinous degeneration, always to be looked + for in neurectomy, would be increased. This, as a matter of fact, is the case, and is + borne out by the statements of those who have tried this method of treatment. In many + cases the lameness even is not got rid of. Even where it is, the operation is + afterwards followed by a great tendency to stumble, by sloughing of the hoof, or by a + marked increase in the adventitious horn, and a consequent greater deformity of the + foot.</p> + <p>Sooner than risk neurectomy, it seems to us wiser to give a trial to the operation + advocated by M.G. Joly, namely, that of ligaturing one of the digital arteries on + each affected foot. This operation is performed in the same position as is the higher + operation of plantar neurectomy, and may be either internal or external. The vessel + is exposed, and a double ligature, preferably of silk, placed on it. The artery is + then divided between the two ligatures. The immediate effect of the operation is to + cause a considerable diminution in the arterial pressure, and so lessen the intensity + of the ostitis in the os pedis. Its consequences are not so serious as those of + neurectomy, and it decongests tissues which neurectomy congests.</p> + <p>In cases related by M. Joly this operation, practised both in conjunction with + removal of the excess of horn and without it, has resulted in a marked improvement in + the gait, the animal going to work one month after the treatment, and remaining sound + for some time afterwards.</p> + <p>2. SEEDY-TOE.</p> + <p><i>Definition</i>.—A defect in the horn of the wall, usually at the toe, but + occurring elsewhere, resulting in loss of its substance in either its internal or + external layers (see Figs. 129, 130, and 131).</p> + <p><i>Causes</i>.—The most common factor in the causation of this defect is + undoubtedly disease of the sensitive laminæ. We have, in fact, just given an + excellent example of the formation of a seedy-toe in the sections of this chapter + devoted to laminitis (see pp. 265 and 286). The cavity here formed by the outpouring + of the inflammatory exudate and the separation of the sensitive and horny + laminæ persists. It becomes filled with the dried remains of the exudate and + perverted secretions from the horny and sensitive laminæ (see p. 287). As yet, + however, the cavity is closed below, and its existence only surmised. Later, with + successive visits to the forge, the layer of solar horn forming its floor is cut + away, and the cavity exposed to view. Its mealy-looking contents are removed, and the + case reported by the smith.</p> + <p>Although occurring in this way with an acute attack of laminitis, it must be + remembered that seedy-toe may arise without previous noticeable cause. The first + intimation the owner has is a report from the forge that seedy-toe is in existence. + To refer to cases so arising a probable cause is far from easy. At one time it was + believed to be due to parasitic infection of the horn. Others have blamed the + pressure of the toe-clip, excessive hammering of the wall, or pressure from nails too + large or driven too close. Others, again, say that seedy-toe may result from a prick + in the forge, from hot-fitting of the shoe, from standing on a dry and sandy soil, or + from the use of high calkins on the front shoes. In these cases—cases with an + insidious onset—we are inclined to the opinion that the disease of the horn + commences from below, and that the sensitive laminæ become implicated later. + Holding this view, one must account for the commencing disease of the horn by giving, + as causes, firstly, those factors (as, for instance, alternate excessive dampness and + dryness) leading to disintegration of the horn tubules; secondly, the penetrating + into and between the degenerated tubules of parasitic matter from the ground; and, + thirdly, the final breaking up of the horn, and spread of the lesion under the + invasion thus started.</p> + <br /> + <a name="a129" id="a129"></a> + <p><a href="images/image129.png"><img src="images/image129sm.png" + alt="DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE (INTERNAL)." /></a></p> + <br /> + + <p>FIG. 129.—DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE (INTERNAL). 1, The horn + of the wall; 2, the horn of the sole; 3, the cavity of the seedy-toe; 4, the os + pedis; 5, the keratogenous membrane.</p> + <p><i>Symptoms</i>.—Lameness sometimes attends seedy-toe, and sometimes does + not. This is an important point to be carried in mind by the veterinary surgeon who + is accustomed in his practice to have many animals pass through his hands for + examination as to soundness. An animal with advanced seedy-toe—a condition + constituting serious unsoundness—may walk and trot absolutely sound, and may + give no indication, either in the shape of the wall or the condition of the sole, + that anything abnormal is in existence. Later, however, after the veterinary surgeon + has passed him, the purchaser lodges the complaint that the horse has a bad + seedy-toe, which, so he is told, must have been there for some time. In this case, + culpable though he may appear, there is every excuse for the veterinary surgeon.</p> + <p>Once the cavity is opened at the toe in the neighbourhood of the white line, then + diagnosis is easy. A blunt piece of wood, the farrier's knife, or a director may be + easily passed into it, sometimes as far up as the coronary cushion (see Fig. 129). + Issuing from the opening is seen occasionally a little inspissated pus; more often, + however, the dry, mealy-looking detritus to which we have before referred. This form + of the disease we may term 'Internal Seedy-Toe.' for, plainly enough, it has had its + origin in chronic inflammatory changes in the keratogenous membrane.</p> + <br /> + <a name="a130" id="a130"></a> + <p><a href="images/image130.png"><img src="images/image130sm.png" + alt="EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR BORDER OF THE WALL." /></a></p> + <br /> + + <p>FIG. 130.—EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR BORDER OF THE + WALL.</p> + <br /> + <a name="a131" id="a131"></a> + <p><a href="images/image131.png"><img src="images/image131sm.png" + alt="EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR FACE OF THE WALL." /></a></p> + <br /> + + <p>FIG. 131.—EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR FACE OF THE + WALL.</p> + <p>Disease of the horn and loss of its substance may, however, also commence from + without. A report on this condition, under the title of 'External Seedy-Toe,' is to + be found in vol. xxix. of the <i>Veterinary Journal</i>, from which we borrow Figs. + 130 and 131.</p> + <p>In Fig. 130 it will be seen that the disease commences at the plantar surface of + the toe, and extends upwards and inwards. The same condition may also appear anywhere + between the coronet and the ground, gradually extending into the substance of the + wall, as shown in Fig. 131. According to the writer, Colonel Nunn, the progress of + the disease in this latter case appears to be faster in a downward than in an upward + direction. This, however, is more apparent than real, as the rate of growth of the + horn downwards detracts from the progress of the disease upwards, although it spreads + over the horn at the same rate.</p> + <p>Before concluding the symptoms, we may again allude to the fact that, although + usually occurring at the toe, the same condition may be met with in other + positions—namely, at either of the quarters. In appearance and in other + respects it is identical with that occurring at the toe.</p> + <p>When the animal is lame and the existence of seedy-toe is surmised, or when the + cause of the lameness is altogether obscure, a little information may perhaps be + gathered from noting the wear of the shoe. If the animal has been going lame for any + length of time as a result of disease in the sensitive laminæ, then the shoe + will be greatly thinned at the heels, and the toe but little worn.</p> + <p><i>Treatment</i>.—As with diseased structures elsewhere, the most rational + treatment, when possible, is that of excision. The entire portion of the wall forming + the anterior boundary of the cavity is thinned down with the rasp and afterwards + removed with the knife, wholly exposing the hypertrophied, but usually soft layer of + horn covering the sensitive structures. These hypertrophied portions are also + removed, and every particle of the dust-like detritus cleaned away. After-treatment + consists in dressing the parts with a good hoof ointment, protecting them, if + necessary, with a pad of tow and a stout bandage. It may be that the removal of a + large portion of the wall may for some time throw the animal out of work. Acting on + Colonel Fred Smith's suggestion, this may be avoided by having made a thin plate of + sheet-iron, slightly larger in circumference than the portion of horn removed, and + shaped to follow the contour of the foot. This made, it is sunk flush with the wall + by hot-fitting it, and kept in position by several small steel screws fixed into the + sound horn, just as in the treatment for sand-crack (see p. 174). This will serve the + useful purpose of maintaining in position any dressing that may be thought necessary, + of acting as a support to the horn left on each side of the portion removed, and of + keeping the exposed structures free from dirt and grit.</p> + <p>Practical points to be remembered in fitting plates of this description to the + feet are: The plate must never quite reach the shoe, or it will participate in the + concussion of progression, and so loosen the screws that hold it in place. For the + same reason, that portion of the sole adjoining the piece of horn removed must have + its bearing on the shoe relieved. The screws holding the plate should be oiled to + prevent rusting, and should take an oblique direction in order to obtain as great a + hold as possible on the wall.</p> + <p>When excision is deemed unwise or unnecessary, treatment should be directed + towards maintaining the cavity in a state of asepsis. To this end it should be + thoroughly cleaned of its contents, and afterwards dressed with medicated tow. The + ordinary tar and grease stopping is as suitable as any. This, together with the tow, + is tightly plugged into the opening and kept in position by a wide-webbed shoe. + Instead of the tar stopping and the tow, there may be used with advantage the + artificial hoof-horn of Defay (see p. 152). Before using this the cavity should again + be thoroughly cleaned out, and should in addition be mopped out with ether. The + latter injunction is important, as unless the grease is thus first removed, the + composition will fail to adhere to the horn. With the cavity thus cleaned and + prepared, the artificial horn, melted ready to hand, is poured into it and allowed to + set.</p> + <p>In every case, no matter what else the treatment, the bearing of the horn adjacent + to the lesion should be removed from the shoe. Whether practising the method of + plugging the cavity or that of excision of the wall external to it, attempts to + quickly obtain a new growth of horn from the coronet should be made. To further that, + frequent stimulant applications should be used. Ointment of Biniodide of Mercury 1 in + 8, of Cantharides 1 in 8, or the ordinary Oil of Cantharides, either will serve.</p> + <p>3. KERAPHYLLOCELE.</p> + <p><i>Definition</i>.—By this term is indicated an enlargement forming on the + inner surface of the wall. In shape and extent these enlargements vary. Usually they + are rounded and extend from the coronary cushion to the sole, sometimes only as thick + as an ordinary goose-quill, at other times reaching the size of one's finger. Often + they are irregular in formation and flattened from side to side.</p> + <br /> + <a name="a132" id="a132"></a> + <p><a href="images/image132.jpg"><img src="images/image132sm.jpg" + alt="A PORTION OF THE HORN OF THE WALL AT THE TOE REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE." /> + </a></p> + <br /> + + <p>FIG. 132.—A PORTION OF THE HORN OF THE WALL AT THE TOE REMOVED IN ORDER TO + SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.</p> + <p><i>Causes</i>.—Keraphyllocele is very often a sequel to the changes + occurring at the toe in laminitis. Probably, however, the most common cause is an + injury upon, or a crack through, the wall. It may thus occur from excessive hammering + of the foot, from violent kicking against a wall or the stable fittings, and from the + injury to the coronet known as 'tread.' It may also occur as a sequel to complicated + sand-crack, and to chronic corn.</p> + <p>That fissures in the wall are undoubtedly a cause has been placed on record by the + late Professor Walley, who noticed the appearance of these horny growths following + upon the operation of grooving the wall.[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. iii, + p. 170.]</p> + <p>This gentleman had a large Clydesdale horse under his care for a bad sand-crack in + front of the near hind-foot, and, as the lameness was extreme, he adopted his usual + method of treatment—viz., rest, fomentations, poulticing, and the making of the + V-shaped section through the wall, and subsequently the application of an appropriate + bar shoe to the foot, and repeated blisters to the coronet. In a short time the + lameness passed off, and the horse was put to work. A few days later the animal met + with an accident, and was killed.</p> + <p>On examining a section of the hoof it was found that a vertical horny ridge + corresponding to the external fissure had been formed on the internal surface of the + wall, and that a well-marked cicatrix extended upwards through the structure of the + hoof at the part forming the cutigeral groove; furthermore, <i>a similar ingrowth had + been taking place in the line of the oblique incisions made for the relief of the + sand-crack</i>.</p> + <p>This case has an important bearing on the operation of grooving the wall, which + operation we have several times in this work advocated for the relief of other + diseases. It teaches us that the incisions should not be carried so completely + through the horn as to interfere with and irritate the sensitive laminæ, and so + set up the chronic inflammatory condition leading to hypertrophy of the horn.</p> + <p>From the position on the os pedis of the indentation made in it by the + keraphyllocele (see Fig. 133) it has been argued that pressure of the toe-clip is a + cause of the new growth. This, we should say, cannot be a very strong factor in the + causation, for, while we admit that the continual pressure of the clip, and the heavy + hammering that sometimes fits it into position, is likely to set up a chronic + inflammatory condition of the sensitive laminæ in that region, we must still + point out that the rarity of keraphyllocele, as compared with the fact that clips are + on every shoe, does not allow of the argument carrying any great weight.</p> + <p><i>Symptoms</i>.—Except under certain conditions this defect is difficult of + detection. As a rule, lameness is not produced by it. In making that statement we are + led largely by the conclusion arrived at by Professor Walley. This observer noted the + fact that ingrowths of horn such as we are describing nearly always take place in + false quarter, or after a sand-crack has been repaired, and that they commonly occur + after the operation of grooving the wall in the manner we have just shown.</p> + <p>Now, we know that quite often under these circumstances the horse goes perfectly + sound. Thus, while we know that in all probability keraphyllocele is in existence, we + have ocular demonstration that the animal is quite unaffected by it.</p> + <p>In some cases, however, lameness is present. During the early stages of the + growth's formation it is but slight, increasing as the keraphyllocele enlarges. + Should this be the case, other symptoms present themselves. The coronet is hot, and + tender to the touch, sometimes even perceptibly swollen, and percussion over the wail + is met with flinching on the part of the animal. In other cases one is led to suspect + the condition by the prominence of the horn of the wall of the toe. This is + distinctly ridge-like from the coronet to the ground, while on either side of it the + quarters appear to have sunk to less than their normal dimensions. We believe this to + be an illusion, as a ridge of any size at the toe readily gives one the impression of + atrophy behind it, without this latter condition being actually present.</p> + <p>Should this ridge-like formation and the accompanying symptoms of pain and + lameness occur after repair of a sand-crack, then keraphyllocele may, with tolerable + certainty, be diagnosed. When these outward signs are wanting, however, and the true + nature of our case is a matter of mere conjecture, a positive diagnosis may still be + made at a later stage—that is, when the abnormal growth of horn reaches the + sole. In this case either there is met with when paring the sole a small portion of + horn, circular in form, distinctly harder than normal, and indenting in a + semicircular fashion the front of the white line at the toe, or solution of + continuity between the tumour and the edge of the sole and the os pedis takes place, + and the lameness resulting from the ingress of dirt and grit thus allowed draws + attention to the case.</p> + <p><i>Pathological Anatomy</i>.—With the sensitive structures removed from the + hoof by maceration or other means, these growths are at once apparent. They may occur + in any position, but are usually seen at the toe, and they may extend from the + coronary cushion to the sole, or they may occupy only the lower or the upper half of + the wall. In places the tumour (or 'horny pillar' as the Germans term it) is + roughened by offshoots from it, and does not always exhibit the smooth surface + depicted in Fig. 132. Commonly, the horn composing the new growth is hard and dense. + Sometimes, however, it is soft to the knife, and is then found to be itself fistulous + in character, a distinct cavity running up its centre, from which issues a black and + offensive pus.</p> + <p>In a few cases the sensitive laminæ in the immediate neighbourhood are found + to be enlarged, but in the majority of cases atrophy is the condition to be observed. + Not only are the sensitive structures found to be shrunken and absorbed, but the + atrophy and absorption extends even to the bone itself (see Fig. 133). This latter is + a result of the continued pressure of the horny growth, in a well-marked case ending + in a sharply-defined groove in the os pedis in which the keraphyllocele rests. The + fact that the softer structures, and even the bone, thus accommodate themselves to + the altered conditions is, no doubt, the reason that lameness in many of these cases + is absent.</p> + <p><i>Treatment</i>.—It is doubtful whether anything satisfactory can be + recommended. When we have suspected this condition ourselves, it has been our + practice to groove the hoof on either side of the toe, after the manner illustrated + in Fig. 120, and, at the same time, point-firing the coronet and applying a smart + cantharides blister. Certainly, after this operation, lameness has often + disappeared—whether, however, as a result of the treatment adopted or by reason + of the structures within accommodating themselves to the condition, we would not care + to say.</p> + <br /> + <a name="a133" id="a133"></a> + <p><a href="images/image133.jpg"><img src="images/image133sm.jpg" + alt="OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY ATROPHY AND ABSORPTION INDUCED BY PRESSURE OF A KERAPHYLLOCELE." /> + </a></p> + <br /> + + <p>FIG. 133.—OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY ATROPHY AND ABSORPTION + INDUCED BY PRESSURE OF A KERAPHYLLOCELE.</p> + <p>Other writers advocate the removal of that portion of the wall to which the tumour + is attached, after the manner described on p. 182, and illustrated in Fig. 98. This, + however, should be a last resource, and should be adopted only when weighty reasons, + such as excessive and otherwise incurable lameness, appear to demand it.</p> + <p>4. KERATOMA.</p> + <p>In our nomenclature the terms 'Keratoma' and 'Keraphyllocele' are both used to + indicate the condition we have just described. There are some, however, who reserve + the term 'Keratoma' for horny tumours occurring only on the sole, and for that reason + we draw special attention to the word here. Keratoma may thus be used to describe + what we have called keraphyllocele directly that growth makes its appearance at the + sole, and is there able to be cut with the knife. Similar hard and condensed growths + may, however, make their appearance on the sole in other positions quite removed from + the white line, plainly being secreted by the villous tissue of the sensitive sole, + and having no connection whatever with the sensitive laminæ. They appear as + circular patches, varying in size from a shilling to a two-shilling piece. Compared + with the surrounding horn, they stand out white and glistening, while in structure + they are dense and hard, and offer a certain amount of resistance to the knife. They + are of quite minor importance, and, beyond keeping them well pared down, need no + attention. Keratoma probably offers us the best analogy we have to corn of the human + subject.</p> + <p>5. THRUSH.</p> + <p><i>Definition</i>.—A disease of the frog characterized by a discharge from + it of a black and offensive pus, and accompanied by more or less wasting of the + organ.</p> + <p><i>Causes</i>.—The primary cause of this affection is doubtless the + infection of the horn, and later the sensitive structures, with matter from the + ground. Those factors, therefore, leading to deterioration of the horn, and so + exposing it to infection, may be considered here. Such will be changes from excessive + dampness to dryness, or <i>vice versâ</i>; work upon hard and stony roads; + prolonged standing in the accumulated wet and filth of insanitary stables, or long + standing upon a bedding which, although dry, is of unsuitable material.</p> + <p>In this latter connection may be mentioned the harm resulting from the use of + certain varieties of moss litter. This we find pointed out by J. Roalfe Cox, + F.R.C.V.S.[A] Tenderness in the foot was first noticed, and, on examination, the horn + of the sole and of the frog was found to be peculiarly softened. It afforded a + yielding sensation to the finger, not unlike that which is imparted by indiarubber, + and on cutting the altered horn it was almost as easily sliced as cheese-rind. The + outer surface being in this way slightly pared off, the deeper substance of the horn + was discoloured by a pinkish stain. The horn of the frog was in many instances found + detaching from the vascular surface, which was very disposed to take on a diseased + action, somewhat allied to canker, and became extremely difficult to treat.</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. xvi., p. 243.]</p> + <p>Conditions such as these, although not constituting the disease itself, certainly + lay the frog open to infection, especially if afterwards the animal is called upon to + work in the mud of the streets of a large town, or to stand in a badly drained and + damp stable.</p> + <p>A further cause of thrush is to be found in the condition of the frog, brought + about by contraction of the heels (see p. 118). We have already seen that one of the + most prominent factors in the causation of contraction is the removal of the frog + from the ground by shoeing, with its consequent diminution in size and deterioration + in quality of horn. This leads to fissures in the horny covering, and favours + infection of the sensitive structures beneath. Thrush is, in fact, nearly always + present in the later stages of contracted foot.</p> + <p>By some thrush is believed to be but the commencement of canker. With this, + however, we do not hold. We believe both to be due to specific causes as yet + undiscovered, but that the cause of thrush is not the one operating in canker. In + arriving at this conclusion we are guided by clinical evidence. The two conditions + are quite dissimilar, even in appearance, and, while one is readily amenable to + treatment, the other is just as obstinately resistant.</p> + <p><i>Symptoms</i>.—The symptoms of thrush are always very evident. Probably + the first thing that draws one's attention to it is the stench of the puriform + discharge. The foot is then picked up and the characteristic putrescent matter found + to be accumulated in the median, and often in the lateral, lacunæ. The organ is + wasted and fissured, the horn in the depths of the lacunæ softened and easily + detachable, and portions of the sensitive frog often laid bare.</p> + <p>With a bad thrush lameness is present, the frog itself is tender to pressure, and + often there is considerable heat and tenderness of the heels and the coronet + immediately above. More especially is this noticeable after a journey.</p> + <p>It is, perhaps, more common in the hind-feet than in the fore, and more often met + with in heavy draught animals than in nags. The hind-feet are, of course, more open + to infection by reason of their being constantly called upon to stand in the animal + discharges in the rear of stable standings, while it is a well-known fact that heavy + animals have their stables kept far less clean, and their feet less assiduously cared + for, than do animals of a lighter type.</p> + <p>In a nag-horse with thrush of both fore-feet lameness becomes sometimes very + great. The gait when first moved out from the stable is feeling and suggestive of + corns, while progress on a road with loose stones is sometimes positively dangerous + to the driver.</p> + <p><i>Treatment</i>.—When this condition has arisen, as it often does, from + want of counter-pressure of the frog with the ground, this pressure must be restored + after the manner described when dealing with the treatment of contracted foot (see p. + 125) either by the use of tip or bar shoes, or by suitable pads and stopping.</p> + <p>So far as direct treatment of the lesion itself is concerned, the first step is to + carefully trim away all diseased horn and freely open up the lacunæ in which + the discharge has accumulated. Good results are then often arrived at by poulticing, + afterwards followed up by suitable antiseptic dressings. With us a favourite one is + the Sol. Hydrarg. Perchlor. of Tuson, used without dilution. Others use a dry + dressing, and dust with Calomel, with a mixture of Sulphate of Copper, Sulphate of + Zinc and Alum, or with Subacetate of Copper and Tannin.</p> + <p>With restoration, so far as is possible, of the frog functions, and with careful + dressing, a cure is nearly always obtained.</p> + <p>6. CANKER.</p> + <p><i>Definition</i>.—Under this unscientific, yet expressive term, is + indicated a chronic diseased condition of the keratogenous membrane, commencing + always at the frog, and slowly extending to the sole and wall, characterized by a + loss of normal function of the horn secreting cells, and the discharge of a serous + exudate in the place of normal horn.</p> + <p><i>Causes</i>.—The exact cause of canker has still to be discovered. + Therefore, before expressing an opinion as to what the <i>probable</i> cause may be, + we may state here that such opinion can only be based upon clinical observation. Such + being the case, we are almost duty bound to give the views of older authors before + those of more modern writers.</p> + <p>From the mass of material ready to hand we may select the following as serving our + purpose.</p> + <p>The earliest opinion appears to have been that canker, as the name indicates, was + of a cancerous or cancroid nature. This was also believed by Hurtrel D'Arboval, who + looked upon canker as carcinoma of the recticular structure of the foot. The same + theory we find enunciated in the <i>Veterinary Journal</i> so late as 1890. Although + the word 'cancer' or 'carcinoma' is not there used, the author employs the terms + 'Papilloma' and 'Epithelioma' with the evident intention of expressing his belief in + the malignant nature of the disease.</p> + <p>Another early opinion was that the disease was a <i>spreading ulcer</i>, gradually + extending and changing the tissues which it invaded.</p> + <p>A further early theory, and one which if not still believed in, has died a hard + death, is the constitutional theory. This was believed in by nearly all the older + writers, and is mentioned so late as 1872 by the late Professor Williams. In his + 'Principles and Practice of Veterinary Surgery,' he says: 'Canker is a constitutional + disease due to a cachexia or habit of body, grossness of constitution, and lymphatic + temperament.' This, we believe, is credited to-day by some, and yet, quite 100 years + before the date of the 1872 edition of Williams's work—in 1756, to be + exact—we find a veterinary writer when talking of grease (a disease, by-the-by, + very closely allied to canker) exclaiming against this habit of referring everything + which we do not rightly understand to some ill-humour of the body. The wisdom his + words contain justifies us in giving them mention here. 'It is a very foolish and + absurd Notion,' he says, 'to imagine a Horse full of Humours when he happens to be + troubled with the Grease. But such Shallow Reasoning will always abound while + Peoples' Judgments are always superficial. Therefore, to convince such unthinking + Folks, let them take a thick Stick and beat a Horse soundly upon his Legs so that + they bruise them in several Places, after which they will swell, I dare say, and yet + be in no danger of Greasing. Now, pray, what were these offending Humours doing + before the Bruises given by the Stick?'</p> + <p>At the present day it is safe to assert that neither the ulcerative, the + cancerous, nor the constitutional theory is believed in widely, and, among the mass + of contrary opinions as to the cause of this disease, we may find that even quite + early many of the older writers had discarded them.</p> + <p>Quoting from Zundel, we may say that Dupuy in 1827 considered canker as a + hypertrophy of the fibres of the hoof, admitting at the same time that these fibres + were softened by an altered secretion; while Mercier in 1841 stated that canker was + nothing more than a chronic inflammation of the reticular tissue of the foot, + characterized by diseased secretions of this apparatus.</p> + <p>Saving that they make no mention of a likely specific cause, these last two + statements express all that we believe to-day. As early as 1851, however, the + existence of a specific cause was hinted at by Blaine in his 'Veterinary Art.' We + find him here describing canker as a <i>fungoid</i> excrescence, exuding a thin and + offensive discharge, which <i>inoculates</i> the soft parts within its reach, + particularly the sensitive frog and sole, and destroys their connections with the + horny covering.</p> + <p>The use of the word 'fungoid,' and particularly that of 'inoculate,' is suggestive + enough, and is evidence sufficient that either Blaine or his editor recognised, + simply through clinical observation, the working of a special cause.</p> + <p>Four years later, Bouley is found holding the opinion that canker was closely + allied to tetter, thus recognising for it a local specific cause. The same observer + also pointed out that the secretion of the keratogenous membrane instead of being + suspended was greatly increased, taking care to explain, as did Dupuy, that the + products of the secretion were perverted and had lost their normal ability to become + transformed into compact horn.</p> + <p>In 1864 this slowly growing recognition of a specific cause received further + impetus from the statements of Megnier. This observer claimed to have discovered in + the cankerous secretions the existence of a vegetable parasite (namely, a cryptogam, + as in favus), which he termed the keraphyton, or parasitic plant of the horn.</p> + <p>Modern research, though failing to substitute anything more definite, has not + confirmed this. The exact and exciting cause of canker is therefore still an open + question, and a matter for research. We may, however, sum the matter up by briefly + discussing the causes, so far as clinical observation teaches us. This we shall do + under two headings—namely, <i>Predisposing</i> and <i>Exciting</i>.</p> + <p><i>Predisposing Causes</i>.—Starting with the assumption that the disease is + due to local infection, we may relate as predisposing causes anything having a + prejudicial effect upon the horn, disintegrating it, and so laying the tissues + beneath open to attack. The most prominent in this connection is certainly a + continued dampness of the material on which the animal has to stand. Particularly is + this the case when the material is also excessively foul and dirty, contaminated with + the animal discharges, and presumably swarming with the lower forms of animal and + plant life. We shall therefore find bad cases of canker in stables where the "sets" + are irregular, or where no paving at all is attempted, where the drainage is + defective, and where darkness and want of proper ventilation favours organismal + growth. The fact that with modern drainage and a general hygienic improvement in + stabling, canker has to a large extent died out, supports this contention.</p> + <p>Again, as with thrush, anything removing the counter-pressure of the frog with the + ground and throwing that organ out of play, may be looked upon as a predisposing + cause. The atrophy of the frog thus occurring, the deterioration in the quality of + its horn and the fissures in its surface lay it specially open to infection. That one + of the principal factors in the treatment of canker is a restoration of + ground-pressure to the frog and the sole is sufficient proof of this.</p> + <p>Further, it is well to note that, although playing no part in the actual + causation, certain constitutional conditions may in some measure predispose the foot + to attack. Clinical observation teaches us that animals of a lymphatic nature, with + thick skins and an abundance of hair, with flat feet and thick, fleshy frogs, are far + more liable to attack than are animals with reverse points.</p> + <p><i>Exciting Causes</i>. Those who give this subject careful consideration cannot + fail to arrive at the conclusion that canker is most certainly due to local infection + with a specific poison, and that poison a germicidal one from the ground. The + symptoms arising may be due to the action of a single germ, or to two or more germs + acting in conjunction. As to whether the parasitic invasion is single or multiple we + cannot feel certain, but that it <i>is</i> parasitic we feel absolutely assured.</p> + <p>It is simply the light that bacteriological advance has made during the last two + decades that enables us to make the statement with such feelings of assurance. We + arrive at our conclusions by reasoning from analogy. Here we have a disease always + exhibiting the same symptoms, more or less peculiar to one class of animal, always + with a similar characteristic appearance and smell, always obstinately refractory to + treatment, showing always a tendency to spread to the other feet of the same animal, + and often to the feet of other animals <i>near enough to become</i> infected, and + always cured—when cured it is—by a treatment which may be summed up in + two words as 'rigid antisepsis.' Other diseases, with points in common with this, + have been directly proved to be due to a specific cause. Common regard for logic + compels us to admit the same for canker.</p> + <br /> + <a name="a134" id="a134"></a> + <p><a href="images/image134.jpg"><img src="images/image134sm.jpg" + alt="A FOOT, THE SUBJECT OF CANKER, SHOWING DESTRUCTION OF THE HORNY FROG, AND A FUNGOID-LOOKING HYPERTROPHY OF THE TISSUES BENEATH." /> + </a></p> + <br /> + + <p>FIG. 134.—A FOOT, THE SUBJECT OF CANKER, SHOWING DESTRUCTION OF THE HORNY + FROG, AND A FUNGOID-LOOKING HYPERTROPHY OF THE TISSUES BENEATH.</p> + <p><i>Symptoms and Pathological Anatomy</i>.—The symptoms of canker are seldom + noticeable at the commencement of an attack. The disease is slow in its progress; for + some time confines its ravages to the sub-horny tissues unseen, and is quite + unattended with pain. It is not observed, therefore, until considerable damage has + been done, and the disease is far advanced. What is usually first seen is a peculiar + softening and raising of the horn of the frog. The infective material has set up a + chronic inflammation of the keratogenous membrane, leading to abnormal secretion, + and, in place of the horny cells it should normally secrete, is thrown out an + abundance of a serous fluid.</p> + <p>This upraised and softened horn once thrown off is not again renewed, and the + whole of the sensitive frog and perhaps a portion of the sensitive sole is left + uncovered. In place of the normal horn, however, is often found a hypertrophy of the + elements of the keratogenous membrane leading to huge fungoid-looking growths with a + papillomatous aspect, damp in appearance and offensive in smell, and readily bleeding + when injured (see Fig. 131).</p> + <p>The horn immediately surrounding the lesion is loose and non-adherent to the + sensitive structures. This indicates, of course, that the disease has spread further + beneath the horny covering than is at first sight apparent. Portions of this loose + horn removed reveal beneath it a caseous foetid matter, easily removed by scraping + (the perverted secretion of the keratogenous membrane). When this is carefully + scraped away, the sensitive structures appear to be covered with a thin, smooth + membrane, gray in colour and almost transparent, while beneath it may be seen the red + appearance of normal sensitive structures.</p> + <p>If the horn surrounding the lesion is not touched with the knife, but little is + seen of the extent of the disease, for that removed by natural means is often very + small in quantity. To all intents and purposes the disease appears to be confined to + the frog. This appearance is misleading, especially if the disease has been in + existence for some time, for it may have easily spread to the whole of the sole, and + even to the greater portions of the laminæ secreting the wall.</p> + <p>It is, in fact, not until the pressure exerted by the normal horn is removed by + its breaking away that the vascular structures of the keratogenous membrane begin to + swell, and the perverted secretions to enlarge in size. Once the pressure is removed, + however, this quickly comes about, and the characteristic fungoid growths rapidly + make their appearance.</p> + <p>This tendency to spread is highly indicative of canker. The serous matter exuding + from the diseased keratogenous membrane appears, in fact, to be highly infective. + Once its flow is commenced, it slowly, but surely, invades the sensitive structures + near it, appearing, as Elaine has put it, to 'inoculate' them. What is really the + case, of course, is not that the discharge itself is infective, but that it is + contaminated with infective material.</p> + <p>The fungoid-looking growths to which we have before referred are, in reality, + nothing more than the villi of the sensitive frog and sole greatly hypertrophied and + irregular in shape. At times the hypertrophy is as a huge and compact enlargement + occupying the position of the frog. Sometimes, however, it occurs as numerous + elongated and twisted fibrous bundles, separated from each other by deep clefts, and + the clefts filled with the offensive cankerous discharge (see Fig. 134).</p> + <br /> + <a name="a135" id="a135"></a> + <p><a href="images/image135.png"><img src="images/image135sm.png" + alt="LOWER ASPECT OF CANKERED FOOT, SHOWING DESTRUCTION OF WALL." /></a></p> + <br /> + + <p>FIG. 135.—LOWER ASPECT OF CANKERED FOOT, SHOWING DESTRUCTION OF WALL.</p> + <p>At a very advanced stage canker leads to destruction of much of the horny sole and + frog; or even parts of the wall may become separated from the tissues beneath, and + break away from the foot (see Fig. 135). At other times the disease brings about a + deformity of the whole of the foot. Its longitudinal and transverse diameters become + enormously increased, and the whole foot apparently flattened from above to below + (see Fig. 136). This indicates that not only has the horny sole been entirely + destroyed, but that the destructive process has also extended to the greater part of + the lower half of the wall, with a consequent hypertrophy of exposed soft structures, + and a sinking of the bony column, similar to that which occurs in laminitis, but not + so pronounced.</p> + <br /> + <a name="a136" id="a136"></a> + <p><a href="images/image136.png"><img src="images/image136sm.png" + alt="FOOT WITH ADVANCED CANKER." /></a></p> + <br /> + + <p>FIG. 136.—FOOT WITH ADVANCED CANKER.</p> + <p>A further aspect of the badly-cankered foot is to be found in an apparently + enormous increase in the length of the wall. This we have seen protruding for quite 5 + inches beyond the plane of the sole. It simply indicates that, in order to keep the + animal at work, the smith has at every shoeing spared the wall, so that the diseased + structures might be kept from contact with the ground.</p> + <p>As we have said before, pain and other symptoms of distress are quite absent. + Animals affected with canker for a long time maintain their condition, feed well, and + are quite capable of performing work under ordinary conditions.</p> + <p><i>Differential Diagnosis and Prognosis</i>.—Perhaps the only disease with + which canker may be confounded is thrush. They should, however, be easily + distinguishable. The discharge from thrush is not so profuse, and is thicker and + darker in colour, while the loosening of the horn is almost entirely absent. + Furthermore, thrush shows no tendency to spread, and, even when left untreated, may + remain confined to the frog for months, and even years. Canker, on the other hand, is + slowly progressive, and soon shows the characteristic fungoid excresences, which + growths are in thrush never seen. A further point of difference is discovered when + treatment is commenced. Canker is found to be refractory to a point that is + absolutely disheartening, while thrush, with careful attention, is soon got under + hand, and a permanent cure effected.</p> + <p>The prognosis must be guarded. By many canker has been said to be incurable. This, + however, has been clearly shown to be wrong. When the animal is young, and treatment + may reasonably be judged to be economical, then a favourable prognosis may be + indulged in, provided the veterinary surgeon intends to put into that treatment a + more than ordinary amount of individual care and attendance. Even then, however, he + will have to be very largely guided by the condition of his case. He should see that + it is not too far advanced, and that a great deformity of the hoof, or actual + exploration, does not indicate disease of the greater part of the wall.</p> + <p><i>Treatment</i>.—From what has gone before, it will be seen that the + eradication of canker is no easy task, that it is, in fact, a most difficult matter, + and one not to be lightly undertaken. At the risk of recapitulating what we have said + before, we may mention here the two points which the veterinarian must bear in mind. + (1) That there is no actual disease or alteration in structure of the deep layers of + the keratogenous apparatus. It is only the superficial, or horn-secreting, layer that + concerns us. (2) That the disease of this superficial layer is infection with a + material that may reasonably be presumed to be infective.</p> + <p>Put thus, treatment of canker would at first sight appear to be easy. One would + imagine that a simple and long-continued soaking of the entire foot in a strong + enough antiseptic would be all that was needed. Clinical observation, however, shows + that this is not so, and for this there must be reasons.</p> + <p>The reasons are these: (1) Between us and the diseased layer upon which our + attention must be directed is often a layer of normal horn, effectually protecting + the tissues beneath from any dressing which we might consider beneficial. (2) + Anything applied with the object of destroying septic material, but strong enough, or + caustic enough, to injure the membrane upon which we are working, only makes the case + worse. The superficial layer of the keratogenous membrane in which we have judged the + disease to exist is, after all, but a delicate structure. When attacked by the + application of too potent a drug its horn-secreting layer is easily destroyed, and + thus, although we may succeed in establishing asepsis, we cannot expect at the point + of injury a growth of horn. In its place we are confronted with large outgrowths of + inflammatory fibrous tissue. (3) Shedding of the diseased horn and removal of the + pressure exerted by the hoof faces us with hypertrophy of the exposed villi. The + difficulty of meeting this with an adequate and evenly-distributed pressure is well + enough known, and we find in that a further reason that the treatment of canker is + superlatively difficult. (4) The material on which the animal has to stand is a + distinct bar to the maintaining of a strict asepsis.</p> + <p>When we have said this, it is easy to understand that canker is not to be + successfully met with any so-called specific—that it makes but little + difference what the application may be so long as it is antiseptic, and is used by a + man thoroughly conversant with the difficulties he has to contend with, and with his + mind firmly set upon surmounting them.</p> + <p>With this point established, we will not devote more of our space to a + consideration of the various dressings that have at different times been highly + advocated in the treatment of the disease. It is interesting, however, to note that + intensely irritating and caustic applications have been greatly in favour. Nitric + acid, sulphuric acid (either alone or its action reduced by the addition of alcohol, + oil, or turpentine), arsenic, butter of antimony, creasote, chromic acid, carbolic + acid, arsenite of soda, and the actual cautery, have all been used.</p> + <p>Without dwelling further on that, we may say at once that a correct treatment + consists in (1) the removal of all horn overlying infected portions of the + keratogenous membrane, (2) the application of an antiseptic not too powerfully + caustic in its action, (3) frequent changes of the dressings in order to insure a + maintenance of antisepsis, and (4) the application of an adequate pressure to the + exposed soft structures. Thus combated, canker is curable.</p> + <p>The man who, at the expense of much time and trouble, has demonstrated the truth + of these axioms is Mr. Malcolm, of Birmingham. The determination with which he clung + to his point that canker was, with correct treatment, in every case curable, was some + years ago provocative of much discussion in veterinary circles. That he was + successful in proving his contention is more to our point here. It is his method of + treatment, therefore, that we shall give, and this we shall do by liberal extracts + from Mr. Malcolm's own writings.</p> + <p>'On the first occasion of operating upon and dressing the cankered foot, it is + usually necessary to cast the horse, and this may have to be done at intervals for a + second or even third time; but in most cases once is sufficient, subsequent dressing + being usually accomplished without much difficulty, frequently even without the aid + of a twitch. After the horse has been secured, the drawing-knife is first employed; + and if the frog alone is affected, it is unnecessary even to pare the sole, the + removal of all frog horn not intimately adherent to its secreting surface being all + that is required. But if both sole and frog be involved, the whole of the sound horn + should be first thinned until it springs under the thumb, and then, using a sharp + knife, every particle of diseased horn must be carefully removed from both sole and + frog, a process much more easily, and with far greater certainty, secured by the + previous thinning of the horn.</p> + <p>'The removal of diseased horn should always commence at the most dependent part of + the foot, so that any hæmorrhage produced may be below the parts still to be + operated on, a matter of considerable moment for effective treatment. But with due + care there will be little hæmorrhage, as, except in the initial stage, there is + no real union between the diseased horn and the diseased vascular secreting + surface.</p> + <p>'After all apparently diseased horn has been removed by the knife, any still + remaining should be at once destroyed by the actual cautery, by which it can be + identified. All the diseased secreting surface should be <i>carefully scraped with a + thin hot iron</i>,[A] fungoid growths excised and cauterized, and, indeed, every + particle of cankered tissue should, if possible, be eradicated. In securing this more + reliance can be placed on the actual cautery than on any other, whether liquid or + solid: it is more under control in application, more decisive in effect, and its + results can be anticipated with a far greater certainty. Moreover, its aid in + diagnosis is of immense value; applied to the thinned horn or secreting surface it + unmistakably demonstrates the presence or absence of canker. Healthy tissue chars + black; cankered tissue, on the contrary, bubbles up white under the hot iron, and + presents an appearance not unlike roasted cheese.</p> + <p>[Footnote A: The words in italics are alterations in the original article made by + Mr. Malcolm in a private letter to the author (H.C.R.).]</p> + <p>'Although this test is certain for horn thinned to the quick, it is not to be + relied upon with thick horn, the outside of which may be practically healthy and char + black, while its underlying surface may be cankered. With this exception the test is + an infallible one, as by it the demarcation between cankered and healthy tissue can + be clearly traced, and as a result we can with equal confidence radically + <i>remove</i>[A] all cankered tissue, and conserve all healthy. As the object of that + abominably cruel and barbarous operation of stripping the sole is the exposure of all + canker, and as this can be done with equal certainty with the aid of the hot iron, + there can be no necessity for performing it. The pain of cauterizing cankered tissue, + which is a necessary operation, is infinitesimal (canker largely destroying + sensation), compared with the pain produced in the totally unnecessary process of + tearing healthy horn from a highly sensitive tissue.</p> + <p>[Footnote A: The words in italics are alterations in the original article made by + Mr. Malcolm in a private letter to the author (H.C.R.).]</p> + <p>'Having by means of the knife and cautery removed every known particle of disease, + the next procedure is to pack the surface of the sole and frog thus exposed with a + <i>mild dressing, such as vaseline; but if the cankered surface has not been + efficiently, scraped, than there is required a more</i> [A] powerful astringent or + caustic dressing, which may vary considerably according to the individual fancy. A + great favourite of mine consists of equal parts of sulphates of copper, iron, and + zinc, mixed with strong carbolic acid, a very little vaseline being added to give the + mass cohesion. The dressing, covered by a pledget of tow, is held in position by a + shoe with an iron or leather sole, and the dressing and tow together should be of + sufficient bulk to produce slight pressure on the sole when the nails of the shoe are + drawn up. This insures contact between the dressing and the exposed surface, as well + as any benefit derivable from pressure.</p> + <p>[Footnote A: The words in italics are alterations in the original article made by + Mr. Malcolm in a private letter to the author (H.C.R.).]</p> + <p>'The dressing of the foot and nailing of the shoe can usually be more + expeditiously performed when the horse is on his feet than when prone. If only the + frog, or the frog and a small part of the sole, be involved, the horse should be kept + at work, but if a large part or the whole of the sole a few days' rest may be + necessary; but as soon as the condition of the foot will allow, work should be + resumed, and it is simply marvellous how sound a horse will walk while minus the + greater part of his sole from canker.</p> + <p>'On the second day following the shoe should be removed, and the foot redressed. + To effect this it is necessary to recast the horse. Commencing at the edge of the + sound horn, at the most dependent part of the foot, all new horn, no matter what its + condition, must be pared to the quick, especial care being taken to effectually + remove any lingering disease. Want of success is frequently attributable to neglect + of this precaution. A small particle of canker remains undetected, forms a new centre + of infection, and just when success is anticipated, much to your chagrin you have to + deal with a fresh outbreak of canker, instead of a rapidly-healing foot. + Parenthetically, I may here remark that the amount of more or less imperfect new horn + produced by a cankered surface after an effective but not too destructive + cauterization is almost incredible, and one cannot fail to be struck with the very + active proliferation here compared with the meagre production of new horn by the + healthy surface.</p> + <p>'After all disease has been excised, carefully clean the foot with waste, + thoroughly protect any raw surface resulting from overcauterization by some mild + agent, such as a saturated calomel ointment, reapply an astringent dressing over the + whole affected surface, and nail on the shoe. This method of procedure should now be + thoroughly carried out daily for a time, and as it is proceeded with a successful + issue soon becomes assured in nearly every case. Where, in spite of these efforts, + the disease still persists, depend upon it the fault is with the operator, who has + failed to eradicate some centre of infection. Under these circumstances it may be + necessary to recast the patient, repare the foot, and by the aid of eye, knife, and + cautery, endeavour to find the cause, and having found it, which can invariably be + done, remove it. The usual treatment will then speedily become successful. As the + case proceeds dressing every other day will soon be sufficient, then twice a week, + and finally, once a week until sufficiently cured.</p> + <p>'During this healing process, and after the complete eradication of canker it may + be again repeated, no agent seems to have a more beneficial effect than calomel, and + for this purpose it is best used as a dry powder. Under this dressing any remaining + spot of canker is readily detected by the wet condition of the calomel when the shoe + is removed the next day. In dealing with such a spot, a very good plan, after all + apparently diseased tissue has been excised, is to touch the cankered part with solid + nitrate of silver, or a feather dipped in one of the strong mineral acids, and then + reapply calomel over the surface. The result of this treatment is frequently very + gratifying.</p> + <p>'In successful treatment the shoe must be removed each time—an adjustable + plate will not do, as no man can thoroughly pare and examine a foot with the shoe on, + and imperfect dressings are worse than useless. Indeed, it is better not to pare or + thin the horn at all, than to imperfectly pare, since canker, if undestroyed, + develops far more rapidly under thin horn than under thick.</p> + <p>'In conclusion, I would again urge the necessity, at the very first operation, + when the horse is down, of removing <i>every single particle</i> of the diseased + tissue, either by excision or effectual cauterization, but at the same time taking + very great care to guard against the latter being too destructive. The cautery should + be laid aside as soon as the tissue cauterized ceases to <i>burn white</i>. The + moment at which the canker has thus been eradicated without destroying sound tissue + is indicated by the appearance of healthy horn, by the intimate union of that with + the secreting surface, and by the healthy aspect of the exuded blood when paring has + been carried to the quick.</p> + <p>'Should subjacent healthy structures be destroyed during the process, that is + shown by the production of a raw sore, or of a sore to which a "sit-fast," + coextensive to the injury, is firmly attached. This seriously retards recovery. The + secreting surface having been destroyed, no new horn can be produced directly from + the part, and a new secreting surface and new horn have now to grow inwards from the + surrounding undestroyed tissue, and that is a slow process. At the same time, on the + principle of choosing the least of two evils, practical experience teaches that it is + better to produce a small sore or a "sit-fast" than to leave a part of the canker + undetected; but, on the other hand, it is better to leave a small part of canker + undetected, which can be recognised and removed at the next examination, than to + cause a large slough. The object of the skilful surgeon is, naturally, to avoid both + extremes; and if trouble be taken to carry out the procedure described, there need be + no fear of the result.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. iv., + p. 24.]</p> + <p>Treated in this way, the horse with cankered feet may be usually kept at work + during the whole time that treatment is carried out, and a cure is obtainable in + periods varying from six weeks to six or even twelve months.</p> + <p>The same essentials in treatment—namely, removal of diseased horn, + antiseptic dressings, and pressure—are insisted on by other writers. + Bermbach,[A] in 1888, treats canker as follows: The horse having been cast, the + undermined hoof-horn is removed with the knife, and the hypertrophied sensitive + structures, if necessary, reduced in the same manner. The chief difficulty in + removing the latter is experienced in the lateral lacunæ of the frog, where it + is most conveniently scraped away with a spoon or sharp curette. Professors Hoffmann + and Imminger also operate in the same way, applying an Esmarch's hæmostatic + bandage, and using the knife and curette freely.[B]</p> + <p>[Footnote A: <i>Ibid</i>., vol. ii., p. 68.]</p> + <p>[Footnote B: <i>Veterinary Journal</i>, vol. xxxv., p. 433.]</p> + <p>Hæmorrhage is afterwards arrested, and a dressing of perchloride of mercury + (a solution, 1/2 per cent., in equal parts of alcohol and water) applied. The + after-dressings succeeding best are those of <i>slightly</i> caustic and astringent + agents, preferably in the form of a powder, and held in position by carbol-jute pads + and linen bandages applied with a certain amount of pressure.</p> + <p>The same author draws attention to the fact that caustic agents such as nitrate of + lead, chloride of zinc, etc., act too powerfully if the bleeding has been arrested + and the wound disinfected. They then form a thick crust, under which profuse + suppuration takes place. The same agents are likewise contra-indicated when + hæmorrhage is still present. In this latter case they combine with the blood to form + metallic albuminates, which lie as an impenetrable layer on the surface of the wound, + and so hinder the action of drugs on the tissue below.</p> + <p>During his after-treatment, Bermbach advocates removal of the dressings every + second day, all cheesy material to be scraped away with the knife, and the sublimate + lotion to be used again. He also insists on the animal being kept standing in a + <i>dry stable</i>,—nothing but a stone pavement kept clean—and put to + regular work in a plate shoe after the first or second week. Cure of advanced cases + is said to be obtainable in from four to six weeks.</p> + <p>As illustrative of the value of pressure in the treatment of canker, we may also + draw attention to a treatment advocated by Lieutenant Rose.[A] This observer holds + that adequate pressure is unobtainable by packing the foot, and, to obtain it, + removes the wall from heel to heel, much after the manner of preparing the foot for + the Charlier shoe, so that the <i>whole</i> of the weight is taken by the sole and + the frog. Tar and tow is then lightly applied, the foot placed in a boot, and the + patient turned into a loose-box. The dressing is repeated at intervals of four or + five days until the animal is cured.</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xi., p. 435.]</p> + <p>Those who have followed this method of treatment have modified it by actually + shoeing the animal Charlier fashion, and keeping him at work, attention, of course, + being at the same time given to a proper antiseptic dressing.</p> + <p><i>Reported Cases</i>.—1. (Malcolm's Treatment[A]). The subject was a + five-year old horse belonging to a client of Mr. Giver's, of Tamworth. The case was + an exceptionally bad one, for not only was the whole of the frog and sole of the near + hind-foot cankered, but the disease on the outside quarter extended to within 1/2 + inch of the coronet, and on the inside quarter to within 2 inches of it. As the + owner, a farmer, had not proper convenience for Mr. Olver to treat the case, the + latter asked me, while visiting him, if I would care to undertake the treatment, + saying at the time it would be a very good test-case, as the disease was so far + advanced. I readily agreed, and, after the necessary arrangements, had the horse + removed to Birmingham on July 2. In this case it was found necessary to cast the + animal and cauterize the foot a second time before a healthy granulating surface was + secured; but after this the progress towards recovery was uninterrupted, although + necessarily slow, on account of the large amount of new secreting surface which had + to be formed.</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. v., p. + 48.]</p> + <p>The horse was finally discharged, after inspection by Mr. Olver, absolutely cured + and free from canker, on January 7.</p> + <p>The illustration (Fig. 135, p. 312) is from a photograph, and it gives a somewhat + imperfect representation of the state of the foot two months after it came under my + care.</p> + <p>2. (Rose's Treatment.[A]) This was a bad case of canker, which had been for two or + three months treated in the ordinary manner, with but little sign of ultimate + success. Commenced in June and carried on until the end of September, the ordinary + treatment consisted in burning down the fungus growth with the hot iron, and dressing + with copper sulphate, zinc sulphate, and boracic acid. The cauterization was repeated + every five days.</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. xi., p. 435.]</p> + <p>The treatment of Lieutenant Rose was commenced at about the end of September, at + which date the disease extended from the toe on one side of the foot right back to + the heel, involving the sole, half of the frog, and the bulb of the heel. One week + after treatment the diseased surface was drier, and granulations were more healthy. + At the expiration of a fortnight the new horn had commenced to grow from the wall, + and also from the frog, right round the diseased surface, the diseased part of the + bulb of the heel being divided from the sole by new horn.</p> + <p>Three to four weeks later the diseased surface was gradually getting smaller, + while in about six weeks it was quite healed up, the last place to heal being a strip + outside the bar, between it and the wall, and a smaller spot on the bulb of the heel. + These healed up simultaneously, and left the animal sound.</p> + <p>3. (Treatment by Pressure, H. Leeney [A]). I was consulted in the early part of + last summer, before the dry weather had begun, as to a farm-horse with canker in + three feet. Her shoes were in the 'disgruntle' condition we so often find on farms, + that, to give her a level bearing until I should call another day with a farrier to + help me to pack the foot up in the old-fashioned way, I had the remaining shoes + pulled off. The case somehow dropped out of my list, and I neglected to call, until + asked one day to see something else.</p> + <p>[Footnote A: <i>Veterinary Records</i>, vol. xi., p. 447]</p> + <p>I then found that, under a pressure of work, the animal had been used in the + shafts of a farm-cart on tolerably level ground, and when the dry weather had already + set in. There was a distinct improvement in all the diseased feet, and as she was + badly wanted I contented myself with rasping off some broken crust, and supplied some + caustic dressing for use at night. Without shoes she worked continuously on the dry + and hard meadow-land for several weeks, and was practically cured in something less + than three months. My astringent or caustic lotion may have had something to do with + the cure of the deep-seated parts, but the bare recital of the case should be + sufficient to show that it is all a question of bearing, or nearly so.</p> + <p>7. SPECIFIC CORONITIS.</p> + <p><i>Definition</i>.—In describing this condition under the above heading, we + are following the lead of Mr. Malcolm. We may define it as a chronic inflammatory + condition of the keratogenous membrane, usually confined to that of the coronary + cushion, the ergots and the chestnuts, but sometimes extending to that of the frog + and the sole, characterized by a malsecretion of the affected membrane similar to + that observed in canker.</p> + <p><i>Causes</i>.—The cause which we have indicated for canker—namely, a + local specific one, is in all probability the one operating here. Apparently there is + a variance of opinion as to whether the condition is actually canker or not. We + think, however, that the character of the secretion of the affected membranes, the + appearance of the growths, the manner in which they react to the hot iron, the + comparative absence of pain, and other points of similarity, point to the fact that + the two conditions are actually identical. In other words, the cause is precisely the + same, and the only point of difference is the alteration in the point of attack.</p> + <p><i>Symptoms</i>.—Like canker, the disease is insidious in onset. In + precisely similar manner the horn, and in this case the skin of the coronet, is + underrun. Later there is the partial shedding and fissuring of the undermined horn + and the exuding of the characteristic discharge—in this case not so watery as + that of canker. The caseous material of canker is also present, as is a disposition + to hypertrophy of the exposed sensitive structures. What horn is left becomes rough + and irregularly fissured, and has been likened by some observers to deeply-wrinkled + bark of an old tree. A peculiar characteristic of this condition is the state of the + ergots and chestnuts. Here the keratogenous membrane participates in the diseased + process, and their horn becomes dry and brittle, and readily splits into small + fibrous bundles very similar to the fibroid growth described in canker. These + excrescences are easily separated from the sensitive structures beneath, and the + exposed surface is seen to be more or less moist, or even exhibiting a slight oozing + of blood.</p> + <p>Again, as in canker, the deeper layers of the sensitive structures appear to be + normal, the horn-secreting layers being the only ones affected. According to Malcolm, + the disease is in its nature equally as inveterate as canker, but it is easier to + treat, on account of its more exposed position.</p> + <p><i>Treatment</i>.—This is exactly that as described for canker.</p> + <br /> + <a name="a137" id="a137"></a> + <p><a href="images/image137.jpg"><img src="images/image137sm.jpg" + alt="SPECIFIC CORONITIS OF ALL FOUR FEET." /></a></p> + <br /> + + <p>FIG. 137.—SPECIFIC CORONITIS OF ALL FOUR FEET.</p> + <br /> + <a name="a138" id="a138"></a> + <p><a href="images/image138.jpg"><img src="images/image138sm.jpg" + alt="OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS." /></a></p> + <br /> + + <p>FIG. 138.—OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS.</p> + <p><i>Recorded Case</i>.—The subject of this case was a young black cart + gelding. The disease is reported as having begun as thrush, and then extended to the + coronet. When I saw him he had been in a similar condition to that depicted in Fig. + 137 for, it was said, two or three months, the driver of the horse meanwhile + endeavouring to effect a cure by some potent drug of his own. The animal was in good + condition, but walked with difficulty owing to the pain. The coronary bands were + swollen to two or three times their natural size, and this caused the hair + immediately above to curl upwards. Just below the coronary bands there was a line of + separation between them and the wall. They themselves were covered with the cheesy + substance typical of canker, and they bled on friction. Down the wall of the off + fore-foot some blood had trickled, which may be seen in Fig. 138. The frogs of all + four feet bulged backwards, and were badly affected. The soles were covered with + normal horn, but I did not resort to paring to see if they were affected. One very + curious feature about the case was the fact that all the callosities (ergots and + chestnuts) seemed to participate in the morbid process, and they, too, were covered + with a thin layer of soft cheesy horn. The animal used to bite at his coronets and + also the callosities above the knees and hocks until they bled, which they did quite + easily. The owner would not go to the expense of having him treated, so he was + destroyed.[A]</p> + <p>[Footnote A: Henry Taylor, <i>Veterinary Record</i>, vol. xvii., p. 311.]</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER X</h3> + <h3><a name="cartilage" id="cartilage">DISEASES OF THE LATERAL CARTILAGES</a></h3> + <h3>A. WOUNDS OF THE CARTILAGES.</h3> + <p>To a consideration of this we shall devote but little space. It is sufficient to + say that any wound in the region of the coronet should always be given the most + careful attention. More particularly should this be so when it is ascertained that + the wound has involved one of the lateral cartilages. Wounds of non-vascular bodies + such as these are always slow to heal, and, by reason of their slowness, invite + septic infection. In many cases, in fact, it happens that they do not heal at all. + Instead, the injured part becomes necrotic, is unable to cast itself off, and remains + as a centre of infection in the depths of the wound, thus constituting what is known + as a quittor.</p> + <p>Apart from this, it will be remembered that the internal face of the cartilage is + in intimate contact with the pedal articulation, especially anteriorly. Wounds in + this situation are, therefore, likely to penetrate the joint, giving us as a + complication of the injury the conditions of synovitis and arthritis.</p> + <p>Immediately a wound is inflicted in this position, attempts should be made to + insure thorough asepsis of the part. When possible, by far the better way of + accomplishing this will be to wholly immerse the foot in a tub of cold antiseptic + solution, and keep it there for an hour three times daily. During the time the foot + is out of the solution the wound should be protected with a pad of carbolized tow or + other suitable dressing, and wrapped in a linen bandage or clean bag. If unable to + use the bath, then antiseptic solutions of more than moderate strength should be + freely applied to the wound and the adjacent parts, a carbolized or other antiseptic + pad placed over it, and the bandage adjusted as before. Repeated injuries to the + cartilages, even if not attended with an actual wound, are apt to bring about their + ossification and end in the formation of side-bones.</p> + <h3>B. QUITTOR.</h3> + <p><i>Definition</i>.—A fistulous wound of the foot, usually opening at the + coronet, and variously complicated according to the structures invaded by its + contained pus. For the reason that quittor is in every-day veterinary nomenclature + <i>usually</i> associated with necrosis or other abnormal condition of the lateral + cartilage, we include its description in this chapter.</p> + <p><i>Classification</i>.—It has been customary with Continental authors to + classify quittor according to the extent and position of the diseased process. There + were thus distinguished:</p> + <p><i>(a)</i> The <i>Simple</i> or <i>Cutaneous Quittor</i>, in which had occurred + nothing more than necrosis of a portion of the coronary skin and the structures + immediately underlying it—that is, the superficial portion of the coronary + cushion.</p> + <p><i>(b)</i> The <i>Tendinous Quittor</i>, in which not only the immediately + subcutaneous tissues were attacked, but also portions of tendon and of ligament.</p> + <p><i>(c)</i> The <i>Sub-horny Quittor</i>, in which the diseased process had invaded + the deeper portions of the coronary cushion, and continued a downward course until + the laminal tissue below the upper margin of the wall was involved, or any other + case, no matter what the starting-point, in which pus existed within the horny box + and was discharging itself by a fistulous opening.</p> + <p><i>(d)</i> The <i>Cartilaginous Quittor</i>, in which a portion of the lateral + cartilage had become attacked and rendered necrotic.</p> + <p>We believe that—in this country, at any rate—the word 'quittor' is + usually held to indicate one or other of the two latter conditions, and probably the + last of these; and that the two first are held of small account, or hardly of + sufficient gravity to allow of the word 'quittor' being applied to them. In fact, by + defining quittor as a 'fistula,' or little pipe, we have ourselves already indirectly + restricted the use of the word to the two latter conditions, for in those varieties + known as Simple or Cutaneous and Tendinous, the wound is generally broad and open, + or, at any rate, superficial, and can scarcely be strictly described as 'fistulous.' + In the two latter, however, a true fistula exists. These, however, have only one + essential difference, and that consists simply in the position of the lesion and the + structures it has attacked. In the main the symptoms will be the same, the disease in + each case about equally serious, and in each the same essentials of treatment will + have to be regarded.</p> + <p>In our opinion, therefore, a lengthy classification serves no useful end, and we + think matters will be simplified by considering quittor under two headings + only—namely, 'Simple or Cutaneous' and 'Sub-horny,' and discussing the other + varieties as simply complications of either of these two.</p> + <p>1. SIMPLE OR CUTANEOUS QUITTOR.</p> + <p><i>Definition</i>.—This condition is simply a sloughing of a portion of the + skin of the coronet, together with a portion of the immediately underlying soft + structures.</p> + <p><i>Causes</i>.—This form of quittor has its origin more often than not in + contusions, punctures, or wounds of the region severe enough to cause death of a + small portion of the tissues. In this case the low vitality of the parts does not + allow of the dead portion being removed piecemeal by a process of phagacytosis, as is + usually the case with similar injuries elsewhere. Instead, the tissues around, aided + by a process of suppuration, cast the offending portion off as a slough. It is the + wound remaining after the slough which we may really regard as a quittor. In this + connection may be considered as causes blows from falling shafts, self-inflicted + treads, or treads from other horses, overreach, etc. On the other hand, simple or + cutaneous quittor may occur without ascertainable cause. In this case we can only + explain its appearance, as we did that of simple coronitis (see p. 231), by + attributing it to septic infection through a wound or a blow that is able to + inoculate the skin, yet which is insufficient to cause pain, or in any other way + attract the attendant's notice. Meanwhile, the spot of infection thus started + spreads, and the end result is an abscess in the coronary region, again accompanied + with necrosis and sloughing of more or less skin and other tissue, which terminates + by discharging its contents and leaving behind a wound which again constitutes a + cutaneous quittor. Thus, as with simple coronitis, anything lowering the vitality of + the parts, and so favouring infection of the skin, may bring about a quittor. Walking + through much water in the winter months, through the dirt and mud of our streets, + through melting ice and snow, or through anything in the nature of a chemical + irritant, may be looked upon as a cause.</p> + <p><i>Symptoms</i>.—Whether commencing from an ascertainable injury, or + beginning at first unnoticed, cutaneous quittor is characterized sooner or later by + the appearance of an inflammatory swelling, usually confined to the seat of injury. + Heat and tenderness are present, and the animal is lame.</p> + <p>Later the inflammatory swelling becomes more profuse, the animal is fevered, and + the symptoms of lameness increased. Poulticing is at this stage perhaps resorted to. + By its means the process of suppuration is aided, and the swelling (at first tense + and hard) either becomes gradually softened, its contents discharged, and a simple + abscess cavity left behind, or the suppuration runs immediately round the necrosed + structures, and casts them off bodily as a slough. This latter condition is always + manifested, where the hair does not hide it, by the colour of the skin. At first this + is only red in colour—the angry red of an inflamed spot. As its intention to + slough away becomes evident, the red gradually gives way to a gray, or even + blue-black appearance, while from around it oozes a slight discharge of pus, yellow + in colour and non-offensive, or blood-stained and dark in appearance, and foetid to + the smell.</p> + <p>Almost invariably these symptoms are added to by a more or less diffuse and + oedematous swelling of the lower portion of the limb, extending in some cases to as + high as the fetlock or the upper third of the cannon.</p> + <p>With the casting off of the slough the phenomena of inflammation to a great extent + subside, the pain ceases, and the case under ordinary conditions commences to + mend.</p> + <p><i>Pathological Anatomy</i>.—In its early stages the condition of simple or + cutaneous quittor is really a condition of acute coronitis (see p. 229), and consists + in an inflammation of the subcutaneous tissue, and the more superficial portions of + the coronary cushion. The tissues implicated are destroyed outright, become + infiltrated with the inflammatory exudate and escaped blood, and act as a source of + irritation to the still living tissues around. Under the irritation the latter, as we + have said before, cast the necrosed portion away by a process of sloughing.</p> + <p>Always, however, it is found that the portion to be sloughed off, while easily + separated from the tissues adjacent to its sides, is closely connected on its + lowermost or deeper face with the structures below, and cannot be torn away without + hæmorrhage and the causing of acute pain.</p> + <p><i>Prognosis</i>.—With wounds about the feet our forecast should always be + guarded. Even with this, the most simple form of quittor, no decided opinion should + be given until the progress of the case warrants one in reasonably assuming that + complications are absent. Once this point is decided, a favourable prognosis may be + given.</p> + <p><i>Complications</i>.—With cutaneous quittor various complications may + arise, according to the extent of the invasion of the septic matter. Necrosis of + tendon, of ligament, or of cartilage, caries of the bone, or a condition of synovitis + and arthritis may be met with. As these complications are equally common to sub-horny + quittor, we shall reserve their description until dealing with that condition. + <i>Treatment (Preventive)</i>.—Immediately after the infliction of an injury in + this position, more especially if it is such as to lead one to judge that necrosis + will follow to any large extent, the patient should be rested. Ill effects may then + be probably warded off by having the foot immersed in a cold antiseptic solution, and + afterwards bound with an antiseptic pad and bandage.</p> + <p><i>Curative</i>.—When the condition has gone undiscovered until commencing + necrosis and suppuration are plainly discernible, then the wisest course we can + follow is to do all we can to hasten removal of the necrosed portion.</p> + <p>This is best done by promoting the suppurative process by means of warmth or + stimulant applications.</p> + <p>To this end hot poultices, or, better still, hot baths, should be resorted to. + Under their influence a greater supply of blood is directed to the still healthy + tissues enabling them to actively continue the inflammatory processes necessary to + the detaching of the portion necrosed, while, at the same time, the pus organisms, + stimulated by the heat, are stirred into greater activity, and the readier accomplish + their purpose of destroying the adhesion still existing between the necrotic portion + and the surrounding living tissues.</p> + <p>When prolonged poulticing or bathing cannot be practised, then the swelling should + be stimulated with a sharp cantharides blister, repeated, if the case demands it, at + intervals of a few days.</p> + <p>Should the swelling show distinct signs of pointing, and an abscess is plainly the + condition to be dealt with, its contents should be liberated by a free use of the + knife. In this connection it is important to insist on the fact that the opening + should be made large enough. One bold incision from the uppermost limit of the + swelling down to the coronary margin of the wall is usually sufficient.</p> + <p>Even when pointing is not very evident, and suppuration is plainly more or less + diffuse, benefit may still be derived from the use of the knife. In this case a deep + scarification of the part is indicated. Three, four, or more vertical incisions are + made in the swelling, and from them obtained a flow of blood mingled with a small + quantity of pus from several different centres. By this means sloughing of the + diseased portion is quickly obtained, and nothing but an ordinary open wound left for + treatment. It should be mentioned, however, that when sloughing can be in any way + induced to take place naturally it is better to allow this to take place. Even when + the necrosed portion is freely movable, and only adherent by its base, it should not + be forcibly removed, but left to the slower but more effectual action of the tissue + reactions. If torn forcibly away, we in all probability leave in the bottom of the + wound remnants of the dead tissue, which, being small and consequently less + productive of inflammatory phenomena, are not so readily sloughed as the larger + portion. These remain as centres of infection, and prolong the case.</p> + <p>Once a suitable slough has occurred, the after-treatment is simple. It consists in + dressing the wound with reliable antiseptics, and maintaining the parts in a healthy + condition until Nature completes the cure by repairing the breach. Solutions of + carbolic acid, of perchloride of mercury, of zinc chloride, or of moderately strong + solutions of copper sulphate, are all of them useful (see also treatment of coronitis + on p. 236).</p> + <p>It is sometimes found that even with careful attention the wound left by the + removal of the slough shows a marked disinclination to heal. The greater portion of + the cavity becomes filled with granulation tissue, and the epidermis gradually closes + round until all is covered except a spot of perhaps the size of half a crown or a + crown piece. Here the regenerative process stops, and the wound obstinately refuses + to effectually close.</p> + <p>In such cases we have derived excellent results with the actual cautery. The + animal is cast, the foot firmly secured by fastening it upon the cannon of another + limb, and the animal chloroformed. A practical point to be remembered in this + connection is that all necessary fixing of the limb is easier performed if the + chloroform is administered first. With the patient thus secured we first of all + ascertain by means of the probe whether or no the non-healing of the wound is due to + the presence of a fistula. Decided in the negative, we take an ordinary flat + firing-iron, and with it cut away a portion of the skin immediately around the still + open wound, carrying our incisions deep enough to 'scoop' out a large portion of the + new inflammatory tissue beneath. With the loss of pressure from beneath, occasioned + by the removal of so much of the cicatricial tissue, the epidermis the more readily + closes over the wound. To a large extent also this new growth of epidermis is helped + by the renewal of the inflammatory phenomena brought into being with the + cauterization.</p> + <p>2. SUB-HORNY QUITTOR.</p> + <p><i>Definition</i>.—A fistulous wound of the foot in which the lower and + blind end of the fistula is situated below the level of the coronary margin of the + wall.</p> + <p><i>Causes</i>.—These, again, will be practically the same as those mentioned + in the cause of cutaneous quittor—namely, bruises, punctures, wounds—in + fact, any injury upon the coronet severe enough to cause death of tissue and a + suppurating wound. We may thus expect sub-horny quittor to follow upon treads, + overreach, accidental injuries with the stable-fork, and kicks from other + animals.</p> + <p>Sub-horny quittor may also arise without original injury at all to the coronet. + Either from a violent blow upon the hoof, or from the animal himself kicking + violently against a wall, death of a portion of the sensitive structures takes place + within the hoof, suppuration ensues, and the formation of quittor commences. With the + escape of the pus at the coronet the quittor is fully formed.</p> + <p>Any other diseased condition of the foot in which suppuration is present may in + like manner terminate in quittor. In complicated sand-crack, suppurating corn, or in + ordinary pricked foot quittor may be a sequel. In these conditions the pus formation + either goes unnoticed or is neglected, and after seriously invading the sensitive + structures within the hoof, breaks out at the coronet. Again, too, as with the + simpler form of quittor, and as with coronitis, we may always regard as a + predisposing cause the action of excessive cold in promoting septic infection of the + wound when occurring at the coronet.</p> + <p><i>Symptoms and Diagnosis</i>.—Where the fistulous wound has had its + starting-point in an injury to the coronet diagnosis is, of course, easy. The history + of the case explains it. Nothing in this instance remains but to probe the opening, + and ascertain its direction, depth, and extent.</p> + <p>An animal with the wound thus open at the coronet, and freely discharging its + contents, may, if no serious complications exist, walk tolerably sound. It is only + when put to the trot that symptoms of lameness are apparent.</p> + <p>It may so happen, however, that we first see the case when the symptoms are wholly + those arising from a painful suppuration within the horny box. This occurs when the + original injury has taken place at a more dependent position than the coronet. Either + from violent blows upon the hoof, puncture from below, from corn or from sand-crack, + or any other causes we have enumerated, suppuration is occurring deeply within the + hoof, with as yet no opening upon the coronet.</p> + <p>Even when an opening has already occurred on the coronet, the same condition of + sub-horny suppuration may be met with in cases when the opening of the fistula has by + some means or other become occluded. Granulation tissue, for instance, may have + temporarily closed the mouth of the fistula. The pus, instead of continuing its + discharge thereat, is made to burrow in other directions.</p> + <p>In either of these cases pain is excessive, the animal walks on three legs, the + foot is painful to percussion, and grave constitutional disturbance is noticeable. + The presence of pus is immediately suspected, and, in the absence of any indication + of an opening having existed at the coronet, searched for at the sole. It may or may + not be found. If found it is given exit, and the case ends as one of ordinary pricked + foot, of suppurating corn, or some other condition equally simple when compared with + quittor. In those cases where the pus is not discovered at the sole, one adopts the + expectant treatment of poulticing. This, if pus is present, is followed by a painful + swelling of the coronet. At one point there forms a hot and tender enlargement, with + the hairs on it standing straight up from the skin, which latter is seen below red + and inflamed in appearance.</p> + <p>Later, the abscess—for abscess it is—discharges its contents, the + opening is explored, and we find that in extent it is not confined to the coronary + region, but that it is deep enough to constitute a true sub-horny quittor.</p> + <p>This discharge of the abscess contents may take place at a well-defined spot on + the coronet, or it may ooze out at the junction of the wall with the skin. In + appearance the discharged pus varies. When the softer structures only are attacked it + is thick, and yellow or white in colour; when bone is involved it is ichorous; and + when attacking the horn itself black or gray. It may or may not be extremely foetid, + and often it is mingled with blood.</p> + <p>When evidence of a previous opening upon the coronet is plain, then it is not + considered wise to attempt a paring of the sole. Instead, poulticing is at once + resorted to, to induce the discharge of the pus through its original channel. Once + this has occurred a fistulous wound remains, which is open for treatment upon one or + other of the lines we shall afterwards indicate.</p> + <p>COMPLICATIONS—<i>(a) Necrosis of the Lateral Cartilage</i>.—This is + the so-called 'cartilaginous quittor' of other writers. In all probability it is the + condition generally understood when the word 'quittor' is used by one practitioner to + the other. Its tendency to keep the disease existing in a chronic form renders it of + grave importance, and for that reason we give it first mention among the + complications.</p> + <p>It may occur as a sequel either of cutaneous or of sub-horny quittor, and may + result either from actual wounding and infection of the cartilage, or from an attack + on it of septic matter originating elsewhere.</p> + <p>Unless there has been discovered a fistula, which on probing is seen to lead + direct to the position in which we know the cartilage to be, we know of no precise + means by which the existence of this condition may be diagnosed. When free from other + complications, the horse with his foot in this state may travel fairly sound. This is + so when the necrosis is situate in the posterior half of the cartilage, in which case + the irritation set up by the disease is confined to the comparatively non-sensitive + tissues of the cartilage itself and the fibrous mass of the plantar cushion. When + attacking the anterior half of the cartilage, the close contiguity of the joint + renders the disease of a more serious nature. It is then that we have acute pain, and + with it extreme lameness, for in this position it is more than likely that we have + involved either the synovial membrane of the articulation or the tops of the + sensitive laminæ. It will be remembered that here the synovial membrane + protrudes as a small sac between the antero- and postero-lateral ligaments of the + joint. More or less easily then it is bound to come into intimate contact with the + septic matter attending the necrosis of the cartilage, and so share in the + inflammatory processes, afterwards communicating them to the interior of the + articulation.</p> + <p>With necrosis of the lateral cartilage is always swelling and thickening of the + skin and subcutaneous structures of the coronet. This is the greater the longer the + disease has been in existence. Upon the swelling is seen the mouth of the fistula, or + it may be the mouths of several, and from them all a discharge of pus.</p> + <p>The mouth of each fistula is generally filled with a mulberry-like granulation + tissue, standing above the level of the skin, and bleeding easily if touched. The + exuding pus is thin and pale gray in appearance, gritty to the touch, and generally + free from pronounced smell. At other times its colour is reddened with contained + blood, and floating in it are tiny particles of a pale-green substance, which when + picked up and rubbed between the fingers are seen to be small fragments of the + diseased cartilage.</p> + <p>Should the mouth of a fistula become occluded with the granulations filling it, + and the discharge prevented from escaping, it soon happens that we have close to the + fistula that has closed a tender fluctuating swelling. This points and breaks, and + pus is again discharged from another opening. In this manner is accounted for the + multiplicity of scars and fistulas seen on the swelling of an old-standing + quittor.</p> + <p>The continued, inflammation thus kept in existence has the effect of rendering the + skin and subcutaneous tissues in the neighbourhood greatly thickened and indurated. + This in time leads to a tumour-like enlargement, and causes the structures of the + coronet to greatly overhang the hoof. At the same time the constant inflammation has + made its stimulant effects noted in a great increase in the growth of the horn of the + wall.</p> + <p>Although more abundant, however, the quality of the horn is deteriorated. The + perioplic ring has become obliterated, and the varnish-like appearance of the healthy + wall destroyed. Cracks and fissures in its surface are numerous, and sometimes deep + enough to lead to exposure of the sensitive structures beneath, complicating the + quittor with a sand-crack of a peculiarly objectionable type.</p> + <p><i>Pathological Anatomy of the Diseased Cartilage</i>.—The bulk of observers + appear to agree in the statement that in quittor the necrotic cartilage is pea-green + in colour, and recognise it by that characteristic. In size the necrotic portion thus + recognisable varies from the tiniest speck to a portion the size of a horse-bean. + Commonly, however, it is about as large only as a pea. It is seen to be more or less + detached from the rest of the cartilage, to which it is adherent by one of its + extremities only. In general appearance we can best liken it to the split half of a + green pea, whilst others have compared it with the green sprouting of a seed. The + portions of cartilage nearest the necrotic piece are also slightly green in colour, + thus indicating that here also the diseased process has commenced. This peculiar + change of colour in the affected cartilage is of great importance to the surgeon. It + enables him when operating to distinguish with some degree of certainty those + portions of the cartilage which are healthy and those which are not.</p> + <p>(<i>b</i>) <i>Necrosis of Tendon and of Ligament</i>.—This complication of + quittor is, as we have said before, treated by other writers as a distinct form of + the disease, and described by them under the heading of Tendinous Quittor.</p> + <p>This simply means, of course, that the diseased process has extended to either of + the flexor tendons, to the tendon of the extensor pedis, or, perhaps, to the + ligaments of the pedal articulation.</p> + <p>Of the flexor tendons, the perforans is the one commonly attacked, by reason, of + course, of its more superficial position. At times, however, especially when its + aponeurotic expansion is diseased, the necrosis of the perforans spreads until the + aponeurosis is eaten through and the phalangeal sheath penetrated. Septic materials + gain entrance thereto, and commence to multiply. In this way the flexor perforatus is + invaded, and comes to share in the diseased process.</p> + <p>The extensor pedis is usually attacked by extension of the disease from a necrotic + cartilage, or results from the infliction of a severe tread in a hind-foot. In this + case the diseased structure has nothing between it and the articulation, the synovial + membrane in one position actually lining its inner face. The result is that a + condition of synovitis is easily set up, and the case aggravated by that and by + arthritis.</p> + <p>With the flexor tendons attacked pain is always very great, and lameness is + excessive. This, however, is not sufficiently characteristic to enable us to + determine the precise seat of the necrotic changes. Later, however, a tender but hard + enlargement made its appearance in the hollow of the heel, which enlargement, later + still, became soft and fluctuating. At this stage there is also considerable swelling + along the whole course of the tendons, as high up as the knee or the hock. The foot + is carried forward with all the phalangeal articulations flexed, and in many cases + the limb is unable to take weight at all. Manipulated after the manner of examining + the tendons for sprain, this swelling is found to be extremely painful. The animal + flinches from the hand, and shows every sign of acute suffering. This condition may, + in fact, be mistaken for sprain, and is only to be distinguished from it by carefully + noting the history of the case—first, the appearance of the swelling in the + hollow of the heel, and, secondly, the <i>after</i>-swelling of the upper portions of + the tendons.</p> + <p>The formation of the abscess, the after-discharge of its contents, and the final + establishing of a fistula, are processes greatly prolonged in this form of quittor. + It will readily be understood why this should be so when one remembers the depth at + which the suppurative process is going on, the thickness of the metacarpo-phalangeal + sheath, and the resistant nature of the material of which this latter is made, and + which must be penetrated before the condition becomes observable.</p> + <p>After the opening of the abscess, which usually takes place in the hollow of the + heel, there is left the fistulous wound which obstinately refuses to heal. Or it may + be, again, that there are several of these fistulas, each opening in the heel, and + the mouth of each marked by a small, ulcer-like projection. The discharge continually + oozing from these keeps the heel constantly wet with a thick purulent discharge, + which is nearly always blood-stained, and very often foetid.</p> + <p>This constitutes what is known as tendinous quittor in its worst form, for more + often than not there is associated with it inflammation of the navicular bursa, + caries of the bones, or arthritis of the pedal articulation.</p> + <p>With the extensor pedis attacked matters are not quite so grave, in spite of the + fact that the articulation is closely situated thereto, for in this case the more + superficial position of the diseased structure allows both of readier exit of the + discharges and of easier removal of the necrosed portion and after-treatment of the + wound.</p> + <p><i>(c) Caries of the Bones</i>.—Portions of the os pedis, more especially of + its wings, and therefore usually occurring in conjunction with necrosed cartilage, + become carious in quittor. In many cases it is impossible to say with certainty when + this has occurred. In a few instances, however, the exuding discharge gives evidence + of what has happened. It is thin, but extremely offensive, with the characteristic + odour of decayed bone or tooth, and with a feel that is gritty with contained + particles of broken-up bone. If, with a discharge of this nature present, the probe + also conveys to the fingers the sensation that bone is reached, then diagnosis may be + sure.</p> + <p><i>(d) Ossification of the Cartilage</i>.—This may take place in part or in + whole. It, of course, constitutes Side-bone, a fuller description of which will be + found in a later portion of this chapter.</p> + <p><i>(e) Penetration of the Articulation</i>.—This may occur either as a + result of the suppurative changes or as an accident in excision of the diseased + cartilage. Unless it is followed by a severe purulent arthritis, it is not so grave a + complication as at first sight it would appear.</p> + <p><i>(f) Synovitis and Arthritis (Purulent)</i>.—Should this complication + arise, the case is a most serious one. Beyond here mentioning the fact that it may + occur, we shall not dwell on it. Fuller consideration is given to it in Chapter + XII.</p> + <p><i>Treatment</i>.—The various treatments adopted for the cure of sub-horny + quittor offer the veterinary surgeon a large number to select from. We will describe + them in the order in which they are, perhaps, most commonly practised.</p> + <p><i>Poultices and Hot Baths</i>.—As in cutaneous quittor, and as in + coronitis, when the pus formation is only suspected, and has not yet broken out at + the coronet or elsewhere, then the first indication in treatment is the use of warm + poultices or of hot baths. Their application is in most cases productive of pointing + at the coronet.</p> + <p>Directly this appears it is a wise plan to thin the wall down with the rasp + immediately below the swelling. To some extent it relieves the pressure of the + inflammatory products within, and at the same time paves the way for operative + measures which may be necessary later on.</p> + <p>With the breaking of the abscess and the discharging of its contents, we may in + some measure ascertain the condition we have to deal with. The probe is used, and the + abscess cavity explored. The size of the wound, its depth below the upper margin of + the wall, the structures involved, and other information, may be thus obtained.</p> + <p>At first, however, the nature of the wound, and the character of the discharges, + must largely guide us as to the treatment we adopt. In many cases, even where the + abscess cavity is far below the upper margin of the wall, and is presumably in an + unfit position to drain and heal, a a regular application of an astringent and + antiseptic dressing is sufficient to bring about resolution. If, however, the + discharge from the wound continues to be liquid, and the wound itself at one spot + refuses to heal, it may be judged that a portion of necrotic tissue is situated under + the wall, and affecting the laminæ, the cartilage, or ligament, as the case may + be. If this is so, then operative measures must be determined on (see Removal of the + Wall, p. 349).</p> + <p><i>Blisters</i>.—Instead of the poultice and hot baths, the pointing of the + abscess and the casting off of the slough may be brought about by the application of + a sharp cantharides blister. We have, in fact, seen many cases where this treatment + was adopted prior to the formation of a fistula, and also in cases where one or more + fistulous openings already existed, where repeated blisters to the coronet have alone + been sufficient to effect a cure.</p> + <p>We are bound to admit, however, that the treatments of poulticing and blistering + are only expectant—we might almost say empirical. At any rate, we admit to + ourselves that what we have advised and carried out is not in itself curative, but + only a means of assisting Nature to satisfactorily work her own ends. Empirical or + not, however, we believe that in every case of quittor it is wise in practice to at + first adopt some such simple measure, for in nearly every instance where operative + measures are practised, the patient must be laid aside for at least several weeks, + whereas in this way he may be kept at work and a cure effected at the same time.</p> + <p><i>The Actual Cautery</i>.—Largely of the same empirical nature, yet doing + something a little more calculated to destroy necrotic tissue and bring about its + sloughing is the use of the cautery, both actual and potential.</p> + <p>The actual cautery may be beneficially employed for the relief of sub-horny + quittor in at least two ways.</p> + <p>In the first place, it is often used—a blunt 'point-firing' iron being the + instrument—instead of the knife as a means of evacuating the contents of the + coronary abscess. Those who use it for this purpose are able to say this in its + favour: it brings about the opening of the abscess without the unsightly + hæmorrhage attending the use of the knife, and at the same time just as + effectually empties it. The opening made is not nearly so likely to close + prematurely—that is, before a proper course of treatment of the wound has been + carried out—and so leave necrotic tissue at its bottom. The intense tissue + reaction it sets up is productive of a large slough, cast off by highly active + inflammatory phenomena, which means that the remaining wound is one in which no dead + tissue is left, and which is more amenable to treatment.</p> + <p>We have also seen the actual cautery used in sub-horny quittor, where that disease + has reached a chronic fistulous stage, as a means of cauterizing the whole length of + the lining of each fistulous passage.</p> + <p>At the present day this method is regarded as barbarous, and savouring too largely + of the methods and practice of the old empirics. There is no denying the fact, + however, that it is at times followed by a speedy and complete cure of what has for + months been an intractable and apparently incurable quittor; and, honestly speaking, + we ourselves can see nothing very greatly against the operation in certain cases save + its appearance. In that it is certainly rough, and is not calculated to favourably + impress the more critical of our clientele. With the animal chloroformed, however, + much of what can really be urged against it disappears, and on farms and other places + where a skilled and competent dressing of an operation wound cannot be looked for, it + is sometimes wise to advise this method of treatment in preference to more advanced + methods of operating. So far as we can judge, the after-effects are very little worse + than those following other operative measures, more especially when a suitable case + has been chosen.</p> + <p>This method of treatment is particularly applicable to cases of chronic sub-horny + quittor in the more posterior parts of the foot. Here, if one or more fistulas exist, + their openings are probed and the direction of the sinuses determined. In all + probability they are burrowing down along-side the wall to the sole, where, for want + of outlet, they are invading the substance of the plantar cushion or the plantar + aponeurosis.</p> + <p>Should this preliminary probing demonstrate that neither of the fistulas run + dangerously near the joint, then the operation may be decided on.</p> + <p>The animal is cast and chloroformed, the foot firmly fixed, and the horn of the + quarter rasped away quite thin. The sole of the same side is also pared with the + knife until the horn of both the quarter and the sole yields easily to pressure of + the thumb. All that is then needed is three or four long, round, and pointed irons + (about 1/4 to 3/8 inch in diameter) heated to redness. These are inserted into the + fistulas, and the false mucous coat of these passages thus destroyed. When the iron, + on being directed into the fistulous opening at the coronet, is found to travel + alongside the wall, and to easily reach the sole, it should be made to go further + still. The sole is penetrated, and a dependent opening thus made for the escape of + the discharge that afterwards accumulates.</p> + <p>What happens now, of course, is that an intense and acute inflammation is set up + along the whole track of the fistula, in which position the inflammatory changes were + heretofore chronic. The whole lining of the fistula, and with it, we hope, all + necrotic tissue, is cast as a slough, leaving nothing but healthy tissue behind. + This, with a suitable dressing, heals and gives no further trouble.</p> + <p>The after-treatment consists in the application of hot poultices. These tend to + greatly ease the pain, and at the same time to facilitate the removal of the slough. + The poulticing should be continued, therefore, until the sloughing comes about, which + happens, as a rule, at about the fifth or seventh day.</p> + <p>Immediately the slough is cast off, the poultices may be discontinued and dressing + of the wound carried out. This consists of injections of solutions of zinc chloride 1 + in 200, perchloride of mercury 1 in 1,000, carbolic acid 1 in 20, of Villate's + solution, or of such other antiseptic as the surgeon may think fit. The dependent + orifice at the sole should be kept open for as long as possible, being occasionally + trimmed round with the drawing-knife, and scooped out with a sharp-edged + director.</p> + <p>Directly a healthy and pink-looking granulation is observed along the track of the + iron, and the discharge therefrom takes on a thick and yellow appearance, the + strength of the antiseptic solutions should be gradually diminished. This point, in + fact, is of great importance in treating all wounds of the foot. There is a great + temptation, on account of the known excessive liability of the parts to septic + infection, to use an antiseptic solution unduly strong. What must be remembered is + that used <i>too</i> strong they themselves give rise to dead tissue, or to + impermeable layers consisting of compounds of the discharges with themselves, and so + create substances that prove a source of irritation and subsequent trouble.</p> + <p><i>The Potential Cautery</i>.—This is employed in the treatment of sub-horny + quittor, either in the solid form (in sticks, in lumps, or in the powder), or in the + liquid form, when it is injected with a quittor syringe.</p> + <p>In the former method such drugs as perchloride of mercury in the lump, or nitrate + of silver, chloride of zinc, and caustic potash or soda in the stick, are introduced + into each of the sinuses present. This is done by means of a director or a probe.</p> + <p>A better method, however, when the dressing lends itself to the purpose, is to use + it in the form of a powder, wrapped in the form of small cubes in extremely thin + paper, such, for instance, as is used for rolling cigarettes. It is then conveniently + inserted into each fistula. Introduced in this more finely divided form the drug is, + perhaps, a little more active in bringing about the desired result.</p> + <p>This method of 'plugging,' although practised by many, we cannot recommend in + preference to the use of the hot iron or of liquid injections. Our reasons are these: + the action of the drug is a protracted one. Almost immediately after its introduction + into the fistula there is formed about it an almost impermeable layer of a metallic + albuminate, which effectively prevents further rapid action of the caustic. In + addition to thus preventing further action of the dressing, this combination of the + tissue albumin with the metal of the salt, together with much necrotic tissue that it + has caused, is extremely hard to remove from the healthy tissues. This we explain by + pointing out that the action of the caustic, prolonged as it is, sets up a tissue + reaction which partakes largely of the type of a chronic rather than an acute + inflammation. With a chronic inflammation there is sooner a tendency to the + production of fibrous tissue (and thus the firmer attachment of the necrosed + portions) rather than an active phagocytosis and the casting-off of a slough. Again, + careful though we may be with the probe, it is extremely difficult to be certain that + we have discovered the whole extent of any fistula. An equal difficulty, therefore, + exists in being certain that we have placed the caustic in the position in which it + is most wanted—namely, at the furthermost end of the fistula where the necrotic + tissue is to be found.</p> + <p>When a caustic is used at all, it is far better to employ it in the liquid form, + when either of the drugs we have just mentioned may again be used. In the first + place, the liquid is far more likely to be brought into contact with the diseased + structures than is the solid salt. Also, its action may be regulated by altering the + strength of the solution, and the liability to form impermeable albuminates thus + diminished.</p> + <p>Probably the best solution for use in this way is the old-fashioned Villate's + solution (see p. 199).</p> + <p>This liquid should be injected at least every day, and, in a bad case, even two or + three times daily. Practical hints to be borne in mind when attempting to cure + quittor by means of injections are these:</p> + <p>If the fistulas are numerous, the fluid should be injected into their various + orifices.</p> + <p>In order to force the fluid to the bottom of each diseased track, it is necessary, + when injecting one opening, to firmly close all others.</p> + <p>Several injections should be made at each time of injection. In other words, we + must not be content with just forcing fluid in. It must be forced in, and again + forced out by a further syringeful. The fistulous tracks must, in fact, be washed in + the liquid.</p> + <p>The effect of the injection during the first eight or ten days is to render + suppuration more abundant and whiter. After two weeks of the treatment sloughing of + the inside of the sinuses occurs, and healing of the wound commences. Signs that this + is occurring are—slight hæmorrhage at the end of each injection, and a + gradually increasing difficulty in forcing in the fluid.</p> + <p><i>The Making of Counter-openings to the Fistulas</i>.—Although Villate's + solution or any other caustic used in the manner we have described often effects a + cure, many practitioners insist on the fact that a counter-opening to the fistula + must also be made.</p> + <p>The probe is used and the direction and depth of the fistula ascertained. Through + the wall is then made an opening at exactly opposite the lowest point found by the + probe, or through the sole if the probe should there lead us. This opening is best + made with a sharp-pointed iron, and may afterwards be kept large enough by an + occasional trimming with the knife. Many of the older authors, and with them writers + of the present day, declare that unless this is done the ordinary injection is likely + to fail in a great many instances where it would otherwise have been successful.</p> + <p>Where a counter-opening is thus made it is found that it very readily closes with + granulation tissue, and the purpose for which it was made defeated. This may be + avoided by the use of a seton. In preference to the seton, however, we ourselves + would advise that the opening be kept free by the occasional use of a sharp-edged + director or a fine scalpel.</p> + <p>An interesting modification of the practice of making a counter-opening is that + related by Veterinary-Captain S.M. Smith.[A] In point of severity it runs a middle + course between the making of a simple counter-opening and the removal of a + wedge-shaped portion of the coronary band and the wall, a method which we shall later + describe.</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol ii., p. 157.]</p> + <p>To perform this operation, the animal is cast and chloroformed. The foot is fixed + and the parts thoroughly cleansed. The horn of the wall is then sawed through in a + direct line from the coronary margin to the solar edge, the saw-line running exactly + over the seat of the sinus.</p> + <p>A strong scalpel is now introduced at the coronary opening, with its cutting-edge + outwards, and is gradually passed down the opening made by the saw. In this way the + sinus is completely destroyed, and from end to end converted into an open wound. The + parts are then washed in a perchloride of mercury solution, covered with a mixture of + powdered iodoform and boracic acid, over which a pledget of carbolized tow is placed, + and then a bandage over the whole. This dressing should be left on three or four + days, after which the injury should be treated as an ordinary wound. In conclusion, + the author says: 'I can safely recommend this line of treatment to any practitioner + having an obstinate case under treatment.'</p> + <p><i>Removal of the Wall and Excision of the Necrotic Tissue</i>.—This we may + term the radical operation for sub-horny quittor, for it is often productive of a + successful issue when all other means have failed. No matter in what position the + sinus is, whether at the extreme anterior portion of the coronet, or whether in the + region of the heels, it is to be thoroughly opened up. To do this, the fistula is + carefully explored with the probe and a knowledge of its exact dimensions arrived at. + This is carefully noted, and the horn of the wall for some little distance around it + then rasped down quite thin. Immediately over the sinus, and for a short distance on + either side of it, the horn is stripped away to the sensitive structures. The cavity + of the fistula is then opened up with a scalpel, and every particle of diseased + tissue removed with this instrument and a pair of forceps. After-dressing consists + simply in the application of suitable antiseptics.</p> + <p><i>When the Complication of Necrosed Tendon or Ligament exists</i>.—We may + take it as an axiom that wherever this exists, whether it is in the extensor pedis, + in the lateral ligaments of the joint, or in portions of the flexors, all diseased + structures should, where possible, be removed. This is done either with a scalpel or + with a curette.</p> + <p>When septic matter has gained the sheath of the perforans, and the formation of + pus therein is indicated by inflammatory swellings in the hollow of the heel, it is + sometimes advisable to lay the sheath open for 1 to 2 inches along the course of the + tendons. This, if a fistula is present, may be best done with a blunt-pointed + bistoury, or with a cannulated director and a scalpel. With the pus thus given exit, + and an antiseptic dressing regularly applied, the case sometimes ends in rapid + resolution. More often than not, however, it is found that the pus has been liberated + too late, and that it has gravitated in the sheath to the extent of affecting the + plantar aponeurosis. Or it may be, of course, that it was in the plantar aponeurosis + the disease commenced. Whichever may have been the case, we have in the hollow of the + heel one or more fistulous openings, or an opening we have made ourselves, leading + down to a necrosed portion of the terminal expansion of the perforans.</p> + <p>In such cases we ourselves have derived benefit from a regular flushing of the + sinuses with a 1 in 2,000 solution of perchloride of mercury, introduced by means of + a glass syringe, followed later by flushing in the same manner with a 1 in 40 + solution of carbolic acid, the hollow of the heel meanwhile being kept clean with an + antiseptic pad and bandage, or by liberal applications of an antiseptic powder.</p> + <p>The septic materials are in this way destroyed, and the wound heals without + further complication. We must admit, however, that the cure of the lesion is + generally at the expense of slight lameness, due, in all probability, to inflammatory + tissue adhesions between the flexor perforans and the perforatus, and to a partial + destruction of the synovial membrane of the sheath.</p> + <p>If, in spite of the antiseptic irrigations, the fistula persists, then nothing + remains but to resort to excision of the aponeurosis, as described on p. 222.</p> + <p><i>When Necrosis of the Lateral Cartilage is present</i>.—In this case we + may at first try the ordinary treatments of poulticing; and blistering, of antiseptic + caustic injections, and of plugging. In some cases a cure is effected. Should these + fail, however, and we intend to see the finish of our case, then operative measures + must be determined on. This means cutting down upon the diseased cartilage, and + either removing the necrosed portion, or excising the cartilage in its entirety.</p> + <p>The latter method is seldom practised in this country. As it is the most radical + of the two, however, we shall describe it here first.</p> + <p><i>Extirpation of the Lateral Cartilage</i>.—The operation of extirpating + the lateral cartilage is by no means a new one, being introduced, according to + Zundel, by the senior Lafosse in 1754. It consisted in removing a portion of the wall + by grooving and stripping it, and of excising the exposed cartilage by means of a + sage-knife.</p> + <p>As to what portion of, and how much of the horn of, the quarter should first be + removed, and as to what particular direction each groove should take, opinion among + the older writers varied considerably. This we know now is not an important matter, + and it is sufficient to say that the first preliminary is a thinning down of the horn + of the quarter with the rasp over the position occupied by the cartilage. At the + present time there are two or three modifications of the operation as originally + introduced. In all, however, the preliminary steps are the same. We shall therefore + describe them collectively, as applying correctly to either of the three methods of + operating we are about to show.</p> + <p><i>Preparation of the Subject and Preliminary Steps in the Operation</i>.—On + the day previous to the operation the horn of the wall immediately over the cartilage + must be so thinned with a rasp as to yield readily to pressure of the thumb in any + position. It should be so thin as to only just avoid wounding the sensitive + structures below.</p> + <p>The whole of the foot must then be thoroughly cleansed, and rendered as nearly + aseptic as possible. The use of warm water, soap, and a stiff brush is the readiest + means of removing the surface dirt. Afterwards the foot should be soaked for some + time in a reliable antiseptic solution, a 1 in 1,000 solution of perchloride of + mercury being the most suitable. When removed from the solution the foot must be + packed round with wool or tow impregnated with corrosive sublimate, and then + bandaged, the whole afterwards wrapped in a thick cloth, or protected with a + boot.</p> + <p>On the following day the animal is brought out and cast, and the foot desired to + be operated on firmly secured, after the manner described on p. 81. The bandages and + sublimate pads are then removed, and the skin of the coronet over the seat of + operation shaved of hair. An Esmarch rubber bandage is next run up the limb, and the + tourniquet applied, thus rendering the operation a nearly bloodless one.</p> + <p>This done, the animal is chloroformed, and an antiseptic douche played over the + foot.</p> + <p>So far, the steps in the operation are common to all methods. There are now, + however, three slightly differing modes of extirpating the cartilage, which modes + vary simply according to the structures severed by the knife.</p> + <p><i>First Method</i>.—This is the oldest method of the three, and consists in + making (1) a horizontal incision through the sensitive laminæ along the lower + border of the cartilage, and (2) a vertical incision through the skin of the coronet, + the coronary cushion, and a portion of the sensitive laminæ (see Fig. 139).</p> + <p>The flaps (Fig. 139, <i>a, a</i>) are now held back by tenaculæ, and the + whole of the cartilage, or only the necrosed portion, carefully excised by means of + right- and left-handed sage-knives. Fistulous openings in either of the flaps <i>a, + a</i> must now be carefully curetted and dressed, and the flaps allowed to fall into + position. They are then sutured with carbolized gut, and the wound finally dressed as + to be described later (p. 357).</p> + <br /> + <a name="a139" id="a139"></a> + <p><a href="images/image139.png"><img src="images/image139sm.png" + alt="EXCISION OF THE LATERAL CARTILAGE (OLD METHOD)." /></a></p> + <br /> + + <p>FIG. 139.—EXCISION OF THE LATERAL CARTILAGE (OLD METHOD). The wall covering + the lateral cartilage first thinned and stripped off; the two flaps (<i>a, a</i>) of + skin and the coronary cushion made by the vertical incision turned back. <i>a</i>, + The operation flaps; <i>b</i>, the exposed cartilage; <i>c</i>, the sensitive + laminæ; <i>d</i>, the coronary cushion.</p> + <p><i>Second Method (after Holler and Frick</i>[A]).—These operators deem it + wise to leave untouched the skin of the coronet and the coronary cushion. They + therefore make their first incision along the lower border of the coronary cushion + (see Fig. 140), afterwards exposing the lower half of the cartilage by removing a + half-moon-shaped portion of the thinned horn and underlying sensitive laminæ + (see Fig. 140, <i>b</i>).</p> + <p>[Footnote A: Two cases of quittor successfully treated by this method are reported + by R. Paine, M.R.C.V.S., in the <i>Journal of Comparative Pathology and + Therapeutics</i>, vol. xv., p. 81.]</p> + <br /> + <a name="a140" id="a140"></a> + <p><a href="images/image140.png"><img src="images/image140sm.png" + alt="EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER AND FRICK.)" /></a></p> + <br /> + + <p>FIG. 140.—EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER AND FRICK.) + <i>a</i>, The thinned horny wall covering the coronary cushion; <i>b</i>, the lateral + cartilage exposed by stripping off the thinned wall; <i>c</i>, the sensitive + laminæ.</p> + <p>This done, the external face of the cartilage is separated from the skin of the + coronet. To do this a double sage-knife is run flatwise between the coronary cushion + and the cartilage, with the convex surface of the blade towards the skin. The knife + is then passed backwards and forwards until the necessary separation is accomplished. + During these movements of the knife a finger of the unoccupied hand should follow the + knife, and guard the coronary cushion against injury.</p> + <p>Following this, the inner surface of the cartilage must be also separated + from the structures lying beneath it. To this end a sage-knife (right- or + left-handed, according as to whether the anterior or posterior portion of the + cartilage is to be first removed) is again passed into the incision. With the + cutting-edge of the knife forward, it is gradually reached round and under the + hindermost end of the cartilage, and the posterior half of the cartilage separated + from underlying structures, and at the same time excised by one clean cut forwards. + Using the second sage-knife in a similar manner, the cutting-edge this time + backwards, it is reached in front of the cartilage, whose anterior half is then + excised by a careful cut backwards. Any small portions of cartilage remaining after + this are sought for with the finger, and carefully removed by means of a scalpel and + a tenaculum.</p> + <p>The fistulous opening or openings in the skin of the coronet should now be + thoroughly curetted, and the whole of the wound dressed as to be described later.</p> + <p>In removing the anterior half of the cartilage it is highly important to remember + the close contiguity to it of the synovial membrane of the pedal articulation. This + projects as a small sac between the antero- and postero-lateral ligaments of the + joint. Risks of injury to it may be diminished by having the foot secured with a + line, and pulled forward by an assistant while the cut is being made.</p> + <p><i>Third Method (after Bayer)</i>.—This operator recommends that, after + stripping a half-moon-shaped piece of horn from the seat of operation, instead of + raising the skin of the coronet and the attached coronary cushion in two flaps (as + Fig. 139, a, a), that the cartilage be exposed by raising up one flap only (Fig. 141, + a), consisting of a portion of the sensitive laminæ, the coronary cushion, and + the skin and underlying structures of the coronet.</p> + <p>With the horse cast and the preliminary steps over, the thinned horn of the + quarter is incised in a semicircular fashion, and the half-moon-shaped piece thus + separated from its surroundings stripped off. At about 1/4 inch from the incision in + the horn, a second incision of similar shape is made through the sensitive + structures, which incision is also carried up into the skin and structures of the + coronet. This incision severs, from bottom to the top, (1) the sensitive laminæ + covering a portion of the pedal bone and a portion of the lateral cartilage, (2) the + coronary cushion, and (3) the skin of the coronet and such structures as lie between + it and the cartilage.</p> + <br /> + <a name="a141" id="a141"></a> + <p><a href="images/image141.png"><img src="images/image141sm.png" + alt="EXCISION OF THE LATERAL CARTILAGE. (AFTER BAYER.)" /></a></p> + <br /> + + <p>FIG. 141.—EXCISION OF THE LATERAL CARTILAGE. (AFTER BAYER.) The horny wall + is stripped off over the seat of operation. <i>a</i>, Semicircular flap of sensitive + laminæ, coronary cushion, and skin; <i>b</i>, the lateral cartilage; <i>c</i>, + the sensitive laminæ; <i>d</i>, the coronary cushion.</p> + <p>That this incision of the sensitive structures should be kept at 1/4 inch from the + one in the horn has a reason. It is that when this flap is again placed into position + (as later it will have to be) we have round its circumference a rim of soft + structures into which to place the sutures. And in this connection it is well to + advise the operator that the thinness of the keratogenous membrane (the laminal + portion of it) should warn him that the portion of it to be turned up—namely, + that forming the tip of the flap—should be <i>scraped</i> away quite close to + the os pedis. Unless this is done, there will not be a sufficient thickness left to + afterwards bring into position and suture.</p> + <p>The half-moon-shaped piece of tissue incised is now carefully dissected away from + the external face of the cartilage, until it may be turned up as a flap (see Fig. + 141, <i>a</i>), and held from off the cartilage by a tenaculum.</p> + <p>The exposed cartilage is now carefully removed by the aid of a sage-knife and a + stout pair of forceps, the same precaution of holding the foot well forward being + again taken in order to avoid wounding of the articular capsule.</p> + <p>At this stage in the operation considerable care is required. The operator must + remember that close beneath him, and more particularly in front, is the pedal + articulation. It is better, therefore, to excise the cartilage piecemeal, and to do + it carefully, than to attempt, at the risk of injury to the joint, to make the + operation 'showy.'</p> + <p>During removal of the cartilage, the terminal branches of the digital arteries are + wounded, as also are the veins of the coronary plexus. Should either of these stand + out with extra prominence from the others, it should be picked up with a pair of + forceps, and ligatured with either carbolized gut or silk.</p> + <p>Attention should then be given to the flap of skin and coronary cushion. Wherever + a sinus has existed in it, it is to be carefully scraped, and all dead portions of + tissue removed. This done, the flap is allowed to fall into position, and is there + carefully sutured, not only at the skin of the coronet, but along the whole + circumference of the incision.</p> + <p><i>Dressing of the Wound and After-Treatment</i>.—The whole secret of the + success of this operation is in afterwards maintaining a strict asepsis of the wound. + Unless there is reasonable room for belief that this may be done, the operation had + far better not be advised, for if the wound is afterwards suffered to get into a + suppurating and dirty condition, the last stage of the case may be worse than the + first Synovitis and arthritis, with certain anchylosis of the joint, and a probable + loss of our patient, is almost bound to follow.</p> + <p>We cannot, therefore, too strongly insist upon the advice that the whole of the + preliminary antisepticising of the foot that we have described, and the after + maintaining of asepsis that we are now about to relate, <i>must</i> be methodically + and thoroughly carried out. It is of even <i>more</i> importance than little details + in the operation itself.</p> + <p>In the first and second methods of operating, directly the actual operation is + over, the surface of the wound and both surfaces of the skin-flaps should first be + thoroughly douched with a 1 in 1,000 solution of perchloride of mercury. Bayer + prefers a 1 in 5 solution of iodoform in ether.</p> + <p>Next, either iodoform or chinosol in the powder should be dusted over the whole + surface, including again both inner and outer faces of the reverted skin-flaps. This + done the flaps are allowed to fall into position and sutured there with carbolized + silk or gut.</p> + <p>Another liberal application of an antiseptic dressing follows this. Iodoform, + iodoform and boracic acid, or chinosol, is freely dusted over the wound and for some + distance around it. Bayer, however, again prefers a dressing of the wound, and + especially the moistening of the line of sutures with the 1 in 5 solution of iodoform + in ether.</p> + <p>Over the wound is then placed a protective layer of gauze, impregnated either with + boric acid, with a mercuric salt, or with iodoform.</p> + <p>Finally, numerous small and lightly-rolled balls of dry carbolized tow are packed + regularly over the whole of the operation wound, and the foot bandaged.</p> + <p>Practical points to be remembered in this after-dressing are: (1) The balls[A] of + tow should be numerous enough to exercise pressure upon the sutured flap when the + foot is finally bandaged. (2) The bandage should be run on from the coronet + downwards, in order to insure pressure being exerted in the exact position over the + sutured flap. (3) Bandages should be used in abundance, commencing always from the + coronet, and carefully applied so as to exert an even and uniform pressure. (4) The + bandages should be of clean, unused linen.</p> + <p>[Footnote A: Bayer recommends that the tow be rolled into cylindrical tampons, + each long enough to cross the wound. These are placed on the wound in alternate + horizontal and vertical layers, so that when rolled round by a bandage they are + pressed into an even and compact pad.]</p> + <p>Once the bandages are adjusted, the hobbles may be removed, and the tourniquet + loosened. Directly the tourniquet is removed there is a steady oozing of blood + through the bandages, no matter how many we have put on. This should occasion no + alarm, as experience has taught that the careful attention to antiseptic measures + observed throughout the operation has the effect of maintaining the lowermost + dressings, those next to the wound, in a state of asepsis. The bandaged foot should + now be wrapped in a piece of thick clean cloth or placed in a boot.</p> + <p>If our antiseptic precautions have been thorough, the dressings and bandages so + adjusted may be allowed to remain without disturbance for from eight to fourteen + days. In this, however, the veterinary surgeon must be largely guided by the symptoms + of his patient. If, at the end of the first three or four days, the animal maintains + a vigorous appetite, if he commences to place a little weight on the foot, and if the + thermometer gives no indication of a rise beyond the one or two degrees of ordinary + surgical fever, then the surgeon may know that things are proceeding satisfactorily. + Pawing movements with the foot, inability to place weight upon it, loss of appetite, + an increase in the number of respirations, and a serious rise of temperature, denote + the opposite state of affairs. The wound is in all probability suppurating. The + bandages and dressings should therefore be removed, and the wound either redressed + and bandaged, or treated as an ordinary open wound.</p> + <p>Ordinarily, however, if the operation has been properly performed, healing takes + place by first intention, and the wound when the bandages are removed at the end of + the first or second week appears clean and <i>dry</i>.</p> + <p>Having assured ourselves that such is the case, we dress the foot in exactly the + same manner as before, save that so many bandages are not put on. A similar dressing + is repeated weekly until such time as the wound shows sufficient growth of + horn—quite a thin pellicle—to act as a protective. It may then be left + undressed, except for some simple hoof dressing and a bandage.</p> + <p>Complete healing of the wound takes from about four to eight weeks, at the end of + which time the animal can be again gradually put into work. The labour, however, + should be light, and quite three or four months should be allowed to elapse before + any attempt is made to put him to heavy work.</p> + <p>Should the second method of operating have been the one adopted, then there is one + slight difference in the after-dressing that needs attention calling to it. In this + case we have more or less of a <i>hidden</i> cavity left to deal with rather than the + broad and <i>open</i> wound left in either of the other methods. This cavity, left by + the extirpation of the cartilage, must be thoroughly dressed with iodoform or + chinosol, or with Bayer's iodoform in ether. The packing with carbolized tow and the + bandaging may then be proceeded with as before.</p> + <p>In conclusion, we may say that the operation is one of some delicacy, and needs a + good surgeon for its successful performance. Furthermore, no one of the antiseptic + precautions we have advised can be omitted. It is, perhaps, these two considerations + (and in justice to the English surgeon we should say most probably the latter of + them) that have prevented this operation from being generally adopted.</p> + <p>That it is successful there is no gainsaying. Professor Bayer, of the Vienna + School, with whose name is associated the last of the three methods of operating we + have described, is enthusiastic in praise of the operation, and says: 'The favourable + results that I have got by this operation have caused me wholly to abandon the + medicinal treatment, and to prefer in all cases the surgical operation as being the + best means to the end.'</p> + <p><i>Partial Excision of the Lateral Cartilage</i>.—Discarding the somewhat + elaborate methods we have just described, there are English operators who removed the + necrosed portion only of the cartilage, and do so in what appears at first sight a + comparatively rough-and-ready manner.</p> + <p>The apparent roughness is that they do not concern themselves with conserving the + coronary cushion, and hesitate but little in cutting portions of it bodily away. One + would imagine that in this case the quarter of the side operated on would be always + more or less bare of horn. Such, however, is not the case.</p> + <p>To perform this operation the animal is again cast and chloroformed. Some + operators, however, use the stocks and dispense with the anæsthetic. The foot + is first well cleaned with soap and water and a stiff brush, and the hair of the + coronet over the seat of operation shaved. Again, too, the horn of the affected + quarter is rasped until it yields easily to pressure of the thumb, and the whole of + the foot washed in an antiseptic solution.</p> + <p>A probe is now inserted into the opening at the coronet, and the direction of the + fistula noted, after which the foot is firmly secured, and an Esmarch bandage and + tourniquet applied to the limb.</p> + <p>This done, a triangular or wedge-shaped portion of skin, coronary cushion, and + thinned horn is removed with a strong sage-knife or scalpel.</p> + <p>The base of the wedge-shaped portion removed contains the opening of the fistula, + and the apex of the wedge should reach to the bottom of the sinus (see Fig. 142).</p> + <p>After the horn is removed and the fistula followed up, it is sometimes found that + what we at first thought was its end, it may now be continued in an altogether + different direction.</p> + <p>It is again followed up with the probe, and the horn and sensitive structures + excised until we are quite certain we have reached its furthest extent.</p> + <p>Attention should next be paid to the cartilage. Wherever spots of necrosis are + found, as indicated by the pea-green colour of the affected parts, they must be + <i>carefully</i> excised. Care should be taken in so doing to carry the line of + excision some little distance around the visibly affected parts. This is done that we + may be quite certain nothing at all remains calculated to give rise to further + trouble.</p> + <p>It goes without saying that, in addition to the necrosed cartilage, all other + diseased and necrotic tissues should also be removed. The os pedis is occasionally + found necrotic just where the cartilage joins it, or it may be that a small portion + of the sensitive laminæ, by reason of its <i>liver-red</i> or even gray + coloration, gives evidence of death of the part.</p> + <p>The former must be well curetted, and the latter cleaned carefully with a scalpel + and forceps.</p> + <br /> + <a name="a142" id="a142"></a> + <p><a href="images/image142.png"><img src="images/image142sm.png" + alt="PARTIAL EXCISION OF THE LATERAL CARTILAGE BY REMOVING A PORTION OF THE CORONARY CUSHION." /> + </a></p> + <br /> + + <p>FIG. 142.—PARTIAL EXCISION OF THE LATERAL CARTILAGE BY REMOVING A PORTION OF + THE CORONARY CUSHION. The dotted lines show the outline of the wedge-shaped portion + of structures to be removed, including skin, coronary cushion, horn, and sensitive + laminæ. <i>a</i>, The opening of the fistula.</p> + <p>The operation finished, the foot is again douched in an antiseptic solution, the + wound mopped dry with carbolized tow, dressed with either of the dressings described + on page 358, and finally bandaged. The dressing should be changed every three days + only, unless in the meanwhile pawing movements and other symptoms of distress + indicate their removal.</p> + <p>The length of coronary cushion removed in this operation is from 1/4 to 1/2 inch + (we ourselves, however, have seen it more), and yet its loss seems to occasion no + serious after-trouble beyond a slight deformity of the parts beneath. The sensitive + structures become sufficiently covered with horn, and the animal in nearly every case + is returned to work, while in a great many instances he may also trot perfectly + sound.</p> + <p>Simple though the operation may appear, and apparently rough in its method, it is + nevertheless successful in effecting a cure in cases where blisters, plugging, + injections, and other means have failed.</p> + <p>Mr. W. Dacre, M.R.C.V.S.,[A] after reading an article on the operation before the + members of the Lancashire Veterinary Medical Association, says: 'My observations have + not been based on a single case, and having had nine of them, and all of them + successful, I felt it to be my duty to bring this subject before the Society.'</p> + <p>[Footnote A: <i>Veterinary Record</i>, vol. v., p. 407.]</p> + <p>Mr. T.W. Thompson, M.R.C.V.S.,[A] says: 'In a great number of cases I have removed + a 1/2 inch of the coronary band.... I have performed the operation a great number of + times, and have never seen a foot that has been damaged by it.'</p> + <p>[Footnote A: <i>Ibid</i>.]</p> + <p>Professor Macqueen[A] says: 'I do not spare the coronary band or sensitive + laminæ when I find those parts diseased. I do not unnecessarily damage those + structures. At the same time, I am confident that excision of a piece of the coronary + band or removal of a few sensitive laminæ has not the untoward consequences so + much dreaded in former days.'</p> + <p>[Footnote A: <i>Ibid</i>., p. 714.]</p> + <p>Mr. John Davidson, M.E.C.V.S.,[A] says: 'The treatment described, if carefully + carried out and details attended to, will be found a success in dealing with the + majority of cases of quittor. If I may be permitted to say so, without being + considered boastful, I have yet to see the first case that has resisted the + treatment.'</p> + <p>[Footnote A: <i>Ibid</i>., vol. xiv., p. 769.]</p> + <p>Should our case of quittor be complicated by caries of the bone, this must, where + possible, be scraped or curetted until the whole of the diseased portion is removed, + and a healthy surface is left. After-dressing must then be carried out as in other + cases.</p> + <p>The treatment of ossified cartilage will be found under treatment of side-bones, + and the methods of dealing with penetrated articulation and purulent arthritis are + treated of in Chapter XII.</p> + <p><i>Surgical Shoeing in Quittor</i>.—In the case of simple or cutaneous + quittor, no alteration in the shoeing is necessary.</p> + <p>When the condition becomes sub-horny, however, and particularly when it is + situated in the region of the quarters, ease is afforded to the diseased parts by + removing the bearing of the shoe in that position.</p> + <p>Should there be no dependent opening at the sole, then the best shoe for the + purpose is an ordinary bar shoe (Fig. 68), with the bearing eased under the affected + quarter.</p> + <p>If, however, there is a dependent orifice, or one is expected, then it will be + necessary either to leave the animal unshod or to provide him with a shoe that admits + of dressing the lesion. In the latter case the most suitable shoe will be found to be + either a three-quarter shoe (Fig. 102) or a three-quarter bar shoe (Fig. 103). Many + operators, however, keep the animal unshod. We must say ourselves that we consider a + shoe useful after either of the operations for removal of the cartilage, if only to + assist in maintaining the bandages and dressings in position.</p> + <p>In this case a very useful shoe will be the three-quarter bar shoe. With a little + manipulation the bandages are easily run under the bar portion of the shoe, and a few + of their turns every now and again wrapped round the bar in order to keep the whole + firmly in position.</p> + <p>In connection with tendinous quittor, when septic matter has gained the sheath of + the flexor tendons, there is, for a long time after healing of the fistula, a marked + tendency for the animal to go on his toe. To a large extent we judge this to be due + to slight adhesions between the two tendons brought about by the growth of + inflammatory fibrous tissue. In such cases benefit is sometimes derived from the + application of a shoe with an extended toe-piece (see Figs. 84 and 108).</p> + <h3>C. OSSIFICATION OF THE LATERAL CARTILAGES, OR SIDE-BONES.</h3> + <p><i>Definition</i>.—An abnormal condition of the lateral cartilages, in which + the substance of the cartilage becomes gradually removed and bone formed in its + place.</p> + <br /> + <a name="a143" id="a143"></a> + <p><a href="images/image143.jpg"><img src="images/image143sm.jpg" + alt="OSSIFIED LATERAL CARTILAGES (SIDE-BONES)." /></a></p> + <br /> + + <p>FIG. 143.—OSSIFIED LATERAL CARTILAGES (SIDE-BONES).</p> + <p><i>Symptoms and Diagnosis</i>.—Side-bones are nearly always met with in + heavy draught animals, and are rarely seen in the feet of nags. They are, moreover, + nearly always confined to the fore-feet. In the ordinary way little need be said + concerning their characteristics, and the way in which they may be detected. Neither + need any concern be ordinarily manifested with regard to the effect they may have on + the animal's gait and future usefulness. Seeing, however, that side-bone constitutes + one of the recognised hereditary diseases, and that at the various agricultural and + horse shows its existence or otherwise in a certain animal is a matter of great + importance, some little attention must be given to these two points.</p> + <p>With a side-bone anywhere approaching full development, diagnosis is easy. The + thumb is pressed into the coronet over the seat of the cartilage, when, in place of + the elasticity we should normally meet with, we have the solid resistance offered by + bone. In some instances diagnosis is even easier still. We refer to those cases in + which the side-bone stands above the level of the coronet with such prominence as to + be readily <i>seen</i> and recognised without manipulation, and where its growth has + caused distinct enlargement and bulging of the wall of the affected quarter. It seems + that in such cases the bone-forming process does not end with simply depositing bone + in place of the removed cartilage, but that, after that is accomplished, the bone + still continues to be produced, as in the case of an exostosis elsewhere.</p> + <p>Although diagnosis in cases such as these is easy, it becomes a very different + matter when we are called upon to give an opinion in cases where ossification of the + cartilage is only just commencing. Whether the result of our examination is to decide + the sale or purchase of an animal, to determine his fitness or otherwise to enter the + show-ring, or to merely advise a client as to whether or no a side-bone is in course + of formation, our position is equally difficult, and in either case our examination + must be searching.</p> + <p>Perhaps the best advice we can give is to say that the whole of the cartilage must + be manipulated both with the foot <i>on</i> and <i>off</i> the ground. What the + reason may be we do not pretend to say, but it is a well-known fact that in many + instances the cartilage, with the foot bearing weight, is so rigid as to at once + convey the impression that ossification has commenced or is even far advanced. And + yet that same cartilage, with the foot removed from the ground, is as pleasantly + yielding to pressure of the thumb as the most exacting of us could wish for. In any + case, then, where doubt exists, the foot should be lifted to the knee, and the + cartilage carefully examined with the foot in that position. If, then, at any spot + above the normal contour of the os pedis we meet with hardness or rigidity, we are to + look upon that foot with suspicion. Nevertheless, providing our conscience is + sufficiently elastic, the animal may be passed <i>sound</i> so far as the + <i>existence</i> of a side-bone is concerned. We know, however, that with commencing + rigidity we may ere long expect one, and if our opinion is asked with regard to that + particular, it must be admitted that with rigidity of the cartilage once commenced it + is usually not long afterwards before a fully-developed side-bone makes its + appearance.</p> + <p>As is only to be expected, the first noticeable hardening of the cartilage is to + be found near the normal bone. We may thus look for it more particularly in the lower + portions of the cartilage. We think we may say, too, that in the vast majority of + cases the ossification of the cartilage commences in its anterior half. It is thus + brought about that often we are called upon to examine and report on the condition + when we have <i>anteriorly</i> a side-bone in course of formation, and + <i>posteriorly</i> a perfectly normal cartilage. It is to the latter half of the + cartilage that dealers and others mainly, if not wholly, devote their attention. A + horse with the cartilage in this transition state will therefore pass muster, and a + nice little point of ethics has again to be decided by the veterinary surgeon before + giving his signature to a certificate of examination of an animal in this + condition.</p> + <p>With regard to alteration in gait, we may say at once that side-bones in heavy + animals are not often the cause of lameness. In fact, where the foot is well + developed, when neither the foot as a whole nor the phalangeal bones give evidence of + disease, and where the pasterns are fairly oblique and well formed, this alteration + of the cartilages may be looked upon as of no serious import at all. Neither is the + side-bone due to blows or other injuries likely to be productive of + lameness—that is, always supposing, of course, that the foot in other respects + is of good shape. If lameness is met with at all, then it is where we have a foot + that is in other respects unsound, with badly contracted heels and upright 'stumpy' + hoof, or where side-bones have occurred in a young animal, and have already reached a + large size before the horse is put to labour. In this latter case, the added effects + of concussion and the evil influences of shoeing are sufficient to turn the scale. + Directly the animal, previously sound, is asked to work, lameness is the result.</p> + <p>It follows, therefore, that side-bone in the feet of young animals is of far more + serious import than when occurring in older horses. In a nag animal they constitute a + positive unsoundness, and lameness in this case is more often than not an + accompanying symptom.</p> + <p><i>Causes</i>.—To commence with, we may remark that, although met with + sometimes in very early life, side-bones are seldom, if ever, congenital, and that + more often than not they may be looked for in animals of three years old, or older, + seldom earlier. They appear, in fact, only when the animal is shod and commences + work.</p> + <p>This at once suggests two of the principal factors in their + causation—namely, concussion and loss of normal function. Directly the horse is + put to work he has for a great part of his time to travel upon roadways—either + macadamized roads or town sets—where everything is calculated to bring + concussion about. In addition to that he has the lateral cartilage itself thrown + largely out of action by shoeing. We explained in Chapter III. (p. 66) that the chief + function of the cartilage was to take concussion received by the plantar cushion and + direct the greater part of it outwards and backwards. Now, with the animal shod, the + plantar cushion does not itself, as normally it should, receive concussion. By the + shoeing the frog is lifted from the ground, and the plantar cushion, together with + the cartilage, taken largely out of active work. In other words, the normal outward + and inward movements of the cartilage are enormously reduced.</p> + <p>It is fair, we think, to take it that the mere fact of the lateral cartilage + persisting <i>as</i> cartilage is due in large measure to its constant movement. + Directly, therefore, it is placed in a state of comparative idleness, then it + commences to ossify, more particularly if there should at the same time be a tendency + to a low type of inflammation of the parts.</p> + <p>Does this latter exist? We may safely say that it does. It is in this way: The + secondary effect of loss of ground-pressure upon the frog and plantar cushion is to + bring about contraction of the heels. With this we get compression of the parts + within, with a certain amount of irritation and the exact low type of inflammatory + phenomena calculated to assist in the bone-forming process.</p> + <p>The fact that concussion acts as a cause explains in great measure how it is that + side-bones are more frequent in cart animals than in nags, and also why they should + be more common in the fore-feet than in the hind. Taking, in both animals, a rough + calculation as to the weight of body carried by feet of a certain size, we notice at + once that the cart animal has proportionately more weight to carry than has the nag. + Concussion to the foot is therefore greater. The greater part of the body-weight is + borne by the fore-limbs. Concussion is therefore greater to the fore-feet than to the + hind.</p> + <p>This, however, does not explain altogether the comparative immunity of the nag + animal from this defect. He, too, must also be subject to the effects of concussion, + especially when his higher and faster action is taken into account. To our minds + there is only one explanation to be offered here. We point at once to the years of + constant and judicious breeding of the nag. Compare that with the relatively few + minutes that have been devoted to a more careful selection of the cart animal, and we + at once see a possible explanation. That the explanation holds some amount of truth + is borne out by the fact that, since a greater attention has been paid to the + selection of our cart animals, side-bone has grown a great deal less common.</p> + <p>Is side-bone hereditary? We can best answer that by saying that, some several + years ago, the Council of the Royal College of Veterinary Surgeons, at the request of + the Royal Commission on Horse Breeding, drew up a list of those diseases 'which by + heredity rendered stallions so affected unfit as breeding sires,' and that in that + list was included side-bone.</p> + <p>Side-bones, therefore, are hereditary. We think, however, the statement needs + qualifying. It is in this way: side-bones occur only at a certain, usually + well-defined, time after birth, and we might say are <i>never</i> congenital. They + occur only after the animal has been put to work, and are more or less plainly due to + mechanical causes—namely, the ill effects of shoeing and concussion. The cause + of their appearance, in short, is more plainly extrinsic than intrinsic, and + side-bone in the horse is, as Professor McCall puts it, about as much due to heredity + as is corn on the human foot.</p> + <p>Between these two opinions—that they are plainly hereditary, and that they + just as plainly are not—it is well to strike a middle course. They are, we will + say, hereditary in this way: So long as a cart animal is bred, to put it vulgarly, + 'top-heavy' (that is, with a body out of reasonable proportion to the feet that have + it to support), so long will the foot be subjected to a greater concussion, and so + long will side-bones in such animals commence to make their appearance at about + middle life.</p> + <p>In addition to the causes we have now mentioned, side-bones are often the result + of other diseases of the foot. They thus occur as a sequel to sub-horny quittor, to + suppurating corn, to complicated quarter sand-crack, or to the inflammation of the + parts occasioned by a prick. They also arise in many instances from the effect of a + prick or injury to the coronet. Among the latter we may mention treads from other + animals, and treads inflicted by the animal himself with the calkin of an opposite + shoe, or the repeated injury occasioned by the shafts being carelessly allowed to + drop on to the foot. In severe cases of laminitis, too, the cartilages are nearly + always affected. In this instance the inflammatory phenomena in the os pedis no doubt + give rise to an abnormal activity of bone-forming cells. The cartilage is invaded, + and the side-bone formed (see Fig. 118).</p> + <p><i>Treatment</i>.—In the ordinary way the 'treatment' of side-bone is a + thing but rarely mentioned. The explanation lies, of course, in the fact that + side-bones are so rarely the cause of lameness. When lameness does occur with a + side-bone, and we have reason to believe that the said side-bone is the cause of the + lameness, it is well before talking of treatment to question ourselves thus: 'In what + way does the side-bone cause lameness?' The now generally-accepted answer to that + query is the explanation put forward several years ago by Colonel Fred + Smith—namely, that the pain, and therefore the lameness, was due to the + compression of the sensitive laminæ between the ossified and enlarged cartilage + and the non-yielding and often contracted wall of the quarters. That, in fact, + constitutes the basis upon which Smith's operation for side-bone (that of grooving + the wall of the quarters) is founded.</p> + <p>Before describing the operation, however, we may say that we are now able to + understand that older operators who claimed success for other methods of treatment, + were to a very great extent justified in so doing.</p> + <p>For instance, take the combined treatments of firing and blistering, and the use + of a bar shoe. Here the beneficial action of the cautery and the blister may be + largely problematical. The bar shoe, however, would be almost certain to give good + results. Frog-pressure with the ground would be again restored, and the contraction + of the heels removed. Pinching of the sensitive structures would be diminished, and + the lameness cured.</p> + <p>Take, again, the treatment of 'unsoling.' It was barbarous, we know barbarous, + because unnecessary and easily avoidable. It was practised, however, certainly very + little more than two decades ago, and practised by men of standing in the profession. + Without dragging the case to light again by mentioning the names of those concerned, + we may mention that not many years ago a highly respected member of the profession + was, at the instigation of the Royal Society for the Prevention of Cruelty to + Animals, prosecuted for practising unsoling for the relief of side-bone. Practically + only one other member of the profession was able to come forward and defend the + operation on the score of its utility. We see now, however, that—as does + Smith's operation—unsoling does permit of the greater expansion of the heels. + The contraction is done away with, the pressure on the sensitive laminæ again + diminished, and the lameness relieved.</p> + <p>Not that we are attempting to defend the operation—far from it. We simply + mention it as interesting, and quote this and the use of the bar shoe (with both of + which methods older operators have claimed success) merely as evidence that the + operation of Smith is based on a logical foundation.</p> + <p>When treatment is decided on, therefore, we may first advise blistering and the + use of a bar shoe. After that, should the lameness continue, and should we still + judge the side-bone to be the cause of it, the operation may be advised.</p> + <p>As we have said before, the operation consists in so grooving the wall as to allow + of the quarters widening sufficiently to relieve pressure on the parts within. In one + or two previous portions of this work we have considered operations involving this + procedure. Before detailing the operation here, therefore, we will first describe the + instruments necessary, and the most satisfactory methods of incising the horn.</p> + <p>To begin with, it must be remembered that all methods of hoof section have for + their object the after-expansion of the horny box, and that this can only be brought + about by making each groove complete from coronary margin to solar edge of the wall, + and carrying it, throughout its length, <i>deep enough to reach the commencement of + the sensitive structures</i>.</p> + <p>To this end, therefore, the operator must bear in mind the comparative thickness + of the various parts of the wall, and must, in particular, remember the relative + thinness of that portion of horn forming the outer boundary of the cutigeral groove, + and accommodating the coronary cushion.</p> + <p>For the making of the incisions there is the special saw devised for this + operation by Colonel F. Smith, A.V.D., and which we illustrate in Fig. 144. With this + the wall is sawn through <i>until the depth arrived at is equal to what is indicated + by a previous examination of the thickness of the crust as viewed from the solar + surface</i>. Here Colonel Smith says: 'I strongly advise everyone to use a metal + gauge (a thin piece of material) to introduce into the incision made by the saw, and + run it up and down to ascertain whether the wall is properly divided throughout. The + depth to which this should be done we know from the previous measurements of our + gauge on the crust.'</p> + <br /> + <a name="a144" id="a144"></a> + <p><a href="images/image144.png"><img src="images/image144sm.png" + alt="SMITH'S SIDE-BONE SAW (EARLY PATTERN)." /></a></p> + <br /> + + <p>FIG. 144.—SMITH'S SIDE-BONE SAW (EARLY PATTERN).</p> + <p>Should the saw be of a pattern in which the set of its teeth makes only a narrow + incision,[A] it should, while operating, be kept well oiled, and should be withdrawn + every few seconds in order that the horn-dust lying in its teeth may be examined. If + this is getting slightly blood-stained, we know, of course, that the sensitive + structures are reached, and the incision has been carried far enough. In so judging + the depth of the incision, however, care must be taken to see that the top of the + coronary cushion is not injured with the saw, for if this is done the blood trickling + into the depth of the incision will tinge the horn-dust, and give the false + impression that the incision is sufficiently deep.</p> + <p>[Footnote A: That is Smith's older pattern. The newer pattern (Fig. 145) has the + teeth so set as to make an incision wide enough to be looked into. In this case the + depth arrived at is to be judged by the appearance of the bottom of the + incision.]</p> + <p>If the operator has had no previous experience of the use of the saw in this + operation, he must also be careful to avoid placing too great a pressure on the teeth + of its lower third. This is done by keeping the hand too greatly depressed. Again, + this leads to wounding of the sensitive structures (this time at the lower end of the + incision), and again the operator is confused by the blood thus allowed to run into + the groove.</p> + <p>The only portion of horn difficult to operate on is that immediately under the + coronet. This is best severed with a succession of downward movements, and is easier + performed with Smith's later pattern of side-bone saw (Fig. 145) in which the set of + the foremost teeth is reversed.</p> + <br /> + <a name="a145" id="a145"></a> + <p><a href="images/image145.png"><img src="images/image145sm.png" + alt="SMITH'S SIDE-BONE SAW (IMPROVED PATTERN)." /></a></p> + <br /> + + <p>FIG. 145.—SMITH'S SIDE-BONE SAW (IMPROVED PATTERN).</p> + <p>In making these grooves we must say that we think the use of the special saw may + be dispensed with, and the incisions just as easily, or, at any rate, just as + successfully, made with the knife. Those who select to use this instrument should + choose a narrow-topped and sharp searcher, or a modern shaped drawing-knife of + suitable size, such as those depicted in Fig. 46, <i>a</i> and <i>b</i>, and they + will find their work much easier if they will make the first steps in the incisions + with an ordinary flat firing-iron. By the use of the latter instrument the grooves + are made conveniently open along their tops, and room left for nicely finishing the + more delicate manner of removing with the knife the softer horn near the sensitive + structures.</p> + <p>Those whose leaning is towards the use of special instruments, but who, at the + same time, do not care to use the saw, will find their wants supplied in the hoof + plane (Smith's), Fig. 146, or the hoof chisel (Hodder's), Fig. 147. With the hoof + plane the groove in the wall is made by a succession of downward scraping movements, + while with the chisel the cut in the wall is made either from below upwards, or from + above downwards, according as the foot is held forward or backward—whichever, + in fact, comes most convenient.</p> + <br /> + <a name="a146" id="a146"></a> + <p><a href="images/image146.png"><img src="images/image146sm.png" + alt="HOOF PLANE (SMITH'S)." /></a></p> + <br /> + + <p>FIG. 146.—HOOF PLANE (SMITH'S).</p> + <p>When using the knife or the hoof plane it is not often that the sensitive + structures are injured. In all cases, however, no matter what the instrument used, + the metal gauge should be employed when the sensitive structures have been touched, + and the operation obscured by blood.</p> + <br /> + <a name="a147" id="a147"></a> + <p><a href="images/image147.png"><img src="images/image147sm.png" + alt="HOOF CHISEL (HODDER'S)." /></a></p> + <br /> + + <p>FIG. 147.—HOOF CHISEL (HODDER'S).</p> + <p>Our instruments at hand, the operation may be proceeded with. The first step is to + ascertain the extent of the side-bone, and to determine the position of the + incisions. To do this the coronet is felt with the thumb, and the anterior extremity + of the side-bone noted. This is marked on the horn with a piece of chalk, and a + vertical line dropped from this position to the inferior margin of the wall (Fig. + 148,1). The line crosses the horn fibres obliquely, and is purposely made in that + direction in order that its inferior end may be far enough back to avoid the last + nail-hole. Should the side-bone reach very far forwards, it may be wise to cause this + line to slant from before backwards (see dotted line <i>a</i>, Fig. 148). Unless this + is done, it is found that in some feet so much of the wall is isolated at the bottom + that insufficient is left to nail the shoe to.</p> + <p>The next line to be made is the rear one. Its correct position is ascertained by + first noting the junction off the wall with the bar (see groove 2, Fig. 149); and its + inferior end must be just anterior to the inflexion of the wall. This is done that we + may avoid cutting the bar. The position of the lower end of the rear line thus + ascertained, it is run upwards with the chalk in the direction of the horn + fibres.</p> + <br /> + <a name="a148" id="a148"></a> + <p><a href="images/image148.png"><img src="images/image148sm.png" + alt="DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES IN THE WALL IN COLONEL SMITH'S OPERATION FOR SIDE-BONE." /> + </a></p> + <br /> + + <p>FIG. 148.—DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES IN THE WALL IN + COLONEL SMITH'S OPERATION FOR SIDE-BONE. 1,2, and 3, mark the grooves in the order in + which they are made; the dotted line <i>a</i> marks the position taken by the + anterior line when the side-bone, is one reaching far forward, while the dotted lines + <i>b</i> and <i>c</i> mark the position of the additional grooves to be made if + thought necessary.</p> + <p>The third line is made in such a position as to divide into two equal portions the + wall between lines 1 and 2. Here, however, some operators prefer to make two, or even + three, lines, adding those as at <i>b</i> and <i>c</i>, Fig. 148; and Smith himself + says that a multiplicity of lines is an advantage rather than not.</p> + <p>In any case, having once determined the position of the lines, they should be + plainly marked out with chalk, and then viewed from a distance with the foot on the + ground, in order to judge of their regularity. If we are satisfied with them, we then + lightly mark them with the saw, with the hot iron, or with the knife, whichever + instrument we may be intending to use.</p> + <p>Unless the details are methodically carried out as here described, it is probable + that more of the foot will be isolated than is necessary, and that as a consequence + very little is left to which to nail the shoe.</p> + <br /> + <a name="a149" id="a149"></a> + <p><a href="images/image149.png"><img src="images/image149sm.png" + alt="DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES MADE IN THE HOOF IN COLONEL SMITH'S OPERATION FOR SIDE-BONES." /> + </a></p> + <br /> + + <p>FIG. 149.—DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES MADE IN THE HOOF + IN COLONEL SMITH'S OPERATION FOR SIDE-BONES. 1, 2, and 3, show the grooves in the + wall in the order in which they are made; 4 shows the groove made at the junction of + the sole with the wall.</p> + <p>The incisions are then made with the saw or the knife, with the foot held in a + convenient position by an assistant. That usually found most comfortable for the + first incision is with the foot held forwards and placed on an assistant's thigh in + the position adopted for 'clenching up' when shoeing, while that for the rear + incision is with the animal's knee flexed, and the foot held well up to the elbow. In + this, however, each operator will suit himself.</p> + <p>Should the preliminary steps in making the incisions be performed with the iron, + it will be easiest done with the foot on the ground.</p> + <p>When the incisions through the wall are complete, our attention must be given to + the sole. A drawing-knife is here used, and a further incision made over the white + line so as to destroy the union of the sole with the wall between incisions 1 and 2, + and so completely isolate the portions of wall included within the four grooves (see + groove 4, Fig. 149). When this is done it should be found that the portions of the + isolated wall spring readily to pressure of the thumb.</p> + <p>The inferior or wearing margin of the isolated wall must now be so trimmed that it + takes no bearing on the ground when the opposite limb is held up by an assistant and + full weight placed upon the foot.</p> + <p>For a day or two after the operation lameness is intense. This is to be treated + with hot poultices or hot baths, and and soon disappears. Three to four days later a + bar shoe is nailed on (taking care that the bearing of the quarters is still eased), + and the hot poultices still continued. Four days later still walking exercise may be + commenced, to be followed shortly afterwards by trotting. At about the twelfth day + some animals may conveniently be put to work, while in other cases a fortnight, or + even a month, must elapse before this can be done. When put to work early, it is wise + to fill in the fissures made in the wall with hard soap, with wax, or with a suitable + hoof dressing, in order that irritation of the sensitive structures with outside + matter may be prevented.</p> + <p>This operation is soon followed by remarkable changes in the shape of the foot. At + about the third week the coronet shows signs of bulging, and the upper part of the + wall operated on is often so protruding as to render the foot wider here than at the + ground surface. This is a sign that the case is doing well.</p> + <p>Should no improvement be noticed at the end of three weeks or a month, or should + the grooves become filled from the bottom (which they do remarkably fast), then the + incisions must be deepened, the exercise reduced, and the fomentations or poulticing + repeated. So treated, many cases of side-bone lameness will be relieved, if not + entirely cured, and, should the worst happen, and no alteration in the lameness is + noticeable, no harm will have been done to the foot. In this connection, the + originator of the treatment says: 'I may assure those induced to doubt either their + diagnosis or the value of hoof section that no harm is done to the foot, even should + the operation be of no value. It may do much good; it cannot do harm. The operation + will never succeed until the inherent timidity of sawing or cutting into the wall is + overcome. The <i>incisions must be deep, and of the same depth from the coronet to + the ground</i>.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. iii., + p. 313.]</p> + <p>It is well to remark here that the operation of hoof section cannot be expected to + succeed in every case. The last man in the world to claim that for it would be its + originator. Failure to relieve the lameness may be accounted for in a variety of + ways. First, of course, will come errors in diagnosis. No one of us is infallible, + and the lameness we have judged as resulting from side-bone may arise from another + cause. There are, too, complications to be reckoned with, the existence or absence of + which cannot always be definitely ascertained. Such are: Ringbone, especially that + form of ringbone known as 'low'; bony deposits on the pedal bone, either on its + laminal or plantar surface, or even changes in the navicular bursa.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER XI</h3> + <h3><a name="bone" id="bone">DISEASES OF THE BONES</a></h3> + <h3>A. PERIOSTITIS AND OSTITIS.</h3> + <p>We head this section, Periostitis <i>and</i> Ostitis, for the reason that in + actual practice it is rare for one of these affections to occur without the other. + The periosteum and the bone are so intimately connected that it is difficult to + conceive of disease of the one failing to communicate itself in some degree to the + other. Pathologically, however, and for purposes of description, it is more + convenient to describe separately the abnormal changes occurring in these two + tissues.</p> + <p>With the main phenomena of inflammation occurring elsewhere we presume our readers + are aware. Briefly we may put it, that under the action of an irritant, either actual + injury, chemical action, or septic infection, the healthy tissues around react in + order to effect repair of the parts destroyed. Also that this reaction involves the + distribution of a greater blood-supply to the part, with an abundant migration of + leucocytes, and the outpouring of an inflammatory exudate, together with symptoms of + heat, pain, redness, and swelling of the affected area. And that in chronic + inflammations, owing to persistence of the cause, the process of repair thus + instituted does not stop at mere restoration of lost tissue, but continues to the + extent of forming an abnormal quantity of such tissue as normally exists in the parts + implicated.</p> + <p>The process of inflammation in bone is essentially the same. It takes place along + the course of the bloodvessels, and is only modified in its attendant phenomena by + the structure of the parts involved. Swelling, for instance, cannot take place in the + centre of compact bone tissue. Otherwise, other changes occur exactly as in + inflammations of other structures.</p> + <p>When the causal irritant has been excessively severe and the migration of + leucocytes abundant, actual formation of pus may occur, the bony tissue being broken + down and mingled with it, and an abscess cavity formed. In milder cases, affected and + necrotic tissue is removed by a process of phagocytosis, and new tissue (this time + osseous) formed in its place.</p> + <p>In the periosteum we may take it roughly that inflammation runs a course similar + to that occurring in soft tissues elsewhere. There is but one exception, and that, as + we shall mention shortly, is connected with its deeper layer.</p> + <p>As we know, the periosteum consists of two layers, an outer fibrous and an inner + yellow elastic, and is extremely vascular. Numerous bloodvessels ramify in it, and, + with their attendant nerves, break up to enter the numberless canals of the Haversian + system. This extreme vascularity, of course, favours abundant exudation. The exudate, + however, is, as it were, shut in by the dense fibrous layer of the membrane, and the + result is that in periostitis it collects between the membrane and the bone, causing + swelling and raising of the membrane, and giving rise to excruciating pain from + pressure upon the nerves.</p> + <p>Should the periostitis be complicated by the formation of pus, then the vessels + entering and supplying the bone are, in the suppurative area, destroyed. With their + destruction it may happen that we get also death of a portion of the osseous tissue. + This, however, when the suppuration is abundant, cannot commonly occur, as the + bloodvessels within the bone—those of the medulla—commence to supply + blood to the affected part. In cases of trouble with the bones of the foot, these + last few remarks have a special significance. Here we have three bones whose + medullary cavity is extremely small—almost nil, in fact—which explains in + some measure how easy it is when suppuration exists to get necrosis and exfoliation + of, say, portions of the os pedis. Necrosis and sloughing of the periosteum itself + may also happen, but as the extreme vascularity of the membrane is a fairly strong + safeguard against that it is of only rare occurrence.</p> + <p>In connection with the deep layer of the periosteum, and forming part of it, are + found numerous bone-forming cells (<i>osteoblasts</i>). These, under ordinary + conditions, are relatively quiescent. Under the slightest irritation or stimulation, + however, their bone-forming functions are stirred into abnormal activity, thus + explaining how easy it is (especially with bones so open to receive slight injuries + as are those of the foot) to get ossific deposits, the starting-point of which we are + quite unable to account for.</p> + <p>With this brief introduction we will now describe such pathological changes as + occur in the separate structures, and which we are likely to encounter in the various + diseases of the foot. While so doing, we shall draw attention to such diseases as we + have previously described in which the pathological conditions we are considering may + be met with.</p> + <p>1. PERIOSTITIS.</p> + <p>This we shall consider under <i>(a)</i> Simple Acute Periostitis, <i>(b)</i> + Suppurative Periostitis, <i>(c)</i> Osteoplastic Periostitis.</p> + <p><i>(a) Simple Acute Periostitis</i>.—This is the periostitis that follows on + the infliction of a slight injury to the membrane—an injury without an actual + wound and free from infective material. It is one, therefore, which we always judge + as existing in those cases where we have distinct evidence or history of injury, but + in which the injury has not been severe enough to lead to fracture or to the + infliction of an actual wound.</p> + <p>Such cases may be those of lamenesses persisting after violent blows upon the + foot—cases where the animal has been kicking against the stable fittings, or + where the foot has been partially passed over by the wheel of a waggon. It may be, + too, that in a case of 'nail-bound' a great deal of the pain and lameness is due to a + simple periostitis caused by pressure of the bulged inner-layer of horn upon the + sensitive structures.</p> + <p>Simple acute periostitis may also occur in cases where an actual wound is in + existence, but where such wound, fortunately, remains aseptic. We may thus have this + condition accompanying ordinary cases of pricked foot, of treads in the anterior + region of the coronet, and of accidental injuries of other kinds.</p> + <p>In simple acute periostitis the membrane is thicker and redder than normal, and is + easily stripped from the bone. As it is pulled off it is noticed that there are + numerous fibril-like processes hanging to its inner surface, and which draw out from + the substance of the bone. These are simply the vessels (bloodvessels and nerves) + which, loosened by the inflammatory exudate, are readily detached and drawn from the + Haversian canals into which they normally run. In addition to its increased redness, + the membrane has a swollen and gelatinous appearance owing to its infiltration with + the inflammatory discharges. Simple acute periostitis may and often does end in + resolution. On the other hand, it may end in suppuration or may become chronic. If + the latter, then the osteoblasts of the innermost layer become active, and abnormal + deposits of bone are the result.</p> + <p>(<i>b</i>) <i>Suppurative Periostitis</i>.—This condition simply indicates + that the inflammation is complicated by the presence of pus organisms. It is, + therefore, a common termination of the simple acute form attending the infliction of + a wound. The wound becomes contaminated, and the case of simple periostitis is soon + changed into the suppurative form. Once having gained entrance to the wound, the pus + increases in quantity, and slowly runs between the membrane and the bone. This, + however, it does not do to any large extent, showing rather a tendency to penetrate + the outer fibrous layer and gain the outside of the membrane.</p> + <p>Suppurative periostitis is met with in foot cases, commonly in connection with + punctured foot. It occurs, too, as a complication in suppurating corn, in severe + tread, in complicated sand-crack, as a result of the spread of suppurative matter in + acute coronitis, and in sub-horny quittor.</p> + <p>In ordinary cases of suppurative periostitis the pus formed is yellow in colour, + creamy thick, and free from pronounced odour—the so-called 'laudable' pus of + the older writers. It so happens in many cases of foot trouble, however, that + putrefactive organisms gain entrance side by side with those of pus. In this case the + characters of the discharge are very different. It is distinctly more fluid, is of a + pink or even light chocolate colour, and extremely offensive. In these instances the + pus shows a marked tendency to spread, strips the periosteum from the bone, + perforates the outer layer of the membrane, and finally infiltrates the surrounding + tissues.</p> + <p>This forms a near approach to what is known in human surgery as an + <i>infective</i> periostitis, and in our subjects is nearly always met with in cases + of severe prick. Its rapidly spreading character makes it always a dangerous + condition, and a punctured foot exuding a discharge of this nature should always be + regarded as serious. The close contiguity of the joint (it can never be <i>far</i> + distant in foot cases), the spreading character of the disease, and the rapidity with + which the horse succumbs to arthritis, are all factors to be taken into + consideration, and to lead to a warning-note being struck when attending a case of + such kind.</p> + <p>A further instance of infective periostitis is that met with in acute laminitis. + The discharge obtained from the sole in these cases very often bears the character we + have just described, and when one considers the thinness of the keratogenous + membrane, one is bound to admit that changes so grave occurring in it cannot fail to + spread and infect the periosteum.</p> + <p>(<i>c</i>) <i>Osteoplastic Periostitis</i>.—This is more particularly a + chronic process, and is, as the suffix '<i>plastic</i>' indicates, associated with + bone-forming changes in the membrane. It may occur as a consequence of slight but + continued irritation, often without ascertainable origin (see Case 2, p. 392), or it + may be the sequel of acute disease.</p> + <p>In this form of periostitis the membrane is again swollen and more vascular than + in health, and is also easily separable from the bone. The exposed bone is generally + rough, in some cases even spicular, and the inner layer of the removed membrane is + rough and gritty to the touch—characters imparted to it by numerous minute + fragments of bone that have been torn away with it from the more compact osseous + tissue beneath.</p> + <p>The results of an osteoplastic periostitis are frequently met with in the bones of + the foot, and are described by veterinary writers under such headings as 'Pedal + Exostoses,' 'Ossifying Ostitis,' and 'Pedal Ossification' (see Figs. 152, 153, 154, + and 155). In many of these cases the disease is purely chronic, and the original + cause nearly always wanting. When the foot has been subjected to laminitis of some + weeks' duration, the same condition is also met with, being at the same time + associated with rarefactive osteoplastic ostitis, conditions which we shall shortly + describe. Cases we have examined have undoubtedly shown this condition of + osteoplastic periostitis, the rarefactive and osteoplastic changes in the bone + itself, met with in older cases, occurring no doubt as a result of non-expansion of + the horny box. So far as we are able to ascertain, there is every reason to believe + that in chronic laminitis the accompanying periostitis leads to the formation of + bone, and would, if it were possible, lead to increase in the size of the os pedis. + If proof were wanted of this, it is only necessary to point out the increased growth + at points where resistance is nil—namely, along the upper margin of the bone + (see Fig. 118). However, increase in size elsewhere is prevented by the resistance of + the hoof, so that, as the bone-forming process progresses, as it inevitably + <i>must</i> under the inflammatory changes going on, it is, as it were, compensated + for by rarefaction or bone-absorption changes occurring simultaneously with it.</p> + <p>2. OSTITIS.</p> + <p>We shall next deal with the inflammatory changes occurring in the bones + themselves, and shall consider them under (<i>a</i>): Rarefying or Rarefactive + Ostitis, (<i>b</i>): Osteoplastic Ostitis, and (<i>c</i>): Caries and Necrosis.</p> + <p>Inflammatory changes occurring in the medulla we may pass without consideration, + for in the bones of the foot the medullary cavity is so small, and the changes taking + place in it of such minor importance, that we may do this without in any way + seriously prejudicing our work.</p> + <p><i>(a) Rarefying or Rarefactive Ostitis</i>.—By this term is indicated an + inflammation of the bone attended by its absorption, the absorption being due to the + action of certain cells, termed <i>osteoclasts</i>. This condition may be due to the + pressure of tumours, may occur as the result of injury when a piece of bone is + stripped of periosteum, or may be the result of an inflammation occurring in the + periosteum elsewhere.</p> + <p>A piece of bone undergoing rarefactive ostitis is redder than normal, and the + openings of the Haversian canals are distinctly increased in size. As a result a + greater number of them become visible. Their increase in size is due to the + inflammatory absorption of the bony tissue forming them, and in the larger of them + may be seen inflammatory granulation tissue surrounding the bloodvessels. This + enlargement of the Haversian canals is well seen when the bone is macerated, the + whole then giving the appearance of a piece of very rough pumice-stone.</p> + <p>This process of rarefaction or absorption of bone tissue may be confined to quite + a small portion, or it may be spread over the whole of the bone, rendering it more + porous than is normal, but stopping short of complete destruction of the bone tissue + (a condition which is sometimes known as inflammatory osteoporosis (see Fig. 118)). + In this latter case the condition is a chronic one, and the bone tissue remaining + often appears to be strengthened by a compensatory process of condensation. For an + example of rarefactive ostitis as met with in cases of disease of the feet, we refer + the reader to laminitis (see Fig. 118). The osteoplastic or condensing process that + appears to exist simultaneously with it explains, no doubt, how it is that bones so + affected do not more commonly fracture.</p> + <p>A further example of this process is illustrated in Fig. 133. The pressure of a + tumour (in this case a keraphyllocele) has led to rarefactive changes in the bone, + forming a neat indentation in the normal contour of the bone which serves to + accommodate the tumour.</p> + <p><i>(b) Osteoplastic Ostitis, Osteosclerosis, or Condensation of + Bone</i>.—This, too, is essentially a chronic process. It may occur as a result + of, or, as we have just shown, exist simultaneously with the condition of, diffuse + rarefactive ostitis. In this case there is a formation of new bone in the connective + tissue surrounding the vessels in the Haversian canals. As a consequence the bone + affected is greatly increased in density, and many of the Haversian canals by this + means obliterated. The end result is an increase in size of the bones in such + positions as the horny box admits of it, and a peculiar ivory-like change in their + consistence.</p> + <p>For an example of this, we again refer the reader to the changes occurring in + chronic laminitis.</p> + <p><i>(c) Caries and Necrosis</i>.—<i>Caries</i> is a word which appears to be + used with a considerable amount of looseness. In addition to the meaning implied by + necrosis (namely, 'death' of the part), caries is generally used to indicate that + there is also a condition of rottenness, decay, and stench. It is particularly + applied, in fact, when the death of the bone is slowly progressive, and is due to the + inroads made upon it by putrefactive or septic matter.</p> + <p><i>Necrosis</i> of bone may be the result of any injury, such as severe blows, or + pricks and stabs. In such cases it would appear that it is loss of a portion of + periosteum that is the starting-point. With death of a portion of this membrane the + vascular supply to a portion of the bone is cut off, and necrosis ensues. It may also + result from the extension of inflammatory affections of the structures adjoining it, + as, for instance, the spread of the infective material in severe tread, or the + encroaches made by pus in cases of quittor, suppurating corn, or complicated + sand-crack.</p> + <p>When the necrosed portion of bone is small, and is free from infective properties, + it is quite possible that it may, as is the case with small spots of necrosis in + softer tissues, be removed by a process of absorption. It must be remembered, + however, that where the necrosis has occurred as a result of septic invasion this + cannot be looked for, for in every case such reparative changes are worked solely by + healthy tissue. If the tissues around the necrosis are engaged in dealing with + organismal invasion and the poisonous products thus poured into their working area, + their state of health is so weakened that they are unable to successfully combat with + the two conditions simultaneously. As a consequence, the necrotic piece of bone + persists, and acts as a permanent source of irritation.</p> + <p>It must be remembered, too, that if the dead portion of bone—even though it + be free from septic matter—is very large, that it may itself act as a continual + irritant, in which case it again persists, and cannot by natural means be + removed.</p> + <p>In our cases necrosis of bone may be met with in punctured foot, in severe cases + of tread, in cases of complicated crack, and in suppurating corn. It is met with, + too, in navicular disease, in the extension of irritating discharges in cases of + quittor, and in cases of chronic laminitis where the solar margin of the os pedis has + penetrated the sole. In this latter case the protruding portion of bone is quickly + denuded of its periosteum. Its blood-supply is destroyed, and necrosis follows.</p> + <p><i>Treatment</i>.—In simple cases of periostitis, those caused by a blow but + free from an actual wound, the most beneficial treatment is the continued application + of cold by means of a hose-pipe or by swabs. If by these means we are successful in + holding the inflammatory phenomena in check, any large formation of new bone is + prevented, and the case does well.</p> + <p>When the case is complicated by a wound, then antiseptic measures, such as those + described in the treatment of punctured foot, will at the same time have to be + practised.</p> + <p>It must be admitted, however, that in all but the most simple cases ordinary + treatment such as this is of very little use; for with only a slight exostosis in + almost any position in the foot, excessive lameness presents itself and remains. In + such cases nothing is left to us but the operation of neurectomy.</p> + <p>When the periostitis and ostitis is the result of a wound, and is complicated by + caries or necrosis of the bone, the diseased portion of bone must in every case be + laid bare and removed. It so happens that the majority of cases of this kind occur in + positions where the diseased bone is easily got at. The lower margin of the os pedis + or portions of the wings are commonly the seat of such changes. We meet with the + former in cases of pricked foot, and with the latter in severe cases of tread, or as + a complication in suppurating corn or in quittor. In such cases the animal must be + cast and the foot secured. The wound is then followed up, the horn if necessary + removed, and the bone curetted with a Volkmann's spoon; or, if showing itself as a + sequestrum, removed with a scalpel and a strong pair of forceps. Care must be taken + that every particle of the diseased bone is removed, and that no part of it is left + to act as an after-source of irritation. With removal of the diseased portion and a + strict attention to antisepsis healing soon takes place.</p> + <p><i>Reported Cases of Periostitis and Ostitis</i>.—1. 'Figs. 150 and 151 + represent the phalangeal bones of the off fore-leg of a thoroughbred horse named + Osman, who was well known as a hunt steeplechaser of considerable merit in the + Midland counties some twenty years ago. I may say that this horse was under my + observation pretty regularly during the whole of his career, and up to the time of + his death, from ruptured aorta, when eight years old. My attention was called to him + as a yearling by his owner, who told me that he sometimes fancied the colt was lame. + I went over to see him, and found that he was unmistakably lame on the off fore-leg. + Careful examination showed no heat or enlargement anywhere. I advised rest and the + colt became pretty sound, though not quite so—in fact, he never did become + quite sound, and sometimes he was very lame indeed.</p> + <br /> + <a name="a150" id="a150"></a> + <p><a href="images/image150.jpg"><img src="images/image150sm.jpg" + alt="EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR BONES" /></a></p> + <br /> + + <p>FIG. 150.—EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR BONES.</p> + <p>'Every imaginable sort of treatment was tried short of neurectomy, without avail. + The curious part of the case was that there never was much heat or any apparent + change of structure, nor was "pointing" a very noticeable feature. The foot always + remained a good-looking one. As the horse won a good number of races he was of some + value, and was seen by a good many members of the profession, who were by no means + unanimous as to the cause of lameness. The favourite theory was that it was a + sequence of "split pastern." A post-mortem examination showed that there was no + fracture. There was no adherence of the tendon to the navicular bone nor any + ulceration. The morbid changes consisted entirely of osseous deposit as shown in the + photographs. The under surface of the navicular bone was much enlarged and roughened + by this bony deposit, which extended on to the os pedis, causing complete anchylosis + at each extremity of the navicular. The lateral cartilages were healthy. The + interesting points in connection with the case are the insidious commencement of + osseous disease, its extensive development, and the entire absence of any external + manifestation, through its being confined entirely within the limits of the hoof.</p> + <br /> + <a name="a151" id="a151"></a> + <p><a href="images/image151.jpg"><img src="images/image151sm.jpg" + alt="EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR BONES" /></a></p> + <br /> + + <p>FIG. 151.—EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR BONES.</p> + <p>'It should also be noted that the animal was able to undergo a severe course of + training for some years, and to gallop successfully over some of the most trying + courses in England. During the whole of this time he walked and galloped apparently + sound, but trotted always lame, and generally dead lame.'[A]</p> + <p>[Footnote A: W. E Litt, M.R.C.V.S., <i>Veterinary Record</i>, vol. viii., p. + 527.]</p> + <br /> + <a name="a152" id="a152"></a> + <p><a href="images/image152.jpg"><img src="images/image152sm.jpg" + alt="EFFECTS OF PERIOSTITIS ON THE OS PEDIS." /></a></p> + <br /> + + <p>FIG. 152.—EFFECTS OF PERIOSTITIS ON THE OS PEDIS.</p> + <p>2. 'I herewith send you photographs of three cases of the above disease, occurring + in the internal surfaces of the wings of the os pedis. The photos were kindly done + for me by Dr. A. Lingard, Imperial Bacteriologist to Government of India. It is a + cause of many cases of obscure foot lameness in India, and frequently accounts for + the numerous entries on veterinary medical history sheets under the heading "Contused + Foot."</p> + <p>'The course of the disease is as follows: The disease makes its appearance very + soon after arrival in India, the animal being admitted to hospital suffering with + undoubted foot lameness, generally slight. One is soon led to suspect this disease by + negative symptoms of other disease being in existence. No coronary enlargement or + flinching on pressure to the coronet, no shrinkage or wiring in of the heels, neither + is the characteristic pointing of navicular present. In the early stages one has + false hopes of recovery by finding gradual improvement for a time by fomentation and + poultices, followed by irrigation and stimulants to the coronet, and perhaps the + animal is discharged from hospital, to be returned after a few days worse than ever. + The disease then becomes insidious and more pronounced, the nodding of the head, even + at a walk, more exaggerated, and, in fact, the animal seems afraid to put his foot to + the ground, and much resembles a horse with an abscess in his foot, either from prick + or picked up nail. He absolutely nurses his foot. There is a certain amount of heat + always present. The disease being now well developed, pressure is caused by the ends + of the navicular bone, and they become involved at their points by bony deposits. The + causes of this disease I attribute, firstly, to hereditary predisposition; and, + secondly the exciting cause, standing confined on board ship, where no doubt pedal + congestion takes place. And perhaps some subjects start it in their marches in mobs + down country in Australia. Concussion may be the cause among older horses, but the + specimens photographed were taken from remounts, that had either done no work or only + very gentle work, in a deeply littered riding school.</p> + <br /> + <a name="a153" id="a153"></a> + <p><a href="images/image153.png"><img src="images/image153sm.png" + alt="EFFECTS OF PERIOSTITIS ON THE OS PEDIS." /></a></p> + <br /> + + <p>FIG. 153.—EFFECTS OF PERIOSTITIS ON THE OS PEDIS.</p> + <p>'<i>Treatment</i>.—It is obvious from the position of this disease that + treatment will be of no avail in producing a cure. As already stated, the disease is + insidious and progressive, and it is hopeless to expect to arrest the growths once + they are started. Unnerving would no doubt remove the symptom (lameness) of the + disease, but an unnerved horse is not of much good for army purposes. I therefore + consider that once the disease becomes firmly established it is an unfortunate and + incurable one.</p> + <br /> + <table summary="Table for display of images"> + <tr> + <td> + <a name="a154" id="a154"></a> + <p><a href="images/image154.jpg"><img src="images/image154sm.jpg" + alt="EFFECTS OF PERIOSTITIS ON THE OS PEDIS." /></a></p> + </td> + <td> + <a name="a155" id="a155"></a> + <p><a href="images/image155.jpg"><img src="images/image155sm.jpg" + alt="EFFECTS OF PERIOSTITIS ON THE OS PEDIS." /></a></p> + </td> + </tr> + <tr> + <td>FIG. 154</td> + <td>FIG. 155</td> + </tr> + </table> + <p>FIG. 154, 155—EFFECTS OF PERIOSTITIS ON THE OS PEDIS.</p> + <p>'Post-mortem reveals the small nodular growths on the inner surfaces of the wings + of the pedal bone, and if long established the ends of the navicular bone are also + involved. Exudation and gradual growth of false material around the nodules takes + place, which also serves to increase pressure.'[A]</p> + <p>[Footnote A: Captain L.M.Smith, A.V.D., <i>Veterinary Record</i>, vol. xi., p. + 229.]</p> + <p>3. 'This case was brought for my opinion. The horse was lame, and walked similar + to one that had had laminitis, putting the heel down first upon the ground. I ordered + the patient to be destroyed. You will note the ossification of the flexor pedis at + its attachment to the pedal bone. I enclose photos of the ground, also of the + articular, surfaces of the bone.'[A]</p> + <p>[Footnote A: F.B.Jones, M.R.C.V.S., <i>Veterinary Record</i>, vol. xi., p. + 230.]</p> + <h3>B. PYRAMIDAL DISEASE, BUTTRESS FOOT, OR LOW RINGBONE.</h3> + <p><i>Definition</i>.—A condition of periostitis and ostitis in the region of + the pyramidal process of the os pedis, usually preceded, but sometimes followed, by + fracture of the process, and characterized by deformity of the hoof and an alteration + in the normal angle of the joint.</p> + <p><i>Causes</i>.—In the majority of cases buttress foot is brought about by + fracture of the pyramidal process. Thus, although distinct evidence of such is nearly + always wanting, we may assume that the original cause is violent injury to the part + in question. Properly, therefore, one would say that this condition should be + described under Fractures of the Os Pedis. It appears, however, that other cases of + the kind arise in which fracture is altogether absent, or in which it is plainly seen + to be subsequent to the diseased processes in the bone. For that reason, and also for + the reason that the condition has come to be known by the name we have given, we give + it special mention.</p> + <p><i>Symptoms and Diagnosis</i>.—Even when the condition arises as the result + of fracture, the ordinary manifestations of such a lesion are absent. By reason of + the situation of the parts within the hoof we are unable to detect crepitation, and + the resulting lameness is perhaps—in fact, nearly always is—neglected + until such time as any heat or swelling caused by the injury has disappeared, in + which case we are denied what evidence we might have obtained from that. All that is + presented is lameness, and lameness that is at times excessive. But with the lameness + there is nothing distinctive. The foot is tender on percussion, and the gait + suggestive of foot lameness, that is all. We are unable, therefore, to make an exact + diagnosis, and the condition goes for some time undetected.</p> + <p>Later, however, changes in the form of the hoof and the coronet begin to appear. + The skin of the coronet, especially in the region of the toe, becomes more or less + thickened and indurated, and the same remark applies to the subcutaneous tissues. The + most marked change, however, is the alteration in the shape of the hoof. The wall + protrudes at the toe in a manner that has been termed 'buttress-like,' and has given + to the condition one of its names. This, of course, entirely alters the contour of + the horny box. From being more or less U-shaped, it approaches nearer the formation + of the letter V, the point of the V being at the toe.</p> + <p>In the later stages the coronary enlargement is plainly seen to be due to an + extensive formation of bone. It is, in fact, a reparative callus, and the reason it + reaches so large a size is probably to be accounted for by the pull of the extensor + pedis upon the detached pyramidal process. As might be expected, this displacement of + the fractured portion, with its effect of giving greater length to the extensor + pedis, leads to a backward displacement of the os coronæ upon the pedal bone. + As a result there is a marked depression at the coronet, the depression being + heightened in effect by the exostosis in front. Pyramidal disease is, as a rule, met + with in the hind-feet, but occurs also in the fore.</p> + <p><i>Pathological Anatomy</i>.—When occurring without fracture, the first + observable change is a thinning of the articular cartilage of the pyramidal process, + through which the bone beneath appears abnormally white. Later the thinning of the + cartilage progresses until at last it becomes entirely obliterated. This destruction + of the cartilage commences first at the highest point of the articular surface of the + pyramid, and gradually reaches further backward into the joint. While this is taking + place the new bone is being formed on the front of the os pedis, below and around the + process, until, as we have already seen, an exostosis is formed, large enough to be + noticeable at the coronet. This, of course, partly implicates the joint and the + points of the insertion of the extensor tendon.</p> + <p>Finally, fracture may, or may not, take place. When it does, the exostosis is + larger, and the general deformity of the hoof greater.</p> + <p><i>Treatment</i>.—Ordinary treatment, such as point or line firing, repeated + blisters, or hoof section, each of which we have tried, appears to be utterly + useless. So far as we have been able to gather from the writings of other + practitioners, however, neurectomy returns the animal for a time to usefulness. If + the fore-limb is the seat of trouble, either plantar or median neurectomy may be + practised; if the hind, then the best results are obtained by section of the + posterior tibial.</p> + <p><i>Reported Cases</i>.—1. This animal, a mare, had been rested for lameness + behind for two or three weeks, and then sent out to work, going sound. This was + repeated several times, and each time the coachman reported, "Goes very lame behind + after she has been at work about fifteen to twenty minutes." She always pulled out + sound when I saw her in a halter on the following day, so I had her ridden, and after + about seven or eight minutes she began to go lame in a hind-limb. Her lameness got + rapidly worse as she was being ridden, and within a quarter of mile of her first + showing lameness, she dropped and carried the lame foot in a way that suggested a + badly fractured pastern. There was no recognisable disease in the limb to account for + this lameness.</p> + <p>'I divided the posterior tibial nerve, and she went back to work moving sound, and + continued to work sound up to her death from one of the regularly fatal bowel lesions + twist or rupture.</p> + <p>'She worked nearly two years after unnerving, and developed the usual thickening + at the coronet.'[A]</p> + <p>[Footnote A: W. Willis, M.K.C.V.S., <i>Journal of Comparative Pathology and + Therapeutics</i>, vol. xv., p. 366.]</p> + <p>2. 'The subject of this note was a chestnut mare, nine years old, and used for + omnibus work.</p> + <p>'<i>History</i>.—For about two months the mare was lame on the off fore-leg, + and in spite of treatment the condition became steadily worse. The off fore-foot was + rather long and narrow, and the fetlock-joint was inclined to be bowed outwards, but + the degree of lameness was out of proportion to these defects, and the diagnosis was + obscure.</p> + <p>'Median neurectomy was performed on May 10, 1902, and reduced the lameness to + about half of what it was before. On June 5 ulnar neurectomy was performed, with the + result that the mare became sound, and went to work three weeks later. She continued + to work soundly and well, being inspected from time to time.</p> + <p>'During February of 1903 the coronet began to enlarge in front and slightly to the + outer side, and gradually a ridge of bone grew down from the coronet to the toe. The + case, in fact, became a typical one of so-called "buttress foot," which my friend Mr. + Willis has described as diagnostic of disease of the pyramidal process of the pedal + bone. Meanwhile the swelling of the coronet, which appeared to be mainly composed of + fibrous tissue, increased in size, until the whole of the front and sides became + involved, assuming the appearance shown in Fig. 156.</p> + <p>'In spite of the coronary enlargement the mare worked well, and remained free from + lameness till June 8, 1903, on which day the limb became swollen up to the site of + the median operation. The appearance of the limb closely simulated an attack of + lymphangitis. The mare was kept under observation till the 13th of the same month, + during which time the swelling increased, as did also the lameness to a slight + degree. During progression she brought the heel to the ground and "rocked the toe," + as in a case of rupture of the perforans tendon. The mare was killed on June 13.</p> + <br /> + <a name="a156" id="a156"></a> + <p><a href="images/image156.jpg"><img src="images/image156sm.jpg" + alt="A CASE OF BUTTRESS FOOT." /></a></p> + <br /> + + <p>FIG. 156.—A CASE OF BUTTRESS FOOT.</p> + <br /> + <a name="a157" id="a157"></a> + <p><a href="images/image157.jpg"><img src="images/image157sm.jpg" + alt="FRACTURE OF THE PYRAMIDAL PROCESS IN BUTTRESS FOOT." /></a></p> + <br /> + + <p>FIG. 157.—FRACTURE OF THE PYRAMIDAL PROCESS IN BUTTRESS FOOT.</p> + <p>'<i>Post-mortem</i>.—In trying to pull away the hoof from the sensitive + structures with a pair of farrier's pincers, the tendons and ligaments of the + corono-pedal articulation gave way, leaving the pedal bone <i>in situ</i>. The flexor + perforans tendon showed inflammatory softening, and was very nearly ruptured through + at the level of the navicular bone. There was slight evidence of navicular disease. + The articular cartilage of the corono-pedal joint had been almost completely removed, + and there was sclerosis of the opposed bony surfaces, which by unequal wear had + brought about deformity of the os coronæ and os pedis.</p> + <p>There was very old-standing fracture of the pyramidal process (see Fig. 157), with + the formation of a false joint between the process and the pedal bone. There was also + a recent fracture of the part of the pedal bone which carries the articulation for + the navicular bone, and this and the tendon lesions probably accounted for the final + symptoms of 'break-down.'</p> + <p>Neurectomy enabled us to get a year's useful work out of what would otherwise have + been a hopeless cripple.[A]</p> + <p>[Footnote A: A.R. Routledge, M.R.C.V.S., <i>Journal of Comparative Pathology and + Therapeutics</i>, vol. xvi., p. 371.]</p> + <h3>C. FRACTURES OF THE BONES.</h3> + <p>More or less by reason of the protection afforded them by the hoof fractures of + the bones of the foot are rare. When occurring they are more often than not the + result of direct injury, as, for example, violent blows, the trapping of the foot in + railway points, the running over of the foot with a heavily-laden waggon, or violent + kicking against a gate or a wall. They occur also as a result of an uneven step upon + a loose stone when going at a fast pace, and as a result of sudden slips and turns, + in which latter case they are met with when animals have been galloping unrestrained + in a field, or when an animal, ridden or driven at a fast pace, is suddenly pulled + up, or just as suddenly turned.</p> + <p>At other times fractures in this region take place without ascertainable cause, + and cases are on record where animals turned overnight into a loose box in their + usual sound condition have been found in the morning excessively lame, and fracture + afterwards diagnosed.</p> + <p>1. FRACTURES OF THE OS CORONÆ.</p> + <p>Fractures of the os coronæ result from such causes as we have just + enumerated, and are nearly always seen in conjunction with fractured os suffraginis. + When this latter bone is also fractured diagnosis is comparatively easy, a certain + amount of crepitus, even when the suffraginis is only split, being obtainable. When + the os corona alone is fractured then diagnosis is extremely difficult, the smallness + of the bone and the comparative rigidity of the parts rendering manipulation almost + useless, and effectually preventing the obtaining of crepitus. It is, in fact, only + when the bone is broken into many pieces that crepitus may be detected, and even then + it is slight.</p> + <p><i>Reported Cases</i>.—1. 'The subject was a four-year old hunter. While at + exercise in the morning of August 10 he bolted, got rid of his rider, and ran about + in a mad fashion, came into contact with a wheelbarrow in a narrow passage, and + finally came into violent contact with a wall, which had the effect of throwing him + down. The rider stated that the animal suddenly put down his head and managed to get + off the bridle; he then bolted, and the only chance for the rider was to throw + himself off.</p> + <p>'On examination I found the horse unable to place any weight on the off fore-leg, + the pastern was swollen and painful, the hollow of the heel was also swollen, and + there was marked constitutional disturbance.</p> + <p>'After a short time he would place the heel on the ground and elevate the toe to a + slight degree. On manipulating the pastern slight crepitation could be discovered, + and there was abnormal mobility in the corono-pedal articulation. On the near + fore-leg there were extensive wounds in the region of the knee, and great laceration + of the tissues. The animal was destroyed.</p> + <p>'On examining the leg I found the subcutaneous tissues infiltrated from below the + knee to the foot, large masses of gelatinous blood-stained material being present + along the flexor tendons and in the hollow of the heel. The inferior articular + surface of the os suffraginis was denuded of cartilage anteriorly; the os + coronæ was fractured into eight moderate sized, irregular fragments, and ten + minute pieces. The surface of the perforans tendon as it glides over the smooth + surface at the back of the os coronæ was lacerated, and minute portions of the + bone were found embedded therein.'[A]</p> + <p>[Footnote A: E. Wallis Hoare, F.R.C.V.S., <i>Veterinary Record</i>, vol. xiv., p. + 133.]</p> + <p>2. 'Here, again, fracture was the result of the animal bolting with his rider. + Trying to avoid collision with a conveyance coming towards him, the animal slipped on + a wooden pavement, sliding along until his near fore-leg came in contact with the + wheel of a standing cab. There was considerable swelling from the knee downwards, + great pain, and evidence of fracture in the region of the pastern.</p> + <p>'Post-mortem revealed the os suffraginis broken into about thirty pieces, and the + os coronæ with a piece broken off the inside of its proximal end.[A]</p> + <p>[Footnote A: A.F. Appleton, M.R.C.V.S., <i>Veterinary Journal</i>, vol. xiii., p. + 411.]</p> + <p>3. 'The patient was a brown mare used for heavy van work in London. About January + 10 she was lame, and as she had a cracked heel, was treated by poulticing for a day, + and then by antiseptic lotions. In a week she was sent to work, but the following day + lameness returned, and continued till about February 15. No special symptom was + detected which indicated the exact position of any cause of lameness. Then the + lameness increased in severity, and some swelling around the coronet began to show + itself.</p> + <p>'In consultation with another veterinary surgeon, two possible causes of this + intense lameness were discussed: one, that we had septic infection of the coronet, + and that probably the swelling of this part would soften, and sloughs occur; the + other, that a fracture of the os pedis or os coronæ existed. The enlargement of + the coronet was hard and firm, not particularly sensitive. It was decided to do + nothing for a few days. In a week the pain abated, and the mare would put her foot on + the ground, and ceased to "nurse" the limb as she had done. When moved over in the + box she put a little weight on the foot, but limped very decidedly.</p> + <p>'Another week passed, and the pain and lameness further abated, but the swelling + around the coronet continued. Perhaps it was a little less in front, but it had not + decreased on the inside. It remained firm, and was not painful on pressure. It showed + no soft places, and the upper part of the leg remained free from oedema.</p> + <br /> + <a name="a158" id="a158"></a> + <p><a href="images/image158.jpg"><img src="images/image158sm.jpg" + alt="FRACTURE IN SITU (OS CORONÆ)." /></a></p> + <br /> + + <p>FIG. 158.—FRACTURE IN SITU (OS CORONÆ).</p> + <p>'The diagnosis was now that a fracture existed, and it was proposed to send the + mare to grass for a few months. The consulting veterinary surgeon suggested that + before doing so a blister might be applied to the coronet. This was done. The mare + was found next day again on three legs. She had apparently been down during the + night. In a few days the coronet increased again in size, and within a week "broke + out" in two places.</p> + <p>'The opinion now formed was that, with a fracture and this additional cause of + inflammation around the joint, it would be most economical for the owner to have her + killed. This was done, and a post-mortem examination was made by Mr. Hunting and Mr. + Willis.</p> + <br /> + <a name="a159" id="a159"></a> + <p><a href="images/image159.jpg"><img src="images/image159sm.jpg" + alt="WITH BROKEN PORTION REMOVED." /></a></p> + <br /> + + <p>FIG. 159.—WITH BROKEN PORTION REMOVED.</p> + <p>'<i>Post-mortem</i>.—The foot, cut off at the fetlock-joint, showed + extensive swelling all round the coronet. There were two wounds on the skin—one + on the front of the coronet, the other on the inner side. From both pus and blood had + escaped. They both communicated under the skin with a large abscess cavity. The + abscess did not communicate with the joint. The pastern bone was sound. On separating + the pastern from the coronet bone the articular surfaces were of a healthy colour, + but the soft tissues immediately surrounding them were inflamed. On the centre of the + articular surface of the coronary bone a thin red ring was noticed, and the portion + of cartilage within it seemed raised. With the point of a scalpel this portion was + lifted, and was found to be not only cartilage, but a layer of bone completely + detached from the os coronæ. On removing the bones from the hoof the rest of + the bone was quite normal, as was the pedal bone.</p> + <p>'Fig. 158 shows the articular surface of the coronet with the fracture <i>in + situ</i>; and Fig. 159 the surface from which the broken portion is removed and laid + to the side of the foot.</p> + <p>'Some interesting questions arise. How was the fracture caused? When did it occur? + Between the broken portion and the main bone there was a layer of granulation tissue, + so that it is certain the injury existed before the blister was applied, and it may + possibly have existed from the commencement of the lameness.'[A]</p> + <p>[Footnote A: R. Crawford, M.R.C.V.S., <i>Veterinary Record</i>, vol. viii., p. + 478.]</p> + <p>2. FRACTURES OF THE OS PEDIS.</p> + <p>These also are a result of the causes we have before given. The os pedis is also + liable to fractures from pricks, from treads in the region of the wings, and from the + malnutrition and careless use of the foot sometimes following neurectomy.</p> + <p>It is interesting to note that, with fracture of this bone, lameness is nearly + always excessive, but that at times it may be entirely absent. Crepitus is, of + course, denied us, and in nearly every instance the case is only diagnosed when the + lameness persists and pus commences to form, or when grave changes in the normal + shape of the foot compel our attention to the parts. When it is the continued + formation of pus that draws our notice to something more than ordinarily grave, it is + in giving exit to the pus that the fracture is nearly always discovered.</p> + <p><i>Reported Cases</i>.—Two interesting cases of fractured os pedis are + reported by Mr. Gladstone Mayall, M.R.C.V.S., in the <i>Veterinary Record</i>, vol. + xiv., p. 54:</p> + <p>1. 'The horse was brought in markedly lame on the off hind-foot, knuckling at the + fetlock, and taking a long stride with the injured limb. There was a punctured wound + at the toe. The horn was pared, and antiseptic poultices applied. Notwithstanding the + antiseptic treatment pus continued to form. At the end of a week sufficient horn was + removed to ascertain the cause of the constant suppuration. A movable object was + found at the bottom of the wound, and a piece of bone as large as a sixpence finally + removed. Recovery was uneventful.'</p> + <br /> + <a name="a160" id="a160"></a> + <p><a href="images/image160.png"><img src="images/image160sm.png" + alt="FRACTURED OS PEDIS." /></a></p> + <br /> + + <p>FIG. 160.—FRACTURED OS PEDIS.</p> + <p>2. 'A filly was attended for a discharging fistula at the coronet. Externally it + had all the appearances of a quittor. At first no history was given. The filly went + scarcely lame at all, and had never been shod. Treatment with poultices and caustic + injections was useless. Finally the filly was cast and the foot examined. A piece of + bone, apparently part of the wing of the os pedis, was removed, and the case made a + good recovery. Subsequent inquiries elicited the fact that the animal had kicked at + and hit a gate-post, and it was judged that then the injury had occurred.'</p> + <p>3. 'The subject was a bay horse, nine years old, used for railway shunting. On + August 7 he was found to be intensely lame of the near hind-limb, and, after + inquiries, there was no evidence bearing on the cause, as is often the case, and at + times this comes to light when least expected.</p> + <p>'I was called in consultation on September 2, and found him suffering acute pain, + with great swelling around the coronet. The foot was examined thoroughly, and the + diagnosis was fracture of the pedal bone, and immediate slaughter was recommended. + However, that was not carried out, and he died on September 22.</p> + <p>'The post-mortem inspection revealed a complete fracture of nearly the whole of + the articulating surface and the left wing of the pedal bone (as shown in Fig. + 160).'[A]</p> + <p>[Footnote A: J. Freeman, M.R.C.V.S., <i>Veterinary Journal</i>, vol. xxxi., p. + 324.]</p> + <p>4. A further interesting case is reported by Mr. William Hurrell.[A] Here the + cause was presumably galloping in the field, for the subject, a cart mare running out + at grass with her foal, was suddenly found to be lame.</p> + <p>[Footnote A: <i>Ibid</i>., vol. v., p. 408.]</p> + <p>As the lameness continued to increase in severity, Mr. Hurrell was called in on + August 1, and diagnosed the case as one of foot lameness. On this date the foot was + pared out, and a large accumulation of pus discovered, Poulticing and antiseptic + dressings were continued until August 16, when a movable piece of the os pedis was + found at the toe.</p> + <p>On August 25 this detached portion of the bone was removed, and turned out to be + the whole of the anterior margin of the os pedis, measuring 3-1/2 inches long, and + varying in width from 1/2 inch to 1-1/2 inches. On September 20 the mare was working + without lameness.</p> + <p>3. FRACTURES OF THE NAVICULAR BONE.</p> + <p>Hidden within the wings of the os pedis, and protected as it is by its tendinous + covering and the yielding substance of the plantar cushion, the navicular bone is + even less liable to fracture than either of the other bones of the foot.</p> + <p>The most common cause of fracture of the navicular is that of stabs or deep pricks + in the region of the point of the frog (see p. 216). Following that, the next most + common cause is violent injury. We thus find the navicular bone fractured, together + with one or both of the other bones of the foot, when the foot is run over by a heavy + vehicle. One such case is reported by Mr. J.H. Carter, F.R.C.V.S., where the horse's + foot was run over by a tram-engine, in which the os pedis and the navicular were + fractured in several places.[A] A further case is on record where a sharp blow on the + front of the hoof was the cause. In this case the os pedis and other structures were + uninjured, but the navicular bone was fractured into three large, and about half a + dozen small, pieces.[B]</p> + <p>[Footnote A: <i>Veterinary Journal</i>, vol. xxxi., p. 246.]</p> + <p>[Footnote B: <i>Veterinarian</i> for 1857, p. 73.]</p> + <p>Fractures of the navicular may occur, however, in which history of a prick or of a + violent injury is absent. See reported case below.</p> + <p>As with fractures of the os pedis and the os coronæ, so with this exact + diagnosis is difficult—we may say almost impossible. With a history of violent + injury, however, some little regard may be paid to a continued heat and tenderness of + the foot, and a distinct inclination on the part of the animal to go on the toe. Even + when the fracture is the result of a prick, and the bone is plainly felt with the + probe, we still cannot be positive as to fracture.</p> + <p><i>Reported Case</i>.—'The animal was a Hungarian, a troop-horse in the 3rd + Hussars (G. 15). On November 22, 1881, on the march from Norwich to Aldershot, the + horse suddenly made a violent stumble, very nearly coming on to his knees. The rider + declared that he put his foot on a stone. The accident caused great lameness in the + near fore-leg, and the horse had to be led the remainder of that day's march. On the + following day he was also led; but, after going some sixteen or eighteen miles, he + was so lame that he was left at the nearest billet (in Edmonton). He was here + attended by Mr. Stanley, M.R.C.V.S., of Edmonton, who pronounced it a case of + navicular disease. I first saw the animal on December 1, 1881, and quite agreed with + Mr. Stanley that it was a case of foot lameness, though, from the horse's former + history, I could not think it a case of ordinary navicular disease. I diagnosed it a + case of fracture, without displacement, either of the os coronæ or the + navicular bone, but was more inclined to the former than the latter. This was after a + full hour's examination. I failed to find any heat in, or any flinching by + manipulation of, any part of the limb; but, in walking, the horse was excessively + lame, going on the toe, and, indeed, trying if possible to keep the foot entirely off + the ground.</p> + <p>'On December 6 the horse was sent on to Aldershot by rail. He was then walking + better, though still very lame. My only treatment for a short time was to apply cold + water constantly to the coronet and foot. For two hours daily this was done by a + hose, the remainder of the time by a cold swab. On December 14 I applied a strong + blister over the coronet, reaching up to the fetlock. This was washed off about the + end of December. The horse was then not nearly so lame. I then resumed the cold-water + treatment, and he got gradually better, and was sent to light duty on February 18, + 1882. He, however, only attended one field-day, and was taken into the Horse + Infirmary again on March 8, very lame. Again, there was an entire absence of heat or + pain on pressure, but the same action, viz., going on the toe. I forgot to remark + that he always pointed the toe of the affected leg when standing in the stable, and + this symptom continued. I put him under the cold-water treatment for a short time, + and about the middle of March again applied a strong blister over the coronet up to + the fetlock. This was washed off about the end of the month, and was succeeded by the + cold water again. Towards the end of April there was no improvement at all, and I + applied for permission to destroy the horse. This was carried out on April 27, at the + recommendation of Mr. Gudgin, I.V.S., Aldershot, and a Board of veterinary + surgeons.</p> + <p>'On making the post-mortem examination I first thought the bone was only partly + fractured or cracked, but on manipulating it, after its being in hot water a short + time, I saw the fracture was complete.'[A]</p> + <p>[Footnote A: S.W. Wilson, M.R.C.V.S., A.V.D., <i>Veterinary Journal</i>, vol. xv., + p. 12.]</p> + <p><i>Treatment of Fractures of the Bones of the Foot</i>.—It will be seen at + once that in most cases anything in the way of bandaging is well-nigh useless. When + the os coronæ is fractured, however, a little more may be added to the natural + rigidity of the parts by enclosing the region of the pastern and the foot in a + plaster-of-Paris bandage. The main treatment, however, in every case, will be a + continual use of the slings for at least seven to eight weeks, by that means + compelling the animal to give to the injured parts the necessary amount of rest.</p> + <p>With fracture of the os pedis, when such is caused by pricks and complicated by a + flow of pus, then attention must be given to removal of the displaced piece of bone. + The pus track is to be followed up with the searcher, sufficient horn removed with + the knife, and the broken piece of bone removed with a scalpel and a pair of strong + forceps, the operation to be afterwards followed up by antiseptic dressings to the + opening. Until this is done the wound refuses to heal.</p> + <p>Fracture of the navicular bone, if in any way diagnosed with certainty, offers us + an almost hopeless case, for it appears to be a commonly reported fact that attempts + at reunion are rare. This, in all probability, is due to the pressure put upon it + every now and again, when the animal's weight presses the bone between the os + coronæ and the os pedis above and the perforans tendon below. Even should + reunion take place, the resulting callus, interfering as it does with the movements + of the perforans, leaves us a case of incurable lameness. When the fracture is + complicated by the formation of pus, as in the case of prick, then the case, with the + attendant purulent synovitis and arthritis, is even more hopeless still.</p> + <p>Diagnosis of fracture of either of the bones of the foot is, as we have said + before, extremely difficult. It so happens, therefore, in those cases caused by + violent blows, that anything approaching an accurate opinion cannot be given until + some months after the injury. After some time we are met with unmistakable changes in + the form of the foot, and are able to assume that the persisting lameness is due to + pressure of a reparative callus within the hoof. In such cases the only treatment of + any use is that of neurectomy.</p> + <br /> + <br /> + <br /> + <br /> + <h3>CHAPTER XII</h3> + <h3><a name="joint" id="joint">DISEASES OF THE JOINTS[A]</a></h3> + <p>[Footnote A: Properly speaking, we have in the foot of the horse but <i>one</i> + joint—namely, the corono-pedal articulation.</p> + <p>Although not a joint in the strict sense of the word, we, nevertheless, intend + here to consider the navicular bursa as such. In this apparatus, although we have no + articular cartilage proper, and no apposition of bone to bone, we still have a large + synovial cavity, and in close proximity to it bone. We may, in fact, and do get in it + exactly similar changes to those termed 'synovitis' and 'arthritis' elsewhere. + Therefore, we include the changes occurring in it in this chapter, and hence the + plural use of the word to which this note refers.]</p> + <h3>A. SYNOVITIS.</h3> + <p><i>Definition</i>.—By the term 'synovitis' is indicated an inflammation of + the synovial membrane. It may be either (<i>a</i>) <i>Simple</i> or <i>Acute</i>, or + it may be (<i>b</i>) <i>Purulent</i> or <i>Suppurative</i>.</p> + <p>In the simple form there is little or no tendency for the affection to implicate + the other structures of the joint, whereas in the suppurative form the joint capsule, + the ligaments, and the bones soon come to participate in the diseased processes, + giving us a condition which we shall afterwards describe as acute arthritis.</p> + <p>(<i>a</i>) SIMPLE SYNOVITIS.</p> + <p>1. <i>Acute—(Causes)</i>.—Simple or acute synovitis is nearly always + brought about by injury to the joint—by blows or bruises, or by sprains of the + ligaments. At other times it occurs without ascertainable cause, and is then put down + to the influence of cold, or to poisonous materials (as, for example, that of + rheumatism) circulating in the blood-stream.</p> + <p><i>Pathology</i>.—Uncomplicated acute synovitis never causes death. The + pathological changes in connection with it have therefore been studied in cases + purposely induced, and the animal afterwards slaughtered. It is then found that, as + in inflammation elsewhere, the synovial membrane is showing the usual inflammatory + phenomena—that it is thick and swollen as a result of the inflammatory + hyperæmia and commencing exudation. Later, the synovial fluid becomes increased + in quantity, is thin and serous, and after a time is seen to be mixed with the + inflammatory exudation poured into it. We then find that it has lost its clear + appearance, has become thick and muddy, and has floating in it flakes of fibrin.</p> + <p>If the case progresses favourably these materials are soon absorbed and resolution + occurs. In rarer cases the thickening and congestion of the membrane increases, and + the articular capsule becomes so distended with the increased synovia and accumulated + inflammatory discharges that a kind of chemosis occurs. In other words, there oozes + through, without actual rupture of the membrane, a thin, blood-stained, and + purulent-looking discharge.</p> + <p>It is an important point to note that in cases of synovitis the fringes of the + synovial membrane become swollen and blood-injected, forming noticeable red + elevations at the margins of the cartilages. It is then that the diseased condition + soon spreads and runs into arthritis.</p> + <p>Further, it is important, especially with regard to the question of the degree of + pain and lameness likely to be caused, to note that often granulations are thrown out + upon the looser folds of the membrane. As these increase in size they come to form + fringed and villous membranous projections inserting themselves between the bones + forming the articulation. In such cases there is no doubt that the intense pain + sometimes observed in these cases is due to pinching of these prolongations of the + synovial membrane by the opposing bones of the joint.</p> + <p><i>Symptoms and Diagnosis</i>.—Acute synovitis of a joint leads to heat of + the parts, pain, distension of the capsule, and, where the joint may be easily felt, + fluctuation. In the articulation with which we are dealing, however, these last two + symptoms are not easily detected, for the surrounding structures—namely, the + lateral and other ligaments of the joint, the extensor pedis tendon in front, and the + perforans behind, together with the dense and comparatively unyielding nature of the + skin of the parts—are such as to prevent distension and fluctuation becoming + marked to a visible extent. We are able to diagnose the case as one of foot lameness, + and, with a history of a severe blow or other injury, are able to assume that this + condition, perhaps attended with periostitis, is in existence.</p> + <p>When other symptoms present themselves diagnosis may be more certain. The animal + becomes slightly fevered, throbbing pains in the joint manifest themselves by + irregular pawing movements on the part of the patient. The animal comes out from the + stable stiff, even dead-lame, and the limb is carried with the lower joints + semiflexed. The breathing is hurried and the pulse firm and frequent, while in a bad + case patchy perspiration breaks out at intervals on various parts of the body. If + with this we get a puffy and tender swelling in the hollow of the heel, our diagnosis + may be certain at any rate as to the existence of joint trouble, although, from + reasons we have given, we may not be able to mark its exact nature.</p> + <p>2. <i>Chronic</i>.—Simple synovitis may in many instances become chronic. In + this case we have simply a pouring into the synovial capsule of serous fluid, and + with it an increased quantity of synovia—this time with an absence of the usual + inflammatory phenomena. Beyond the swelling of the capsule there is little to be + noticed. The joint becomes perhaps a little weaker, but pain or tenderness and heat + are entirely absent. Such a condition, by reason of the natural rigidity of the + parts, is not to be observed in the foot, although at times it must most certainly + occur. Examples of such a condition are to be found in bog-spavin, in hygroma of the + stifle, and sometimes in the fetlock. From a study of these, we know that they may be + induced by frequent attacks of acute synovitis, from repeated slight injuries or + bruises, or from strains to the ligaments of the joint; or that they may be chronic + from the outset. We know, too, that in such cases the synovial membrane becomes + thickened, and that in places it may have extended somewhat over the edges of the + articular cartilages. It is only fair to suppose that such changes occur also in the + pedal articulation. In that case we may take it for certain that the natural rigidity + of the surrounding structures has the effect of pushing the thickened membrane + further between the bones of the joint than occurs in a like condition elsewhere, + leading, of course, to a lameness that is marked in degree but occult as to + cause.</p> + <p>In our minds there is no doubt that many of the occult and chronic forms of + foot-lameness we meet with in practice are in this way to be accounted for. We may, + in fact, explain them by suggesting either a chronic synovitis alone, or a synovitis + complicated with periostitis.</p> + <p><i>Treatment of Synovitis</i>.—If a joint has been injured, as we have + suggested, by slight blows or other causes—in other words, if the injury is + subcutaneous, and no wound is in existence—then there is no treatment which + offers better results than does the continued application of cold.</p> + <p>At the same time, the animal should be slung, or, if non-excitable and inclined to + rest, allowed at intervals to lie on a thick and comfortable straw bed, the cold + fomentations during such intervals being discontinued. When the case is a marked one + and the animal valuable, benefit will be derived from the application of crushed + ice.</p> + <p>The animal's condition must be watched, and the case helped as far as is possible + by the administration of a mild dose of physic, by saline drinks, and, when + necessary, by the giving of small but repeated doses of Fleming's tincture of Aconite + in order to relieve the pain. In a chronic case the repeated application of a blister + is indicated.</p> + <p>(b) PURULENT OR SUPPURATIVE SYNOVITIS.</p> + <p>In this condition we have synovitis complicated by the presence of pus. Unlike the + simple form, it shows a marked disposition to spread, and quickly involves the + surrounding structures. Very soon the ligaments of the joint, the periosteum, the + articular cartilages, and the bones are implicated. This, of course, constitutes a + condition of acute purulent arthritis. Under that heading, therefore, the condition + will be later discussed.</p> + <h3>B. ARTHRITIS.</h3> + <p>(a) SIMPLE OR SEROUS ARTHRITIS.</p> + <p>With an attack of simple synovitis it may be always assumed that the changes + commenced in the synovial membrane, communicate themselves more or less readily to + the surrounding tissues, and are not confined to the synovial membrane alone. We may + thus have the inflammatory phenomena asserting themselves in the surrounding + ligaments, in the periosteum, in the bone, and in the articular cartilages. It + depends, in fact, upon the severity of our case whether we call it synovitis or + arthritis. The two conditions merge so the one into the other that no hard-and-fast + rule may be laid down whereby they may with certainty be differentiated. Such + symptoms, therefore, as we have given for synovitis may be also read as indicating a + condition of simple arthritis. The course of the case will be very similar, and the + treatment to be followed identical with that just given.</p> + <p>(b) ACUTE ARTHRITIS.</p> + <p><i>Causes</i>.—An attack of acute arthritis may commence with the affection + of the synovial membrane, and spread from that to the other structures. In other + cases the disease of the synovial membrane, and after it the disease of the joint, + may be secondary to diseases commencing in the structures around the joint. This + affection may therefore follow on a case of acute coronitis, a case of suppurating + corn, a case of quittor, a severe case of tread, or may attend a case of + laminitis.</p> + <p><i>Symptoms</i>.—In our cases we get very little beyond a magnification of + such symptoms as we have described under acute synovitis. The heat and the pain is + perhaps greater, and the lameness more marked. It is rather to the constitutional + disturbance we must look, however, for a confirmation of our opinion that arthritis + is in existence. This is always severe, and of an acute febrile nature. The pulse is + fast, thin, and thready, the respirations enormously increased, and the temperature + high. The appetite is in abeyance, the animal quickly becomes what is termed + 'tucked-up,' or greyhound-like, in the body, and patchy perspirations break out about + him. The limb is held with the joints all semiflexed, and severe and intense + throbbing pains are indicated by the frequent pawing movements the animal makes in + the air. Manipulation of the foot is resented, and the agonizing intensity of the + pain so caused is shown by the drawn and haggard appearance of the eyes.</p> + <p>In a favourable case the symptoms from now onwards may gradually subside. The + appetite returns, the breathing and other signs of disturbance show a return to the + normal, weight is placed on the limb, and resolution slowly but surely takes place. + In many of these, our favourable cases, however, resolution is incomplete, and + recovery only takes place at the expense of anchylosis of the joint, a condition we + shall refer to later.</p> + <p>In unfavourable cases, and these unfortunately are only too common, the condition + terminates in suppuration.</p> + <p>(c) PURULENT OR SUPPURATIVE ARTHRITIS.</p> + <p><i>Definition</i>.—By this term we indicate an arthritis complicated by the + formation of pus within the joint.</p> + <p><i>Causes</i>.—The organisms of pus may infect the joint by extension of a + suppurating process from without. For example, in the case of a suppurating corn, in + quittor, in tread, or in the case of a suppurating wound caused by a prick, the pus + formed may in many instances be very near the capsular ligament of the articulation. + Under such circumstances, unless there is a free and unhindered flow of the pus from + an outside opening, inroads will be made by it upon the thin capsule. The latter is + quickly penetrated, and pus is admitted to the interior of the joint.</p> + <p>In other cases infection of the joint may proceed from within, from a poisoned + state of the blood-stream. The condition occurs, for instance, in bad attacks of + laminitis. We ourselves, too, have seen two cases where suppuration of the pedal + articulation occurred in the septic pyæmia of foals, a disease known commonly + as 'joint-ill,' and characterized by an infected state of the circulation. Cases have + also come under our notice where this condition has resulted from slight injuries in + the region of the insertion of the extensor pedis inflicted by the animal himself + when galloping away.</p> + <p>Perhaps, however, the most common cause of suppurative arthritis in the foot is + direct penetration of the articulation in the case of pricks. The penetrating object + is nearly always dirty—bacterially dirty, at any rate—and suppuration + only too readily commences. Even should such a wound be inflicted by an aseptic body, + infection would quickly ensue as a result of the wound gathering dirt from the + ground, or even from admission to the joint of impure and bacilli-laden air.</p> + <p><i>Symptoms and Diagnosis</i>.—This is one of the most serious conditions we + are called upon to face when dealing with diseases of the foot, for in many cases it + quickly ends in exhaustion and death of the patient, while in even the most + favourable cases nothing better than a condition of complete and bony anchylosis is + to be expected. The owner, therefore, should be warned accordingly.</p> + <p>As in the other joint affections, so here, we get all the symptoms of acute + febrile constitutional disturbance. The pulse, the temperature, the respirations, and + the general haggard, 'tucked-up,' and distressed appearances of the animal all tell + too plain a tale. Our patient is in constant pain, and the seat of the trouble is + clearly enough shown by the constant pawing movements of the affected foot. If he has + room to get up and down in comfort the animal adopts for long periods at a stretch + the recumbent position, and is not upon his legs long enough to take the necessary + amount of food to keep him going. Even when down, it is plain to see that the animal + is not at rest. The pawing movement is still maintained with the foot, and every now + and again the eyes are opened and the headed lifted to give a troubled look round. + The appetite, too, is capricious, and in many cases almost entirely lost.</p> + <p>In some slight degree the condition is less to be feared in a fore than in a hind + foot—that is, so far as absolutely fatal results are concerned. With the + condition confined to one fore-foot, the animal is able to get up and down with a + moderate degree of comfort. At intervals, therefore, he rises to take nourishment, + and as soon as his wants are satisfied again lies down.</p> + <p>With the disease in a hind-foot matters are not taken so comfortably. The patient + finds that with each day's increasing weakness the difficulty that at first he had to + raise himself with only one sound hind-foot becomes enormously increased. The + consequence is that he fears to go down, and the standing position is maintained + until sheer weakness overcomes him, and he goes down, not to rise again without + assistance.</p> + <p>If judiciously attended he is, of course, put in slings before this stage is + reached; but there are instances, as in the case of a cart-mare heavy with foal, + where the use of slings is most decidedly contra-indicated.</p> + <p>If doubt before existed as to the nature of the case, it is at a later stage + dispelled by the appearance, generally in the hollow of the heel, of a hot and + painful swelling. This at first is hard, but later fluctuates. Finally it breaks at + one or more spots, and there exudes from the opening or openings a purulent and + oftentimes sanious discharge, which coagulates about each fistula after the manner of + ordinary synovia.</p> + <p>With the discharge of the abscess contents there is some slight improvement in the + symptoms. Here, with a suitable treatment, and with a patient of a particularly + robust constitution, the case appears to turn, and slowly but surely progresses + towards the only end we can hope for—namely, a more or less painless anchylosis + of the articulation.</p> + <p>In less favourable cases the purulent discharge continues, and (always a bad sign) + becomes more or less chocolate-like in colour, distinctly thin, and stinking. The + diseased process spreads until the ligaments of the joint, both by reason of their + infiltration with the inflammatory discharges, and also on account of the ravages + made on them by the invading pus, either greatly stretch or altogether rupture.</p> + <p>The joint, after its ligaments have been destroyed in this manner, is loosened, + and the bones are now freely movable. Their manipulation gives to the touch a + sickening, grating sound—in other words, we have crepitus. This, of course, + indicates that the articular cartilages have become greatly eroded by the + inflammatory process, and so left what we may term 'raw' surfaces of bone to rub + together. When the animal is put to the walk the toe of the foot is elevated, and the + extreme mobility of the foot gives one the idea of fracture. With every step there is + a peculiar sucking noise, comparable to that of a foot moving in a boot of water, and + putrescent matter is squeezed from every opening each time the foot is put to the + ground. Although we have seen cases even advanced thus far recover, it is + questionable whether it is now wise to attempt to prolong life. Slaughter is far more + humane, and, in our opinion, except with a valuable brood animal, more + economical.</p> + <p>If the animal is allowed to linger, other symptoms will nearly always present + themselves before death occurs. Whether in slings or not, a careful watch should be + kept upon the sound limb. For some time the patient stands upon it incessantly, but + sooner or later it happens that a farther visit show us the animal standing with full + weight on the diseased foot, and making painful pawing movements with what before was + the sound. We immediately jump to the conclusion 'laminitis.' And so it is, but it is + a laminitis brought about by pyæmia. This is indicated by the swollen and + oedematous nature of the lymphatics of the limb. Plainly enough they indicate the + road by which the poison has travelled. It is in this way: Pus and putrefactive + organisms have gained entrance to the lymphatics of the original diseased limb. From + these they have rapidly gained the blood-stream and set up infection elsewhere. In + this particular instance it is demonstrated by the laminitis and lymphangitis of the + previously sound limb. With the poison thus circulating in the blood-stream, we often + also get spots of infection commenced in one or other of the more vital + organs—notably the lungs or the kidneys. The end of our case is then either a + gangrenous pneumonia or complications induced by a condition of widespread + pyæmia.</p> + <p>With the animal in slings there are one or two other symptoms that call for + attention. In many cases, especially with animals of a lymphatic and indolent nature, + the use made of them is inordinate. The patient rests so continually in them that + alarming swellings commence to make their appearance about the rectum, or in the case + of a mare about the vulva. The animal must then be let down at regular intervals and + again raised when rest is obtained.</p> + <p>A more alarming symptom still is when the animal, instead of resting in the slings + by his buttocks, casts his weight bodily into the belly-rest and hangs with a heavy + head into the head-stall. This indicates complete exhaustion and a wish for death. + Matters should therefore be explained to the owner, and his consent obtained for + immediate destruction.</p> + <p><i>Pathology</i>.—The pathological changes occurring in suppurative + arthritis we shall pass over briefly. It is almost sufficient, in fact, to say that + the whole of the joint becomes completely disorganized.</p> + <p>The synovial membrane becomes so tremendously thickened and injected as to be + scarcely recognisable as such, the thickening in the later stages being due to large + growths of granulation tissue which entirely alter the appearance of the membrane as + we know it normally. In the early stages the contents of the joint are composed of + thin pus and synovia. Later, as destruction of the synovial membrane proceeds, the + flow of synovia is stopped, while the pus formation goes on until finally nothing but + pus and dead tissue products fill the cavity.</p> + <p>If the suppurative process has commenced from within, the pus that is formed is, + as a rule, thick and creamy, comparatively unstained, and free from marked odour. If, + on the other hand, air has gained access to the joint, or the suppurative process has + started from the materials introduced by a foreign body, the joint contents are thin, + blood-stained, and stinking.</p> + <p>The inflammatory changes in the joint soon spread to the ligaments, and to the + soft structures in contact with them. This means that the ligaments become + infiltrated with inflammatory exudate, that the fibrous bundles composing them become + separated, and that the ligaments are weakened and easily stretched. As a + consequence, a certain amount of displacement or dislocation of the bones is + allowed.</p> + <p>In like manner the inflammatory changes keep spreading until we have the + periosteum next the ends of the bones affected. The periostitis thus set up + invariably takes the osteoplastic form, and as a result of this we have growths of + new bone in the near neighbourhood of the joint. It is in the later stages of the + disease—that is, when the pus has been evacuated and reparative changes + commenced—that this osteoplastic periostitis is most marked, and it plays a + large part in bringing about the condition of anchylosis, which we shall afterwards + describe.</p> + <p>Grave changes also occur in the articular cartilages. They quickly lose their + peculiar glistening polish, their semitransparency is lost, and the natural tint of a + pearl-like blue gives way to a dirty yellow. Later this is followed by erosion of the + cartilages at such points as they happen to be in greatest contact. The ends of the + bones are thus exposed, and their medullary cavities exposed to infection. As a + result we get in them the changes we have already described under Ostitis.</p> + <p><i>Treatment</i>—<i>(a) Preventive</i>.—Seeing that many of these + cases have their starting-point in stabs or penetrating wounds of the sole, we shall + be concerned first with a consideration of the correct treatment to be adopted when + we know the wound to have reached the articulation.</p> + <p>Only too frequently the treatment practised is that of poulticing. In other + portions of this work we have pointed out the advantages that a continued antiseptic + bathing has over the application of a poultice, the greater readiness with which the + solution comes into contact with the deeper parts of the wound, and the far greater + chance there is of maintaining water in an antiseptic condition than there is of + keeping a poultice in the same state. There is no doubt, that in this case also, the + cold or warm antiseptic bath is to be preferred to the poultice. It is questionable, + however, whether even the bath is sufficient for our purpose here. We have in this + case a deep punctured wound, and a wound that in every probability is infected with + the organisms of pus or of putrefaction. It is a wound, moreover, which is likely to + impede the thorough access to it of the solution in which the foot is fomented, on + account of the flakes of coagulated fibrin which fill it.</p> + <p>The most rational treatment, therefore, if we get to the case early enough, is to + irrigate the wound freely with a solution of carbolic acid in water (1 in 20), or + with a solution of perchloride of mercury (1 in 1,000), injected by means of a glass + syringe, or the pattern of syringe devised for quittor. This injecting should be done + thoroughly, and by that we mean that several syringefuls of the solution should be + injected, the joint after each injection being manipulated so as to distribute the + solution as far as possible over it. When this is done the opening in the sole may be + plugged with a little perchloride of mercury, or, better still, with a little piece + of tow saturated with a concentrated solution of perchloride of mercury or a solution + of iodoform in alcohol and an antiseptic pad of tow or lint placed over all. The foot + should then be bandaged and encased in a boot or sacking protective. The bandage + should be removed daily and the antiseptic pad changed. At each visit the animal's + condition must be carefully noted. So long as constitutional disturbance is slight, + the foot appears comfortable, is free from marked heat and tenderness, and pawing + movements are absent, and so long as the discharge on the pad appears non-purulent, + free from marked odour, and small in quantity, then this dressing may be persisted + in.</p> + <p>This treatment of open joint, preventive as it is of arthritis, is also indicated + in the case of open navicular bursa. In several instances we have practised this + treatment for the dressing of wounds implicating the bursæ of tendons and the + capsules of joints. It is also spoken of favourably by Mr. C.H. Flynn in the + <i>American Veterinary Review</i> for June, 1888, whose treatment is as follows: + 'Place the patient in a clean, well-ventilated, and drained stable. Have all the + litter removed, and insist on the stall being kept clean. Either place the animal in + slings, or tie the head so as to prevent lying down. Clip the hair and cleanse the + parts well. He prefers the corrosive sublimate solution (1 in 1,000). Should the + wound be of two or more days' standing, inject the joint with the corrosive sublimate + solution. Now dry the parts with a clean towel and sprinkle the wound with iodoform. + Over this place a thick layer of absorbent cotton-wool, filled with iodoform, bandage + securely, and keep the patient on a moderate diet, preserving the utmost quietude + possible. Should the bandage remain in position and the animal free from pain, leave + the bandage and dressing in place from five days to a week. Then change it, and + should the discharge be little, do not disturb it, but renew the iodoform and cotton + dressing, leaving it on for another week.'</p> + <p>Other treatments for the same condition are practised, in which the wound is + dusted with powdered iodoform, with potassium permanganate, or with corrosive + sublimate, or where the wound, instead of being dusted, has the corrosive sublimate + applied in the form of a plug. In each case the preliminary irrigation with the + corrosive sublimate solution is dispensed with. This, however, should on no account + be omitted. In our opinion it constitutes the very essence of the rationality of the + treatment.</p> + <p><i>(b) Curative</i>.—It may happen, however, and often does, that this first + injection of an antiseptic is unsuccessful in preventing organismal infection of the + wound. In this case grave constitutional disturbance and other untoward symptoms such + as we have already described quickly make their appearance.</p> + <p>The animal should now be placed in slings and preparations made for actively + treating the wound with antiseptics. Whether we fail or not, we have the satisfaction + of knowing that we have given to the patient the best and the only chance of + recovery.</p> + <p>It should be remembered, however, and should be pointed out to the owner, that + with purulent arthritis fully developed, with the grave constitutional changes it + occasions, and with the ever-present danger of a general septic invasion of the + blood-stream, that the human surgeon under such circumstances offers to his patient + the alternatives of amputation or probable death. With us no such alternative is + possible. It is either return the joint to some semblance of its former usefulness, + or destroy the patient.</p> + <p>In this case we advise the injection of the original wound, and also such + fistulous openings as may have formed, with the 1 in 1,000 sublimate solution. Also, + in order to avoid the sometimes abortive attempts of the antiseptic pad, to maintain + a condition of asepsis around the wound, we advise the continual soaking of the whole + foot in a cold antiseptic bath. This may be either carbolic acid 1 in 20, + or—what is less volatile, perhaps more effectual, and certainly more + economical—perchloride of mercury 1 in 1,000.</p> + <p>It has been our good fortune, even when we have seen the foot almost detached from + the limb by the devastating inroads of the pus, to see the suppurative process by + this means gradually overcome, a reparative anchylosis set in, and the animal + restored to good health and usefulness, if not to soundness.</p> + <p>Once the suppurative process is checked and anchylosis commences, it is good + treatment to smartly blister the whole of the region of the coronet, the pastern, and + the wound itself with a mixed blister of cantharides and biniodide of mercury, + repeated at intervals of a fortnight. This prevents to some extent further infection + of the wound, and assists also in promoting the changes that tend to anchylosis.</p> + <p><i>(d)</i> ANCHYLOSIS.</p> + <p>The word anchylosis signifies the stiffening of a joint. When one has read the + serious changes occurring within the joint in the more serious forms of arthritis, it + is easy to understand how it comes about. In suppurative arthritis, for instance, we + have the synovial membrane destroyed, the articular cartilages partly or wholly + obliterated, and the former boundaries of the joint entirely lost. If the animal + lives, nature is bound to make repair of a sort. The synovial membrane and the + articular cartilages utterly destroyed, as we have described, cannot again be + replaced. Nature can only build again from such materials as are left to her. In this + case the material is bone.</p> + <p>It must be remembered, however, that often the bone has been so diseased that + spots of necrosis or caries within it are bound to remain unless moved by operative + interference. Such diseased portions, when dealing with the foot, are beyond reach of + the surgeon's knife, and we have no alternative but to allow them to remain. We get, + therefore, in many cases, a condition of rarefactive ostitis occurring side by side + with a slowly progressive caries within the bone, while outside is occurring an + osteoplastic periostitis. The concurrence of these conditions leads in time to great + increase in size of the parts, together with increasing anchylosis and deformity.</p> + <h3>C. NAVICULAR DISEASE.</h3> + <p><i>Definition</i>.—Chronic inflammatory changes occurring in connection with + the navicular bursa, affecting variously the bursa itself, the perforans tendon, or + the navicular bone, and characterized by changes in the form of the hoof and + persisting lameness. The disease is commonly noticed in thoroughbreds or in horses of + the lighter breeds, and is but seldom observed in heavy cart animals. Usually it is + met with in one or both fore-feet. Although of extremely rare occurrence, it has been + noticed in the hind.</p> + <p><i>History</i>.—To English veterinarians appears to belong the credit of + discovering navicular disease. As early as 1752 we find one, Jeremiah Bridges, in 'No + Foot, No Horse,' drawing attention to 'coffin-joint lameness,' and advocating for its + treatment setoning of the frog. It appears, too, that Moorcroft, prior to his + departure for India in 1808, was acquainted with what was then known as + coffin-joint[A] lameness, having drawn attention to it in 1804 in a letter to Sir + Edward Codrington.[B] In 1819 Moorcroft made it even plainer still that he was fully + acquainted with what we now know as navicular disease. This we learn from a letter + written by him to Sewell, in which he laid claim to being the originator of + neurectomy. In this letter he says:</p> + <p>[Footnote A: The coffin-joint at this time included the navicular bursa.]</p> + <p>[Footnote B: Percival's 'Hippopathology,' vol. iv., p. 132.]</p> + <p>'On dissecting feet affected with these lamenesses, the flexor tendon was now and + then observed to have been broken, partially or entirely, but more commonly to have + been bruised and inflamed in its course under the navicular or shuttle bone, or at + its insertion into the bone of the foot. Sometimes, although seldom, the navicular + bone itself has been found to have been fractured; at others its surface has been + deprived of its usual coating, and studded with projecting points or ridges of new + growth, or exhibiting superficial excavations more or less extensive.'[A]</p> + <p>[Footnote A: <i>Ibid</i>.]</p> + <p><i>Pathology and Point of Commencement of the Disease</i>.—The exact + position in which the diseased process starts has for a long time been a subject of + discussion, and even now it is doubtful whether the point has been definitely + settled. To mention but a few among many: We find Mr. Broad, of Bath, strenuously + insisting on the fact that the disease commences in the interior of the navicular + bone. Just as strenuously we find the editor of the journal in which the matter is + being discussed, the late Mr. Fleming, asserting that the disease commences in the + bursa.[A] Others, too, hold that the disease commences primarily in the tendon. + Wedded to this view was the discoverer, Mr. Turner, of Croydon; while Percival + commits himself to the statement that it is either the central ridge or the + postero-inferior surface of the navicular bone, or the opposed concavity in the + perforans tendon, that shows the earliest signs of the disease. The observations made + by Dr. Brauell, the first Continental writer to fully describe the disease, led him + to the statement that neither the bone nor the bursa was the <i>invariable</i> + starting-point of the trouble, but that usually it commenced in inflammation of the + bursa itself.</p> + <p>[Footnote A: Percival's 'Hippopathology,' vol. iv., p. 132.]</p> + <p>Without, therefore, committing ourselves to an expression of opinion as to the + precise starting-point of the affection, we shall describe the pathological changes + occurring in navicular disease as noted in (1) the bursa, (2) the cartilage, (3) the + tendon, and (4) the bone.</p> + <p>1. <i>Changes in the Bursa</i>.—Upon the internal surface of the bursal + membrane is first noticed a slight inflammatory hyperæmia, accompanied by more + or less swelling and tumefaction, owing to its infiltration with inflammatory + exudate. The portion covering the hyaline cartilage of the navicular bone has lost + its peculiar pearl-blue shimmer, and become a dirty yellow.</p> + <p>Remembering that the bursal membrane is a synovia-secreting one, and bearing in + mind what happens in ordinary synovitis and arthritis (with which, of course, this + may be very closely compared), we shall first expect changes in the bursal contents. + It is highly probable, though difficult of proof, that in the very early stages the + chronic inflammatory stimulus has the effect of increasing the flow of synovia. In + every case, however, where it can with any certainty be said that navicular disease + exists, it is too late to meet with this condition. The disease has then progressed + until destruction of the secreting layer of the bursal membrane has been seriously + interfered with, and in this case we find a distinct deficiency in the quantity of + synovia in the bursa. In advanced cases it is even found that the bursa is + <i>absolutely dry</i>.</p> + <p>2. <i>Changes in the Cartilage</i>.—Directly that portion of the bursal + membrane covering the cartilage is the subject of inflammatory change, the cartilage + itself, by reason of its low vitality, soon suffers.</p> + <p>Under a process, which we may term 'dry ulcerative,' the cartilage covering the + ridge on the lower surface of the bone commences to become eroded, and in appearance + has been likened, both by English and Continental writers, to a piece of wood that + has been worm-eaten (see Fig. 161).</p> + <br /> + <a name="a161" id="a161"></a> + <p><a href="images/image161.jpg"><img src="images/image161sm.jpg" + alt="NAVICULAR BONE (POSTERO-INFERIOR SURFACE) SHOWING THE 'WORM-EATEN' APPEARANCE CAUSED BY EROSION OF THE HYALINE CARTILAGE, AND COMMENCING RAREFACTIVE ARTHRITIS." /> + </a></p> + <br /> + + <p>FIG. 161.—NAVICULAR BONE (POSTERO-INFERIOR SURFACE) SHOWING THE 'WORM-EATEN' + APPEARANCE CAUSED BY EROSION OF THE HYALINE CARTILAGE, AND COMMENCING RAREFACTIVE + ARTHRITIS.</p> + <p>'At this stage, or much earlier'—we are quoting Colonel Smith, + A.V.D.—'may be found calcareous deposits in the fibro-cartilage and the bone. + They are scattered like fine sand here and there, generally across the inferior half + of the face of the bone; they are sometimes numerous, frequently scanty, occasionally + entirely absent. The amount of calcareous degeneration depends upon the lesions + present. If much destruction of bone exists, there will be but few calcareous + deposits; whilst if there are many calcareous deposits, there may be but slight + ulceration of bone tissue, and perhaps none at all. In fact, I have held the opinion, + and see no reason to modify it, that calcareous deposits are safeguards against + caries.'[A]</p> + <p>[Footnote A: <i>Journal of Comparative Pathology and Therapeutics</i>, vol. vi., + p. 195.]</p> + <p>3. <i>Changes in the Tendon</i>.—The effect of these calcareous deposits on + the under surface of the bone is to produce a certain amount of roughness. Seeing + that with every movement of the foot the perforans tendon is called upon to glide + over this surface, it is clear that a secondary effect must be that of inducing + erosion and destruction of the tendon. The point at which this usually commences is + at the bottom of the depression that accommodates the ridge on the bone. With erosion + of the cartilage and of the tendon at points exactly opposite each other, we have two + surfaces come together that are prone to readily unite, and fibrous tissue adhesions + often take place between the bone and the tendon. In some measure this accounts for + the torn and ragged appearance of the tendon. Adhesions take place, and, under some + small strain, are broken down. This may happen more than once or twice, and with each + breaking of the adhesion between the bone and tendon, fibres from the latter are + lacerated and torn from their place (see Fig. 162).</p> + <p>4. <i>Changes in the Bone</i>.—The changes occurring in the bone are + essentially those of a rarefactive ostitis. These changes are described by many + writers, and, whether originating primarily in the bone or not, it seems certain that + extensive changes may have occurred within the bone, with but little or nothing to be + noted on its outer surface. It would seem that the first change is one of congestion + of the vessels of the bone's cancellous tissue. With the cause, whatever it may be, + in constant operation, the congestion persists until a low type of inflammation is + set up, interfering, not only with the flow of synovia in the adjoining bursa, but + with the nutrition of the bone itself. As the disease progresses, there is softening + and enlarging of the cancellated tissue towards the centre of the bone. The cells + break up, and absorption takes place. This goes on until a large portion of the + interior of the bone is in a state of dry necrosis, with, in many cases, but slight + signs of mischief on the exterior of the bone.</p> + <p>In other cases, however, the changes in the interior of the bone are accompanied + by well-marked lesions on its gliding or postero-inferior surface, and by evidences + of an osteoplastic periostitis along its edges.</p> + <p>That an osteoplastic periostitis has been in existence is witnessed by the + appearance along the edges of the bone of numerous outgrowths of bone, termed + osteophytes (see Fig. 163).</p> + <br /> + <a name="a162" id="a162"></a> + <p><a href="images/image162.jpg"><img src="images/image162sm.jpg" + alt="A FOOT WITH THE SEAT OF NAVICULAR DISEASE EXPOSED." /></a></p> + <br /> + + <p>FIG. 162.—A FOOT WITH THE SEAT OF NAVICULAR DISEASE EXPOSED. On the anterior + surface of the perforans fibres of the tendon are seen to be torn away from their + abnormal adhesion with the navicular bone, while others are seen to be still attached + thereto. The surface of the navicular bone itself exhibits small defects in the bony + substance, which have been brought about by a rarefactive ostitis. <i>a</i>, The + perforans tendon cut through and reflected; <i>b</i>, the sole.</p> + <p>The interosseous and postero-lateral ligaments of the articulation often + participate in the inflammatory changes, and in many cases become completely + ossified. The true articulatory surface of the bone, that articulating with the os + pedis and with the os coronæ, is never affected.</p> + <p><i>Causes</i>.—In enumerating the causes of navicular disease, we shall + follow the example of Colonel Smith and classify them under certain + headings—namely, (1) <i>Hereditary Predisposition</i>; (2) <i>Compression</i>; + (3) <i>Concussion</i>; (4) <i>A Weak Navicular Bone</i>; (5) <i>A Defective or + Irregular Blood-supply to the Bone</i>; and (6) <i>Senile Decay</i>.</p> + <br /> + <a name="a163" id="a163"></a> + <p><a href="images/image163.jpg"><img src="images/image163sm.jpg" + alt="THE NAVICULAR BONE FROM A CASE OF LONG-STANDING NAVICULAR DISEASE." /></a></p> + <br /> + + <p>FIG. 163.—THE NAVICULAR BONE FROM A CASE OF LONG-STANDING NAVICULAR DISEASE. + The erosion of the cartilage on its central ridge is most marked, and the porous + appearance of the bone thus uncovered points to the existence within it of a + rarefactive ostitis. Along its edges large osteophytic outgrowths speak of the + effects of an osteoplastic periostitis.</p> + <p>1. <i>Hereditary Predisposition</i>.—That navicular disease is hereditary is + a fact that has for a long time been insisted on, and has come to be so generally + admitted that we do not intend to dwell on it here. As we have said before, it is + found in the lighter breeds of horses (and, according to Zundel, especially in the + English breeds), and is there seen to be frequently transmitted from parent to + offspring.</p> + <p>2. <i>Compression</i>.—By this is meant the compression of the navicular + bone between the os pedis and the os coronæ in front, and the perforans tendon + behind.</p> + <p>In order to appreciate this explanation of the causation of navicular disease at + its true value, it will be well to consider briefly the physiology of the parts in + question.</p> + <p>The navicular bone is what we may term a complement of the os pedis. It exists, in + fact, simply in order that the os coronæ may have a sufficiently large + articulatory surface to play upon. One wonders at first that Nature did not arrive at + this by originally placing a larger bone below. Colonel Smith explains this by + suggesting that this would in all probability have meant its fracture. In progression + the hind part of the foot comes to the ground first, and upon the hinder portion of + the articulation would fall the first effects of concussion, together with the + greater part of the body-weight. A yielding joint was in this position necessary, and + that formed by the navicular bone fills all requirements.</p> + <p>In this connection one next considers the part played by the front limbs during + progression. As Zundel expresses it, they are columns of support rather than of + impulsion, and, as the body-weight is thrown forward by the hind-limbs, it is the + duty of the fore-limbs to receive it. The shock or concussion of the body-weight thus + thrown forwards is first received by the muscles uniting the limb to the trunk, and a + great part of it there minimized by their sling-like attachment. It is further + absorbed by the shoulder-joint, and from there passed on to the almost vertical bony + column represented by the radius and ulna, the knee, and the metacarpus. On reaching + the first phalanx, a portion of the remaining force is passed on to the front of the + phalanges and loses itself in front of the hoof, while the other portion is + transmitted to the flexor tendons, finally to the perforans, and to the posterior + parts of the foot. During progression, therefore, the navicular bone is constantly + pushed downwards and backwards by the bony column, and is just as constantly pushed + forwards and upwards by the resistance of the perforans tendon. This means, of + course, that the navicular bone is more or less constantly subject to compression, + and constant pressure, as we know full well, is a pretty sure factor in bringing + about malnutrition of the parts, with atrophy or chronic inflammatory changes as an + end result.</p> + <p>Even with the limb at rest the pressure on both sides of the navicular bone is + still constant. The only circumstances under which we can conceive of it being + entirely absent, in fact, are when the tension on the tendon is relaxed, and the + body-weight altogether removed by the animal adopting the recumbent position.</p> + <p>The compression theory as to the causation of navicular disease was, we believe, + first originated by Colonel Smith. He, at any rate, has laid much stress on it in his + writings. If we accept it, and we see every reason that we should, then we must, with + the author, admit the possibility of navicular disease arising from long standing in + one position.</p> + <p>3. <i>Concussion</i>.—This we are bound to admit as a cause, and in so doing + partly explain the comparative, almost total, immunity of the hind-feet from the + disease. The fore-limbs, as we have already pointed out, are little more than props + of support, and the force of the propelled body-weight is transmitted largely down + their almost vertical lines, to end largely in concussion in the foot. With the + hind-limbs matters are different. 'These,' as Percival explains it, 'have their bones + obliquely placed, so as to constitute, one with the other, so many obtuse angles, to + the end, that by forming powerful levers, and affording every advantage for action to + the muscles attached to them, they may be fitted for the purpose of propulsion of the + body onward.'</p> + <p>The effect of these several obtuse-angled joints in the limb is to absorb the + greater part of the force exerted by the body-weight before it reaches the foot. When + with this we take the facts that the fore-limbs have to carry the head and neck, and + that they have to bear this added weight, plus a propelling force from behind, we see + why it is that they should be so subject to the disease, and the hind-limbs so + exempt.</p> + <p>As pointing out the part that concussion plays in its causation, we may mention + that navicular disease is a disease of the middle-aged and the worked animal. It is + interesting to note, too, that it occurs in animals with well developed + frogs—in feet in which frog-pressure with the ground is most marked. This at + first sight appears to flatly contradict what we have said with regard to + frog-pressure in other portions of this work. With this, however, must be reckoned + other predisposing causes. In this case it is not to frog-pressure alone we must + look, but to the condition of the frog itself, and that of the neighbouring parts. It + is when we have a frog which, though well developed and apparently satisfying all + demands as to size and build, is at the same time composed of a hard, dry, and + non-yielding horn that we must look for trouble.</p> + <p>The foot predisposed to navicular disease is the strong, round, short-toed or + clubby foot, open at the heels, with a sound frog jutting prominently out between + them. Here is a frog exposed to all the pressure that might be desired for it, + bounded at its sides by heels thick and strong, and indisposed to yield, and itself + liable, from its very exposure, to become, in the warm stable, hard and dry, and + incompressible' (Percival).</p> + <p>Here, instead of acting, as normally it should, as a resilient body, and an aid to + the absorption of concussion, it seems rather to play the part of a foreign body, and + to bring concussion about. Seeing, then, that the navicular bursa is in very near + contact with it, it is conceivable that this joint-like apparatus should suffer, and + the pedal articulation be left unaffected, the more so when we take into + consideration the compression theory just described.</p> + <p>4. <i>A Weak Navicular Bone</i>.—When the disease commences first in the + bone—and there is no denying the fact that sometimes, although not invariably, + it does—it may be explained by attributing to the structure of the bone an + abnormal weakness in build.</p> + <p>The navicular bone consists normally of compact and cancellated tissue arranged in + certain proportions, the compact tissue without, and the cancellated within. These + proportions can only be judged of by the examinations of sections of the bone, and + when it is found in any case that the cancellated tissue bulks more largely in the + formation of the bone than normally it should, we have what we may term a weak + navicular bone. In this connection Colonel Smith says: 'Though it is far from present + in every case of the disease, still I consider it a factor of great importance.'</p> + <p>5. <i>A Defective or Irregular Blood-supply to the Bone</i>.—This, Colonel + Smith considers, is brought about by excessive and irregular work, and by the + opposite condition—rest. The author points out that the bloodvessels passing to + and from the navicular bone run in the substance of the interosseous ligaments, or in + such proximity to them that it is conceivable that under certain circumstances + mechanical interference may occur to the navicular circulation. He further points out + a fact that is, of course, well known to every veterinarian, that in periods of work + the circulation of the foot is hurried, and that in rest there is always a tendency + to congestion; and he says in conclusion: 'I cannot help thinking that irregularities + in the blood-supply in a naturally weak bone must be a factor of some importance, + especially when the kind of work the horse is performing is a series of vigorous + efforts followed by rest.'</p> + <p>6. <i>Senile Decay</i>.—With approaching age the various tissues lose their + vigour, and are prone to disease. The navicular bone and surrounding structures are + not exempt. With the other and more active causes we have described acting at the + same time it is not surprising that navicular disease is seen as a result.</p> + <p>In conclusion, it is well, perhaps, to say that, no matter to which particular + theory of causation we may lean, we should make up our minds to consider them as a + whole. While one cause may be exciting, the other may be predisposing, and the two + must act together before evil results are noticed. It may be that even more than two + are concerned in bringing on the disease, and to each the careful veterinarian will + give due consideration.</p> + <p><i>Symptoms and Diagnosis</i>.—In the early stages of navicular disease the + symptoms are obscure. Pointing of the affected limb is the first evidence the animal + gives. This, however, more often than not, goes unnoticed, and the first symptom + usually observed by the owner or attendant is the lameness. Even this is such as to + at first occasion no alarm, being intermittent and slight, and only very gradually + becoming marked. In a few cases, however, lameness will come on suddenly, and is + excessive from the commencement. It is the lameness, slow in its onset, intermittent + in its character, and gradual in its progress, however, that is ordinarily + characteristic of navicular disease.</p> + <p>The animal is taken out from the stable sound, with just a vague suspicion, + perhaps, that he moved a bit stiffly. While out he is thought by his driver or rider + to be going feelingly with one foot or with both. Even this is not marked, and the + driver has some difficulty in assuring himself whether or no he really observed it, + or whether it was but imagination.</p> + <p>On the return home the limb is examined, and nothing abnormal is to be found. The + leg is of its normal appearance, and neither heat nor tenderness is to be observed in + it or in the foot. On the following day the animal again is sound, and the lameness + of the previous day is put down to a slight strain or something equally simple. The + patient is then, perhaps, rested for a day or two. When next he is worked he again + moves out from the stable sound, but again during the going gives the driver the + unpleasant impression that something is amiss; and so the case goes on. One day the + owner fears the animal is becoming seriously enough affected to warrant him in + calling in his veterinary surgeon; the next he is confidently assuring himself that + nothing is wrong.</p> + <p>Perhaps the animal is now rested for a week or two, or even for a month or two, + hoping that this will put him sound. Immediately on commencing work, however, the + same symptoms as before assert themselves, and the veterinary surgeon is called + in.</p> + <p>With a history such as we have given the veterinarian's suspicions are aroused. He + has the animal trotted, and may notice at this stage that there is an inclination to + go on the toes, that the lame limb or limbs are not put forward freely, and that + progression is stilty and uncertain; it is such, in fact, as to at once suggest the + possibility of corns being present.</p> + <p>In some cases there is just the suspicion of a limp with one limb, and this only + at intervals during the trot. At one moment the veterinarian is positive that he sees + the animal going lame; at another he is just as confident he sees him coming towards + him sound.</p> + <p>Nothing is found in the limb—neither heat, tenderness, nor swelling. There + is nothing in the gait (either a limited movement of the radius, or a circular sweep + with the leg) to indicate shoulder or other lameness, and the veterinary surgeon, by + eliminative evidence, is bound to conclude that the trouble is in the foot.</p> + <p>The foot is then examined—pared, percussed, pinched, and in other ways + manipulated—but nothing further is forthcoming. In such a case the veterinary + surgeon is wise to declare the abortive result of his examination, to hint darkly of + his suspicions, and to suggest a second examination at some future date. It may be + that two, three, four, or even more, such examinations are necessary before he can + justly pronounce a positive verdict.</p> + <p>Later he is enabled to do this by an increase in the severity of the symptoms, and + by the changes that take place in the form of the foot. The lameness is now more + marked, and the 'pointing' in the stable more frequent. With regard to the latter + symptom, it has been seriously discussed whether the horse with navicular disease + points with the heel elevated or with it pressed to the ground. In either case, of + course, the limb is advanced; but while some hold that the phalangeal articulations + are flexed and the heel slightly raised, in order to relieve the pressure of the + perforans tendon on the affected area, and so obtain ease, there are others who hold + that the heel is pressed firmly to the ground in order to deaden the pain. It may be, + and most probably is, that both are right; but, in our opinion, there is no doubt + whatever that pointing with the heel elevated is by far the most common.</p> + <p>The lameness is now excessive, and is especially noticeable when the animal is put + to work on a rough or on a hard ground. Even now, however, heat of the foot or + tenderness is so slight as to be out of all proportion to the alteration in gait.</p> + <p>With the case thus far advanced, evidence of pain may be obtained by pressing with + the thumb in the hollow of the heel. Evidence of pain may also be obtained by using + the farrier's pincers on the frog. These methods, however, are never wholly + satisfactory, as a horse with the soundest of feet will sometimes flinch under these + manipulations.</p> + <p>Extreme and forcible flexion of the corono-pedal articulation also sometimes gives + evidence of tenderness. In this case the foot is held up, the animal's metacarpus + resting on the operator's knee, and the toe of the hoof pushed downwards with some + degree of force.</p> + <p>The same movement of the joint is given by causing the animal to put full weight + upon the diseased limb, a small wedge of wood being first placed under the toe. In + this manner the pressure of the perforans tendon upon the bursa is greatly increased, + and the animal is caused to show symptoms of distress.</p> + <p>The lameness may also be increased, and diagnosis helped, by paring the heels, so + as to leave the frog prominent and take the whole of the body-weight. The same end is + also obtained by applying a bar shoe. This was originally pointed out by Brauell, and + is quoted by Zundel and by Möller.</p> + <p>The changes in the form of the hoof may now be noticed. These are largely + dependent on the fact that more or less constantly the patient saves the heel. The + horn of the walls in this region, and the horn of the frog, is thereby put out of + action and induced to atrophy. The hoof gradually assumes a more upright shape, and + the heels contract. We thus get a hoof which is visibly narrowed from side to side, + with a frog that is atrophied and often thrushy, and with a sole that is abnormally + concave, hard, and affected with corns.</p> + <p>When occurring in the hind-feet—a condition that is rare, but which has been + noticed by Loiset, and quoted by Zundel—the animal is stiff behind, walks on + his toes, and gives one the impression that he is suffering from some affection in + the region of the loins.</p> + <p>One such case is reported by an English veterinary surgeon, and we quote it + here:</p> + <p>'A gray gelding, and a capital hunter, the property of a gentleman in this + neighbourhood, became lame in the near fore-foot after the hunting season of 1859. + The lameness was believed to be due to navicular disease. The operation of neurectomy + was ultimately had recourse to. The horse subsequently did his work as well as ever, + and was ridden to hounds regularly till the end of the year 1861, when he went lame + of the off fore-foot. From this date he also showed very peculiar action behind, and + was at times lame of both hind-limbs without any apparent cause.</p> + <p>'In the year 1862, from the groom's indiscreet use of physic, super-purgation was + brought on which caused the animal's death. On a post-mortem examination being made, + the horse was found to have <i>navicular disease of all four feet</i>. It is worthy + of note that this horse had always "extravagant" action behind, but was a remarkably + quick and good jumper.'[A]</p> + <p>[Footnote A: F. Blakeway, M.R.C.V.S., <i>Veterinarian</i>, vol. ii., p. 21.]</p> + <p><i>Differential Diagnosis</i>.—Navicular disease may be mistaken for + ordinary contracted foot. It will be remembered, however, that in the early stages of + navicular disease contraction is absent, and that it is only when the disease in the + bursa is of long standing that contraction comes on. With ordinary contracted foot, + too, careful paring and suitable shoeing soon sees a diminution in the degree of + lameness, and a return to the normal in shape (see Treatment of Contracted Foot, p. + 125). With navicular disease, however, such shoeing as is beneficial in the treatment + of contracted foot (notably the various methods of giving to the frog + counter-pressure with ground) soon brings on an aggravation of the lameness.</p> + <p>It is, perhaps, even more likely to be confounded with contraction when we have + with the contraction a state of atrophy and thrush of the frog. With a frog in this + condition pressure will give rise to pain, and navicular disease be erroneously + judged to be present. In such a case we must rely wholly upon either extreme flexion + or extreme extension of the joint to guide us, when, if contraction <i>only</i> is + the offending condition, no symptom of pain will be shown.</p> + <p>Navicular disease may also be confused with rheumatic affections, with sprain of + the posterior ligaments of the first interphalangeal articulation, and with sesamoid + lameness. Mistakes are sometimes made, too, especially with a hasty observer, in + confounding it with shoulder lameness.</p> + <p>In rheumatism the constant changing of the seat of pain, the sometimes elevated + temperature, and the appearance of symptoms of heat, tenderness, and swelling in the + affected area should guide one to a right conclusion.</p> + <p>In sprain of the posterior ligaments of the coronet and in sesamoid lameness, + nothing but a careful examination and manipulation of the parts will ward off error, + for in each of these cases there is 'pointing' and resting of the limb, and + considerable disinclination to put weight firmly upon it. If at the same time + manipulation gives distinct evidence of pain, all doubt may be set at rest.</p> + <p>Roughly speaking, sesamoid lameness is a condition of the gliding surface of the + sesamoids, and the face of the tendon playing over them, similar to that found in + navicular disease. All symptoms of pointing, the constant maintaining of the limb in + a state of flexion, and a feeling manner of progression are again all present. It is + plain from this that in all cases where an animal with a gait at all suggestive of + navicular disease is brought for our examination, the manipulation of the limb should + be thorough. The character of the lameness is almost sure to deceive us; and it is + not until we are able to obtain local symptoms pointing to the one or the other of + the conditions we have enumerated that a decisive opinion may be given. In sesamoid + lameness the local symptoms are those of heat and pain in the fetlock on palpation, + and a swelling of the affected parts, such swelling being at first slight, yielding, + and barely distinguishable, and afterwards larger, bony and hard, and more marked. + Later still there is distinct evidence of 'knuckling' over at the fetlock and + inability to fully flex it.</p> + <p>In cases of shoulder lameness the gait alone should be sufficient to render + liability of error small, for with nearly every case there is a manifest inability to + 'get the limb forward', and this is best seen at a side view when the animal is + trotting past the observer. When trotting towards one, there is a further and + unmistakable symptom common to most shoulder lamenesses that serves to distinguish it + at once, and that is the peculiar 'sweeping' outwards with the affected limb.</p> + <p>Lastly, with either of the conditions we have just mentioned, it is the exception + to get contracted foot follow on. With navicular disease it sooner or later makes its + appearance.</p> + <p><i>Prognosis</i>.—The prognosis of navicular disease (once diagnosed with + certainty) must almost of necessity be unfavourable. The facts that the disease has + made serious progress before it is really noticeable, that the situation of the parts + prohibits operative interference, and that the disease is one of a chronic and slowly + progressive type, all point to an unfavourable termination.</p> + <p><i>Treatment</i>.—We have seen from the pathology of this disease that it + may commence either as a rarefactive ostitis, or as a synovitis and tenositis in + connection with the bursa. With the former condition in existence, or when this and + the synovitis has led to erosion of the cartilage, treatment is probably of no avail, + on account of the more chronic nature of these two conditions. When, however, the + condition is simply that of synovitis or tenositis, a more or less acute condition, + we may assume that suitable treatment and a long rest will bring about + resolution.</p> + <p>The first indications in treatment are those of what we may term 'nursing' the + foot. It should have sufficient rest, should be placed so as to minimize as far as + possible compression of the parts, and should have its posterior half treated so as + to render it softer and less liable to concussion.</p> + <p>The period of rest required cannot be satisfactorily advised, and the practitioner + is wise who makes it a long one. Best should be advised, in fact, long after symptoms + of lameness have disappeared and recovery is judged to have taken place.</p> + <p>Compression of the parts may be somewhat minimized, if the animal be kept in the + stable, by allowing the floor upon which the front-feet are to stand to be slightly + sloping from behind forwards. The same effect, though not so marked, is obtained by + removing the shoes, and considerably lowering the wall at the toe, while allowing + that of the heels to remain. It may here be remarked that it is a good practice to + allow the shoes to remain on, and this even when the animal is at grass. They should, + however, be frequently removed, and the foot trimmed as we have directed.</p> + <p>With the foot thus trimmed so as to most suitably adjust the angles of the + articulations, it should next be thoroughly pared and rasped in its posterior half, + so as to render the horn of the sole and the frog and the horn of the quarters as + thin as possible. The heels, however, should not be excessively lowered, <i>if at + all</i>. We now have the foot in a soft condition, and easily expanded. It should, if + possible, be kept so; and this may be done either by the use of poultices, by tepid + baths, or by standing the animal upon a bedding that may easily be kept constantly + damp. Such materials as tan, peat moss, or sawdust, are either of them suitable.</p> + <p>All this, of course, calls for keeping the animal in the stable. It is far better, + however, more especially if a piece of marshy land is at hand, to turn him out in + that. A moderate amount of exercise is beneficial rather than not, and the feet are + thus constantly kept damp without trouble to the attendants.</p> + <p>The second indication in the treatment is that of applying a counter-irritant as + near to the diseased parts as possible. Regarding its efficacy we must confess to + being somewhat sceptical. The treatment has been constantly practised and advised, + however, and we feel bound to give it mention here. A smart blister may, therefore, + be applied to the whole of the coronet, and need not be prevented from running into + the hollow of the heel.</p> + <p>Instead of blistering the coronet (or in conjunction with that treatment), the + counter-irritant may be applied by passing a seton through the plantar cushion or + fibro-fatty frog. Setoning the frog appears to have been introduced by Sewell. In + many cases great benefit is claimed to have been derived from it, especially by + English veterinarians of Sewell's time, and by others on the Continent. Percival, + however, was not an advocate for it, and, at the present day, it is a practice which + appears to have dropped out of use altogether.</p> + <br /> + <a name="a164" id="a164"></a> + <p><a href="images/image164.png"><img src="images/image164sm.png" + alt="FROG SETON NEEDLE." /></a></p> + <br /> + + <p>FIG. 164.—FROG SETON NEEDLE.</p> + <p>To perform this operation a seton needle of a curved pattern is needed (see Fig. + 164). This is threaded with a piece of stout tape dressed with a cantharides, + hellebore, or other blistering ointment, and then passed in at the hollow of the + heel, emerging at the point of the frog. The course the needle should take will be + understood from a reference to Fig. 165.</p> + <p>The seton may be passed with the horse in the standing position. Previously the + point of the frog should be thinned, and the animal should be twitched. + After-treatment consists simply in moving the seton daily, and dressing it + occasionally with any stimulating ointment, or with turpentine.</p> + <p>If, in spite of these treatments, the disease persists, then nothing remains but + neurectomy.</p> + <h3>D. DISLOCATIONS.</h3> + <p>The firm and rigid manner in which the bones of the pedal articulation are held + together renders dislocation of this joint an exceedingly rare occurrence, and then + it is only liable to happen under the operation of great force. In the literature to + our hand we have only been successful in discovering one reported instance, and, + strange to say, in this, a well-marked case, the cause was altogether obscure. We + quote the case at the end of this section.</p> + <br /> + <a name="a165" id="a165"></a> + <p><a href="images/image165.png"><img src="images/image165sm.png" + alt="DIAGRAM SHOWING THE COURSE TAKEN BY THE NEEDLE WHEN SETONING THE FROG." /> + </a></p> + <br /> + + <p>FIG. 165.—DIAGRAM SHOWING THE COURSE TAKEN BY THE NEEDLE WHEN SETONING THE + FROG. This is shown by the dotted curved line <i>a, b</i>. 1, The navicular bone; 2, + the plantar cushion; 3, the os pedis; 4, the perforans tendon.</p> + <p>A partial dislocation of this articulation is the condition met with in 'Buttress + Foot.' In this case the fracture of the pyramidal process, and the consequent + lengthening of the tendon of the extensor pedis, allows the os coronæ to occupy + upon the articulatory surface of the os pedis a more backward position than normally + it should.</p> + <p>It is quite probable, too, that slight lesions of the other restraining ligaments + and tendons of the articulation may bring about a similar though less marked + condition. We may be quite sure of this—that whenever such lesions (as, for + example, sprain and partial rupture of the lateral ligaments) do occur, and the + normal position of the opposing bones is changed, if only slightly, that great pain + and excessive lameness must be the result, and this with but little to show in the + foot. Many of our cases of obscure foot lameness might, if capable of demonstration, + turn out to be cases of sprain and partial dislocation of the pedal articulation.</p> + <p><i>Recorded Case</i>.—'The animal, a trooper of the 8th Hussars, was found + on the morning of April 17 unable to bear any weight on the limb (the near hind). + Cause not known—the heel-rope I thought at first; but on investigation I found + the heel-rope had been on the other leg.</p> + <p><i>Diagnosis</i>.—Dislocation of the left os coronæ from the + articulating surface of the os pedis in a backward direction.</p> + <p>'Every devisable means were unsuccessful in reducing the limb to its natural + position. The horse was thrown, and a strong rope, with four men pulling at it, was + fastened round the hoof, whilst I put my knee to the back of the pastern, using all + possible force, with one hand to the foot and the other to the fetlock, but all to no + purpose. Next day other means were tried. First by throwing the horse and placing him + on his belly, with the fore-legs stretched out forwards, and the hind-legs backwards. + This I did so as to get the injured limb placed as nearly flat on the ground as + possible, with its anterior aspect downwards. Then a very heavy man, with his boots + off, was made to jump on the back of the pastern, where the prominence showed most; + and afterwards, when these means failed, a strong piece of wood, well covered with + leather, was placed (where the hollow of the heel ought to have been) on the most + prominent part, and hit several times with a heavy hammer; but all efforts were + futile.</p> + <p>'<i>Prognosis</i>.—Unfavourable. During the latter operations I had a very + strong pressure applied to the hoof, and the horse firmly fastened in every way, and + it appeared as though no amount of force would ever reduce the dislocation.</p> + <p>'<i>Tautological</i>.—The case was destroyed on April 30, being of no + further use to the service.</p> + <p>'<i>Post-mortem</i>.—The os coronæ was found to have slipped out of + the articulating cavity of the os pedis, backwards and past the lateral ligaments. + These last-named structures prevented the bone being forced forward into its proper + position, being firmly locked over the lateral prominences. The capsular ligament was + considerably lacerated and inflamed, causing slight effusion and swelling about the + region of the coronet.'[A]</p> + <p>[Footnote A: T. Flintoff, A.V.D., <i>Veterinary Journal</i>, vol. xix., p. + 74.]</p> + <p><i>Treatment</i>.—After the forcible means of reduction related by Mr. + Flintoff, we may add that when they are successful, they should be followed by + suitable bandaging of the parts, and rest. The first is effected by applying plaster + of Paris and linen, and the second by having the animal put in slings.</p> + <br /> + <br /> + <br /> + + <h3>INDEX</h3> + <ul> + <li>Accidental tearing off of the entire hoof</li> + <li> + Acute arthritis + <ul> + <li>causes of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Acute laminitis + <ul> + <li>causes of</li> + <li>complications in</li> + <li>congestion in</li> + <li>course of</li> + <li>definition of</li> + <li>diagnosis in</li> + <li>exudation in</li> + <li>pathological anatomy of</li> + <li>prognosis in</li> + <li>suppuration in</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Acute periostitis simple</li> + <li> + Acute simple coronitis + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>prognosis of</li> + <li>treatment of</li> + </ul> + </li> + <li>Acute simple synovitis</li> + <li>Advantages of neurectomy</li> + <li>Amputational neuroma after neurectomy</li> + <li>Anatomy, pathological, of corn</li> + <li>Applying poultices, method of</li> + <li>Arteries of the foot</li> + <li> + Arthritis, acute + <ul> + <li>causes of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Arthritis, simple or serous</li> + <li> + Arthritis, suppurative + <ul> + <li>causes of</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>pathology of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Articulation, the first interphalangeal</li> + <li>Articulation, the second interphalangeal<br /> + <br /> + </li> + <li>Bar pad and a half-shoe in the treatment of contracted feet</li> + <li>Bar shoes in the treatment of contraction</li> + <li>Bayer's treatment for chronic laminitis</li> + <li>Bermbach's treatment for canker</li> + <li>Bind</li> + <li>Bone, caries of</li> + <li>Bones, fracture of the, after neurectomy</li> + <li>Bones, fracture of the</li> + <li>Bones, necrosis of</li> + <li>Bones, the</li> + <li> + Brittle hoof + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Broad's treatment of laminitis</li> + <li>Broué's expansion shoe</li> + <li>Bruised sole, chronic</li> + <li>Buttress foot<br /> + <br /> + </li> + <li> + Canker + <ul> + <li>Bermbach's treatment of</li> + <li>causes of</li> + <li>definition of</li> + <li>differential diagnosis in</li> + <li>history of</li> + <li>Hoffmann's treatment of</li> + <li>Imminger's treatment of</li> + <li>Malcolm's treatment of</li> + <li>pathological anatomy of</li> + <li>prognosis in</li> + <li>Rose's treatment of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Caries of bone</li> + <li>Caries of the os pedis in pricked foot</li> + <li>Cartilage, the lateral</li> + <li>Cartilaginous quittor</li> + <li> + Causes of acute laminitis + <ul> + <li>of acute simple coronitis</li> + <li>of brittle hoof</li> + <li>of canker</li> + <li>of chronic coronitis</li> + <li>of chronic laminitis</li> + <li>of club-foot</li> + <li>of corn</li> + <li>of contracted feet</li> + <li>of coronary contraction of the foot</li> + <li>of crooked foot</li> + <li>of curved hoof</li> + <li>of false quarter</li> + <li>of flat-foot</li> + <li>of keraphyllocele</li> + <li>of nail-bound</li> + <li>of navicular disease</li> + <li>of pumiced foot</li> + <li>of punctured foot</li> + <li>of ringed hoof</li> + <li>of sand-crack</li> + <li>of seedy-toe</li> + <li>of side-bone</li> + <li>of simple chronic coronitis</li> + <li>of simple cutaneous quittor</li> + <li>of specific coronitis</li> + <li>of sub-horny quittor</li> + <li>of thrush</li> + <li>of weak heels</li> + </ul> + </li> + <li>Caustic solution, Villate's</li> + <li> + Changes in the bone in navicular disease + <ul> + <li>in the bursa in navicular disease</li> + <li>in the cartilage in navicular disease</li> + <li>in the internal structures of the foot in contraction</li> + <li>in the tendon in navicular disease</li> + </ul> + </li> + <li>Charlier shoe, the</li> + <li>Charlier shoeing for contracted foot</li> + <li>Chemical properties of horn</li> + <li> + Chronic coronitis, simple + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Chronic bruised sole + <ul> + <li>treatment of</li> + </ul> + Chronic laminitis + <ul> + <li>Bayer's treatment of</li> + <li>causes of</li> + <li>definition of</li> + <li>Gross's treatment of</li> + <li>Gunther's treatment of</li> + <li>Imminger's treatment of</li> + <li>Joly's treatment of</li> + <li>Meyer's treatment of</li> + <li>pathological anatomy of</li> + <li>surgical shoeing for</li> + <li>symptoms of</li> + <li>treatment of</li> + <li>treatment of, by ligaturing the digital arteries</li> + </ul> + </li> + <li>Chronic oedema of the leg after neurectomy</li> + <li>Chronic synovitis</li> + <li> + Clamp, sand-crack, Koster's + <ul> + <li>McGill's</li> + <li>Vachette's</li> + </ul> + </li> + <li>Clamping sand-cracks, methods of</li> + <li> + Classification of corns + <ul> + <li>of punctured foot according to the situation of the wound</li> + <li>of sand-crack</li> + <li>of quittor</li> + </ul> + </li> + <li> + Club-foot + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Cocaine injections as an aid to diagnosis in foot lamenesses</li> + <li>Colic, metastatic, in laminitis</li> + <li>Commencement, point of, in navicular disease</li> + <li>Common situations of the wound in punctured foot.</li> + <li>Complicated sand-crack, operations for</li> + <li> + Complications in coronitis + <ul> + <li>in laminitis</li> + <li>in pricked foot</li> + <li>in sand-crack</li> + <li>in simple or cutaneous quittor</li> + <li>in sub-horny quittor</li> + </ul> + </li> + <li>Compression as a cause of navicular disease</li> + <li>Concussion as a cause of navicular disease</li> + <li>Conformation, faulty</li> + <li>Congestion in laminitis</li> + <li> + Contracted foot + <ul> + <li>causes of</li> + <li>changes in the internal structures of</li> + <li>definition of</li> + <li>local or coronary</li> + <li>prognosis of</li> + <li>surgical shoeing for</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Contraction of the foot, a bar pad and a half-shoe in the treatment of + <ul> + <li>bar shoes in the treatment of</li> + <li>expansion shoes in the treatment of</li> + </ul> + </li> + <li> + Corn + <ul> + <li>causes of</li> + <li>classification of</li> + <li>definition of</li> + <li>pathological anatomy of</li> + <li>prognosis in</li> + <li>surgical shoeing in</li> + <li>symptoms of</li> + <li>the dry</li> + <li>the moist</li> + <li>the suppurating</li> + <li>treatment of</li> + </ul> + </li> + <li> + Coronary contraction of the foot + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Coronary cushion, the</li> + <li>Coronary edge of the wall, expansion and contraction of the</li> + <li> + Coronitis + <ul> + <li>acute simple</li> + <li>causes of</li> + <li>complications in</li> + <li>definition of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Coronitis, simple chronic + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Coronitis, specific + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Course of acute laminitis</li> + <li> + Crooked foot + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Curved hoof + <ul> + <li>causes of</li> + <li>definition of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Cushion + <ul> + <li>the coronary</li> + <li>the plantar</li> + </ul> + </li> + <li>Cutaneous or simple quittor<br /> + <br /> + </li> + <li>De Fay's expansion shoe.</li> + <li> + Defective or irregular blood-supply to the bone a cause of navicular + <ul> + <li>disease</li> + </ul> + </li> + <li> + Definition + <ul> + <li>of acute laminitis</li> + <li>of acute simple coronitis</li> + <li>of brittle hoof</li> + <li>of canker</li> + <li>of chronic coronitis</li> + <li>of chronic laminitis</li> + <li>of club-foot</li> + <li>of contracted foot</li> + <li>of corn</li> + <li>of coronary contraction of the foot</li> + <li>of crooked foot</li> + <li>of curved hoof</li> + <li>of false quarter</li> + <li>of flat-foot</li> + <li>of keraphyllocele</li> + <li>of nail-bound</li> + <li>of navicular disease</li> + <li>of pumiced foot</li> + <li>of punctured foot</li> + <li>of pyramidal disease</li> + <li>of quittor</li> + <li>of ringed hoof</li> + <li>of sand-crack</li> + <li>of seedy-toe</li> + <li>of side-bone</li> + <li>of simple chronic coronitis</li> + <li>of specific coronitis</li> + <li>of spongy hoof</li> + <li>of sub-horny quittor</li> + <li>of thrush</li> + <li>of weak heels</li> + </ul> + </li> + <li>Development of the hoof</li> + <li> + Diagnosis + <ul> + <li>of acute laminitis</li> + <li>of canker</li> + <li>of foot lameness by injections of cocaine</li> + <li>of navicular disease</li> + <li>of punctured foot</li> + <li>of pyramidal disease</li> + <li>of side-bone</li> + <li>of sub-horny quittor</li> + </ul> + </li> + <li> + Differential diagnosis in canker + <ul> + <li>in navicular disease</li> + </ul> + </li> + <li>Diseases arising from faulty conformation</li> + <li> + Dislocation of the os coronæ + <ul> + <li>recorded case of</li> + </ul> + </li> + <li>Dislocations</li> + <li>Dry corn<br /> + <br /> + </li> + <li>Einsiedel's expansion shoe</li> + <li>Examining the foot method of</li> + <li>Exercise, forced, in the treatment of laminitis</li> + <li> + Expansion and contraction + <ul> + <li>of the coronary edge of the wall</li> + <li>of the hoof under the body-weight</li> + <li>of the solar edge of the wall</li> + <li>of the sole</li> + </ul> + </li> + <li> + Expansion shoe Broué's + <ul> + <li>De Fay's</li> + <li>Einsiedel's</li> + <li>Hartmann's</li> + <li>Smith's</li> + </ul> + </li> + <li>Expansion shoes in the treatment of contraction</li> + <li>Extensor pedis tendon, the</li> + <li> + Extirpation + <ul> + <li>of the lateral cartilage in quittor</li> + <li>of the lateral cartilage, after Moller and Frick</li> + <li>of the lateral cartilage, after Bayer</li> + </ul> + </li> + <li>Exudation in laminitis<br /> + <br /> + </li> + <li> + False quarter + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Faulty conformation + <ul> + <li>diseases arising from</li> + </ul> + </li> + <li>Feeding a cause of laminitis</li> + <li> + Flat-foot + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Flexor pedis perforans tendon, the</li> + <li>Flexor pedis perforatus tendon, the</li> + <li>Foot, buttress</li> + <li>Foot, changes in the internal structures in contraction of the</li> + <li> + Foot, contracted + <ul> + <li>causes of</li> + <li>definition of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Forced exercise in laminitis</li> + <li>Fractures</li> + <li> + Fractures of the bones after neurectomy + <ul> + <li>of the navicular bone</li> + <li>of the os coronæ</li> + <li>of the os pedis</li> + </ul> + </li> + <li>Frog, the</li> + <li>Functions of the lateral cartilages<br /> + <br /> + </li> + <li>Gangrene of the sensitive structures in laminitis</li> + <li>Gathered nail</li> + <li>Gelatinous degeneration after neurectomy</li> + <li> + Grooving the wall + <ul> + <li>in laminitis (Smith's operation)</li> + <li>in treatment of sand-crack</li> + <li>in treatment of side-bone (Smith's operation)</li> + </ul> + </li> + <li>Gross's treatment of chronic laminitis</li> + <li>Growth of hoof, rate of</li> + <li>Gunther's treatment of chronic laminitis<br /> + <br /> + </li> + <li>Hartmann's expansion shoe</li> + <li> + Heels, weak + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Heredity + <ul> + <li>as a cause of navicular disease</li> + <li>as a cause of side-bone</li> + </ul> + </li> + <li>Histology of horn</li> + <li> + History + <ul> + <li>of canker</li> + <li>of navicular disease</li> + <li>of neurectomy</li> + </ul> + </li> + <li>Hind-feet, navicular disease in the</li> + <li>Hind-limb with the side-line, method of securing</li> + <li>Hoffmann's treatment of canker</li> + <li> + Hoof, the + <ul> + <li>accidental tearing off of</li> + <li>expansion and contraction of</li> + <li>development of</li> + <li>rate of growth of</li> + </ul> + </li> + <li> + Horn + <ul> + <li>chemical properties of</li> + <li>histology of</li> + </ul> + </li> + <li>Hutlederkitt<br /> + <br /> + </li> + <li> + Imminger's treatment + <ul> + <li>for chronic laminitis</li> + <li>for canker</li> + </ul> + </li> + <li>Immobilizing a sand-crack by grooving the wall, methods of</li> + <li>Infection of the limb, septic</li> + <li>Injections of cocaine as an aid to diagnosis in foot lameness</li> + <li> + Interphalangeal articulation + <ul> + <li>the first</li> + <li>the second</li> + </ul> + </li> + <li> + Instruments + <ul> + <li>required in plantar neurectomy</li> + <li>in operations on the foot</li> + </ul> + </li> + <li>Irregular blood-supply to the bone as a cause of navicular disease<br /> + <br /> + </li> + <li>Joly's treatment of chronic laminitis<br /> + <br /> + </li> + <li>Koster's sand-crack clamp</li> + <li> + Keraphyllocele + <ul> + <li>causes of</li> + <li>definition of</li> + <li>pathological anatomy of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Keratoma<br /> + <br /> + </li> + <li>Lameness, cocaine injections as an aid to diagnosis in</li> + <li>Laminæ, the sensitive</li> + <li> + Laminitis + <ul> + <li>acute</li> + <li>Broad's treatment of</li> + <li>causes of</li> + <li>complications in</li> + <li>congestion in</li> + <li>course of</li> + <li>definition of</li> + <li>diagnosis in</li> + <li>exudation in</li> + <li>feeding, a cause of</li> + <li>forced exercise in the treatment of</li> + <li>gangrene of the sensitive structures in</li> + <li>grooving the wall in the treatment of</li> + <li>local applications in the treatment of</li> + <li>local bleeding in the treatment of</li> + <li>metastatic colic in</li> + <li>metastatic pneumonia in</li> + <li>neurectomy in</li> + <li>opening the sole in the treatment of</li> + <li>parturient</li> + <li>pathological anatomy of</li> + <li>periostitis and ostitis in</li> + <li>phlebotomy in the treatment of</li> + <li>prognosis in</li> + <li>rocker bar shoes in the treatment of</li> + <li>Smith's operation in</li> + <li>suppuration in</li> + <li>symptoms of</li> + <li>symptoms of, in the four feet</li> + <li>symptoms of, in the fore-feet alone</li> + <li>symptoms of, in the hind-feet alone</li> + <li>treatment of</li> + </ul> + </li> + <li> + Laminitis + <ul> + <li>chronic</li> + <li>Bayer's treatment of</li> + <li>causes of</li> + <li>definition of</li> + <li>Gross's treatment of</li> + <li>Gunther's treatment of</li> + <li>Imminger's treatment of</li> + <li>Joly's treatment of</li> + <li>Meyer's treatment of</li> + <li>pathological anatomy of</li> + <li>surgical shoeing for</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Laminitis, parturient</li> + <li> + Lateral cartilage, the + <ul> + <li>extirpation of, in quittor, after Holier and Frick</li> + <li>extirpation of, in quittor, after Bayer</li> + <li>functions of</li> + <li>necrosed, pathological anatomy of</li> + <li>necrosis of</li> + <li>ossification of</li> + <li>wounds of</li> + </ul> + </li> + <li>Leg, chronic oedema of the, after neurectomy</li> + <li>Length of rest required after neurectomy</li> + <li>Ligaments, the</li> + <li>Ligaturing the digital arteries, in chronic laminitis</li> + <li>Limb, septic infection of</li> + <li>Local applications in laminitis</li> + <li>Local bleeding in laminitis</li> + <li>Local or coronary contraction of the foot</li> + <li>Low ringbone<br /> + <br /> + </li> + <li>Malcolm's treatment of canker</li> + <li>McGill's sand-crack clamp</li> + <li>Median neurectomy</li> + <li>Metal plates in the treatment of sand-crack</li> + <li>Metastatic colic in laminitis</li> + <li>Metastatic pneumonia in laminitis</li> + <li> + Methods of applying poultices + <ul> + <li>of examining the foot</li> + <li>of immobilizing sand-crack by grooving the wall</li> + </ul> + </li> + <li> + Methods of restraint + <ul> + <li>of securing a hind-limb with the side-line</li> + <li>of securing the foot to the cannon of another limb</li> + </ul> + </li> + <li>Meyer's treatment of chronic laminitis</li> + <li>Moist corn<br /> + <br /> + </li> + <li> + Nail-bound + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Nail-tread</li> + <li> + Navicular bone, the + <ul> + <li>fracture of</li> + </ul> + </li> + <li>Navicular bursa, puncture of the, in pricked foot</li> + <li>Navicular bursa punctured, treatment of</li> + <li> + Navicular disease + <ul> + <li>causes of</li> + <li>changes in the bone in</li> + <li>changes in the bursa in</li> + <li>changes in the cartilage in</li> + <li>changes in the tendon in</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>differential diagnosis of</li> + <li>history of</li> + <li>in the hind-feet</li> + <li>point of commencement of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Necrosed lateral cartilage + <ul> + <li>pathological anatomy of</li> + </ul> + </li> + <li> + Necrosis of bone + <ul> + <li>of tendon and ligament in sub-horny quittor</li> + <li>of the lateral cartilage (cartilaginous quittor)</li> + </ul> + </li> + <li>Necrotic plantar aponeurosis, treatment of</li> + <li>Nerve, reunion of, after neurectomy</li> + <li>Nerves, the</li> + <li> + Neurectomy + <ul> + <li>advantages of</li> + <li>amputational neuroma in</li> + <li>fracture of the bones after</li> + <li>gelatinous degeneration after</li> + <li>history of</li> + <li>instruments required in</li> + <li>in laminitis</li> + <li>length of rest required after</li> + <li>persistent pruritus after</li> + <li>pricked foot after</li> + <li>reunion of divided nerve after</li> + <li>sequelæ of</li> + <li>stumbling after</li> + <li>use of the horse after</li> + </ul> + </li> + <li> + Neurectomy + <ul> + <li>median</li> + <li>plantar</li> + </ul> + </li> + <li>Neuroma, amputational, after neurectomy<br /> + <br /> + </li> + <li>Oedema of the leg after neurectomy</li> + <li>Opening the sole in the treatment of laminitis</li> + <li> + Operation for complicated sand-crack + <ul> + <li>for laminitis</li> + <li>for necrosed lateral cartilage in quittor</li> + <li>for necrosed plantar aponeurosis</li> + <li>for side-bone</li> + </ul> + </li> + <li>Operations on the foot, instruments required in</li> + <li>Operations on the horn, treatment of contracted foot by</li> + <li> + Os coronæ, the + <ul> + <li>dislocation of</li> + <li>fracture of</li> + </ul> + </li> + <li> + Os pedis, the + <ul> + <li>caries of, in pricked foot</li> + <li>fracture of</li> + </ul> + </li> + <li>Osteoplastic ostitis</li> + <li>Osteoplastic periostitis</li> + <li>Ostitis in laminitis</li> + <li> + Ostitis + <ul> + <li>rarefying</li> + <li>osteoplastic</li> + </ul> + </li> + <li>Ossification of the lateral cartilages (side-bone)</li> + <li> + Overreach + <ul> + <li>shoeing for</li> + <li>treatment of</li> + </ul> + <br /> + </li> + <li>Parturient laminitis</li> + <li> + Pathological anatomy of acute laminitis + <ul> + <li>of canker</li> + <li>of chronic laminitis</li> + <li>of corn</li> + <li>of keraphyllocele</li> + <li>of necrosed lateral cartilage</li> + <li>of pyramidal disease</li> + <li>of simple cutaneous quittor</li> + <li>of navicular disease</li> + </ul> + </li> + <li>Pedal articulation, puncture of the</li> + <li>Perforans tendon, the flexor pedis</li> + <li>Perforates tendon, the flexor pedis</li> + <li>Periople, the</li> + <li>Periostitis and ostitis in laminitis</li> + <li>Periostitis, osteoplastic</li> + <li>Periostitis, recorded cases of</li> + <li> + Periostitis, + <ul> + <li>simple acute</li> + <li>suppurative</li> + </ul> + </li> + <li>Periostitis, treatment of</li> + <li>Persistent pruritus after neurectomy</li> + <li>Phlebotomy in laminitis</li> + <li> + Plantar aponeurosis, + <ul> + <li>wounds of the</li> + <li>treatment of necrosed</li> + </ul> + </li> + <li>Plantar cushion</li> + <li> + Plantar neurectomy + <ul> + <li>history of</li> + <li>instruments required in</li> + <li>operation of</li> + </ul> + </li> + <li> + Pneumonia in laminitis + <ul> + <li>metastatic</li> + </ul> + </li> + <li>Point of commencement of navicular disease</li> + <li>Poultices, methods of applying</li> + <li>Preventive treatment of cutaneous quittor</li> + <li> + Pricked foot + <ul> + <li>after neurectomy</li> + <li>complications of</li> + </ul> + </li> + <li> + Prognosis + <ul> + <li>in acute simple coronitis</li> + <li>in canker</li> + <li>in contracted foot</li> + <li>in corn</li> + <li>in laminitis</li> + <li>in navicular disease</li> + <li>in punctured foot</li> + <li>in sand-crack</li> + <li>in simple cutaneous quittor</li> + </ul> + </li> + <li>Properties of horn, chemical</li> + <li>Protection of sand-crack by metal plates</li> + <li>Pruritus after neurectomy</li> + <li> + Pumiced foot + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Punctured foot + <ul> + <li>causes of</li> + <li>classification of</li> + <li>common situation of the wound in</li> + <li>complications in</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Puncture of the navicular bursa + <ul> + <li>treatment of</li> + </ul> + </li> + <li>Puncture of the pedal articulation</li> + <li>Purulent synovitis</li> + <li>Pyramidal disease<br /> + <br /> + </li> + <li> + Quittor + <ul> + <li>classification of</li> + <li>definition of</li> + </ul> + </li> + <li> + Quittor, simple or cutaneous + <ul> + <li>causes of</li> + <li>complications in</li> + <li>curative treatment of</li> + <li>definition of</li> + <li>pathological anatomy of</li> + <li>preventive treatment of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Quittor, sub-horny + <ul> + <li>causes of</li> + <li>complications in</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>extirpation of the lateral cartilage in, after Moller and Frick</li> + <li>extirpation of the lateral cartilage in, after Bayer</li> + <li>necrosis of the lateral cartilage in (cartilaginous quittor)</li> + <li>necrosis <i>of</i> tendon and ligament in (tendinous quittor)</li> + <li>surgical shoeing in</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + <br /> + </li> + <li>Rarefying ostitis</li> + <li> + Recorded case of dislocation + <ul> + <li>of the os coronæ</li> + <li>of navicular disease in both hind-feet</li> + <li>of periostitis</li> + <li>of pyramidal disease</li> + </ul> + </li> + <li>Rest required after neurectomy, length of</li> + <li>Restraint, methods of</li> + <li>Reunion of the divided nerve after neurectomy</li> + <li>Ringbone, low</li> + <li> + Ringed hoof + <ul> + <li>causes of</li> + <li>definition of</li> + <li>treatment of</li> + </ul> + </li> + <li>Rocker bar shoes in laminitis</li> + <li>Rose's treatment of canker<br /> + <br /> + </li> + <li> + Sand-crack + <ul> + <li>causes of</li> + <li> + clamp + <ul> + <li>Koster's</li> + <li>McGill's</li> + <li>Vachette's</li> + </ul> + </li> + <li>clamping, methods of</li> + <li>classification of</li> + <li>complications in</li> + <li>definition of</li> + <li>operations for complicated</li> + <li>prognosis in</li> + <li>surgical shoeing for</li> + <li>symptoms of</li> + <li>treatment of</li> + <li>treatment of, by grooving the wall</li> + <li>treatment of, by wedging the fissure</li> + </ul> + </li> + <li>Second interphalangeal articulation, the</li> + <li>Securing a hind-limb with the side-line, method of</li> + <li>Securing the foot to the cannon of another limb, method of</li> + <li> + Seedy-toe + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Senile decay as a cause of navicular disease</li> + <li>Sensitive laminæ, the</li> + <li>Sensitive structures, gangrene of, in laminitis</li> + <li>Septic infection of the limb</li> + <li>Sequelæ of neurectomy</li> + <li>Serous arthritis</li> + <li> + Shoe, bar + <ul> + <li>Charlier's</li> + <li>Charlier's tip</li> + <li> + expansion + <ul> + <li>Broué's</li> + <li>De Fay's</li> + <li>Einsiedel's</li> + <li>Hartmann's</li> + <li>Smith's</li> + </ul> + </li> + <li>for overreach</li> + <li>plate</li> + <li>rocker bar</li> + <li>slipper, Broué's</li> + <li>slipper and bar-clip, Einsiedel's</li> + <li>three-quarter</li> + <li>three-quarter bar</li> + <li>thinned tip</li> + <li>tip</li> + <li>with 'dropped' heel</li> + <li>with extended toe-piece</li> + <li>with extended toe-piece (Nunn's)</li> + <li>with heel-clip</li> + <li>with 'set' heel</li> + </ul> + </li> + <li> + Side-bone + <ul> + <li>causes of</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>heredity a cause of</li> + <li>Smith's operation for</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Side-line, the</li> + <li>Simple acute coronitis</li> + <li>Simple acute periostitis</li> + <li> + Simple coronitis + <ul> + <li>acute</li> + <li>chronic</li> + </ul> + </li> + <li> + Simple or cutaneous quittor + <ul> + <li>causes of</li> + <li>complications in</li> + <li>curative treatment of</li> + <li>definition of</li> + <li>pathological anatomy of</li> + <li>preventive treatment of</li> + <li>prognosis of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Simple serous arthritis</li> + <li>Simple synovitis, acute</li> + <li> + Smith's expansion shoe + <ul> + <li>operation for laminitis</li> + <li>operation for side-bone</li> + </ul> + </li> + <li>Solar edge of the wall, expansion and contraction of the</li> + <li>Sole, chronic bruised</li> + <li>Sole, expansion and contraction of the</li> + <li>Sole, the</li> + <li> + Specific coronitis + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li> + Spongy hoof + <ul> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Stumbling after neurectomy</li> + <li> + Sub-horny quittor + <ul> + <li>causes of</li> + <li>complications in</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>necrosis of the lateral cartilage in (cartilaginous quittor)</li> + <li>necrosis of tendon and ligament in (tendinous quittor)</li> + <li>symptoms of</li> + <li>treatment of</li> + <li>surgical shoeing for</li> + </ul> + </li> + <li>Suppurating corn</li> + <li>Suppuration in laminitis</li> + <li> + Suppurative arthritis + <ul> + <li>causes of</li> + <li>definition of</li> + <li>diagnosis of</li> + <li>pathology of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Suppurative periostitis</li> + <li>Suppurative synovitis</li> + <li> + Surgical shoeing for corn + <ul> + <li>for chronic laminitis</li> + <li>for laminitis, acute</li> + <li>for sand-crack</li> + <li>for quittor</li> + </ul> + </li> + <li> + Symptoms + <ul> + <li>of acute simple coronitis</li> + <li>of brittle hoof</li> + <li>of canker</li> + <li>of chronic coronitis</li> + <li>of chronic laminitis</li> + <li>of club-foot</li> + <li>of contracted foot</li> + <li>of corn</li> + <li>of coronary contraction of the foot</li> + <li>of crooked foot</li> + <li>of false quarter</li> + <li>of flat-foot</li> + <li>of keraphyllocele</li> + <li>of laminitis</li> + <li>of laminitis in all four feet</li> + <li>of laminitis in the fore-feet alone</li> + <li>of laminitis in the hind-feet alone</li> + <li>of nail-bound</li> + <li>of navicular disease</li> + <li>of pumiced foot</li> + <li>of punctured foot</li> + <li>of pyramidal disease</li> + <li>of sand-crack</li> + <li>of seedy-toe</li> + <li>of side-bone</li> + <li>of simple chronic coronitis</li> + <li>of simple cutaneous quittor</li> + <li>of specific coronitis</li> + <li>of spongy hoof</li> + <li>of sub-horny quittor</li> + <li>of synovitis, chronic</li> + <li>of synovitis, purulent or suppurative</li> + <li>of synovitis, simple acute</li> + <li>of thrush</li> + <li>of weak heels</li> + </ul> + </li> + <li> + Synovitis, acute simple + <ul> + <li>causes of</li> + <li>treatment of</li> + </ul> + <br /> + <br /> + </li> + <li>Tearing off of the entire hoof, accidental</li> + <li> + Tendon + <ul> + <li>the extensor pedis</li> + <li>the flexor pedis perforans</li> + <li>the flexor pedis perforatus</li> + </ul> + </li> + <li>Tendons, the</li> + <li> + Thrush + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Tight-nailing</li> + <li>Tip-shoes</li> + <li>Tissue, the velvety</li> + <li>Tread, See Overreach</li> + <li> + Treatment + <ul> + <li>of acute laminitis</li> + <li>of acute simple coronitis</li> + <li>of brittle hoof</li> + <li>of canker</li> + <li> + of canker + <ul> + <li>Bermbach's</li> + <li>Hoffmann's</li> + <li>Imminger's</li> + <li>Malcolm's</li> + <li>Rose's</li> + </ul> + </li> + <li>of chronic bruised sole</li> + <li>of chronic coronitis</li> + <li>of chronic laminitis</li> + <li>of chronic laminitis by ligaturing the digital arteries</li> + <li>of club-foot</li> + <li>of contracted feet</li> + <li>of contracted feet by expansion shoes</li> + <li>of contracted feet by operations on the horn</li> + <li>of corns</li> + <li>of coronary contraction of the foot</li> + <li>of crooked foot</li> + <li>of curved hoof</li> + <li>of cutaneous quittor</li> + <li>of false quarter</li> + <li>of keraphyllocele</li> + <li>of nail-bound</li> + <li>of navicular disease</li> + <li>of necrotic plantar aponeurosis</li> + <li>of periostitis</li> + <li>of pumiced foot</li> + <li>of punctured foot</li> + <li>of punctured navicular bursa</li> + <li>of pyramidal disease</li> + <li>of ringed hoof</li> + <li>of sand-crack</li> + <li>of sand-crack by clamping the fissure</li> + <li>of sand-crack by grooving the wall</li> + <li>of sand-crack by wedging the fissure</li> + <li>of seedy-toe</li> + <li>of side-bone</li> + <li>of simple chronic coronitis</li> + <li>of specific coronitis</li> + <li>of spongy hoof</li> + <li>of sub-horny quittor</li> + <li>of synovitis</li> + <li>of thrush</li> + <li>of weak heels</li> + </ul> + <br /> + <br /> + </li> + <li>Use of the horse that has undergone neurectomy></li> + <li>Vachette's sand-crack clamp</li> + <li>Veins, the</li> + <li>Velvety tissue, the</li> + <li>Villate's caustic solution<br /> + <br /> + </li> + <li>Wall, the</li> + <li> + Weak heels + <ul> + <li>causes of</li> + <li>definition of</li> + <li>symptoms of</li> + <li>treatment of</li> + </ul> + </li> + <li>Wedging the fissure in the treatment of sand-crack</li> + <li>Wound in punctured foot, common situations of the</li> + <li>Wounds of the lateral cartilages</li> + <li>Wounds of the plantar aponeurosis</li> + </ul> + <h3>THE END</h3> + + + + + + + +<pre> + + + + + +End of the Project Gutenberg EBook of Diseases of the Horse's Foot +by Harry Caulton Reeks + +*** END OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + +***** 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You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Diseases of the Horse's Foot + +Author: Harry Caulton Reeks + +Release Date: February 21, 2004 [EBook #11204] + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + + + + +Produced by Juliet Sutherland, Leonard D Johnson and the Online +Distributed Proofreading Team. + + + + + +DISEASES OF THE HORSE'S FOOT + +By +H. CAULTON REEKS + +Fellow of the Royal College of Veterinary Surgeons +Author of 'The Common Colics of the Horse' + + + +1906 + + +To +J. MacQueen, F.R.C.V.S., + +Professor of Surgery at the Royal Veterinary College, London, as a slight +acknowledgment of his ability as a teacher, and in return for many kindly +services, this volume is gratefully inscribed by + +THE AUTHOR. + + +PREFACE + + +Stimulated by the reception accorded my 'Common Colics of the Horse,' both +in this country and in America, and assured by my publishers that a work on +diseases of the foot was needed, I have been led to give to the veterinary +profession the present volume. + +While keeping the size of the book within reasonable limits, no effort +has been spared to render it as complete as possible. This has only been +achieved by adding to my own experience a great deal of the work of others. +To mention individually those who have given me permission to use their +writings would be too long a matter here. In every case, however, where the +quotation is of any length, the source of my information is given, either +in the text or in an accompanying footnote. A few there are who will, +perhaps, find themselves quoted without my having first obtained their +permission to do so. They, with the others, will, I am sure, accept my +hearty thanks. + +The publishers have been generous in the matter of illustrations and +diagrams, and although to the older practitioner some of these may appear +superfluous, it is hoped they will serve to render the work an acceptable +textbook for the student. + +H. CAULTON REEKS. + +SPALDING, _January, 1906_. + + +CONTENTS + + +CHAPTER I + +INTRODUCTION + + +CHAPTER II + +REGIONAL ANATOMY + +A. The Bones +B. The Ligaments +C. The Tendons +D. The Arteries +E. The Veins +F. The Nerves +G. The Complementary Apparatus of the Os Pedis +H. The Keratogenous Membrane +I. The Hoof + + +CHAPTER III + +GENERAL PHYSIOLOGICAL AND ANATOMICAL OBSERVATIONS + +A. Development of the Hoof +B. Chemical Properties and Histology of Horn +C. Expansion and Contraction of the Hoof +D. The Functions of the Lateral Cartilages +E. Growth of the Hoof + + +CHAPTER IV + +METHOD OF EXAMINING THE FOOT + + +CHAPTER V + +GENERAL REMARKS ON OPERATIONS ON THE FOOT + +A. Methods of Restraint +B. Instruments required +C. The Application of Dressings +D. Plantar Neurectomy + History of the Operation + Preparation of the Subject + The Operation + After-treatment +E. Median Neurectomy +F. Length of Rest after Neurectomy +G. Sequelae of Neurectomy + Liability of Pricked Foot going undetected + Loss of Tone in the Non-sensitive Area + Gelatinous Degeneration + Chronic Oedema of the Leg + Persistent Pruritus + Fracture of the Bones + Neuroma + Reunion of the Divided Nerve + The Existence of an Adventitious Nerve-supply + Stumbling +H. Advantages of the Operation +I. The Use of the Horse that has undergone Neurectomy + + +CHAPTER VI + +FAULTY CONFORMATION + +A. Weak Heels +B. Contracted Foot + (_a_) Contracted Heels + (_b_) Local or Coronary Contraction +C. Flat-foot +D. Pumiced-foot, Dropped Sole, or Convex Sole +E. 'Ringed' or 'Ribbed' Hoof +F. The Hoof with Bad Horn + (_a_) The Brittle Hoof + (_b_) The Spongy Hoof +G. Club-Foot +H. The Crooked Foot + (_a_) The Foot with Unequal Sides + (_b_) The Curved Hoof + + +CHAPTER VII + +DISEASES ARISING FROM FAULTY CONFORMATION + +A. Sand-crack + Definition + Classification + Causes + Complications + Treatment + Surgical Shoeing for Sand-crack + +B. Corns + Definition + Classification + Causes + Pathological Anatomy and Histology + Treatment + Surgical Shoeing for Corn + +C. Chronic Bruised Sole + + +CHAPTER VIII + +WOUNDS OF THE KERATOGENOUS MEMBRANE + +A. Nail-bound + Definition + Causes + Symptoms + Treatment + +B. Punctured Foot + Definition + Causes + Common Situations of the Wound + Classification + Symptoms and Diagnosis + Complications + Prognosis + Treatment + +C. Coronitis (Simple) + + 1. Acute + Definition + Causes + Symptoms + Complications + Prognosis + Treatment + + 2. Chronic + Definition + Causes + Symptoms + Treatment + +D. False Quarter + Definition + Causes + Treatment + +E. Accidental Tearing off of the Entire Hoof + + +CHAPTER IX + +INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS + +A. ACUTE + Acute Laminitis + Definition + Causes + Symptoms + Pathological Anatomy + Complications + Diagnosis and Prognosis + Treatment + Broad's Treatment for Laminitis + Smith's Operation for Laminitis + +B. CHRONIC + + 1. Chronic Laminitis + Definition + Causes + Symptoms + Pathological Anatomy + Treatment + + 2. Seedy-Toe + Definition + Causes + Symptoms + Treatment + + 3. Keraphyllocele + Definition + Causes + Symptoms + Treatment + + 4. Keratoma + + 5. Thrush + Definition + Causes + Symptoms + Treatment + + 6. Canker + Definition + Causes, Predisposing and Exciting + Symptoms and Pathological Anatomy + Differential Diagnosis and Prognosis + Treatment + Malcolm's, Lieutenant Rose's, Bermbach's, Hoffmann's + and Imminger's Treatment for Canker + + 7. Specific Coronitis + Definition + Causes + Symptoms + Treatment + + +CHAPTER X + +DISEASES OF THE LATERAL CARTILAGES + +A. Wounds of the Cartilages + +B. Quittor + Definition + Classification + + 1. Simple or Cutaneous Quittor + Definition + Causes + Symptoms + Pathological Anatomy + Prognosis + Complications + Treatment, Preventive and Curative + + 2. Sub-horny Quittor + Definition + Causes + Symptoms and Diagnosis + Complications + Necrosis of the Lateral Cartilage + Pathological Anatomy of the Diseased Cartilage + Necrosis of Tendon and of Ligament + Ossification of the Cartilage + Treatment + Operations for Extirpation of the Cartilage + +C. Ossification of the Lateral Cartilages (Side-bones) + Definition + Symptoms and Diagnosis + Causes + Treatment + Smith's Operation for Ossification of the Lateral Cartilages + + +CHAPTER XI + +DISEASES OF THE BONES + +A. Periostitis and Ostitis + 1. Periostitis + (_a_) Simple Acute Periostitis + (_b_) Suppurative Periostitis + (_c_) Osteoplastic Periostitis + + 2. Ostitis + (_a_) Rarefying Ostitis + (_b_) Osteoplastic Ostitis + (_c_) Caries and Necrosis + +Treatment of Periostitis + +Recorded Cases of Periostitis + +B. Pyramidal Disease, Buttress Foot, or Low Ringbone + Definition + Symptoms and Diagnosis + Pathological Anatomy + Treatment + Recorded Cases of Buttress Foot + +C. Fractures of the Bones + 1. Fractures of the Os Coronae + Recorded Cases of Fractures of the Os Coronae + + 2. Fractures of the Os Pedis + Recorded Cases of Fractures of the Os Pedis + + 3. Fractures of the Navicular Bone + Recorded Case of Fracture of the Navicular Bone + + Treatment of Fractures of the Bones of the Foot + + +CHAPTER XII + +DISEASES OF THE JOINTS + +A. Synovitis + (_a_) Simple + (1) Acute + (2) Chronic + (_b_) Purulent or Suppurative +B. Arthritis + (_a_) Simple or Serous + (_b_) Acute + (_c_) Purulent or Suppurative + (_d_) Anchylosis + +C. Navicular Disease + Definition + History + Pathology + Changes in the Bursa + Changes in the Cartilage + Changes in the Tendon + Changes in the Bone + Causes + Heredity + Compression + Concussion + A Weak Navicular Bone + An Irregular Blood-supply to the Bone + Senile Decay + Symptoms and Diagnosis + Differential Diagnosis + Prognosis + Treatment + +D. Dislocations + +LIST OF ILLUSTRATIONS + +1. The Bones of the Phalanx +2. The Os Coronae (Anterior View) +3. The Os Coronae (Posterior View) +4. The Os Pedis (Postero-lateral View) +5. The Os Pedis (viewed from Below) +6. The Navicular Bone (viewed from Below) +7. The Navicular Bone (viewed from Above) +8. Ligaments of the First and Second Interphalangeal Articulations + (Lateral View). (_After Dollar and Wheatley_) +9. Ligaments of the First and Second Interphalangeal Articulations + (viewed from Behind). (_After Dollar and Wheatley_) +10. The Flexor Tendons and the Extensor Pedis. (_After + Hauebner_) +11. The Flexor Perforans and Perforatus +12. The Flexor Perforans and Perforatus (the Perforans cut through and + deflected) +13. Median Section of Normal Foot +14. The Arteries of the Foot +15. The Veins and Nerves of the Foot +16. The Lateral Cartilage +17. The Keratogenous Membrane (viewed from the Side) +18. The Keratogenous Membrane (viewed from Below) +19. The Wall of the Hoof +20. Internal Features of the Hoof +21. Inferior Aspect of the Hoof +22. Hoof with the Sensitive Structures removed +23. Section of Epidermis +24. Section of Skin with Hair Follicle and Hair +25. Section of Human Nail and Nail-bed +26. Section of Foot of Equine Foetus. (_Mettam_) +27. Section from Foot of Sheep Embryo. (_Mettam_) +28. Section from Foot of Calf Embryo. (_Mettam_) +29. Section from Foot of Equine Foetus. (_Mettam_) +30. Section through Hoof and Soft Tissues of a Foal at Term. (_Mettam_) +31. Perpendicular Section of Horn of Wall +32. Horizontal Section of Horn of Wall +33. Horizontal Section through the Junction of the Wall with the Sole +34. Section of Frog. (_Mettam_) +35. Professor Lungwitz's Apparatus for Examining the Foot Movements +36. Professor Lungwitz's Apparatus for Examining the Foot Movements +37. The Movements of the Solar and Coronary Edges of the Hoof illustrated. + (_Lungwitz_) +38. The Blind +39. The Side-line +40. Method of securing the Hind-foot with the Side-line +41. The Hind-foot secured with the Side-line +42. The Casting Hobbles +43. Method of securing the Hind-leg upon the Fore +44. The Hind-leg secured upon the Fore +45. The Drawing-knife (Ordinary Pattern) +46. Modern Forms of Drawing-knives +47. Symes's Knife +48-51. Illustrating Colonel Nunn's Method of applying a Poultice to the + Foot +52. Poultice-boot of Canvas and Steel +53. Poultice-boot of Cocoa-fibre +54. Foot-swab +55. The Shoe with Plates +56. Quittor Syringe +57. The Esmarch Bandage and Tourniquet +58. Tourniquet with Wooden Block +59. Neurectomy Bistoury +60. Neurectomy Needle +61. Double Neurectomy Tenaculum +62. Adventitious Nerve-supply to Foot. (_Sessions_) +63. Tip Shoe +64. The Tip Shoe 'let in' to the Foot +65. The Thinned Tip +66. Drawing-knife for Charlier Shoeing +67. The Foot prepared for the Charlier Shoe +68. Bar Shoe +69. Rubber Bar Pad on Leather +70. The Bar Pad applied with a Half-shoe +71. Frog Pad +72. Frog Pad applied +73. Smith's Expansion Shoe for Contracted Feet +74. A Contracted Foot treated with Smith's Shoe +75. De Fay's Vice +76. Hartmann's Expanding Shoe +77. Broue's Slipper Shoe. (_Gutenacker_) +78. Einsiedel's Slipper and Bar-clip Shoe. (_Gutenacker_) +79. Hoof showing Coronary Contraction. (_Gutenacker_) +80. Flat-foot (Solar Surface). (_Gutenacker_) +81. Hoof showing Laminitis Rings on the Wall. _(Gutenacker)_ +82. Hoof showing 'Grass' Rings on the Wall. (_Gutenacker_) +83. Club-foot. (_Gutenacker_) +84. Shoe with extended Toe-piece. (_Gutenacker_) +85. A Crooked Foot in Cross-section. (_Gutenacker_) +86. Sand-crack Firing-iron +87. Sand-crack Forceps and Clamp. (_Vachette's_) +88. McGill's Sand-crack Clamp +89. Koster's Sand-crack Clamp +90. Sand-crack Belt +91. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +92. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +93. Method of 'Easing' the Bearing of the Wall on the Shoe in the Treatment + of Sand-crack +94 96. Grooving the Wall in the Treatment of Sand-crack +97. Removing the Wall in the Treatment of Sand-crack +98. Removing the Wall in the Treatment of Sand-crack +99. Horizontal Section of Corn. (_Gutenacker_) +100. Inner Surface of the Wall, showing Changes in Chronic Corn. + (_Gutenacker_) +101. Perpendicular Section of the Wall in a Case of Chronic Corn. + (_Gutenacker_) +102. Three-quarter Shoe +103. Three-quarter Bar Shoe +104. Shoe with a 'Dropped' Heel +105. Shoe with a 'Set' Heel +106. Curette, or Volkmann's Spoon +107. Resection of the Terminal Portion of the Perforans Tendon + (_Gutenacker_) +108. Shoe with extended Toe-piece. (_Colonel Nunn_) +109. Mesian Section of Foot with Lesions following Coronitis. + (_Gutenacker_) +110. Toe of Ordinary Hind-shoe +111. Toe of Hind-shoe Bevelled for the Prevention of Overreach +112. Hoof showing Lesion in the Wall following Coronitis. + (_Gutenacker_) +113. Foot with Lesions of Chronic Coronitis. (_Gutenacker_) +114. Hoof Accidentally Tom from Foot. (_Cartledge_) +115. Hoof Accidentally Tom from Foot. (_Rogerson_) +116. Section of Foot with Laminitis of Eight Days' Duration. +(_Gutenacker_) +117. Section of Foot with Laminitis of Fourteen Days' Duration. + (_Gutenacker_) +118. Chronic Ostitis of the Os Pedis in Laminitis. +119. Broad's Rocker Bar Shoe for Laminitis. +120. The Foot showing Grooves made in the Wall for Treatment of Laminitis + (Anterior Surface). +121. The Foot showing Grooves made for the Treatment of Laminitis (Solar + Surface). +122. Foot with Chronic Laminitis. (_Gutenacker_) +123. Inferior Aspect of Foot with Chronic Laminitis. (_Gutenacker_) +124. Section of Foot with Laminitis of Three Weeks' Duration. + (_Gutenacker_) +125. Section of Foot with Laminitis of Several Years' Duration. + (_Gutenacker_) +126. Diagram showing Position of the Abnormal Growth of Horn in Chronic + Laminitis. +127. Diagram showing the same Abnormal Growth of Horn Removed prior to + Shoeing. +128. Shoe with Heel-clip. +129. Internal Seedy-Toe. +130. External Seedy-Toe. (_Colonel Nunn_) +131. External Seedy-Toe. (_Colonel Nunn_) +132. A Keraphyllocele on the Inner Surface of the Horn of the Wall at the +Toe. (_Gutenacker_) +133. Os Pedis showing Absorption of Bone caused by the Pressure of a + Keraphyllocele. (_Gutenacker_) +134. Foot with Canker of the Frog and Heels. (_Gutenacker_) +135. Foot with Canker extending to the Wall. (_Malcolm_) +136. Foot with Advanced Canker. (_Gutenacker_) +137. Feet affected with Specific Coronitis. (_Taylor_) +138. Fore-foot with Specific Coronitis. (_Taylor_) +139. Excision of the Lateral Cartilage (Old Method). (_Gutenacker_) +140. Excision of the Lateral Cartilage. (_After Moller and Frick_). + (_Gutenacker_) +141. Excision of the Lateral Cartilage. (_After Bayer_.) + (_Gutenacker_) +142. Partial Excision of the Lateral Cartilage +143. Ossified Lateral Cartilages, or Side-bones. +144. Smith's Side-bone Saw (Old Pattern). +145. Smith's Side-bone Saw (Improved Pattern). +146. Smith's Hoof Plane. +147. Hodder's Hoof Chisel. +148. Foot showing the Grooves made in Smith's Operation for Side-bones + (viewed from the Side). +149. Foot showing the Grooves made in Smith's Operation for Side-bones + (viewed from Below). +150. Periostitis involving the Pedal and Navicular Bones. (_Litt_) +151. Periostitis involving the Pedal and Navicular Bones. (_Litt_) +152. Effects of Periostitis on the Os Pedis. (_Smith_) +153. Effects of Periostitis on the Os Pedis. (_Smith_) +154. Effects of Periostitis on the Os Pedis. (_Jones_) +155. Effects of Periostitis on the Os Pedis. (_Jones_) +156. Case of Buttress Foot. (_Routledge_) +157. Foot showing Fracture of the Pyramidal Process in a Case of Buttress + Foot. (_Routledge_) +158. Fracture of the Os Coronae. (_Crawford_) +159. Fracture of the Os Coronae. (_Crawford_) +160. Fractured Os Pedis. (_Freeman_) +161. Navicular Bone showing Lesions of Navicular Disease. + (_Gutenacker_) +162. Foot with the Seat of Navicular Disease exposed (showing Lesions). + (_Gutenacker_) +163. Navicular Bone showing Lesions of Navicular Disease (a Case of + Long-standing). (_Gutenacker_) +164. Frog Seton Needle. +165. Diagram showing Course of the Needle in Setoning the Frog. + + + +DISEASES OF THE HORSE'S FOOT + + + +CHAPTER I + +INTRODUCTION + + +The importance of that branch of veterinary surgery dealing with diseases +of the horse's foot can hardly be overestimated. That the animal's +usefulness is dependent upon his possession of four good feet is a fact +that has long been recognised. Who, indeed, is there to be found entirely +unacquainted with one or other of such well-known aphorisms as: 'Whoever +hath charge of a horse's foot has the care of his whole body'; 'As well a +horse with no head as a horse with no foot'; or the perhaps better known, +and certainly more epigrammatic, 'No foot, no horse.' + +Without taking these sayings literally, it will be admitted by almost +everyone that they contain a vast amount of actual truth. This allowed, it +at once becomes clear that a ready understanding of the diseases to which +the foot is liable, the means of holding them in check, and the correct +methods of treating them should figure largely in the knowledge at the +command of the veterinary surgeon. + +In the very great majority of instances the horse's ability to perform +labour is the one thing that justifies his existence, and to that end the +presence of four good, sound feet is an almost indispensable qualification. +And yet how many circumstances do we see tending to militate against that +one essential. + +Even in colthood the foot, if neglected, may become a source of trouble. +Unless periodically examined and properly trimmed, its shape is liable to +serious alteration. From that in which it is best calculated to withstand +the effects of the wear it will be called upon to endure in after life, it +may become so changed for the worse as to seriously affect the animal's +value. + +In the matter of feeding, too, trouble is likely to ensue. Particularly is +this the case where the colt shows points of exceptional merit. He is 'got +up' for show, and the feet are likely to fall victims to the mismanagement +that frequent exhibition so often carries with it. An extra allowance of +peas, beans, wheat, or other equally injurious food is given. The result is +a severe attack of laminitis, and an otherwise valuable and promising colt +is permanently ruined. + +Exposed as it is, too, to injury, the foot of a young horse, even at grass, +is frequently the seat of injuries from picked up nails, stakes, or other +agents which, unless detected and carefully treated, may terminate in a +troublesome case of quittor and incurable lameness. + +With the passing of colthood, and the coming into effect of the evils of +further domestication, the troubles to which the foot is open become more +numerous. Foremost among them will come those having their starting-point +in errors of practice originating in the forge; for, in spite of attempts +at their education, smiths, as a class, are as yet grievously unversed in +even the elementary knowledge of the delicate construction of the member +that is entrusted to their care. + +This fact has been dilated on in books devoted to shoeing, and in the +prefatory note to the last edition of Fleming's manual on this subject we +find the following statement: 'The records of all humane societies show +that, of prosecutions for cruelty to animals, an overwhelming majority +refer to the horse; and of these, a large proportion are for working horses +while suffering from lameness in one form or other. + +'So frequent are such cases that observers have concluded that their +prevalence must result from some specific cause, and, not unnaturally, +attention has thus been directed to the various modes of management +practised in relation to the horse's foot, to the manner of shoeing, and, +in particular, to the way in which the foot is prepared for the shoe.' + +It must be remembered, however, that although harm in the forge may +frequently arise from culpable roughness or carelessness, such is not +necessarily always the case, and that quite as much injury may result from +careful and conscientious workmanship when it is unfortunate enough to be +based upon principles wrong in themselves to commence with. + +It so happens, too, that shoeing, in itself a necessary evil, may be +responsible for injuries in the causation of which the smith can have +played no part. Take, for example, the ill effects following upon the +animal's attendant allowing him to carry his shoes for too long a time. +In this case the natural growth of the horn carries the heel of the shoe +further beneath the foot than is safe for a correct bearing; in fact, +anterior to the point of inflection of the wall. The shoe, at the same +time, is greatly thinned from excessive wear. Result, a sharp and +easily-bended piece of iron situate immediately under the seat of corn. +Pressure or actual cutting of the sole is bound to occur, and the animal is +lamed. + +Again, apart from the question of negligence or otherwise on the part of +the smith or the animal's attendant, it must be remembered that the nailing +on to the foot of a plate of iron is not giving to the animal an easier +means of progression. The reverse is the case. In place of the sucker-like +face of the natural horn is substituted a smooth, and, with wear, +highly-polished surface. Slipping and sliding attempts to gain a foothold +become frequent, and strains of the tendons and ligaments follow in their +wake. + +As, however, this treatise is not intended to deal with the art of shoeing, +the reader must be referred to other works for further information. In +addition to Fleming's, there may be mentioned, among others, Hunting's 'Art +of Horse Shoeing,' and the very excellent volume of Messrs. Dollar and +Wheatley on the same subject. Leaving the forge, we may next look to the +nature of the animal's work, and the conditions under which he is kept, for +active causes in the production of disorders of the foot. From the yielding +softness of the pasture he is called to spend the bulk of his time upon the +hard macadamized tracks of our country roads, or the still more hard and +more dangerous asphalt pavings or granite sets of our towns. The former, +with the bruises they will give the sole and frog from loose and scattered +stones, and the latter, with the increased concussion they will entail on +the limb, are active factors in the troubles with which we are about to +deal. Upon these unyielding surfaces the horse is called to carry slowly or +rapidly, as the case may be, not only his own weight, but, in addition, is +asked to labour at the hauling of heavy loads. The effects of concussion +and heavy traction combined are bound primarily to find the feet, and such +diseases as side-bones, ringbones, corns, and sand-cracks commence to make +their appearance. + +Again, as opposed to the comparative healthiness of the surroundings when +at grass, consideration must be given to the chemical changes the foot is +frequently subjected to when the animal is housed. + +Only too often the bedding the animal has to stand upon for several hours +of the twenty-four can only be fitly described as 'filthy in the extreme.' +The ammoniacal exhalations from these collected body-discharges must, and +do, have a prejudicial effect upon the nature of the horn, and, though slow +in its progress, mischief is bound sooner or later to occur in the shape of +a weakened and discharging frog, with its concomitant of contracted heels. +Lucky it is in such a case if canker does not follow on. + +Observers, too, have chronicled the occurrence in horse's feet of disease +resulting from the use of moss litter. Tenderness in the foot is first +noticeable, which tenderness is afterwards followed by a peculiar softening +of the horn of the sole and the frog. What should be a dense, fairly +resilient substance is transformed into a material affording a yielding +sensation to the fingers not unlike that imparted by a soft indiarubber, +and as easily sliced as cheese-rind. + +Lastly, though the foot is extremely liable to suffer from the effects +of extreme dryness or excessive humidity, especially with regard to the +changes thus brought about in the nature of the horn, it is perforce +exposed at all times to the varying condition of the roads upon which it +must travel. The intense dryness of summer and the constant damp of winter, +each in their turn take part in the deteriorating influences at work upon +it. + +Though this subject might be indefinitely prolonged, this brief resume of +the adverse circumstances to which the foot of the horse is exposed +is sufficient to point out the extreme importance of its study to the +veterinary surgeon. So long as the horse is used as a beast of burden so +long will this branch of veterinary surgery offer a wide and remunerative +field of labour. + + + +CHAPTER II + +REGIONAL ANATOMY + + +Considered from a zoological standpoint, the foot of the horse will include +all those parts from the knee and hock downwards. For the purposes of this +treatise, however, the word foot will be used in its more popular sense, +and will refer solely to those portions of the digit contained within +the hoof. When, in this chapter on regional anatomy, or elsewhere, the +descriptive matter or the illustrations exceed that limit, it will be with +the object of observing the relationship between the parts we are concerned +with and adjoining structures. + +Taking the limit we have set, and enumerating the parts within the hoof +from within outwards, we find them as follows: + +A. THE BONES.--The lower portion of the second phalanx or os coronae; the +third phalanx, os pedis, or coffin bone; and the navicular or shuttle bone. + +B. THE LIGAMENTS.--The ligaments binding the articulation. + +C. THE TENDONS.--The terminal portions of the extensor pedis and the flexor +perforans. + +D. THE ARTERIES. + +E. THE VEINS. + +F. THE NERVES. + +G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS. + +H. THE KERATOGENOUS MEMBRANE. + +I. THE HOOF. + + +A. THE BONES. + +THE SECOND PHALANX, OS CORONAE, OR SMALL PASTERN BONE.--This belongs to +the class of small bones, in that it possesses no medullary canal. It is +situated obliquely in the digit, running from above downwards and from +behind to before, and articulating superiorly with the first phalanx or os +suffraginis, and inferiorly with the third phalanx and the navicular bone. + +[Illustration: FIG. 1.--THE BONES OF THE PHALANX. 1, The os suffraginis; 2, +the os coronae; 3, the os pedis; 4, the navicular bone, hidden by the wing +of the os pedis, is in articulation in the position indicated by the barbed +line.] + +[Illustration: FIG. 2.--SECOND PHALANX OR OS CORONAE (ANTERIOR VIEW). +1, Anterior surface; 2, superior articulatory surface; 3, inferior +articulatory surface; 4, pits for ligamentous attachment.] + +[Illustration: FIG. 3.--SECOND PHALANX OR OS CORONAE (POSTERIOR VIEW). 1, +Posterior surface; 2, gliding surface for passage of flexor perforans; 3, +lower articulatory surface.] + +Cubical in shape, it is flattened from before to behind, and may be +described as possessing six surfaces: _An anterior surface_, covered with +slight imprints; _a posterior surface_, provided above with a transversely +elongated gliding surface for the passage of the flexor perforans; _two +lateral surfaces_, each rough and perforated by foraminae, and each bearing +on its lower portion a thumb-like imprint for ligamentous attachment, and +for the insertion of the bifid extremity of the perforatus tendon; _a +superior surface_, bearing two shallow articular cavities, separated by an +antero-posterior ridge, for the accommodation of the lower articulating +surface of the first phalanx; _an inferior surface_, also articulatory, +which in shape is obverse to the superior, bearing two unequal condyles, +separated by an ill-defined antero-posterior groove, which surface +articulates with the os pedis and the navicular bone. + +_Development_.--The bone usually ossifies from one centre, but often there +is a complementary nucleus for the upper surface. + +THE THIRD PHALANX, OS PEDIS, OR COFFIN BONE.--This also belongs to the +class of short bones. It forms the termination of the digit, and, with the +navicular bone, is included entirely within the hoof. For our examination +it offers _three surfaces_, _two lateral angles_, and _three edges_. + +_The Anterior or Laminal Surface_, following closely in contour the wall of +the hoof, is markedly convex from side to side, nearly straight from above +to below, and closely dotted with foraminae of varying sizes. On each side +of this surface is to be seen a distinct groove, the _preplantar groove_, +or _preplantar fissure_, which, commencing behind, between the basilar and +retrossal processes, runs horizontally forwards from the angles or wings of +the bone, and terminates anteriorly in one of the larger foraminae. As the +name 'laminal' indicates, it is this surface which in the fresh state is +covered by the sensitive laminae. + +_The Inferior or Plantar Surface_, hollowed in the form of a low arch, +presents for our inspection two regions, an anterior and a posterior, +divided by a well-marked line, the _Semilunar Crest_, which extends forward +in the shape of a semicircle. The anterior region, as is the laminal +surface, is covered with foraminae; in this case more minute. In the recent +state it is covered by the sensitive sole. The posterior region, lying +immediately behind the semilunar crest, shows on each side of a median +process a large foramen, the _Plantar Foramen_. From this foramen runs the +_Plantar Groove_, a channel, bounded above by the superior edge, and below +by the semilunar crest of the bone, which conducts the plantar arteries +into the _Semilunar Sinus_, a well-marked cavity in the interior of the +bone. + +_The Superior or Articular Surface_ consists of two shallow depressions, +divided by a slight median ridge. Its posterior part shows a transversely +elongated facet for articulation with the navicular bone. + +_The Superior Edge_, outlining the superior margin of the laminal surface, +describes a curve, with the convexity of the curve forward. In the centre +of the curve is a triangular process, the _Pyramidal Process_, which serves +as the point of attachment of the extensor pedis. + +_The Inferior Edge_, the most extensive of the three, separates the laminal +from the solar surface. It is semicircular in shape, sharp, and finely +dentated, and is perforated by eight to ten large foraminae. + +_The Posterior Edge_, very slightly concave, divides the small, +transversely elongated facet of the superior surface from the posterior +region of the inferior surface. + +_The Lateral Angles_ of the bone, also termed the _Wings_, are two +projections directed backwards. Each is divided by a cleft into an upper, +the _Basilar Process_, and a lower, the _Retrossal Process_. In old animals +the posterior portion of the cleft separating the two processes gradually +becomes filled in with bony deposit, thus transforming the cleft into a +foramen, which gives passage to the preplantar artery. We may mention +in passing that the lateral angles give attachment to the lateral +fibro-cartilages, and that the lateral angles themselves in old horses +become increased in size owing to ossification of portions of the adjacent +lateral cartilages. + +_Development_.--The os pedis ossifies from two centres, one of which is for +the articular surface; but this epiphysis fuses with the rest of the bone +before birth. + +[Illustration: FIG. 4.--THIRD PHALANX OR OS PEDIS (POSTERO-LATERAL VIEW). +1, Anterior or laminal surface; 2, preplantar foramen; 3, preplantar +groove; 4, basilar process of the wing; 5, retrossal process of the wing; +6, foramen caused by the ossifying together posteriorly of the basilar and +retrossal processes.] + +[Illustration: FIG. 5.--THIRD PHALANX OR OS PEDIS (VIEWED FROM BELOW). 1, +Plantar surface; 2, plantar foramen and plantar groove; 3, semilunar crest; +4, tendinous surface; 5, retrossal processes of the wings.] + +THE NAVICULAR BONE, SHUTTLE BONE, OR SMALL SESAMOID.--Placed behind +the articulating point of the second and third phalanges, this small +shuttle-shaped bone assists in the formation of the pedal articulation. It +is elongated transversely, flattened from above to below, and narrow at its +extremities. In it we see two surfaces, and two borders. + +_The Superior or Articular Surface_ of the bone, which may easily be +recognised by its smoothness, is moulded upon the lower articular surface +of the second phalanx, being convex in its middle, and concave on either +side. + +_The Inferior or Tendinous Surface_ resembles the preceding in form, but +is broader and less smooth. In the recent state it is covered with +fibro-cartilage for the passage of the flexor perforans. + +_The Anterior Border_ possesses above a small transversely elongated facet +for articulation with the os pedis, and below a more extensive grooved +portion, perforated by numerous foraminae, affording attachment to the +interosseous ligaments of the articulation. + +_The Posterior Border_, thick in the middle, but thinner towards the +extremities, is roughened for ligamentous attachment. + +_Development_.--The bone ossifies from a single centre. + + +B. THE LIGAMENTS. + +THE ARTICULATION OF THE FIRST WITH THE SECOND PHALANX, OR THE PASTERN +JOINT.--Adhering to the limit we have set, this articulation should not +receive our attention. As, however, we shall in a later page be concerned +with fractures of the os coronae, which fractures may affect the +articulation above mentioned, a brief note of its formation will not be out +of place. + +It is an imperfect hinge-joint, permitting of extension and flexion, +allowing the first phalanx to pivot on the second, and admitting of the +performance of slight lateral movements. It is formed by the opposing of +the inferior surface of the os suffraginis with the superior surface of the +os coronae. The articulating surface of the os coronae is supplemented by +the addition behind of a thick piece of _fibro-cartilage (the glenoid_) +attached inferiorly to the posterior edge of the upper articulatory surface +of the os coronae, and superiorly by means of three fibrous slips on each +side to the os suffraginis. The innermost of these three slips becomes +attached to about the middle of the lateral edge of the suffraginis, and +the remaining two, beneath the first, attach themselves to nearer the lower +end of that bone. The posterior surface of the complementary cartilage +forms a gliding surface for the passage of the perforans. + +[Illustration: FIG. 6.--THE NAVICULAR BONE (VIEWED FROM BELOW). 1, Inferior +surface (smooth for the passage of the flexor perforans); 2, anterior edge +of inferior surface; 3, posterior edge of inferior surface.] + +[Illustration: FIG. 7.--THE NAVICULAR BONE (VIEWED FROM ABOVE, THE BONE +TILTED POSTERIORLY TO SHOW ITS ANTERIOR BORDER). 1, Superior articulatory +surface; 2, anterior border (grooved portion of); 3, anterior border +(articulatory portion of).] + +[Illustration: FIG. 8.--LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL +ARTICULATIONS (VIEWED FROM THE SIDE). (AFTER DOLLAR AND WHEATLEY.) 1, +Outermost slip from the glenoidal fibro-cartilage; 2, lateral ligament of +the first interphalangeal articulation; 3, prolongations of the lateral +ligament of the first interphalangeal articulation attached to the end of +the navicular bone to form the postero-lateral ligament of the pedal joint; +4, end of the navicular bone; 5, antero-lateral ligament of the pedal +joint.] + +_The Lateral Ligaments_.--These are large and thick, an outer and an inner, +running obliquely from above downwards and backwards. Each is inserted +superiorly into the lateral tubercle of the lower end of the first phalanx, +and inferiorly to the side of the second phalanx, their most inferior +fibres becoming finally fixed to the extremities of the navicular bone, +where they form the postero-lateral ligaments of the pedal articulation. +In front of the joint the extensor pedis plays the part of an additional +ligament. + +_The Synovial Membrane_.--This is limited in front by the tendon of the +extensor pedis, on each side by the lateral ligaments of the joint, and +behind by the glenoid fibro-cartilage. At this point it is prolonged +upwards as a pouch behind the lower extremity of the first phalanx. + +THE ARTICULATION OF THE SECOND PHALANX WITH THE THIRD, THE PEDAL, OR THE +COFFIN JOINT.--This also is an imperfect hinge-joint, permitting only of +flexion and extension, which movements are more restricted than in the +previous articulation. Three bones enter into its formation: the second +phalanx, the third phalanx, and the navicular bone. The lower articulatory +surface is formed by the third phalanx and the navicular bone combined. +To effect this the navicular is closely and firmly attached to the third +phalanx by an interosseous ligament. The two bones, as one, are then +connected to the second phalanx by four lateral ligaments, an anterior and +a posterior on each side. + +_The Interosseous Ligament_ consists of extremely short fibres running from +the extensively grooved portion of the anterior surface of the navicular +bone to become attached to the os pedis immediately behind its articular +surface. + +_The Antero-lateral Ligaments_ are attached by their superior extremities +to the lateral surfaces of the second phalanx, and by their inferior +extremities into the depressions on either side of the pyramidal process of +the os pedis. + +_The Postero-lateral Ligaments_.--As mentioned when describing the first +interphalangeal articulation, these are in reality continuations of the +lateral ligaments of that joint. Running obliquely downwards and backwards +from their point of attachment to the first phalanx they curve round the +lower part of the side of the second phalanx and end on the extremities and +posterior surface of the navicular bone. Having reached that position, they +send short attachments to the retrossal process of the os pedis and to the +inner face of the lateral cartilage. + +[Illustration: FIG. 9.--LIGAMENTS OF THE FIRST AND SECOND INTERPHALANGEAL +ARTICULATIONS (VIEWED FROM BEHIND). (AFTER DOLLAR AND WHEATLEY.) 1, +Suspensory ligament; 2, innermost slip from complementary cartilage of +pastern joint; 3, middle slip from complementary cartilage of pastern +joint; 4, outermost slip from complementary cartilage of pastern joint; 5, +glenoid or complementary cartilage of pastern joint; 6, postero-lateral +ligaments of the pedal joint; 7, the navicular bone; 8, interosseous +ligaments of the pedal joint; 9, semilunar crest of os pedis; 10, plantar +surface of os pedis.] + +_Synovial Membrane_.--This extends below the facets uniting the navicular +to the pedal bone, and offers for consideration two sacs. A large one +posteriorly running up behind the second phalanx to nearly adjoin the +sesamoidean bursae, and a small one, a prolongation of the synovial membrane +between the antero-lateral and postero-lateral ligaments of the same side. +This latter is often distended, and on account of its close proximity to +the seat of operation, is liable to be accidentally opened in excision of +the lateral cartilage for quittor. + + +C. THE TENDONS + +In order to convey an intelligent understanding of the tendons it will be +wise to briefly describe the course of their parent muscles from their +commencement. + +THE EXTENSOR PEDIS.--The extensor pedis arises from the lower extremity +of the humerus in two distinct portions of unequal size, a muscular and a +tendinous. These are succeeded by two tendons passing in common through a +vertical groove at the lower end of the radius. Lower in the limb these +tendons separate, the outer and smaller joining the tendon of the extensor +suffraginis, and the inner and main tendon continuing its course downwards. +With the exception of the navicular, it is attached to all the bones of the +foot, and is covered internally by the capsular ligaments of the joints +over which it passes, those with which we are concerned being the pastern +joint and the pedal joint. Before its attachment to the os pedis it +receives on each side of the middle of the first phalanx reinforcement in +the shape of a strong band descending obliquely over the fetlock from the +suspensory ligament. Widening out in fanlike fashion, it is inserted into +the pyramidal process of the os pedis. + +_Action_.--The action of this muscle is to extend the third phalanx on the +second, the second on the first, and the first on the metacarpus. It also +assists in the extension of the foot on the forearm. + +[Illustration: FIG. 10.--THE FLEXOR TENDONS AND EXTENSOR PEDIS. (AFTER +HAUeBNER.) 1, Tendon of flexor perforans; 2, its supporting check-band from +the posterior ligament of the carpus; 3, tendon of the flexor perforatus; +4, ring and sheath of the flexor perforatus; 5, widening out of the flexor +perforatus to form the plantar aponeurosis; 6, suspensory ligament; 7, +reinforcing band from the suspensory ligament to the extensor pedis; 8, the +extensor pedis.] + +THE FLEXOR PEDIS PERFORATUS, OR THE SUPERFICIAL FLEXOR OF THE +PHALANGES.--In common with the perforans, this muscle arises from the inner +condyloid ridge of the humerus. It is reinforced at the lower end of the +radius by the superior carpal ligament, passes through the carpal and +metacarpo-phalangeal sheaths, and, arriving behind the fetlock, forms a +ring for the passage of the flexor perforans. Its termination is bifid, and +it is inserted on either side to the lateral surface of the second phalanx. + +[Illustration: FIG. 11.--THE FLEXOR PERFORANS AND FLEXOR PERFORATUS +TENDONS. The metacarpo-phalangeal sheath and the ring of the perforatus +laid open posteriorly, and the cut edges reflected to show the passage +of the perforans. 1, Reflected cut edges of the perforatus ring and the +metacarpo-phalangeal sheath; 2, the perforans tendon; 3, point of insertion +of the perforans tendon into the semilunar crest of the os pedis (this +widened and thickened extremity of the perforans is known as the plantar +aponeurosis).] + +[Illustration: FIG. 12.--THE FLEXOR PERFORATUS AND FLEXOR PERFORANS +TENDONS. The metacarpo-phalangeal sheath and the ring of the perforatus +laid open posteriorly, and the cut edges reflected; the flexor perforans +cut through at about the region of the sesamoids, and its inferior portion +deflected. 1, Superior end of severed perforans tendon; 2, inferior end of +severed perforans tendon; 3, insertion of flexor perforans into +semilunar crest of os pedis; 4, the cut and reflected edges of the +metacarpo-phalangeal sheath and perforatus ring; 5, the bifid insertion of +the flexor perforatus into the lateral surfaces of the os corona; 6, +the capsular ligament of the pedal joint; 7, the navicular bone; 8, the +posterior surface and glenoid fibro-cartilage of the os coronae.] + +_Action_.--This muscle flexes the second phalanx on the first, the first on +the metacarpus, and the entire foot on the forearm. Mechanically, it +acts as a stay when the animal is standing by maintaining the +metacarpo-phalangeal angle. + +[Illustration: FIG. 13.--MEDIAN SECTION OF FOOT. _A_, Os suffraginis; _B_, +os coronae; _C_, os pedis; _D_, navicular bone; _E_, tendon of the extensor +pedis; _F_, insertion of the extensor pedis into the pyramidal process of +the os pedis; _G_, the tendon of the flexor perforatus; _H_, insertion of +perforatus into the os coronae; _I_, tendon of the flexor perforans; _J_, +its passing attachment to the os coronae; _K_, its final insertion into the +semilunar crest of os pedis; _a_, section of coronary cushion; _b_, section +of plantar cushion; _c_, semilunar sinus of os pedis.] + +THE FLEXOR PEDIS PERFORANS, OR THE DEEP FLEXOR OF THE PHALANGES.--This +muscle consists of three easily-divided portions: an ulnar, a humeral, and +a radial, and has for points of origin the olecranon process of the ulna, +the inner condyloid ridge of the humerus, and the posterior surface of the +radius. These portions are continued by a common tendon which enters the +carpal sheath with the tendon of the perforatus, and continues with it +through the synovial sheath of the metacarpo-phalangeal region. Like the +last-named tendon, it receives a supporting check-band, in this case from +the posterior ligament of the carpus. Passing down between the suspensory +ligament in front, and the perforatus tendon behind, it glides over the +sesamoid pulley and passes through the ring formed by the perforatus. +Continuing its course, it passes between the bifurcating portions of the +extremity of the perforatus, glides over the smooth posterior surface of +the supplementary glenoid cartilage of the articulation of the first and +second phalanges, plays over the inferior surface of the navicular bone, +and finally becomes inserted into the semilunar crest of the os pedis. On +reaching the posterior border of the navicular bone it widens out to form +the plantar aponeurosis. + +In connection with the lower portion of this tendon must be noticed the +Navicular Sheath. This is a synovial sheath lining the deep face of the +tendon, and reflected on to the navicular bone and the interosseous +ligament of the pedal joint. This will be of particular interest when we +come to deal with cases of pricked foot from picked up nails. Above, it is +in connection with the synovial membrane of the pedal articulation and that +of the metacarpo-phalangeal sheath. + +_Action_.--The action of the perforans is to flex the third on the second, +and the second on the first phalanx. The latter it flexes in turn on the +metacarpus. It also assists in the flexion of the entire foot on the +forearm, and in supporting the angle of the metacarpo-phalangeal +articulation when the animal is standing. + + +D. THE ARTERIES. + +So far as the arteries supplying the foot are concerned, we shall be +interested in following up the distribution of the two digitals, which are +the terminal branches of the Large Metacarpal. + +THE LARGE METACARPAL, OR COLLATERAL ARTERY OF THE CANNON.--This, the larger +terminal branch of the posterior radial artery, needs brief mention, for +the reason that we shall be afterwards concerned with it in the operation +of neurectomy. Its point of origin is the inside of the inferior extremity +of the radius. Descending in company with the flexor tendons, and passing +behind the carpus and beneath the carpal sheath, it continues its descent, +in company with the internal plantar nerve and the internal metacarpal +vein, on the inner side of the flexor tendons until just above the fetlock. +At this point it bifurcates into the digital arteries. + +From the carpus downwards the large metacarpal artery, the internal +metacarpal vein, and the internal plantar nerve are in close relation with +each other. The vein holds the anterior position. The artery is between the +two, and has the nerve in close contact with it behind. + +THE DIGITAL ARTERIES, OR COLLATERAL ARTERIES OF THE DIGIT.--These are of +large volume, and carry the blood to the keratogenous apparatus of the +foot. They separate from each other at an acute angle, and pass over the +side of the fetlock, one to the inside, the other to the outside, to reach +the internal face of the basilar process of the os pedis, where they +bifurcate to form the _Plantar_ and _Preplantar_ arteries. In the whole +of their course the digital arteries follow the flexor tendons, and are +related in front to the digital vein, and behind to the posterior branch of +the plantar nerve. This is the nerve implicated in the lower operation of +neurectomy, and its relation to adjoining structures will be detailed +under Section F. of this chapter. During its course the digital artery +gives off branches in the following positions: + +1. _At the Fetlock_ numerous branches to the metacarpo-phalangeal +articulation, the sesamoid sheath, and the tendons. + +2. _At the Upper Extremity of the First Phalanx_ branches for the supply of +the surrounding tissues, and for the tissues of the ergot. + +3. _Towards the Middle of the Third Phalanx_, the _Perpendicular_ artery +of Percival. This arises at a right angle from the main vessel, and +immediately divides into two series of ramifications--an ascending and +a descending. The ramifications of these series freely anastomose with +corresponding vessels of the opposite side. + +4. _At the Superior Border of the Lateral Cartilage_, the _Artery of the +Plantar Cushion_. This is directed obliquely downwards and backwards, under +cover of the cartilage, and is distributed to the middle portion of the +complementary apparatus of the os pedis, as well as to the villous tissue +and the coronet. A branch of it is turned forwards to join with the +coronary circle in forming the _circumflex artery of the coronet_. + +[Illustration: FIG. 14.--THE ARTERIES OF THE FOOT. The digital; 2, the +perpendicular--(_a_) its ascending branch, (_b_) its descending branch; +3, circumflex artery of coronary cushion; 4, the preplantar (ungual) +artery--this is seen issuing from the preplantar foramen, and distributing +numerous ascending (_c_) and descending (_d_) branches (the latter concur +in forming the circumflex artery of the toe); 5, the circumflex artery +of the toe; 6, at the point marked (*) the terminal branch of the +digital--namely, the plantar ungual--is hidden behind the lateral +cartilage; 7, the lateral cartilage.] + +5. _Under the Lateral Cartilage_ two transverse branches, an anterior and +a posterior, to form the _Coronary Circle_. The numerous ramifications +of these branches anastomose both anteriorly and posteriorly with their +corresponding branches of the artery of the opposite side. This circle +closely embraces the os coronae. Among the larger branches given off from +its anterior portion are two descending, one on each side of the extensor +pedis, to assist in the formation of the _Circumflex Artery of the Coronary +Cushion_. The formation of this last-named artery is completed posteriorly +by the before-mentioned branch from the artery of the plantar cushion. + +THE PREPLANTAR (UNGUAL[A]) ARTERY.--This, the smaller of the two terminal +branches of the digital, is situated inside the basilar process of the os +pedis. It turns round this to gain the fissure between the basilar and +retrossal processes, and becomes lodged in the preplantar fissure. Here +it terminates in several divisions which bury themselves in the os pedis. +Before leaving the inner aspect of the pedal wing it supplies a deep branch +to the heel and the villous tissue. Gaining the outer aspect of the +wing, it distributes a further backward branch, which passes behind the +circumflex artery of the pedal bone, and, during its passage in the +preplantar fissure, gives off ascending and descending branches, which +ramify in the laminal tissue. + +THE PLANTAR (UNGUAL[A]) ARTERY.--This, the larger of the two terminals +of the digital, may be looked upon as a continuation of the main vessel. +Running along the plantar groove, it gains the plantar foramen. Here it +enters the interior of the bone (the semilunar sinus) and anastomoses with +the corresponding artery of the opposite side. The circle of vessels so +formed is called the _Plantar Arch_ or the _Semilunar Anastomosis_. + +[Footnote A: The epithet 'ungual' is added by Chauveau to distinguish +these arteries from the properly so-called plantar arteries--the terminal +divisions of the posterior tibial artery.] + +From the semilunar anastomosis radiate two main groups of arterial +branches, an ascending group and a descending one. The _ascending_ branches +penetrate the substance of the os pedis, and emerge by the numerous +foraminae on its laminal surface. The _descending_ branches, larger in size, +also penetrate the substance of the pedal bone, and emerge in turn from +the foraminae cribbling its outer surface--in this case the set of larger +foraminae opening on its inferior edge. Having gained exit from the bone, +their frequent anastomosis, right and left, with their fellows forms a +large vessel following the contour of the inferior edge of the os pedis. +This constitutes the _Circumflex Artery of the Toe_. + + +E. THE VEINS. + +These commence at the foot with a series of plexuses, which may be +described as forming (1) AN INTERNAL OR INTRA-OSSEOUS VENOUS SYSTEM, and +(2) AN EXTERNAL OR EXTRA-OSSEOUS VENOUS SYSTEM. + +1. THE INTRA-OSSEOUS VENOUS SYSTEM.--This is a venous system within the +structure of, and occupying the semilunar sinus of the os pedis. It follows +in every respect the arrangement of the arteries as before described in the +same region. Efferent vessels emerge from the plantar foraminae, follow the +plantar fissures, and ascend within the basilar processes of the os pedis. +Here they lie under shelter of the lateral cartilages, and assist in the +formation of the deep layer of the coronary plexus of the extra-osseous +system. + +2. THE EXTRA-OSSEOUS VENOUS SYSTEM.--This may be regarded as a close-meshed +network enveloping the whole of the foot. Although a continuous system, it +is best described by recognising in it three distinct parts: + + _(a) The Solar Plexus_. + _(b) The Podophyllous Plexus_. + _(c) The Coronary Plexus_. + +_(a) The Solar Plexus_.--The veins of this plexus discharge themselves in +two directions: (1) _By a central canal_ or canals running along the bottom +of the lateral lacunae of the plantar cushion to gain the deep layer of the +coronary plexus. (2) _By the Circumflex or Peripheral Vein of the Toe_, a +canal formed by ramifications from the solar and the podophyllous plexuses, +and following the direction of the artery of the same name. The circumflex +vein terminates by forwarding branches to concur in the formation of the +superficial coronary plexus. + +_(b) The Podophyllous or Laminal Plexus_.--The podophyllous veins +anastomose below with the circumflex vein of the solar plexus, and above +with the veins of the coronary plexus. + +_(c) The Coronary Plexus_.--This proceeds from the podophyllous, the +intra-osseous, and the solar networks, and consists of a _central_ and _two +lateral parts_. + +The _central_ portion lies between the lateral cartilages and immediately +under the coronary cushion. The _lateral portions_ are ramifications on +both surfaces of the lateral cartilages. The ramifications on the lateral +cartilages may be again distinguished as _superficial_ and _deep_. The +superficial layer is distributed over the external face of the cartilage, +forming thereon a dense network, and finally converges towards the superior +limit of the plexus to form ten or twelve principal branches, which again +unite to form two large vessels. These vessels, by their final fusion at +the lower end of the first phalanx, constitute the digital vein. The deep +layer is formed, as before described, by ascending branches from the +posterior parts of the podophyllous and solar plexuses, and by branches +from the intra-osseous system of the pedal bone. The veins of this deep +layer finally drain into the two vessels proceeding from the superficial +layer, which go to the formation of the digital vein. + +THE DIGITAL VEINS--These arise from the network formed on the surfaces of +the lateral cartilages, and ascend in front of the digital arteries to +unite above the fetlock, where they form an arch between the deep flexor +and the suspensory ligament. From this arch (named the _Sesamoidean)_ +proceed the Metacarpal Veins. + +THE METACARPAL VEINS.--Three in number, they are distinguished as an +_Internal_ and an _External Metacarpal_, and a _Deep_ or _Interosseous +Metacarpal_. As we shall be concerned with these in the higher operation of +neurectomy, we may give them brief mention. + +THE INTERNAL METACARPAL VEIN, the largest of the three, has relations +with the internal metacarpal artery and the internal plantar nerve. These +relations were shortly discussed under the section devoted to the arteries, +to which the reader may refer. + +THE EXTERNAL METACARPAL VEIN.--This ascends on the external side of the +flexor tendons in company with the external plantar nerve. + +_The Interosseous Vein_.--This is an irregular vessel running up between +the suspensory ligament and the posterior face of the large metacarpal +bone. + + +F. THE NERVES. + +THE PLANTAR NERVES.--These are two in number, and are distinguished as +Internal and External. + +THE INTERNAL PLANTAR NERVE lies behind and in close contact with the great +metacarpal artery during that vessel's course down the region of the +cannon. A point of interest is that it gives off at about the middle of +the cannon a branch which bends obliquely downwards and behind the flexor +tendons to join its fellow of the opposite side--namely, the external +plantar. This it joins an inch or more above the bottom of the splint bone. +Measured in a straight line, this is about 2-1/2 inches below its point +of origin. Near the fetlock, at the level of the sesamoids, the internal +plantar nerve ends in several digital branches. + +THE EXTERNAL PLANTAR NERVE.--This holds a position to the outside of the +metacarpal region, analogous to that of the internal plantar nerve on +the inside of the limb, running down on the external edge of the flexor +tendons. Unlike the internal nerve, it is accompanied by a single vessel +only, the external metacarpal vein, behind which it lies. At the level of +the sesamoid bones it divides, as does the _internal_ nerve, into three +main branches--the digital nerves. + +[Illustration: FIG. 15.--THE VEINS AND NERVES OF THE FOOT. 1, The digital +vein; 2, its main tributaries, draining the podophyllous plexus, and +concurring to form the digital; 3. the digital artery (the main trunk only +of this is shown, in order to show its relationship with the vein and +nerve); 4, the plantar nerve, with its three branches--(_a_) the anterior +digital, (_b_) the middle digital, (_c_) the posterior digital; 5, the +podophyllous plexus; 6, superficial portion of the coronary plexus; 7, the +peripheral or circumflex vein of the toe.] + +THE DIGITAL NERVES.--These are distinguished as Anterior, Middle, and +Posterior. + +_The Anterior Branch_ descends in front of the vein, distributing cutaneous +branches to the front of the digit, and terminating in the coronary +cushion. + +_The Middle Branch_ descends between the artery and the vein, and freely +anastomoses with the two other branches. It terminates in the coronary +cushion and the sensitive laminae. + +_The Posterior Branch_.--This is the largest of the three, and may be +regarded as the direct continuation of the plantar. At the fetlock it is +placed immediately above the digital artery, but afterwards takes up a +position directly behind that vessel. Together with the digital artery it +descends to near the basilar process of the os pedis. Here it passes with +the plantar artery into the interior of the os pedis, and continues its +main branch, with the preplantar artery, in the fissure of the same name, +to finally furnish supply to the os pedis and the sensitive laminae. It is +this nerve which is divided in the low operation of neurectomy. + +Beyond the fact of this branch descending, in the region of the pastern, 1 +inch behind the digital artery, a further point of interest presents itself +to the surgeon, and one to which attention must be paid. This is the +presence in close proximity to the nerve of the Ligament of the Pad +(Percival), or the Ligament of the Ergot (McFadyean). This is a +subcutaneous glistening cord originating in the ergot of the fetlock, +passing in an oblique direction downwards and forwards, and crossing over +on its way both the digital artery and the posterior branch of the digital +nerve. + +In the foregoing description of the anatomy, we have taken the fore-limb as +our guide. In the hind-limb, where they reach the foot, the counterparts of +the tendons, arteries, veins, and nerves differ in no great essential from +their fellows in the fore. They will therefore need no special mention. + + +G. THE COMPLEMENTARY APPARATUS OF THE OS PEDIS. + +This consists of two lateral pieces, the LATERAL CARTILAGES or +_Fibro-cartilages_ of the pedal bone, united behind and below by the +_Plantar Cushion_. + +1. THE LATERAL CARTILAGES.--Each is a flattened plate of cartilage, +possessing two faces and four borders separated by four angles. + +The external face is convex, covered by a plexus of veins, and slightly +overhangs the pedal bone. The internal face is concave, and covers in +front the pedal articulation and the synovial sac, already mentioned as +protruding between the antero- and postero-lateral ligaments of that joint. +We have already remarked that this is a point of interest to be remembered +in connection with the operation for quittor. Below and behind, the +internal face of the cartilage is united to the plantar cushion. + +[Illustration: FIG. 16.--EXTERNAL FACE OF THE OUTER LATERAL CARTILAGE. 1, +External face of cartilage--(_a_) its upper border, (_b_) its posterior +border, (_c_) its anterior border, (_d_) its inferior border; 2, the os +pedis; 3, wing of os pedis.] + +The upper border, sometimes convex, sometimes straight, is thin and +bevelled, and may easily be felt in the living animal. It is this border +that the digital vessels cross to gain the foot, and the border is often +broken by a deep notch to accommodate them. The inferior border is attached +in front to the basilar and retrossal processes, behind which it blends +with the plantar cushion. The posterior border is oblique from before to +behind, and above to below, and joins the preceding two. The anterior +border is oblique in the same direction, and is intimately attached to the +antero-lateral ligament of the pedal articulation. The cartilages of the +fore-feet are thicker and more extensive than those of the hind. + +2. THE PLANTAR CUSHION on FIBRO-FATTY FROG.--Composed of a fibrous +meshwork, in the interstices of which are lodged fine elastic and +connective fibres and fat cells, this wedge-shaped body occupies the space +between the two lateral cartilages, the extremity of the perforans tendon, +and the horny frog. It offers for consideration an antero-superior and an +infero-posterior face, a base, an apex, and two borders. + +The antero-superior face is in contact with the terminal expansion of the +perforans tendon. The infero-posterior face is covered by the keratogenous +membrane, and follows closely the shape of the horny frog, on whose inner +surface it is moulded. It presents, therefore, at its centre a single +conical prolongation, the _Pyramidal Body_, which is continued behind, as +is the horny frog, in the shape of two lateral ridges divided by a median +cleft. The _base_ of the cushion lies behind, and consists of two lateral +masses, _the Bulbs of the Plantar Cushion_. In front these are continuous +with the ridges of the pyramidal body, while behind they become confounded +with the lateral cartilages and the coronary cushion. The _apex_ is fixed +into the plantar surface of the os pedis, in front of its semilunar ridge. +The _borders_, right and left, are wider behind than before, and are in +relation with the inner faces of the lateral cartilages. + + +H. THE KERATOGENOUS MEMBRANE. + +THE KERATOGENOUS, OR HORN-PRODUCING MEMBRANE, is in reality an extension +of the dermis of the digit. It covers the extremity of the digit as a sock +covers the foot, spreading over the insertion of the extensor pedis, the +lower half of the external face of the lateral cartilages, the bulbs of the +plantar cushion, the pyramidal body, the anterior portion of the plantar +surface of the os pedis, and over the anterior face of the same bone. In +turn, as the human foot with its sock is covered by the boot, this is +encased by the hoof, the formation of which we shall study later. + +To expose the membrane for study the hoof must be removed. This may be done +in two ways. By roasting in a fire, and afterwards dragging off the horny +structures with a pair of pincers, a knife having first been passed round +the superior edge of the horny box. Or by maceration in water for several +days, when the hoof will become loosened by the process of decomposition, +and may be easily removed by the hands. The latter method is less likely +to injure the sensitive structures, and will expose them with a fresh +appearance for observation. + +For purposes of description the keratogenous membrane is divided into three +regions: + + 1. The Coronary Cushion. + 2. The Velvety Tissue. + 3. The Podophyllous Tissue, or the Sensitive laminae. + +1. THE CORONARY CUSHION. In the foot stripped of the hoof the coronary +cushion is seen as a rounded structure overhanging the sensitive laminae +after the manner of a cornice. It extends from the inner to the outer bulbs +of the plantar cushion, and is bounded above by the perioplic ring, and +below by the laminae. + +When _in situ_ it is accommodated by the _Cutigeral Groove_, a cavity +produced by the bevelling out of the superior portion of the inner face of +the wall of the hoof. Its superior surface is covered by numerous elongated +papillae, set so closely as to give the appearance of the 'pile' of velvet. +This is observed to the best advantage with the foot immersed in water. + +_The Superior Border_ of the cushion is bounded by the _Perioplic Ring_, +the cells of which have as their function the secreting of the _Periople_, +a layer of thin horn to be noted afterwards as covering the external face +of the wall. From the perioplic ring the cushion is separated by a narrow +and shallow, though well-marked, groove. + +The inferior border is bounded by the sensitive laminae. + +[Illustration: FIG. 17.--THE KERATOGENOUS MEMBRANE (VIEWED FROM THE SIDE). +(THE HOOF REMOVED BY MACERATION.) 1. The sensitive laminae, or podophyllous +tissue; 2, the coronary cushion; 3, the perioplic ring; 4, portion of +plantar cushion; 5, groove separating perioplic ring from coronary cushion; +6. the sensitive sole.] + +The upper portions of the laminae, those in contact with the cushion, are +pale in contrast with the portions immediately below, and thus there is +given the appearance of a white zone adjoining the inferior border of the +cushion. + +Widest at its centre, the cushion narrows towards its extremities, which, +arriving at the bulbs of the plantar cushion, bend downwards into the +lateral lacunae of the pyramidal body, where they merge into the velvety +tissue of the sole and frog. + +The papillae of the coronary cushion secrete the horn tubules forming the +wall, and the papillae of the perioplic ring secrete the varnish-like veneer +of thin horn covering the outside surface of the hoof. + +[Illustration: FIG. 18.--THE KERATOGENOUS MEMBRANE (VIEWED FROM BELOW). +(THE HOOF REMOVED BY MACERATION.) 1, The sensitive sole; 2, the sensitive +frog[A]--(a) its median lacuna, (6) its lateral lacuna; 3. V-shaped +depression accommodating the toe-stay; 4, the sensitive laminae which +interleave with the horny laminae of the bar.] + +[Footnote A: The sensitive frog thinly invests the plantar cushion or +fibre-fatty frog, the outline of which is here indicated.] + +2. THE VELVETY TISSUE.--This is the portion of the keratogenous membrane +covering the plantar surface of the os pedis and the plantar cushion. To +the irregularities of the latter body--its bulbs, pyramidal body, and its +lacunae--it is closely adapted. Its surface may, therefore, be divided into +_(a) The Sensitive Frog_, and _(b) The Sensitive Sole_. + +_(a) The Sensitive Frog_ is that part of the velvety tissue moulded on the +lower surface of the plantar cushion. The shape of the plantar cushion has +already been described as identical with that of the horny frog. It only +remains to state that, like the coronary cushion, the surface of the +sensitive frog is closely studded with papillae. The cells clothing the +papillae are instrumental in forming the horny frog. + +_(b) The Sensitive Sole_.--As its name indicates, this is the portion of +the keratogenous membrane that covers the plantar surface of the os pedis. +It also is clothed with papillae, which again give rise to the formation of +that part of the horny box to which they are adapted--namely, the sole. + +3. THE PODOPHYLLOUS TISSUE, OR SENSITIVE LAMINAE.--This portion of the +keratogenous membrane is spread over the anterior face and sides of the os +pedis, limited above by the coronary cushion, and below by the inferior +edge of the bone. It presents the appearance of fine longitudinal streaks, +which, when closely examined with a needle, are found to consist of +numerous fine leaves. These extend downwards from the lower border of the +coronary cushion to the inferior margin of the os pedis. At this point each +terminates in several large villous prolongations, which extend into the +horny tubes at the circumference of the sole. At the point of the toe this +membrane sometimes shows a V-shaped depression, into which fits a inverted +V-shaped prominence on the inner surface of the wall at this point. + +The sensitive laminae increase in width from above to below. Their free +margin is finely denticulated, while their sides are traversed from top to +bottom by several folds (about sixty), which, examined microscopically, are +seen to consist of secondary leaves, or _laminellae_. + +Examined on the foot, deprived of its horny covering, the sensitive laminae +are, the majority of them, in close contact with each other. In the normal +state this is not so. The interstices between the leaves are then occupied +by the horny leaves, to be afterwards described as existing on the inner +surface of the wall. + +Reaching and rounding the heels, the sensitive laminae extend forward for a +short distance, where they interleave with the horny laminae of the bars. + +Much discussion has centred round the point as to whether or no the cells +of the sensitive laminae take any share in the formation of the horn of the +wall. This will be alluded to in a future chapter. + + +I. THE HOOF. + +Removed from the foot by maceration a well-shaped hoof is cylindro-conical +in form, and appears to the ordinary observer to consist of a box or case +cast in one single piece of horn. Prolonged maceration, however, will show +that the apparently single piece is divisible into three. These are known +as (1) THE WALL, (2) THE SOLE, and (3) THE FROG. In addition to these, we +have also an appendage or circular continuation of the frog named (4) THE +PERIOPLE, or CORONARY FROG BAND. These various divisions we will study +separately. + +1. THE WALL is that portion of the hoof seen in front and laterally when +the horse's foot is on the ground. Posteriorly, instead of being continued +round the heels to complete the circle, its extremities become suddenly +inflected downwards, forwards, and inwards. These inflections can only be +seen with the foot lifted from the floor, and form the so-called _Bars_. It +will be noticed, too, with the foot lifted, that the wall projects beyond +the level of the other structures of the plantar surface, taking upon +itself the bearing of the greatest part of the animal's weight. + +The horn of the wall, viewed immediately from the front, is known as the +_Toe_, which again is distinguished as _Outside Toe_ or _Inside Toe_, +according as the horn to its inner or outer aspect is indicated. The +remainder of the external face of the wall, that running back to the heels, +is designated the _Quarters_. + +In the middle region of the toe, the wall following the angle of the bones +is greatly oblique. This obliquity decreases as the quarters are reached, +until on reaching the heels the wall is nearly upright. + +[Illustration: FIG. 19.--THE WALL OF THE HOOF. 1, The toe; 2, inner toe; 3, +outside toe; 4, the quarter; 5, entigeral groove; 6, horny laminae.] + +For observation the wall offers two faces, two borders, and two +extremities. + +_The External Face_ is convex from side to side, but straight from the +upper to the lower border. Examined closely, it is seen to be made up of +closely-arranged parallel fibres running in a straight line from the upper +to the lower border, and giving the surface of the foot a finely striated +appearance. In addition to these lines, which are really the horn tubules, +the external face is marked by a series of rings which run horizontally +from heel to heel. These are due to varying influences of food, climate, +and slight or severe disease. This will be noted again in a later page. In +a young and healthy horse the whole of the external face of the wall +is smooth and shining. This appearance is due to a thin layer of horn, +secreted independently of the wall proper, termed the periople. + +[Illustration: FIG. 20.--INTERNAL FEATURES OF THE WALL, FROG, AND SOLE +(MESIAN SECTION OF HOOF). 1, Horny laminae covering internal face of wall; +2, superior border of wall; 3, junction of wall with horny sole; 4, the +cutigeral groove; 5, the horny sole; 6, the horny frog (that portion of +it known as the 'frog-stay'); 7, inverted V-shaped ridge on wall and sole +(known as the 'toe-stay'); 8, anterior face of wall; 9, inferior border of +wall.] + +_The Internal Face_ of the wall, that adapted to the sensitive laminae, +is closely covered over its entire surface with white parallel leaves +_(Keraphyllae_, or horn leaves, to distinguish them from the _Podophyllae_, +or sensitive leaves). These keraphyllae dovetail intimately with the +sensitive laminae, covering the os pedis. Running along the superior portion +of the inner face is the _Cutigeral Groove_. This cavity has been mentioned +before as accommodating the coronary cushion, whose shape and general +contour it closely follows, being widest and deepest in front, and +gradually decreasing as it proceeds backwards. It is hollowed out at the +expense of the wall, and shows on its surface numberless minute openings +which receive the papillae of the coronary cushion. + +At the bottom of the internal face, at the point where the toe joins the +sole, will be noted the before-mentioned inverted V-shaped prominence. +Its position will be clearly understood when we say that it gives the +appearance of having been forced there by the pressure of the toe-clip of +the shoe. This will be noted again when dealing with the sole. + +_The Inferior Border_ of the wall offers little to note. It is that portion +in contact with the ground, and subject to wear. A point of interest is its +union with the sole. This will be noticed in a foot which has just been +pared as a narrow white or faint yellow line on the inner or concave face +of the wall at its lower portion. It marks the point where the horny leaves +of the wall terminate and become locked with corresponding leaves of the +circumference of the sole. + +_The Superior Border_ follows closely the line marked by the perioplic ring +and the groove separating the latter from the coronary cushion. + +_The Extremities_ of the wall are formed by the abruptly reflected portions +of the wall at the heels. Termed by some the 'Inflexural Nodes,' they are +better known to us as the '_Points of the Heels_.' + +2. THE SOLE.--The sole is a thick plate of horn which, in conjunction +with the bars and the frog, forms the floor of the foot. In shape it is +irregularly crescentic, its posterior portion, that between the horns of +the crescent, being deeply indented in a V-shaped manner to receive the +frog. Its upper surface is convex, its lower concave. It may be recognised +as possessing two faces and two borders. + +_The Superior or Internal Face_ is adapted to the sole of the os pedis. Its +highest point, therefore, is at the point of its V-shaped indentation. From +this point it slopes in every direction downwards and outwards until near +the circumference. Here it curves up to form a kind of a groove in which +is lodged the inferior edge of the os pedis. In the centre of its anterior +portion--that is to say, at the toe--will be seen a small inverted V-shaped +ridge, which is a direct continuation of the same shaped prominence before +mentioned on the internal face of the wall. This Fleming has termed the +toe-stay, from a notion that it serves to maintain the position of the os +pedis. The whole of the superior face of the sole is covered with numerous +fine punctures which receive the papillae of the sensitive sole. + +_The Inferior Face_ is more or less concave according to circumstances, its +deepest part being at the point of the frog. Sloping from this point to its +circumference, it becomes suddenly flat just before joining the wall. Its +horn in appearance is flaky. + +[Illustration: FIG. 21.--INFERIOR ASPECT OF HOOF. _a_ The inferior face of +horny sole; _b_, inferior border of the wall; _c_, body or cushion of the +frog; _d_, median lacuna of the frog; _e_, lateral lacuna of the frog; _f_, +the bar; _g_, the quarter; _h_, the point of the frog; _i_ the heel.] + +_The External Border_ or Circumference is intimately dovetailed with the +horny laminae of the wall. At its circumference the sole, if unpared, is +ordinarily as thick as the wall. This thickness is maintained for a short +distance towards its centre, after which it becomes gradually more thin. + +_The Internal Border_ has the shape of an elongated V with the apex +pointing forwards. It is much thinner than the external border, and, +like it, is dovetailed into the horny laminae of the inflections of the +wall--namely, the bars. In front of the termination of the bars it is +dovetailed into the sides and point of the frog. Where unworn by contact +with the ground, the horn of the sole is shed by a process of exfoliation. + +3. THE FROG.--Triangular or pyramidal in shape, the frog bears a close +resemblance to the form of the plantar cushion, upon the lower surface of +which body it is moulded. It offers for consideration two faces, two sides, +a base, and a point or summit. + +[Illustration: FIG. 22.--HOOF WITH THE SENSITIVE STRUCTURES REMOVED. 1, +Superior face of horny frog; 2, the frog-stay; 3, the lateral ridges of +the frog's superior surface; 4, the horny laminae at the inflections of the +wall.] + +_The Superior Face_ is an exact cast of the lower surface of the plantar +cushion. It shows in the centre, therefore, a triangular depression, with +the base of the triangle directed backwards. Posteriorly, the depression +is continued as two lateral channels divided by a median ridge. The median +ridge widens out as it passes backwards, forming the larger part of the +posterior portion of the frog. This median ridge fits into the cleft of the +plantar cushion. It serves to prevent displacement of the sensitive from +the horny frog, and has been rather aptly termed the '_Frog-stay_.' + +_The Inferior Surface_ is an exact reverse of the superior. The triangular +depression of the superior surface is represented in the inferior surface +by a triangular projection, and the ridge-like frog-stay of the upper +surface is represented below by a median cleft, the _Median Lacuna_ of the +frog. The triangular projection in front of the median lacuna is the +body or cushion of the frog. It is continued backwards as two ridge-like +branches, which, at the points of the heels, form acute angles with the +bars. On the outer side of each lateral ridge is a fissure. These are known +as the Lateral Lacunae. + +_The Sides_ of the frog are flat and slightly oblique. They are closely +united to the bars and to the triangular indentation in the posterior +border of the sole. + +_The Base_ of the frog is formed by the extremities of its branches, which, +becoming wider and more convex as they pass backwards, form two rounded, +flexible, and elastic masses separated from each other by the median +lacuna. These constitute the 'glomes' of the frog. They are continuous with +the periople. + +_The Point of the Frog_ is situated, wedge-like, within the triangular +notch in the posterior border of the sole. + +4. THE PERIOPLE, OR CORONARY FROG BAND.--This is a continuation of the +substance of the frog around the extreme upper surface of the hoof. It is +widest at the heels over the bulbs or glomes of the frog, and gradually +narrows as it reaches the front of the hoof. It is, in reality, a thin +pellicle of semi-transparent horn secreted by the cells of the perioplic +ring. When left untouched by the farrier's rasp it serves the purpose, by +acting as a natural varnish, of protecting the horn of the wall from the +effects of undue heat or moisture. + + + +CHAPTER III + +GENERAL PHYSIOLOGICAL AND ANATOMICAL OBSERVATIONS + + +The matter embraced by the heading of this chapter will offer for +discussion many subjects of great interest to the veterinary surgeon. +Around some of them debate has for many years waxed more than keen. Of the +points in dispute, some of them may be regarded as satisfactorily settled, +while others offer still further room for investigation. + +In this volume we can only hope to deal with them in brief, and must select +such as appear to have the greatest bearing on the veterinarian's everyday +practice. + +Always prolific of heated discussion has been one question: 'Are the horny +laminae secreted by the sensitive?' To answer this satisfactorily, it will +be best to give a short account of the mode of production of the hoof in +general. + + +A. DEVELOPMENT OF THE HOOF. + +Starting with the statement that it is epidermal in origin, we will +first consider the structure of the skin, and follow that with a brief +description of the structure and mode of growth of the human nail, a short +study of which will greatly assist us when we come to investigate the +manner of growth of the horse's hoof. + +THE SKIN is composed of two portions, the EPIDERMIS and the CORIUM. + +THE EPIDERMIS is a stratified epithelium. The superficial layers of the +cells composing it are hard and horny, while the deeper layers are soft and +protoplasmic. These latter form the so-called _Retae Mucosum_ of Malpighi. + +[Illustration: FIG. 23.--VERTICAL SECTION OF EPIDERMIS (HUMAN). (AFTER +RANVIER) _A_, The horny layer of the epidermis; _B_, the rete mucosum; +_a_, the columnar pigment-containing cells of the rete; _b_, the polyhedral +cells; _c_, the stratum granulosum; _d_, the stratum lucidum; _e_, swollen +horny cells; _f_ the stratum squamosum.] + +Commencing from below and proceeding upwards, we find that the lowermost +cells of the rete mucosum, those that are set immediately on the corium, +are columnar in shape. In animals that have a coloured skin these cells +contain pigment granules. Directly superposed to these we find cells which +in shape are polyhedral. Above them, and forming the most superficial layer +of the rete mucosum, is a series of flattened, granular-looking cells known +as the _stratum granulosum_. + +Immediately above the stratum granulosum the horny portion of the epidermis +commences. In the human skin this is formed of three distinct layers. +Undermost a layer of clear compressed cells, the _stratum lucidum_. +Next above it a layer of swollen cells, the nuclei of which are +indistinguishable. Finally, a surface layer of thin, horny scales, the +_stratum squamosum_, which become detached and thrown off in the form of +scurf or dandruff. In the skin of the horse, except where it is thickest, +these layers are not clearly defined. + +It is the Malpighian layer of the epidermis that is most active in cell +division. As they are formed the new cells push upwards those already +there, and the latter in their progress to the surface undergo a chemical +change in which their protoplasm is converted into horny material. This +change, as we have already indicated, takes place above the stratum +granulosum. + +In addition to its constant formation of cells to replace those cast +off from the surface, the active proliferation of the elements of the +Malpighian layer is responsible for the development of the various +appendages of the skin, the hairs with their sebaceous glands, the sweat +glands, horny growths and the hoof, and, in the human subject, the nail. +These occur as thickenings and down-growths of the epithelium into the +corium. + +The epidermis is devoid of bloodvessels, but is provided with fine nerve +fibrils which ramify between the cells of the rete mucosum. + +THE CORIUM is composed of dense connective tissue, the superficial layer +of which bears minute papillae. These project into the epidermis, which is +moulded on them. For the most part the papillae contain looped capillary +vessels, rendering the superficial layer of the corium extremely vascular. +Why this must be a moment's reflection will show. The epidermis, as we have +already said, is devoid of bloodvessels. It therefore depends entirely for +its nourishment upon the indirect supply it receives from the vessels of +the corium. The need for extreme vascularity of the corium is further +explained when we call to mind the constant proliferation and casting off +of the cells of the epidermis, the growth of the hairs, the production of +the horn of the hoof, and the work performed by the numerous sweat and +other glands. + +Others of the papillae contain nerves, ending here in tactile corpuscles, or +continuing, as we have mentioned before, to ramify as fine fibrils in the +rete mucosum of the epidermis. + +THE HAIRS are growths of the epidermis extending downwards into the deeper +part of the corium. Each is developed in a small pit, the _Hair Follicle_, +from the bottom of which it grows, the part lying within the follicle being +known as the _Root_. It is important to note their structure, as it will be +seen later that they bear an extremely close relation to the horn of the +hoof. + +Under a high power of the microscope, and in optical section, the central +portion of a hair is tube-like. In some cases the cavity of the tube is +occupied by a dark looking substance formed of angular cells, and known as +the _Medulla_. The walls of the tube, or the main substance of the hair, is +made up of a pigmented, _horny, fibrous material_. This fibrous structure +is covered by a delicate layer of finely imbricated scales, and is termed +the _Hair Cuticle_. + +The root of the hair, that portion within the follicle, has exactly the +same formation save at its extreme end. Here it becomes enlarged into +a knob-like formation composed of soft, growing cells, which knob-like +formation fits over a vascular papilla projecting up in the bottom of the +follicle. + +We have already stated that the hairs are down-growths of the epidermis. +It follows, therefore, that the hair follicles, really depressions +or cul-de-sacs of the skin itself, are lined by epithelial cells and +connective tissue. So closely does the epidermal portion of the follicle +invest the hair root that it is often dragged out with it, and is known +as the _Root Sheath_. This is made up of an outer layer of columnar cells +(_the outer root sheath_) corresponding to the Malpighian layer of the +epidermis, and of an inner horny layer, next to the hair, corresponding to +the more superficial layer of the epidermis, and known as the _inner root +sheath_. + +The hair grows from the bottom of the follicle by a multiplication of the +cells covering the papilla upon which its root is moulded. When a hair is +cast off a new one is produced from the cells covering the papilla, or, in +case of the death or degeneration of the original papilla, the new hair is +produced from a second papilla formed in place of the first at the bottom +of the follicle. + +[Illustration: FIG. 24.--SECTION OF SKIN WITH HAIR FOLLICLE AND HAIR. _a_, +The hair follicle; _b_, the hair root; _c_, the medulla; _d_, the hair +cuticle; _e_, the outer root sheath; _f_, the inner root sheath; _g_, the +papilla from which the hair is growing; _h_, a sebaceous gland; _i_, a +sudoriferous gland.] + +THE SEBACEOUS GLANDS are small saccular glands with their ducts opening +into the mouths of the hair follicles. They furnish a natural lubricant to +the hairs and the skin. + +THE SUDORIFEROUS OR SWEAT GLANDS are composed of coiled tubes which lie in +the deeper portion of the skin, and send up a corkscrew-like duct to open +on the surface of the epidermis. They are numerous over the whole of the +body. + +[Illustration: FIG. 25.--LONGITUDINAL SECTION THROUGH NAIL AND NAIL-BED OF +A HUMAN FOETAL FINGER.[A] _a_, The nail; _b_, the rete mucosum; _c_, the +longitudinal ridges of the corium.] + +[Footnote A: Seeing that the section is a longitudinal one, it would appear +from the way the ridges cut that they are running transversely beneath the +nail. Their extreme delicacy, however, prevents a single one showing itself +along the length of the section, and their constant accidental cutting +makes them _appear_ to run transversely (H.C.R.).] + +THE HUMAN NAILS are thickenings of the lowermost layer of the horny portion +of the epidermis, the stratum lucidum. They are developed over a modified +portion of the corium known as the nail-bed. The horny substance of the +nail is composed of clear horny cells, and rests immediately upon a +Malpighian layer similar to that found in the epidermis generally. Instead +of the papillae present elsewhere in the skin, the corium of the nail-bed is +marked by longitudinal ridges, a similar, though less distinct, arrangement +to that found in the laminae of the horse's foot. + +Having thus paved the way, we are now in a better position to discuss our +original question (Are the horny laminae secreted by the sensitive?), +and better able to appreciate the work that has been done towards the +elucidation of the problem. + +A most valuable contribution to this study is an article published in 1896 +by Professor Mettam.[A] Here the question is dealt with in a manner that +must effectually silence all other views save such as are based upon +similar methods of investigation--namely, histological examination of +sections of equine hoofs in various stages of foetal development. + +[Footnote A: The _Veterinarian_, vol. lxix., p.1.] + +Professor Mettam commences by drawing attention to the error that has +been made in this connection by studying the soft structures of the foot +separated by ordinary putrefactive changes from the horny covering. "In +this way," the writer points out, "a wholly erroneous idea has crept in +as to the relation of the one to the other, and the two parts have been +treated as two anatomical items, when, indeed, they are portions of one +and the same thing. As an illustration, and one very much to the point at +issue, the soft structures of the foot are to the horny covering what the +corium of the skin and the rete Malpighii are to the superficial portions +of the epidermis. Indeed, the point where solution of continuity occurs in +macerating is along the line of the soft protoplasmic cells of the rete." + +In the foregoing description of the skin we have seen that the corium +is not a _plane_ surface, but that it is studded by numerous papillary +projections, and that these projections, with the depressions between them, +are covered by the cells of the epidermis. + +The corium of the horse's foot, however, although possessed of papillae in +certain positions (as, for example, the papillae of the coronary cushion, +and those of the sensitive frog and sole), has also most pronounced ridges +(laminae) which run down the whole depth of the os pedis. Each lamina again +carries ridges (laminellae) on its lateral aspects, giving a section of +a lamina the appearance of being studded with papillae. We have already +pointed out the ridge-like formation of the human nail-bed, and noted that, +with the exception that the secondary ridges are not so pronounced, it is +an exact prototype of the laminal formation of the corium of the horse's +foot. + +The distribution of the laminae over the foot we have discussed in the +chapter devoted to the grosser anatomy. In a macerated foot the sensitive +laminae of the corium interdigitate with the horny laminae of the hoof; that +is to say, there is no union between the two, for the simple reason that it +has been destroyed; they simply interlock like the _unglued_ junction of +a finely dovetailed piece of joinery. But no further, however, than the +irregularities of the underneath surface of the epidermis of the skin can +be said to interlock with the papillae of the corium does interlocking of +the horny and sensitive laminae occur. It is only apparent. The horny laminae +are simply beautifully regular epidermal ingrowths cutting up the corium +into minute leaf-like projections. + +In a macerated specimen, then, the exposed sensitive structures of the +foot exhibit the corium as (1) the _Coronary Cushion_, fitting into the +cutigeral groove; (2) the _Sensitive Laminae_, clothing the outer surface of +the terminal phalanx, and extending to the bars; (3) the _Plantar Cushion_, +or sensitive frog; and (4) the _Sensitive Sole_. + +The main portion of the wall is developed from the numerous papillae +covering the corium of the coronary cushion. We have in this way numberless +down-growing tubes of horn. Professor Mettam describes their formation in +a singularly happy fashion: "Let the human fingers represent the coronary +papillae, the tips of the fingers the summits of the papillae, and the folds +of skin passing from finger to finger in the metacarpo-phalangeal region +the depressions between the papillae. Imagine that all have a continuous +covering of a proliferating epithelium. Then we shall have a more or less +continuous column of cells growing from the tip of the finger or papilla (a +hollow tube of cells gradually moving from off the surface of the finger +or papilla like a cast), and similar casts are passing from off all the +fingers or papillae." + +From this description it will be noticed that each down-growing tube of +horn bears a striking resemblance to the growth of a hair, described on p. +47. In fact, the horn tube may be regarded as what it really is, a modified +hair. + +We next continue Professor Mettam's illustration, and note how the modified +hairs or horn tubes become as it were matted together to form the hoof +wall. The cells lining the depressions are also proliferating, and their +progeny serve to cement together the hollow casts of the papillae, thus +giving the _inter_-tubular substance. We have thus produced hollow tubes, +united together by cells, all arising from the rete Malpighii of the +coronary corium. Section of the lower part of the horn tubes shows them to +contain a cellular debris. + +Thus, in all, in the horn of the wall we find a tubular, an intertubular, +and intratubular substance. In fact, hairs matted together by intertubular +material, and only differing from ordinary hairs in their development in +that they arise, not from papillae sunk in the corium, but from papillae +projecting from its surface. + +Although this disposes of the wall proper, there still confronts us the +question of the development of the horny laminae. To accurately determine +this point it is absolutely essential to examine, histologically, the feet +from embryos. + +In the foot of any young ungulate in the early stages of intra-uterine +life horizontal sections will show a covering of epidermis of varying +thickness.[A] This may be only two or three cells thick, or may consist of +several layers. Lowermost we find the cells of the rete Malpighii. As some +criterion of the activity with which these are acting, it may be noted that +with the ordinary stains their nuclei take the dye intensely. The cells of +this layer rest upon a basement membrane separating the epidermis from the +corium. At this stage _the corium has a perfectly plane surface_. + +[Footnote A: Equine foetus, seventy-seven days old.] + +[Illustration: FIG. 26.--SECTION OF FOOT OF EQUINE FOETUS, SEVENTY-SEVEN +DAYS OLD. The rete Malpighii rests on a plane corium; the rent in the +section is along the line of the cells of the rete (Mettam).] + +[Illustration: FIG. 27.--SECTION FROM FOOT OF SHEEP EMBRYO. It shows a +pronounced epithelial ingrowth into the corium (Mettam).] + +The next stage will demonstrate the first step in the formation of the +sensitive laminae.[A] The plain surface of the corium has now become broken +up, and what is noticed is that the broken-up appearance is due to the +epithelial cells irrupting and advancing _en echelon_ into its connective +tissue. Each point of the ingrowing lines of the _echelon_ has usually +one cell further advanced into the corium than its neighbours, and may be +termed the _apical cell_. The fine basement membrane separating epithelium +from corium is still clearly evident. This epidermal irruption of the +corium takes place at definite points right round the foot. It is extremely +probable, however, that it commences first at the toe and spreads +laterally. + +[Footnote A: Sheep embryo, exact age unknown.] + +As yet, these cellular ingrowths (which are destined to be the _horny_ +laminae, and cut up the corium into _sensitive_ laminae) are free from +irregularities or secondary laminae. Before these are to be observed other +changes in connection with the ingrowths are to be noticed. + +[Illustration: FIG. 28.--SECTION FROM CALF EMBRYO. The epithelial ingrowths +hang down from the epidermis into the corium like the teeth of a comb +(Mettam).] + +The first is merely that of elongation of the epithelial processes into the +connective tissue, until the rete Malpighii gives one the impression that +it has hanging to its underneath surface and into the corium a number of +thorn-like processes. These extend all round the front of the foot, and +even in great part behind. Accompanying this elongation of the processes +is a condensation of the epithelial cells immediately above the rete +Malpighii, with a partial or total loss of their nuclei. This is the first +appearance of true horn, and its commencement is almost coincident with the +first stages of ossification of the os pedis. + +[Illustration: FIG. 29.--SECTION OF AN EPITHELIAL INGROWTH FROM AN EQUINE +FOETUS. It shows commencing secondary laminar ridges. In the centre are +epithelial cells which are undergoing change into horny elements to form +the horn core, or 'horny laminae' (Mettam).] + +With the appearance of horn comes difficulty of sectioning. The last +specimen that Professor Mettam was able to satisfactorily cut upon the +microtome was from a foetus between three and four months old. In this the +secondary laminar ridges were clearly indicated, and the active layer of +the rete Malpighii could be traced without a break from one ingrowing +epithelial process to the next, and around this, following all the +irregularities of its outline, and covering the branches of the nascent +laminae. The laminae mostly show this branching as if a number of different +growing points had arisen, each to take on a function similar to the +epithelial process as it at first appeared. + +In the centre of the processes a few nuclei may be observed, but they are +scarce, and stain only faintly; they have arisen from the cells of the rete +Malpighii which have grown into the corium. In fact, the active cells are +passing their daughters into the middle of the process, and these pass +through similar stages as those derived from the ensheathing epidermis. In +other words, the daughter cells of the constituents of the rete Malpighii +which have grown into the corium pass through a degeneration precisely +similar to that undergone by cells shed at desquamation, or those which +eventually give rise by their agglutination to a hair. + +This is the real origin of the horny laminae, and the thickness of these is +increased merely by an increase in the area covered by the cells of the +rete Malpighii--i.e., by the development of secondary laminar ridges. If +a section from a foal at term be examined, the processes will be found far +advanced into the corium, and, occupying the axis of each process, will +be seen a horny plate, continuous with the horn of the wall. No line of +demarcation can be observed between the horn so formed and the intertubular +material of the wall. They merge into and blend with each other, with no +indication of their different origins. The cells that have invaded the +corium have thus _not lost their horn-forming function_. There has merely +been an increase in the area for horn-producing cells. The horny processes +are continuous with the hoof proper at the point where the epithelial +ingrowth first commenced to invade the corium, and fuses here with the +horn derived from the cells of the rete Malpighii which have _not_ grown +inwards, and which are found between the processes in the intact foot. From +this it is clear that some considerable portion of the horn of the wall is +derived from the cells of the rete Malpighii covering the corium of the +foot. It becomes even more clear when we remember the prompt appearance of +horn in cases where a portion, or the whole, of the wall has been removed +by operation or by accident (see reported cases in Chapter VII.). + +The activity of the cells of the rete Malpighii of the corium covering the +remainder of the foot will be quite as necessary as the activity of the +cells of the coronary papillae which form the horn tubes themselves. 'For,' +in Professor Mettam's own words, 'I am inclined to believe that much of the +"white line" which is found uniting the wall of the hoof to the sole has +been derived from the horn formed from the rete of the foot corium. This +origin will explain the absence of pigment from this thin uniting "line," +as it does from the horn lining the interior of the wall. The cells of the +rete are free of colouring matter.' + +[Illustration: FIG. 30.--SECTION THROUGH HOOF AND SOFT TISSUES OF A FOAL AT +TERM. The horn of the wall is shown, and the horn-core ('horny laminae') of +the epithelial ingrowth. The latter has advanced far into the corium, and +is now provided with abundant secondary laminar ridges (Mettam).] + +From the matter here given us it is easy to understand how, in a macerated +foot, the appearance is given of interlocking of the sensitive and horny +laminae. We see that the horny laminae are ingrowths of the rete Malpighii, +ploughing into and excavating the corium into the shape of leaves--the +sensitive laminae. Putrefactive changes simply break into two separate +portions what originally was one whole, by destroying the cells along its +weakest part. This part is the line of soft protoplasmic cells of the rete +Malpighii. Thus the more resistant parts (the horn on the one hand, and the +corium covering the foot on the other) are easily torn asunder. + +As a result of the evidence we have quoted, we are able to answer our +original question in the affirmative. Seeing that the horny and the +sensitive laminae are both portions of the same thing--namely, a modified +skin, in which the epidermis is represented by the horny laminae, and the +corium by the sensitive--it is clear to see that the cells covering the +inspreading horny laminae are dependent for their growth and reproduction +upon the cells with which they are in immediate contact--namely, those +of the sensitive laminae--and that therefore the sensitive laminae are +responsible for the growth of the horny. + + +B. CHEMICAL PROPERTIES AND HISTOLOGY OF HORN. + +Horn is a solid, tenacious, fibrous material, and its density in the hoof +varies in different situations. It is softened by alkalies, such as caustic +potash or soda and ammonia, the parts first attacked being the commissures, +then the frog, and afterwards the sole and wall. Strong acids, such as +sulphuric acid and nitric acid, also dissolve it. + +The chemical composition of the hoof shows it to be a modification of +albumin, its analysis yielding water, a large percentage of animal matter, +and materials soluble and insoluble in water. The proportions of these, as +existing in the various parts of the hoof, have been given by Professor +Clement as follows: + + Wall. Sole. Frog. + Water 16.12 36.0 42.0 + Fatty matter 0.95 0.25 0.50 + Matters soluble in water 1.04 1.50 1.50 + Insoluble salts 0.26 0.25 0.22 + Animal matter 81.63 62.0 55.78 + +Horn appears to be identical with epidermis, hair, wool, feathers, and +whalebone, in yielding 'keratin,' a substance intermediate between albumin +and gelatine, and containing from 60 to 80 per cent. of sulphur. + +That horn is combustible everyone who has watched the fitting of a hot shoe +knows. That it is a bad conductor of heat, the absence of bad after-effects +on the foot testifies. + +[Illustration: FIG. 31.--PERPENDICULAR SECTION OF HORN OF WALL.] + +In a previous page we have described the manner of growth of the horn +tubules, and noted the direction they took in the wall; also, we have +noticed the existence between them of an intertubular horn or cement. + +Those who wish to give this subject further study will find an excellent +series of articles by Fleming in the _Veterinarian_ for 1871. We +shall content ourselves here with introducing one or two diagrams and +photo-micrographs, and dealing with the histology very briefly. + +Under the microscope the longitudinal striation of the wall is found to be +due to the direction taken by the horn tubules. + +Fig. 31 is a magnified perpendicular section of the wall. In it the +parallel dark striae are the horn tubules in longitudinal section. The +lighter striae represent the intertubular material. + +Fig. 32 gives us the wall in horizontal section. To the left of this +picture we find the horn tubules cut across, and standing out as so many +concentrically ringed circles. In the centre of the figure are seen the +horny laminae, with their laminellae, and the sensitive laminae. The right +portion of the figure pictures the corium. + +[Illustration: FIG. 32.--HORIZONTAL SECTION OF HORN OF WALL.] + +Fig. 33 is, again, a horizontal section, cut this time at the junction of +the wall with the sole. To the left are seen, again, the horn tubules of +the wall, and to the centre the horny laminae. In this position, however, +the structures interdigitating with the horny laminae are not sensitive, but +are themselves horny. As the diagram shows, they contain regularly arranged +horn tubules cut across obliquely. It is this horn which forms the 'white +line.' To the extreme right of the figure are seen the horn tubules of the +sole. + +There remains now but to notice the arrangement of the horn tubules in the +frog. The peculiar, indiarubber-like toughness of this organ is well known. +Histological examination gives a reason for this. + +[Illustration: FIG. 33.--HORIZONTAL SECTION OF HORN THROUGH THE JUNCTION OF +THE WALL WITH THE SOLE. _a_, Horn tubule of the wall; _b_, horn tubule of +the sole; _c, d_, horny laminae.] + +[Illustration: FIG. 34.--SECTION OF FROG THROUGH CORIUM AND HORN. The long +finger-like projections of corium into epidermis are sections of the long +papillae from which the horn-tubes of the sole grow. In the stainable +portion of the epidermis are to be clearly seen light and dark streaks +pointing out the alternate strata-like arrangement of cells mentioned in +the text (Mettam).] + +The horn tubules of the frog are sinuous in their course. This is accounted +for by the fact that in the horn of the frog there is a large amount of +intertubular material, this having the effect of frequently turning the +horn tubules from the straight. In addition to this, the intertubular +material has a peculiar arrangement of the cells composing it. These +are laid down in alternating striae (1) of cells with their long axes +longitudinal, and (2) of cells with their long axes horizontal. This is +seen in Fig. 34, between the long papillae of the corium, where the lines of +longitudinally arranged cells in horizontal section stand out darker than +the adjoining strata in which their arrangement is horizontal. The tortuous +direction of the horn tubules, and the almost interlocking nature of the +alternating strata of the intertubular material, together combine to give +the frog its characteristic toughness and resiliency. + + +C. EXPANSION AND CONTRACTION OF THE HOOF. + +Among other questions productive of heated argument come those relating to +expansion of the horse's hoof. In the past many observers have strenuously +insisted on the fact that expansion and contraction regularly occur during +progression. Opposed to them have been others equally firm in the belief +that neither took place. Quite within recent times this question also +has been settled once and for all by the experiments of A. Lungwitz, of +Dresden. His conclusions were published in an article entitled 'Changes in +Form of the Hoof under the Action of the Body-weight.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +iv., p. 191. The whole of the matter in this article, from which we have +borrowed Figs. 35 and 36, is too long for reproduction here. It forms, +however, most instructive reading, and its careful perusal will well repay +everyone interested in this most important question (H.C.R.).] + +In connection with this it is interesting to note how, all unconsciously, +two separate observers were simultaneously arriving by almost identical +means at an equally satisfactory answer to the question. Prior to the +publication of Lungwitz's article on the subject, Colonel F. Smith, A.V.D., +had arrived at similar conclusions by working on the same methods. + +[Illustration: Fig. 35. I. Electric Bell with Dry Element. a, Under +part, with box, for the dry element; 6, roller for winding up the +conducting-wires; c, dry element, with screw-clamp for attachment of the +conducting-wires; c', conducting-wire leading to the screw-clamp, with +contact-spring in c', Fig. 2, or to the wall in Fig. 3; d, upper part, with +bell; d', conducting-wire to the shoe d' in Figs. 2 and 3; e, strap for +slinging the apparatus around the body of the assistant or rider; f, +connecting-wire between bell and dry element.] + +[Illustration: Fig. 35. II. Hoof Shod with Shoe provided with Toe-piece and +Calkins; Wall of the Hoof covered with Tinfoil. a, Heel angle, with b, the +contact-screws; c, screw-clamp, with contact-spring (isolated from +the shoe); c' conducting-wire from the same; d, screw-clamp, with +conducting-wire (d') screwed into the edge of the shoe; e, nails isolated +by cutting a small window in the tinfoil.] + +[Illustration: Fig. 35. III. Hoof Shod with Plain Shoe; Horny Wall covered +with Tinfoil. a, Toe and heel angle, with b, the contact-screws; c, +conducting-wire passing from the tinfoil on the wall; d, conducting-wire +passing from the shoe; c', d', ends of the conducting-wires, which must be +imagined connected with the ends c', d', passing from the apparatus.] + +It is unnecessary for our purpose here to minutely describe the exact +_modus operandi_ of these two experimenters. Briefly, the method of inquiry +adopted in each case was the 'push and contact principle' of the ordinary +electric bell, and the close attention which was paid to detail will be +sufficiently gathered from Figs. 35 and 36. + +[Illustration: Fig. 36. I. LEFT FORE-FOOT SHOD AND MOUNTED TO RECOGNISE THE +SINKING OF THE SOLE. _a_, Iron plate covering the inner half of the horny +sole; _b_, openings in the same, with screw-holes for the reception of the +contact-screw _c_ (the part of the sole under the plate is covered with +tinfoil, which at _d_ passes out under the outer branch of the shoe, and +becomes connected with the tinfoil of the wall; in order to give the +freshly applied tinfoil a better hold, copying-tacks are at _e_ passed +through it into the horn, and one is similarly used to protect the tinfoil +at the place where the contact-screw touches the latter); _f_, holes +with screw thread for the fastening of the angle required to measure the +movement of the wall, and also for the fastening of the conducting-wire, +_g; h_, conducting-wire passing from the tinfoil; _i_, isolated nails.] + +[Illustration: Fig. 36. II. BAR-SHOE WITH OPENINGS. _a_, Near the inner +margin and in the longitudinal bar; _b_, for the reception of the +contact-screw _c; d_, openings for fastening the angle and the +conducting-wires.] + +After numerous experiments with the depicted contact-screws, moved to the +various positions indicated in the drawings, the following conclusions were +arrived at: + +1. BEHAVIOUR OF THE CORONARY EDGE.--During uniform weighting of all four +hoofs the coronary edge shows a tendency to contraction in the anterior and +lateral regions of the hoof, and a tendency to expansion posteriorly. With +heavy weighting of the hoof, which is shown by a backward inclination of +the fetlock, contraction in the anterior and lateral regions is slight, but +the expansion behind, in the region of the heels, is distinct, commencing +gradually in front, becoming stronger, and diminishing again posteriorly. +The coronary edge of the heels becomes slightly bulged outwards. The bulbs +of the heels swell up and incline a little backwards and downwards. + +When the fetlock is raised the expansion of the coronary edge of the heels +disappears from behind forwards, passing forwards like a fluid wave. In +the lateral and anterior regions of the coronary edge the contraction +disappears; and when the weight is thrown off the foot it passes into a +gentle expansion of the coronary edge of the toe. During the opposite +movement of the fetlock, that of sinking backwards, this change of form is +executed in the converse manner. + +In short, the coronary edge resembles a closed elastic ring, which yields +to pressure, even the most gentle, of the body-weight, in such a way that a +bulging out of any one part is manifested by an inward movement of another +part. + +In Fig. 37, _b_, the dotted line represents the changes of form in +comparatively well-formed and sound hoofs at the moment of strongest +over-extension[A] of the fetlock-joint. + +[Footnote A: The term 'over-extension,' as employed by Lungwitz, is +intended to indicate that position assumed by the fetlock-joint when the +opposite foot is raised from the ground.] + +2. BEHAVIOUR OF THE SOLAR EDGE.--Under the action of the body-weight this +is somewhat different from that of the coronary edge. Anteriorly, and at +the sides, as far as the wall forms an acute angle with the ground, +the tendency to expansion exists, but the change of form first becomes +measurable in the region where the lateral cartilages begin. Quite +posteriorly the expansion again diminishes. + +Fig. 37, _a_, by the dotted line represents the expansion at the moment of +over-extension of the fetlock-joint. This expansion is itself rather less +than at the coronary edge, and it shows itself distinctly _only when the +weighted hoof is exposed to a counter-pressure on the sole and frog_, no +matter whether the counter-pressure is produced naturally or artificially. +Thus anything tending to the removal of the pressure from below, such as +a decayed condition of the frog or excessive paring in the forge, will +diminish the extent of expansion of the solar edge. + +Contraction of the solar edge of the heels occurs at the moment of greatest +over-extension of the fetlock-joint--that is, in a foot with pressure +from below absent. On the face of it, this appears impossible. Lungwitz, +however, has perfectly demonstrated it; and, when dealing with the +functions of the lateral cartilages in a later paragraph, we shall show +reason for why it is but a simple and natural result of the foot dynamics. + +3. BEHAVIOUR OF THE SOLE.--The horny sole becomes flattened under the +action of the body-weight. This is most distinct at the solar branches, and +gradually shades off anteriorly and towards the circumference. As might be +supposed, width of hoof and thickness of the solar horn exert an influence +on the extent of this movement. The sinking of the horny sole is most +marked in flat hoofs. + + +D. THE FUNCTIONS OF THE LATERAL CARTILAGES.[A] + +[Footnote A: Extracted from a paper by J.A. Gilruth, M.R.C.V.S., in the +_Veterinary Record_, vol. v., p. 358.] + +We have just referred to contraction of the heels as taking the place of a +normal expansion in those cases where ground frog-pressure was absent. We +shall readily understand this when we bear in mind the anatomy of the +parts concerned, especially that of the plantar cushion. This wedge-shaped +structure we have already described as occupying the irregular space +between the two lateral cartilages, the extremity of the perforans tendon, +and the horny frog. + +Now, when weight or pressure is exerted from above on to this organ, and +the _frog is in contact with the ground below_, it is clear from the +position the cushion occupies that, whatever change of form pressure from +above will cause it to take, it must certainly be limited in various +directions. + +[Illustration: FIG. 37. _a_, The dotted lines in this diagram represent the +expansion of the solar edge of the hoof at the moment of over-extension of +the fetlock-joint; _b_, the dotted line represents the change in form of +the coronary edge under similar circumstances.] + +Because of the shape of the cushion its change of form cannot be forwards +(simultaneous pressure from above and below on to this wedge with its apex +forwards must tend to give it a backward change of form). Because of the +pastern being horizontal, and aiding in the downward pressure, its +change of form cannot be upwards. And because of the ground it cannot be +downwards. It follows, therefore, that the movement must be backwards and +outwards, being especially directed outwards because of its shape and the +median lacuna in its posterior half--this latter, the lacuna, accommodating +as it does the frog-stay, preventing the tendency to backward movement +becoming excessive, and directing the change of form to the sides. Where +the greatest pressure is transmitted, then, is to the inner aspects of the +flexible lateral cartilages. The coronary cushion being continuous with the +plantar, the backward and outward movements of the latter will tend to pull +upon and tighten the former, especially _in front_. This will account for +the contraction noted by Lungwitz in the _anterior half_ of the coronary +edge of the hoof. + +Remove the body-weight, and naturally the elastic nature of the lateral +cartilages and the coronary and plantar cushions, with, in a less degree, +that of the hoof, cause things to assume their normal position. + +Repeat the weighting of the hoof, in this second case _without +frog-pressure_, and we shall see at once that we have done away with one of +the greatest factors in determining the outward and backward movements of +the plantar cushion--namely, the pressure from below on its wedge-shaped +mass. The movement of the plantar cushion will now be _downwards_ as well +as backwards; and, seeing that it is attached to the inner aspect of each +lateral cartilage, we shall expect these latter, by the downward movement +of the plantar cushion, to be drawn _inwards_. This Lungwitz has shown to +occur. + +The chief function of the lateral cartilages, therefore, is to _receive +the concussion engendered by locomotion_, which concussion is directed +backwards and outwards by the pad-like plantar cushion. + +In addition to this, the lateral cartilages, together with the plantar and +coronary cushions, _play the part of a valve to the whole of the veins of +the foot_. + +It is in this way: We have only to refer to the chapter on anatomy to see +that the whole of the foot is covered with a tissue of extreme vascularity. +Thus we find papillae--the over the coronary cushion; enlarged and modified +papillae sensitive laminae--covering the anterior face of the os pedis; and +numberless papillae again covering the sole. There can be no doubt that the +quantity of fluid brought by the bloodvessels of these papillae to the foot +acts largely as a means of hydraulic protection to the soft structures.[A] +In like manner as that delicate organ, the brain, is best protected by +being floated upon the cerebro-spinal fluid and bloodvessels (which fluids +transmit waves of concussion or pressure _through_ the organ without injury +to the delicate cells forming it), so, in like manner, does the extreme +vascularity of the foot protect the cells of its softer structures from the +effects of pressure and concussion. + +[Footnote A: The _Veterinary Record_, vol. iii., p. 518.] + +That this law of hydraulics may operate in the horse's foot to the best +advantage, the veins must be provided with valves, and valves of no +mean strength. These we know to be absent. It is here that the lateral +cartilages and the elastic substances of the coronary and plantar cushions +step in to supply the deficiency. + +At the time when weight is placed upon the foot (with, of course, a +tendency to drive the blood upwards in the limb), and, therefore, the time +when a valvular apparatus is needed to retain the fluid in the foot, we +find the wanting conditions supplied by the pressure outwards of the +plantar cushion compressing the large plexuses of veins on each side of the +lateral cartilages, to which plexuses, it will be remembered, the bulk +of the venous blood from the foot was directed. A more perfect valvular +apparatus, automatic and powerful, it would be difficult to imagine. + + +E. GROWTH OF THE HOOF. + +We will conclude this chapter with a few brief remarks on the growth of +the hoof. That the rate of growth is slow is a well-known fact to every +veterinarian, and it will serve for all practical purposes when we state +that, roughly, the growth of the wall is about 1/4 inch per month. This +rate is regular all round the coronet, from which it follows that the time +taken for horn to grow from the coronary edge to the inferior margin +will vary according as the toe, the quarters, or the heels are under +consideration. + +As might naturally be expected, the rate of growth will depend on various +influences. Any stimulus to the secreting structures of the coronet, such +as a blister, the application of the hot iron, or any other irritant, +results in an increased growth. Growth is favoured by moisture and by +the animal going unshod, as witness the effects of turning out to grass. +Exercise, a state of good health, stimulating diets--in fact, anything +tending to an increased circulation of healthy blood--all lead to increased +production of horn. With the effects of bodily disease and of ill-formed +legs and feet on the wear of the hoof, and the growth of horn, we shall be +concerned in a future chapter. + + + +CHAPTER IV + +METHOD OF EXAMINING THE FOOT + + +As a general rule, it may be taken that most diseases of the foot are +comparatively easy of diagnosis. When, however, the condition is one which +commences simply with an initial lameness, the greatest care will have to +be exercised by the practitioner. + +What remarks follow here should rightly be confined to a treatise on +lameness. This much, however, we may state: As compared with lameness +arising from abnormal conditions in other parts of the limb, that emanating +from abnormalities of the foot is easy of detection. With a case of +lameness before him, concerning which he is in doubt, the practitioner +remembers that a very large percentage may safely be referred to the foot, +and, if wise, subjects the foot to a rigorous examination. + +Much may be gathered by first putting the animal through his paces. When +at a trot, notice the peculiarity of the 'drop,' whether any alteration in +going on hard or soft ground, and watch for any special characteristic in +gait. At the same time inquiry should be made as to the history of the +case; its duration; whether pain, as evidenced by lameness, is constant or +periodic; the effect of exercise on the lameness; and the length of time +elapsed since the last shoeing. + +This failing to reveal adequate cause for the lameness in any higher part +of the limb, one is led, by a process of negative deduction, to suspect +the foot. If 'pointing' is a symptom, its manner is noticed. The foot is +compared with the other for any deviation from the normal. In some cases +the two fore or the two hind feet may differ in size. Though this may not +necessarily indicate disease, it may, nevertheless, be taken into account +if the lameness is not easily referable to any other member. Measurement +with calipers will then be of help, and a pronounced increase in size, +especially if marked in one position only, given due consideration. The +hand is used upon each foot alternately to look for change of temperature, +to detect the presence of growths small enough to escape the eye, and to +discover evidence of painful spots along the coronet. + +At this stage the method of percussion recommends itself, and in many cases +no more useful diagnostic agent is to be found than the ordinary hammer. As +a preliminary, the foot of the sound limb should be always tapped first. +This precaution will serve to bring to light what is frequently met +with--the aversion nervous animals sometimes exhibit to this manner of +manipulation of the hoof. Unless this is done, the ordinary objection to +interference is apt to be read as evidence of pain. No aversion to the +method being shown, the suspected foot is gently tapped in various places +round the wall, a keen look-out being kept for any manifestation of +tenderness. This may vary from a slight resentment to each tap, indicated +by a sudden lifting and setting down again of the foot, to a complete +removal of the foot from the ground, and a characteristic pawing of the air +that points out clearly enough the seat of pain. + +Evidence of pain once given, the tapping is persisted in until, in some +cases, the exact position of the tender spot is definitely located. + +Failing evidence obtained from percussion, attention should next be given +to the shoeing. We may add here that, even when difficulties have to be +encountered in doing it, it is always a wise plan to have the shoe removed. + +The nails should be removed one by one, the course they have taken, their +point of emergence on the wall, and the condition of their broken ends all +being carefully noted as they are withdrawn. + +The removed shoe should next be examined as to the coarseness or fineness +of its punching and the 'pitch' of its nail-holes, and close attention +given to the shape of its bearing surface. + +From that we may pass to a consideration of the underneath surface of +the foot. The drawing-knife should be run lightly over the whole of its +surface, the first thing to be noticed being the point of entrance of the +nails as compared with the coarseness or fineness of the punching, and the +staining or otherwise of the horn immediately around. We may thus be guided +towards mischief arising from tight nailing apart from actual prick of the +foot. + +This done, more than usual care should be taken in following up any other +small prick or dark spot that may show itself upon the white surface of the +cleaned sole. In any case, a suspicious-looking speck should be followed up +with the searcher until it is either cut out or is traced to the sensitive +structures. + +While this is done, we should also have noticed the condition of the horn +at the seat of corn; should have noticed the shape of the heels, contracted +or otherwise; and the appearance of the frog, clean or discharging. + +A point to be remembered in making this exploratory paring of the foot is +the peculiar consistency of the horn of the frog, and its tendency to hide +the existence of punctures. In like manner, as a pin pierces a piece of +indiarubber, and leaves no clearly visible trace of the hole it has made, +so does a nail or other sharp object penetrate the frog, leaving but little +to show for the mischief that has been done. + +After all, even though we may have fully decided the foot is at fault, our +case of lameness may remain obscure so far as a cause is concerned. Nothing +remains, then, but to acknowledge the inability to discover it, to advocate +poulticing, or some other expectant palliative measure, and to bring the +case up for further examination at no distant date. Where, though we +may have suspected the foot, we have not been able to definitely assure +ourselves that there the mischief is to be found, a further method of +examination presents itself--namely, subcutaneous injections of cocaine +along the course of the plantar nerves. + +The salt of cocaine used is the hydrochlorate, 2-1/2 grains for a pony, +4 grains for a medium-sized animal, and 6 grains for a large horse. A +solution of this is made in boiled water (about 3 drams), and injected at +the seat of the lower operation of neurectomy. + +It is advisable to first render aseptic the seat of operation, and to +sterilize both the needle and the syringe by boiling. A suitable point to +choose for the injection is exactly over the upper border of the lateral +faces of the two sesamoids, the needle being introduced behind the cord +formed by the nerve and accompanying vessels, and parallel with it. + +It is possible that the vein or the artery may be wounded, but such +accident is of little importance. All that is necessary in that case is to +partly withdraw the needle and again insert it. It is advisable to use a +twitch. + +When the needle is in position, the injection should be made slowly, and +at the same time the point of the needle should be made to describe a +semicircular sweep, so as to spread the solution over as wide an area as is +possible. + +Anaesthesia ensues in from six to twenty minutes, and if the cause of the +lameness is below the point of injection the animal moves sound. + +Regarding this method of diagnosis, Professor Udriski of Bucharest, after a +series of trials, sums up as follows: + +1. For the diagnosis of lameness cocaine injections are of very +considerable value. + +2. These injections should be made along the course of the nerves. + +3. Solutions heated to 40 deg. or 50 deg. C. produced quicker, deeper, and longer +anaesthesia than equally strong cold solutions. + +4. In the sale of horses cocaine injections conceal fraud. + +Cocaine being an irritant, it must be remembered that after the anaesthesia +the lameness is somewhat more marked than before. + +To the cocaine other practitioners add morphia in the following +proportions: + + Cocaine hydrochlorate 2-1/2 grains. + Morphia 1-1/2 " + Aqua destil 1-1/2 drams. + +As a diagnostic this mixture of the two is said to be far superior to +either cocaine or morphia alone. + +In connection with this subject, Professor Hobday has published, among +others, the following cases illustrating the practical value of this method +of diagnosis:[A] + +[Footnote A: The _Journal of Comparative Pathology and Therapeutics_ vol. +viii., pp. 27, 43.] + +CASE I.--Cab gelding. Seat of lameness somewhat obscure; navicular disease +suspected. Injected 2 grains of cocaine in aqueous solution on either side +of the limb, immediately over the metacarpal nerves. + +_Five Minutes_.--Lameness perceptibly diminished. + +_Ten Minutes_.--Lameness scarcely perceptible. + +CASE II.--Mare. Obscure lameness; foot suspected. Injected 30 minims of a 5 +per cent. solution on either side of the leg just above the fetlock. + +_Ten Minutes_.--No lameness, thus proving that the seat of lameness was +below the point of injection. + +CASE III.--Cab gelding, aged, free clinique; Messrs. Elme's and Moffat's +case. Obscure lameness; foot suspected of navicular disease; very lame. +Injected 30 minims of a 5 per cent. solution of cocaine on either side of +the leg over the metacarpal nerves. + +_Six Minutes_.--Lameness perceptibly less; there was no response whatever +on the inside of the leg to the prick of a pin. On the outside, which had +not been injected so thoroughly, there was sensation, although not so much +as in a healthy foot. + +_Ten Minutes_.--Lameness had almost disappeared; so much so, that the +opinion as to navicular disease was confirmed, and neurectomy was +performed. Immediately after this operation there was no lameness whatever. + +The same author also reports numerous cases among horses and cattle, dogs +and cats, pointing out the toxic properties of the drug. The symptoms +following an overdose are interesting enough to relate here, and I select +the following case of Professor Hobday's as being fairly typical:[A] + +[Footnote A: _Loc. cit_.] + +CASE IV.--Cart gelding. Free clinique; navicular disease. Injected +subcutaneously over the metacarpal nerves on each side 6 grains of cocaine +in aqueous solution. During the operation the animal manifested no signs +of pain whatever, not even when the nerve was cut. This animal received +altogether 12 grains of cocaine (3 grains were given on either side first, +then fifteen minutes afterwards the same dose repeated). The effect was +manifested on the system in ten minutes after the second injection by +clonic spasms of the muscles of the limbs (the legs being involuntarily +jerked backwards and forwards at intervals of about twenty seconds), which +materially interfered with the performance of the operation. The animal was +also continually moving the jaws, and was very sensitive to sounds, moving +the ears backwards and forwards. This hyperaesthesia, as evinced by the +movement of the ears, lasted for some considerable time after the animal +had been allowed to get up. + +Cocaine hydrochlorate solutions, if intended to be kept for any length of +time, should have added to them when freshly made 1/200 part of boric acid +in order to preserve them. Even then they are liable to spoil, and should, +for subcutaneous injection, be made up just before needed for use. + + + +CHAPTER V + +GENERAL REMARKS ON OPERATIONS ON THE FOOT + + +A. METHODS OF RESTRAINT. + +Many of the simple operations on the foot, such as the probing of a sinus, +the paring out of corns, or the searching of pricks, may most suitably be +performed with the animal's leg held by the operator as a smith holds it +for shoeing. According to the temperament of the animal, even the operation +for the removal of a portion of the sole, or the injection of sinuses with +caustics, may be carried out with the animal simply twitched. + +When the operation is still a simple one, casting inconvenient or +impossible, and the animal restive, the twitch must be supplemented by some +other method. The most simple and one of the most effective is the blind, +cap, or bluff (Fig. 38). With it the most vicious animal or the most +nervous is in many instances either cowed into submission or soothed into +quietness. + +At the same time, more forcible means than the operator's own strength +must be taken to hold the animal's foot from the ground. If the foot is a +fore-foot, and the point desired to be operated on is to the outside, the +pastern should be firmly lashed to the forearm by means of a thin, short +cord, or a leather strap and buckle. Much may then be done in the way of +paring and probing that would otherwise be impossible. + +[Illustration: Fig. 38--The BLIND.] + +[Illustration: Fig. 39--THE SIDE-LINE.] + +If the foot is a hind one, one of the many methods of using what is +termed by Liautard, in his 'Manual of Operative Veterinary Surgery,' the +plate-longe, must be adopted. This, in its most useful form, is a length of +closely-woven cotton webbing, from about 2 to 2-1/2 inches wide, and from 5 +to 6 yards long, provided with a small loop formed on one of its ends, and +perhaps better known to English readers as a 'side-line.' If webbing be not +available, a length of soft cotton rope, or a rope plaited and sold for the +purpose, as Fig. 39, will serve equally well. One of the most convenient +methods of using the side-line for securing the hind-foot is depicted in +Figs. 40 and 41. + +[Illustration: FIG. 40.--THE SIDE-LINE ADJUSTED PREPARATORY TO SECURING THE +NEAR HIND-FOOT.] + +[Illustration: FIG. 41.--THE NEAR HIND-FOOT SECURED WITH THE SIDE-LINE.] + +Here the side-line has formed upon it a loop sufficiently large to form a +collar. This is placed round the animal's neck, the free end of the line +run round the pastern of the desired foot, and the foot drawn forward, as +in Fig. 40. + +The loose end of the line is then twisted once or twice round the tight +portion, and finally given to an assistant to hold (see Fig. 41). The foot +is thus held from the ground, and violent kicking movements prevented. + +Where the operation is a major one, restraint of a distinctly more forcible +nature becomes imperative. Many of the more serious operations can most +advantageously be performed with the patient secured in some form or other +of stock or trevis, and the foot suitably fixed. It is not the good fortune +of every veterinary surgeon, however, to be the lucky possessor of one of +these useful aids to successful operating. Perforce, he must fall back on +casting with the hobbles (Fig. 42). + +[Illustration: FIG. 42.--CASTING HOBBLES.] + +With the use of these we will assume our readers to be conversant, and will +imagine the animal to be already cast. It remains, then, but to detail the +most suitable means for firmly fixing the foot to be operated on. + +Here the side-line is again brought into use. Care should previously have +been taken when casting to throw the animal so that the portion of the foot +to be operated on, whether inside or outside, falls uppermost, and that the +buckle of the hobble on that particular foot is placed so that it also is +within easy reach when the animal is down. + +In the case we are illustrating the point of operation was the outside of +the near hind coronet. We will, therefore, describe the mode of fixing the +near hind-foot upon the cannon of the near fore-limb. + +[Illustration: FIG. 43.--PHOTOGRAPH ILLUSTRATING METHOD OF ADJUSTING THE +SIDE-LINE PREPARATORY TO FIXING THE HIND-LEG UPON THE FORE.] + +The side-line is first adjusted as follows: It is fixed upon the cannon of +the near hind-leg (A) by means of its small loop. From there it is passed +under the forearm of the same limb, over the forearm, under the rope +running from A to B; from there over and under the thigh, to be finally +brought in front of the thigh, and below the portion of rope running from +arm to thigh. The loose end of the side-line is then given to an assistant +standing behind the animal's back, the buckle of the hobble restraining the +foot unloosed, and strong but steady traction brought to bear from behind +upon the line. The operator should now stand in front of the fore-limbs, +and, by placing a hand on the rope passing round the arm, prevent the line +from slipping below the knee. + +By this means the hind-limb is pulled forward until the foot projects +beyond the cannon of the front-limb. When that position is reached, the +operator grasps the hock firmly with one hand, and, directing the side-line +to be slackened, gently slides downward the coils of rope round the arm +and thigh until they encircle the cannons of both limbs. The cannon of the +hind-limb is firmly lashed to the cannon of the fore, and the foot firmly +and securely fixed in the best position for operating (see Fig. 44). + +[Illustration: FIG. 44.--PHOTOGRAPH SHOWING THE NEAR HIND-FOOT SECURED UPON +THE CANNON OF THE NEAR FORE-LIMB.] + +Similarly, with the horse still on his off side, the off hind-limb may be +fixed to the near fore, and the near fore and the off fore to the near +hind. + +With the animal on his near side, we may fix the near hind and the off hind +to the off fore, and the off fore and near fore to the near hind. + +The points to be remembered in fixing the limbs thus are: (1) The side-line +should always commence upon the cannon of the limb to be operated on; (2) +it should next pass under and over (or over and under, it is immaterial +which) first the arm and then the thigh, or the thigh and the arm, as the +case may be; (3) in every case, whether rounding the thigh and the arm from +above or below, the piece of rope completing the round should always finish +below that portion preceding it, so that traction upon it from behind the +animal's back should tend to keep all portions of it from slipping below +the knee and the hock. + +With the uppermost fore-limb secured to the hind-limb in the manner we have +described, we have the underneath fore-limb suitably exposed for both the +higher and lower operations of neurectomy. The position for this operation +will be made better still if the lowermost limb (the one to be operated on) +is removed from the hobbles and drawn forward by an assistant by means of a +piece of rope fastened to the pastern. + +Taking what we have described as a general guide, other modifications of +thus securing the foot will suggest themselves to the operator to meet the +special requirements of the case with which he is dealing. + +Regarding the administration of chloroform, no description of the method +is needed here, as it will be found fully detailed in most good works on +general surgery. Where great immobility is needed, it is one of the most +valuable means of restraint we have. Apart from that, its use in any +serious operation is always to be advocated, if only on the score of humane +consideration for the dumb animal helpless under our hands. + + +B. INSTRUMENTS REQUIRED. + +In addition to those required for operations on the softer structures--such +as scalpels, forceps, artery forceps, directors, scissors, etc.--the +surgery of the foot demands instruments specially adapted for dealing with +the horn. + +A great deal will depend upon the operator as to whether these are few or +many. The average man of resource will deem a smith's rasp and one or two +strong drawing-knives amply sufficient, and on no account should they be +omitted from the list of those ready to hand. + +[Illustration: FIG. 45.--THE ORDINARY DRAWING-KNIFE.] + +The ordinary smith's drawing-knife (Fig. 45) is well known to almost +everyone, and is well suited for much of the rougher part of the work. +The careful following up of pricks, however, and some of the more special +operations demanding removal of portions of the lateral cartilages call for +instruments of a more delicate character and peculiar construction. These +are to be found in the so-called sage-knife, and the modern (French) +pattern of drawing-knife. + +[Illustration: FIG. 46. _a, b_, Modern forms of drawing-knife; _c, d, e_, +sage-knives.] + +The modern drawing-knife differs from the smith's instrument in being +attached to a straight, instead of a curved, handle, and in usually being +sharp on both edges instead of only on one. These are made in various sizes +(Fig. 46, _a, b_), and the blades flat, curved on the flat, or curved at an +angle with the edges of the haft. + +The sage-knife, as its name indicates, is a knife with a lanceolate-shaped +blade. These also may be obtained in varying forms and sizes (Fig. 46, _c, +d, e_). Fig. 46, _c_, is a single-edged, right-handed sage-knife. Fig. +46, _d_, is a left-handed instrument of the same type. The double-edged +sage-knife is represented in Fig. 46, _e_. + +[Illustration: FIG. 47.--SYMES'S ABSCESS-KNIFE.] + +It may be mentioned too, in passing, that the ordinary Symes's +abscess-knife (Fig. 47) is a most useful instrument when performing the +operation of partial excision of the lateral cartilages, its peculiar shape +lending itself admirably to the niceties of the operation. + +One or two good-shaped firing-irons will also be found useful. They will +lighten the labour of tediously excavating grooves with the knife, +where that procedure is necessary; and, used in certain positions to be +afterwards described, will afford just that necessary degree of stimulus to +the horn-secreting structures of the foot, which the use of the knife alone +will not. + +The man in country practice will also be well advised in carrying to every +foot case a compact outfit, such as that carried by the smith. This will +consist of hammer and pincers, drawing-knife and buffer. Much valuable time +is then often saved which would otherwise be wasted in driving round for +the nearest smith. + +There are other special operations requiring the use of specially-devised +instruments for their successful carrying out. These we shall mention when +we come to a consideration of the operations in which they are necessary. + + +C. THE APPLICATION OF DRESSINGS. + +One of the most common methods of applying a dressing to the foot is +poulticing. Usually resorted to on account of its warmth-retaining +properties, the poultice may also be medicated. In fact, a poultice, +strongly impregnated with perchloride of mercury or other powerful +antiseptic, is a useful dressing in a case of a punctured foot, or a +wise preliminary to an operation involving the wounding of the deeper +structures. The poultice may consist of any material that serves to retain +heat for the longest time. Meal of any kind that contains a fair percentage +of oil is suitable. Crushed linseed, linseed and bran, or linseed-cake dust +are among the best. + +To prepare it, all that is necessary is to partly fill a bucket with the +material and pour upon it boiling water. The hot mass is emptied into a +suitable bag, at the bottom of which it is wise to first place a thin layer +of straw, in order to prevent the bag wearing through, and then secured +round the foot. This is generally done by means of a piece of stout cord, +or by straps and buckles fastened round the pastern and above the fetlock. + +An improved method of fastening has been devised by Lieutenant-Colonel +Nunn: + +'A thin rope or stout piece of cord about 5 feet long is doubled in two, +and a knot tied at the double end so as to form a loop about 5 or 6 inches +long, this length depending on the size of the foot (as at A, Fig. 48). The +poultice or other dressing is applied to the foot, and the cloth wrapped +round in the ordinary way, the loop of the cord being placed at the back of +the pastern (as in A, Fig. 49); the ends of the cord are passed round, one +on the inside and the other on the outside, towards the front (as in B, +Fig. 49). These ends are then twined together down as far as the toe (see C +in Fig. 49). The foot is now lifted up, and the ends of the cord (CC, Fig. +49), are passed through the loop A (as at D, Fig. 49), and then drawn +tight. The ends of the cord are now separated, and carried up to the +coronet (as at EE, Fig. 49), one on the outside, the other on the inside of +the foot. They are then again twisted round each other once or twice (as at +F, Fig. 50), and are passed round the pastern once or twice on each side. +They are now passed under the cord (E, Fig. 49), and then reversed, so +as to tighten up E, and are finally tied round the pastern in the usual +manner. The arrangement of the cords on the sole is shown in Fig. 51, which +is a view from the posterior part. + +[Illustration: FIGS. 48, 49, 50, 51.--ILLUSTRATING LIEUTENANT-COLONEL +NUNN'S METHOD OF APPLYING A POULTICE TO THE FOOT.] + +'The advantages of this method of fastening have been found to be: (1) It +does not chafe the skin; (2) if properly applied it has never been known +to come undone; (3) it is the only way we know that a poultice can be +satisfactorily applied to a mule's hind-foot; (4) horses can be exercised +when the poultice is on the foot, which is almost impossible with the +ordinary leather boot; (5) the sacking or canvas does not cut through so +quickly.' + +[Illustration: FIGS. 52, 53.--TWO FORMS OF POULTICE-BOOT.] + +A further method of applying the poultice is by using one of the +poultice-boots made for that purpose (see Figs. 52 and 53). + +These have an objection. They are apt to be allowed to get extremely dirty, +and so, by carrying infective matter from the foot of one animal to that of +another, undo the good that the warmth of the poultice is bringing about. +The advantage of the ordinary sacking or canvas is that it may be cast +aside after the application of each poultice. Where the boot is kept clean, +however, it will save a great deal of time and trouble to the attendant. + +While on the subject of poulticing, it is well to remark that in many cases +it may be more advantageous to supply the necessary warmth and moisture to +the foot by keeping it immersed in a narrow tub of water maintained at the +required temperature. By this means the warmth is carried further up the +limb (sometimes an important point), and the water can more conveniently be +medicated with whatever is required than can the poultice. In fact, it is +the author's general practice, where the attendants can be induced to take +the necessary pains, to always advise this latter method. + +[Illustration: FIG. 54.--SWAB FOR APPLYING MOISTURE TO THE FOOT.] + +Where a dressing is relied upon by some practitioners on account of the +warmth it gives, others, even in identical cases, will depend upon the +effects of cold. This may be applied by means of what are called 'swabs.' +In their simplest form swabs may consist only of hay-bands or several +layers of thick bandage bound round the foot and coronet, and kept cool by +having water constantly poured upon them. In many cases the form of swab +depicted in Fig. 54 will be found more convenient. + +When only one foot is required to be dressed, and a water-supply is +available, by far the preferable method is to attach one end of a length +of rubber tubing to the water-tap, and fasten the other just above the +coronet, allowing the water to trickle slowly over the foot. In cases where +a forced water-supply is unobtainable, and the case warrants the extra +trouble, much may be done with a medium-sized cask of water placed +somewhere over the animal, and the rubber tubing connected with that. + +Where the dressing is desired to be kept applied to the sole and frog only, +there is no method more satisfactory than the shoe with plates. + +[Illustration: FIG. 55.--THE SHOE WITH PLATES. _A_, The plates in position; +_B_, the plates separated from the shoe.] + +[Illustration: FIG. 56.--THE QUITTOR SYRINGE.] + +The plates are of metal, preferably of thin sheet iron or zinc, and are +slipped between the upper surface of the shoe and the foot after the manner +shown in Fig. 55. The plates themselves are shaped as depicted in Fig. +55, _a, b, c, a_ and _b_ curved to meet the outlines of the shoe, and _c_ +shaped so as to wedge tightly over the posterior ends of the side plates, +and between them and the shoe. A distinct advantage of the plate method of +dressing is that a certain amount of pressure may be maintained on the sole +and frog, a very important consideration in connection with some of the +diseases with which we shall later deal. + +When dealing with sinuous wounds of the foot, another favourite mode of +applying dressings is by means of the syringe, and no better instrument for +all cases can be found than that known as a quittor syringe (Fig. 56). + +A further mode of applying dressing, and one frequently practised +in connection with the foot, is known as 'plugging.' This is almost +sufficiently indicated by its name. It consists in rolling portions of +the dressing into little cylinders, wrapped round with thin paper, and +introduced into a sinus or other position where considered necessary. + + +D. PLANTAR NEURECTOMY. + +As a last resort in the treatment of many diseases of the foot the +operation of neurectomy is often advised. It will be wise, therefore, to +insert a description of the operation here. + +_Derivation of the Word_.--For many years the operation was known simply as +'nerving' or 'unnerving,' and it was not until 1823, at the suggestion +of Dr. George Pearson, that Percival introduced the word _neurotomy_ +to signify the operation with which we are now about to deal. The word +neurotomy, however, used strictly, means the act or practice of dissection +of nerves, and, when applied to the operation as practised to-day, +describes only a step in the procedure. + +As the operation really consists in cutting down upon, and afterwards +excising a portion of the nerve, the modern appellation of +_neurectomy_--from the Greek _neuron_, a nerve; and _tome_, a cutting, +signifying the cutting out of a nerve or the portion of a nerve--is far +more suitable. + +According as the nerve operated on is the plantar or the median, the +operation is known as plantar or median neurectomy. + +_History of the Operation_.--It is to two English veterinarians that we +owe the introduction of the operation to the veterinary world. In 1819 +Professor Sewell announced himself as the originator of neurotomy. This +claim was disputed by Moorcraft, who appears to have successfully +shown himself to be the real person entitled to that honour, he having +satisfactorily performed the operation on numerous animals for fully +eighteen years prior to Professor Sewell's announcement. It appears that +Moorcraft left this country for India in 1808, having practised the +operation in more or less obscurity for some six or seven years previous +to that. After his departure neurectomy, as introduced by him, either died +away in repute, or was not made by him sufficiently public to become a +matter of general knowledge. To Professor Sewell, therefore, although not +the actual originator of the operation, belongs the honour of making it +public to the veterinary profession. + +In 1824, five years after Sewell's introduction, we find it practised on +the Continent by Girard. We gather, however, from the writings of Percival +and Liautard, that both in this country and on the Continent the operation +was for several years largely in the stage of experiment. Unsuitable +subjects were operated on; the work afterwards given to the animal +improperly adjusted to his altered condition; and the bad after-results of +the operation almost ignored by some, and greatly exaggerated by others. +In fact, some long time elapsed before veterinary surgeons allotted to the +operation that measure of credit which the results following it warranted. + +_The Object of the Operation_ is to render the foot insensitive to pain, +and to give to an otherwise incurably lame animal a further period of +usefulness. After the operation, as time goes on, this object may become +defeated by the reunion of the divided ends of the nerve. In that case, +neurectomy must necessarily be performed again. + +_The Operation_.--Two forms of neurectomy are recognised--the high +operation and the low. The low operation deals with the posterior digital +branch of the plantar nerve, and the high operation with the plantar +itself. + +It is the latter operation with which we shall deal first. In our opinion +it is that most likely to be followed by satisfactory results. The area +supplied by the posterior digital is mainly the posterior portion of the +digit. Thus, unless the cause of the lameness is diagnosed with certainty +to be situated somewhere in the posterior region of the foot, section of +the posterior digital alone will not give total insensibility to pain. +Added to that, we may remember this: Below the point at which the digitals +branch off from the plantar there is always more likelihood of the part +we are attempting to render insensible being supplied by another and +adventitious branch, or a branch that, as regards its direction, is +abnormally distributed. As a last consideration, we may say that the higher +operation is the easier to perform. + +Percival, in his works on lameness, has some very sage remarks to make by +way of a preliminary, and we cannot do better than quote them here. He +says: + +'To command success in neurectomy three considerations demand attention: + +'1. The subject must be fit and proper; in particular, the disease for +which neurectomy is performed should be suitable in kind, seat, stage, etc. + +'2. The operation must be skilfully and effectually performed. + +'3. The use that is made of the patient afterwards should not exceed what +his altered condition appears to have fitted him for. + +'The veterinarian who is guided by considerations such as those will find +that he has restored to work horses who would otherwise have been utterly +useless. A plain and safe argument wherewith to meet the objections to +neurectomy is simply to ask the question what the animal is worth, or to +what useful purpose he can be put, that happens to be the subject of such +an operation. + +'If the horse can be shown to be still serviceable and valuable, then he is +not a legitimate subject for the operation. The rule of procedure I have +laid down is to operate on no other but the _incurably lame horse_; and +whenever this has been attended to, not only has success been the more +brilliant, but indemnification from blame or reproach has been assured.' + +_Preparation of the Subject_.--But little in the way of medicinal +preparation is necessary. When the animal is a gross, heavy feeder, and +carries a more than ordinary amount of cupboard, all that is needed is to +withhold his usual allowance of food for some time prior to the operation, +simply to avoid risk of rupture when casting. If considered advisable, a +dose of physic may also be administered. + +To the seat of operation, however, careful attention should be given. On +the day previous to the operation the hair should be closely removed with +the clipping machines, and the skin thoroughly cleansed with warm water +and soap. After this, a bandage soaked in a 4 per cent, watery solution +of carbolic acid should be wrapped lightly round the limb, and allowed to +remain in position until the animal is cast and ready for the operation the +following morning. On removing the bandage prior to operating, the part +should again be bathed with a cold 5 per cent. solution of carbolic acid +and swabbed dry. Attention to these details will serve to leave the wound +in that favourable condition in which it heals nicely, and with the minimum +amount of trouble. + +_Preliminary Steps_.--By some practitioners the operation is performed with +the animal standing, local anaesthesia having been first obtained by the use +of cocaine, or an ethyl chloride spray. There is no gainsaying the fact, +however, that the operation of neurectomy is a painful one, and that, with +most operators, success will be more fully guaranteed with the animal cast +and the limb held in a suitable position by an assistant. + +The animal is thrown by the hobbles upon the side of the leg which is to be +operated on. The cannon of the upper fore-limb is then fixed to the cannon +of the upper hind, as described under the section of this chapter devoted +to the methods of restraint, and the lower limb freed from the hobbles and +drawn forward by an assistant by means of a stout piece of cord round the +pastern. + +An alternative method of holding the limb is to bind both fore-legs +together above the knee by means of the side-line run round a few times in +the form of the figure 8, and then fastened off. As in the former method, +the lower foot is then removed from the hobble, and again held forward by +an assistant. By either method the inside of the limb is operated on first. + +[Illustration: FIG. 57.--THE ESMARCH RUBBER BANDAGE AND TOURNIQUET.] + +Although it is not absolutely necessary, it is an advantage, especially to +the inexperienced operator, to apply before operating an Esmarch's bandage +and tourniquet (Fig. 57). This expels the greater part of the blood from +the limb, and renders the operation comparatively bloodless. + +[Illustration: FIG. 58.--RUBBER TOURNIQUET WITH WOODEN BLOCK.] + +The Esmarch bandage is composed of solid rubber, and with it the limb is +bandaged tightly from below upwards. On reaching the knee the tourniquet is +stretched round the limb, fastened by means of its buckle and strap, and +the bandage removed. Those who feel they can dispense with the bandage use +the tourniquet alone. For this purpose the form depicted in Fig. 58, and +the one in general use at the Royal Veterinary College, is more suitable, +on account of its wooden block, which may be placed so as to press on the +main artery of supply. + +[Illustration: Fig. 59. NEURECTOMY BISTOURY.] + +_Instruments Required_.--These should be at hand in an earthenware or +enamelled iron tray containing just sufficient of a 5 per cent. solution +of carbolic acid to keep them covered. Those that are necessary will be a +sharp scalpel, or, if preferred, one of the many forms of bistoury devised +for the purpose (see Fig. 59), a pair of artery forceps, a needle ready +threaded with silk or gut, one of the patterns of neurectomy needle (see +Fig. 60), and a pair of blunt-pointed scissors curved on the flat. It is +also an advantage, when once the incision through the skin is made, to +employ one of the forms of elastic, self-adjusting tenacula (see Fig. 61) +for keeping the edges of the wound apart while searching for the nerve. + +[Illustration: FIG. 60. NEURECTOMY NEEDLE.] + +_Incision through the Skin_.--We remember that the plantar nerve of the +inner side is in close relation with the internal metacarpal artery, and +that both, in company with the internal metacarpal vein, run down the limb +in close proximity with the inner border of the flexor tendons. Also, we +remember that the external plantar nerve has no attendant artery, although, +like its fellow, it is to be found in close touch with the edge of the +flexor tendons. + +Bearing these landmarks in mind, we feel for the nerve in the hollow +just above the fetlock-joint by noting the pulsations of the artery, and +determining the edge of the flexor tendons. This done, a clean incision is +made with the bistoury or the scalpel in the direction of the vessels. The +incision should be made firmly and decisively, so that the skin may be +cleanly penetrated with one clear cut. If judiciously made, little else in +the shape of dissection will be needed. + +[Illustration: FIG. 61.--DOUBLE TENACULUM.] + +It is now that the double tenaculum (Fig. 61) is applied. One clip is fixed +to the anterior edge of the wound, and the other carried beneath the limb +and made to grasp the posterior edge. If found desirable to keep the +edges of the wound apart, and no tenaculum to hand, the same end may be +accomplished by means of a needle and silk. In like manner as is the +tenaculum, the silk is attached to one edge of the wound, carried under the +limb, and firmly secured to the other. + +Having made the incision, the wound should be wiped free from blood by +means of a pledget of cotton-wool previously soaked in a carbolic acid +solution and squeezed dry. At the bottom of the wound will now be seen +the glistening white sheath, containing the vein, artery, and nerve. This +should be picked up with the forceps, and a further incision made with the +bistoury. Care should be exercised in making this second incision, or the +artery may accidentally be opened. If an ordinary scalpel is used, the +lower end of the sheath should be picked up and the point of the scalpel +inserted through it. With the cutting edge of the scalpel turned towards +the opening of the wound, the sheath is then slit from below upwards. The +second incision satisfactorily made, the wound is again wiped dry, and the +nerve seen as a piece of white, curled string in the posterior portion of +the wound. + +At this stage it is advisable to accurately ascertain whether what we have +taken to be the nerve actually is it. This is done by taking it up with the +forceps and giving it a sharp tweeze. A sudden struggle on the part of the +patient will then leave no doubt in the operator's mind that it is the +nerve he has interfered with. + +_Section of the Nerve_.--The neurectomy needle (Fig. 60) is now taken, and, +excluding the other structures, passed under the nerve. A piece of stout +silk or ordinary string is then threaded through the eye of the needle, the +needle withdrawn, and the silk left in position under the nerve. The silk +is now tied in a loop, and the nerve by this means gently lifted from its +bed. With the curved scissors or the scalpel it is severed as high up as is +possible. The lower end of the severed nerve is then grasped firmly with +the forceps, pulled downwards as far as possible, and then cut off. At +least an inch of the nerve should be excised. + +The animal is then turned over, and the opposite side of the limb operated +on in the same manner. + +The tourniquet is now removed, and the wound is examined for bleeding +vessels. If the haemorrhage is only slight, the wound should be merely +dabbed gently with the antiseptic wool until it has stayed. A larger vessel +may be taken up with the artery forceps and ligatured, or the haemorrhage +stopped by torsion. On no account, unless it it done to stay haemorrhage +that is otherwise uncontrollable, should the wound be sutured with blood in +it. With the wound once dry and clean, it is well to insert three or four +silk sutures, but care must be taken not to draw them too tightly. This +done, the patient may be allowed to get up. _After-treatment_.--This is +simple. Over each wound is placed a pledget of antiseptic cotton-wool or +tow, and the whole lightly covered with a bandage soaked in an antiseptic +solution. For the first night the animal should be tied up short to the +rack, and the following morning the bandages removed. A little boracic +acid or iodoform, or a mixture of the two combined with starch (starch and +boracic acid equal parts, iodoform 1 drachm to each ounce) should now be +dusted over the wounds, the antiseptic pledgets renewed, and the bandage +readjusted over all. + +At the end of three or four days the bandages may be dispensed with. All +that is necessary now is an occasional dusting with an antiseptic powder, +and, as far as possible, the restriction of movement. At the end of a week +the sutures may be removed, and the animal turned into a loose box or out +to pasture. + + +E. MEDIAN NEURECTOMY. + +As a palliative for lameness when confined to the foot, one would imagine +that the plantar operation would be all sufficient. There are operators, +however, who state that the results following section of the median nerve +have been such as to cause them to entirely abandon the lower operation in +its favour. If only for that reason a brief mention of the operation must +be made here. + +The operation was first performed in this country in October, 1895, the +subject being one of the out-patients at the Royal Veterinary College Free +Clinique. + +For five or six years following this date Professor Hobday performed the +operation some several hundred times, and was certainly instrumental in +bringing the operation into prominence. Though so recently introduced here, +it appears to have been practised for several years on the Continent, +originating in Germany as early as 1867. In that country a first public +account of it was published in 1885 by Professor Peters of Berlin, while in +France it was introduced by Pellerin in 1892. In this operation a portion +of the median nerve is excised on the inside of the elbow-joint just below +the internal condyle of the humerus. Here the nerve runs behind the artery, +then crosses it, and descends in a slightly forward direction behind the +ridge formed by the radius. + +The position of the limb most suitable for the operation is exactly that we +have described as most convenient for the plantar excision. The animal is +cast, preferably anaesthetized, and the limb removed from the hobbles, and +held as far forward as is possible by an assistant with the side-line. + +Professor Hobday's description of the operation is as follows: + +'A bold incision is made through the skin and aponcurotic portion of +the pectoralis transversus and panniculus muscles, about 1 to 3 inches +(depending on the size of the horse) below the internal condyle of the +humerus, and immediately behind the ridge formed by the radius. This +latter, and the nerve which can be felt passing over the elbow-joint, form +the chief landmarks. The haemorrhage which ensues is principally venous, and +is easily controlled by the artery forceps. In some cases I have found it +of advantage to put on a tourniquet below the seat of operation, but this +is not always advisable, as it distends the radial artery. We now have +exposed to view the glistening white fascia of the arm, which must be +incised cautiously for about an inch. This will reveal the median nerve +itself situated upon the red fibres of the flexor metacarpi internus +muscle. If not fortunate enough to have cut immediately over the nerve, it +can be readily felt with the finger between the belly of the flexor muscle +and the radius.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. ix., +p. 181.] + +The nerve exposed, the remainder of the operation is exactly as that +described in removing the portion of the nerve in the plantar operation. +The wound is sutured and suitably dressed, and a fair amount of exercise +afterwards allowed the patient. + + +F. LENGTH OF REST AFTER NEURECTOMY. + +This is placed by the majority of surgeons at about three weeks to a +month. Within that period no excessive exertion should be undergone by +the patient. A certain amount of quiet exercise, however, is beneficial, +facilitating the healing of the wounds, and accustoming the animal to the +altered condition of his limb. + + +G. SEQUELAE OF NEURECTOMY. + +These we shall relate collectively, making no distinction between those +following excision of the plantar nerve and those succeeding section of the +median. It must be remembered by the surgeon, however, that the unfortunate +sequelae we are now about to describe are likely to be far more grave when +following section of the larger nerve. + +_Liability of Pricked Foot going undetected_.--On account of the warning +they convey to the surgeon, first place among the sequelae of neurectomy +must be given to accidents following loss of sensation. Take, for example, +punctured foot. In any case, in the sense of being unforeseen, it is +accidental. In the neurectomized foot it becomes doubly accidental, in that +not only is it unforeseen, but that it is for some time indiscoverable. +With the foot deprived of sensation, a nail may be picked up, or a prick +sustained at the forge, and no intimation given to the attendant until pus +has underrun the horn, and broken out at the coronet. What follows, then, +is that the hoof as a whole, or the greater part of it, sloughs off. + +No neurectomy should be undertaken unless this contingency has been allowed +for. The owner should be advised of it by the surgeon, who should at the +same time enjoin on his client the absolute necessity of giving to the +neurectomized foot daily and careful attention. + +_Loss of Tone in the Non-sensitive Area_.--In addition to the mischief +resulting from a wound going undetected, it must be remembered that the +loss of tone resulting from the operation gives to every wound (however +slight), in the region supplied by the removed nerve, a sluggish and +troublesome character. Difficult to deal with as wounds about the foot +ordinarily are, they are rendered more so by a previous neurectomy. + +_Gelatinous Degeneration_. This is a condition liable to occur in cases +where the operation has been too long deferred, and when considerable +structural alteration has already taken place in the shape of diseased bone +or tendon, more especially in navicular disease. It consists in a peculiar +softening of the structures of the limb, accompanied with enlargement, +due to swelling of the connective tissues, the enlargement and softening +generally making itself first apparent by a soft, pulpy swelling in the +hollow of the heel. + +From this onwards the enlargement increases, and lameness becomes +excessive, the animal going more and more on his heels, until, finally, no +portion of the solar surface of the foot comes to the ground at all. + +The case is hopeless, and destruction should be advised. + +_Reported Case_.--'The patient, a brown carriage gelding, was brought to +the Royal Veterinary College infirmary in a cart on December 31, the only +previous history obtainable being that it had suddenly fallen lame a month +before. + +'The symptoms presented were excessive lameness of the near fore-limb. On +being trotted, the toe was elevated each time the foot reached the ground, +progression being entirely on the heels. Separation of the hoof for about 2 +inches at the hinder part of the coronet; oedematous swelling from foot to +knee, extending during the next three days to the elbow. Great tenderness +between the knee and the fetlock; below this no sensation whatever, as a +pin was inserted in several places round the coronet without causing any +symptoms of pain. On further examination, two unnerving scars were found. +No treatment was adopted, and the horse was destroyed on January 6. + +'On dissecting the leg, the following appearances presented themselves: + +'The limb was very much enlarged, due to thickening of the connective +tissue, the skin being removed only with difficulty. The tendons were soft +and much thickened. A rupture of the skin at the coronet, just where the +skin meets the wall of the foot. Large extravasations of blood at the back +of the tendons, situated in the lower half. _External_ nerve trunk had +become reunited, at the point of junction there being a hard lump about +the size of a walnut. _Internal_ nerve trunk also had become reunited, and +presented a thickened portion at the point of junction, but not so large as +that of the outer side, and situated in the lower half of the tendon, about +2 inches higher than that on the external nerve. This nerve trunk was +atrophied below the thickening, and had undergone gelatinous degeneration. +Judging from the scars on the skin, this side had evidently been unnerved a +week or ten days previously to that on the outer side. The band stretching +across the back of the perforatus, between the external and internal +nerves, appeared on the inside to have become firmly fixed into the tendon. + +'On removing the hoof, under the sole there appeared a large quantity of +very foetid pus; the laminae were very much inflamed in patches. There +was an enormous thickening of connective tissues in the heel. On cutting +longitudinally through the perforatus tendon, there was exposed a large +blood-coloured mass, of a gelatinous appearance, situated on the perforatus +tendon, the latter being very much thickened, and growing to the navicular +bone. The underneath surface of the superior suspensory ligament was much +thickened, and firmly adherent to the bone; at the posterior surface of +the metacarpus there was a quantity of gelatinous substance. The anterior +ligament of the fetlock-joint was thickened; the navicular bone was entire, +but showed lesions of navicular disease, being ulcerated. Section through +the bone did not reveal anything further. It may be here remarked that the +ulcerations were on either side of the central ridge, and not at all on the +ridge itself. + +'Microscopic examination of the tissue joining the two ends of the nerve +together revealed a few nerve fibres; the general appearance was that +of granulation tissue, containing capillary vessels, which were fairly +plentiful, and comparatively large in size.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 386 (Hobday)] + +_Chronic Oedema of the Leg_.--In some cases there is a distinct swelling +of the leg some time after the operation. This exposes the limb to the +infliction of sores from striking with the opposite foot, with, of course, +the difficulty in healing we have just described. + +_Persistent Pruritus_.--This annoying sequel occurs in the neurectomized +limb, with or without gelatinous degeneration, and appears to be without a +remedy. The itching in some cases is so intense as to lead the animal to +constantly gnaw at the top of the foot. As one observer has remarked, the +animal may begin literally biting pieces out of his limb. The result of the +irritation and gnawing is fatal. Great sloughing of the parts takes place, +and the animal has eventually to be slaughtered. + +_Fracture of the Bones_.--The sudden loss of sensation in a foot may cause +the animal to use violently the limb he has for months past been carefully +nursing. It may be that the lameness for which the operation has been +performed has been due to disease existing in the navicular bone, and +extending, perhaps, to the os pedis. By the disease the bone has already +been made brittle, its substance and ligamentous attachments perchance +weakened and broken up by a slow-spreading caries, and rarefaction of the +remaining bone substance rendered almost certain. In this instance, the +free use of the foot, and the application to the diseased structures of an +unwonted pressure immediately after the operation results in fracture. With +the rupture of the structures we get the elevated toe and soft swelling in +the heel, as described in gelatinous degeneration. Treatment, of course, is +out of the question. + +_Neuroma_.--A further sequel is the appearance at the seat of the operation +of what is termed an 'amputational neuroma.' This is a tumour-like +growth occurring on the end of the divided nerve. It is composed of +connective-tissue elements permeated by nerve fibres which have grown out +from the axis-cylinders of the nerve stump. It may vary in size from a pea +to a hazel-nut, and is frequently the cause of much pain. This must be cut +down upon and cleanly removed, taking away at the same time as much of the +nerve as is possible. + +_Reunion of the Divided Nerve_.--We may say at once that 'reunion' in the +popular sense of the word does not take place. At a varying period after +section, however, we do get a return of sensation. This is brought about in +the following manner: The axis-cylinder of the nerve, still in connection +with the spinal cord, swells somewhat, and hypertrophies. The cells of this +hypertrophied portion show a great tendency to proliferate and produce +new nerve structure. This growing point splits, and gives rise to several +fibrils, which are new axis-cylinders. These commence to grow towards the +periphery, and, in so doing, grow through the cicatricial tissue that has +formed at the seat of the operation. + +After passing through the cicatricial tissue (the amount of which tissue, +of course, controls the length of time that insensibility remains), the +growing axis-cylinders reach the degenerated portions of the nerve below +the point of section. It is along the track of the old nerve that the new +growths from the stump reproduce themselves. + +The fact of the new growths having to pass through the fibrous tissue of +the cicatrix before they can gain the course of the old nerve, along which +latter their progress of growth is comparatively easy, affords ample +illustration that as large a portion as is possible of the nerve should be +removed when operating, in order to convey insensibility for the longest +time. After reunion, of course, nothing remains but to repeat the +operation. + +_The Existence of an Adventitious Nerve-supply_.--While not exactly a +sequel of the operation, the fact that it is not discovered until after the +operation has been performed warrants us in mentioning it here. It is +not an uncommon thing in the lower operation to find that sensation and +symptoms of lameness still persist after section of the nerve. In many +cases this has been traced to the existence of an abnormal nerve branch. +In the higher operation this is not so likely to be met with. That it may +occur, however, is shown by the following interesting case related by +Harold Sessions, F.R.C.V.S.:[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +xii., p. 343.] + +'In June of 1898 I saw a hunter suffering from navicular disease. After +carefully examining the leg, I advised the owner to have the operation of +neurectomy performed upon him. This he decided to do, and the horse was +sent to me about the beginning of July. + +[Illustration: FIG. 62.--DISSECTED EXTERNAL METACARPAL NERVE AND BRANCHES. +_a_, Metacarpal; _b_, anterior plantar; _c_, extra branch (probably from +the internal metacarpal), conveying sensation after division of the +external metacarpal.] + +'The operation was performed in the ordinary way, without any difficulty +whatever. The wounds healed nicely, but the horse still continued to go +lame. Careful examination showed that there was still sensation on the +outside of the foot. Thinking that possibly there might be two external +metacarpal nerves, the horse was again cast, the operation being performed +slightly lower down. Only the main branch of the external metacarpal nerve +could be found. A piece of this was taken out, and the horse let up. On +examination, sensation was still found in the posterior part of the outside +of the foot. It was very evident that there was some abnormal distribution +of the nerve, as sensation was still being conveyed to that part of the +foot. + +'As the horse was absolutely useless, and would have to be shot unless this +piece of nerve could be found, he was again thrown, and after he had been +anaesthetized I determined to follow the course of the nerve down, until I +found where the accessory branch came from. This I found a little below the +fetlock, about 1/2 inch below the point where the anterior plantar nerve is +given off from the metacarpal nerve. It was about 1/2 inch below the spot +where the anterior plantar nerve passes between the artery and vein of the +foot, and it was somewhat difficult to get at it. + +'Fig. 62 shows the exact size and distribution of the nerves. After the +separation of the accessory branch, sensation was taken from the foot, and +the horse went perfectly sound.' + +_Stumbling_.--In addition to the sequelae we have mentioned, it is urged +against the operation of neurectomy that one of the first effects of +depriving the foot of the sense of touch is a tendency on the part of +the animal to stumble. From the cases we have seen we cannot regard +this objection as a serious one. Nevertheless, as veterinarians, with a +knowledge of the physiology of the structures with which we are dealing, +we must treat the objection with respect, for, after all, we are bound to +allow that stumbling, and a bad form of it, would be but a natural sequence +of the operation we have just performed. The real fact remains, however, +that cases of stumbling, even immediately after the operation, are +rare; and that even when they do occur, the animal seems easily able to +accommodate himself to the altered condition, and as readily uses the +comparatively inert mass at the end of his limb as he did previously the +intact foot. + + +H. ADVANTAGES OF THE OPERATION. + +From the prominence we have given to the unfortunate sequelae of the +operation it might possibly be inferred that, while not giving it our +absolute condemnation, we regard neurectomy with a certain amount of +distrust. That we may contradict any such false impression, we state here +that in many cases the operation is the only measure which will offer +relief from pain, and restore to work an otherwise useless animal. In +support of that we will now quote the recognised advantages of the +operation. + +That in many cases, when all other methods--surgical and medicinal--have +failed, there is an immediate and total freedom from pain and lameness no +one will deny. This, if it restores to active work an animal that would +otherwise have had to have been cast aside, is ample justification for +giving the operation, in spite of its many unfortunate terminations, a real +place among the more highly favoured remedial measures to our hand. + +'For _Contracted Hoofs_, viewing them in the light of idiopathic disease, +or as being the immediate cause of the existing lameness in the uninflamed +condition of the foot, and when consequential changes of its organism have +taken place which bid defiance to therapeutic measures, _neurotomy_ is a +_warrantable resource_' (Percival). + +'For _Ringbone_ neurotomy has been practised with perfect success, after +blistering and firing had both failed, notwithstanding the work the animal +had to perform afterwards was of the most trying nature' (_ibid_.). + +For _Navicular Disease_, when that malady is diagnosed, the earlier +neurectomy is performed the better. The greater work given to the diseased +bursa and bone, and the return of the contracted heels to the normal, +brought about by the greater freedom with which the foot is used, are +claimed by many to effect a cure. + +Writing of navicular disease, and mentioning his belief in the possibility +of the diseased bone effecting its own repair after the operation, Harold +Leeney, M.R.C.V.S., says: + +'The expansion of the heel, and rapid development of the frog (in this and +many other cases) immediately after the operation, has not, I venture to +think, attracted so much attention as it deserves, and may have something +to do with those cases which appear to be actually _cured_, not merely made +to go sound by absence of pain.'[A] + +[Footnote A: _Veterinary Record_, vol. xi., p. 297.] + +Speaking of the median operation before a meeting of the Central Veterinary +Medical Society, Professor Hobday says:[A] + +[Footnote A: _Veterinary Record_, vol. xiii., p. 427.] + +'For old-standing lamenesses, when due to splints, exostoses, chronically +sprained, thickened, and painful perforans and perforatus tendons, or cases +of that kind which cause pain by pressing on the adjacent nerve structures, +after all other known methods have failed, median neurectomy is the +operation which will be most likely to give the animal a new lease of life +and usefulness.' + +'Of the _Humanity and Utility of Neurectomy_ there can be no question +whatever, and provided the cases are well selected, and the operation +is efficiently performed, the advantages to be derived from it are most +striking as well as enduring. But the disadvantages attending the loss of +sensation in the foot have been brought forward on many occasions as +an argument against neurectomy, and no one can deny that the foot with +sensation is better than one without that faculty. But in a long experience +of the operation I have never found these disadvantages outweigh the great +advantages which have immediately followed it.'[A] + +[Footnote A: _Veterinary Journal_, vol. ix., p. 178 (Fleming).] + +Beyond these, the direct advantages of neurectomy, are other and more +indirect advantages which claim attention. + +The most astonishing among them is the fact noted by many writers of repute +that exostoses (ringbones, side-bones, splints, etc.) rapidly diminish in +size. This is vouched for by such well-known authorities as Zundel and +Nocard. + +Percival, too, mentions at some length the effect of the removal of pain on +the oestral and generative functions, quoting a case of a brood cart-mare +by reason of bony deposits being stayed from breeding for some years. Two +months after the operation she went to work, and moved sound, her altered +condition leading her to breed several healthy foals. + + +I. THE USE OF THE HORSE THAT HAS UNDERGONE NEURECTOMY. + +No operation is of any considerable value to the veterinary surgeon unless +he is able to show that after it he has left his patient workable. The +alleviation of pain alone, commendable as it is from a humanitarian +standpoint, is of no interest to the average owner of horse-flesh, unless +with it he sees his animal capable of justifying his existence by the +amount of labour performed. + +Criticised in this way, is the operation of neurectomy justifiable? Upon +that point the opinions of many practitioners, even at the present day, +differ. We have already partly answered the objections likely to be raised +on this score by stating that the work afterwards allotted the animal +should be fixed to suit his altered condition. It may be taken as a general +rule that in all cases where the animal's usefulness depends upon his +delicacy of touch, as, for example, animals used solely for hacking or +hunting, his future usefulness in that special sphere of work will be done +away with. + +Percival himself, always a strong advocate for the operation, fully +recognises this. 'Does the neurotomized horse maintain the same step +as before?' he asks. 'To this important question,' he replies, 'I +unhesitatingly answer no; he does not. There can be no doubt but that the +horse _feels_ the ground upon which he is treading, and that he regulates +his action in consonance with such feeling, so as to render his step the +least jarring and fatiguing to himself, and therefore the easiest and +pleasantest to his rider.... Such impressions'--those of touch--'being +in the neurotomized subject, so far as regards the feeling of the foot, +altogether wanting, a bold, fearless projection of the limb in action will +be the consequence, followed by a putting down of the hoof flat upon the +ground, as though it were a block, creating a sensation alike unpleasant +both to horse and rider.' + +Emphatic as Percival is upon this point, there are, nevertheless, others +who maintain with equal stoutness that the unnerved animal is positively as +safe, if not safer, than the animal who has not been so treated. + +'That the tactile sense in the horse's foot is useful, it would be idle to +deny; but that it is absolutely essential, even to safe progression, no one +who has paid attention to the results of plantar neurectomy will maintain. +On several occasions for years I have hunted, hacked, and driven horses +which have been deprived of sensation in their fore-feet, and never had an +accident with them. Their action has not been impaired by the operation; on +the contrary, it has been vastly improved compared with what it had been +previous to it. And my opinion has not been single in this respect, as many +competent horsemen can give like evidence after long and severe trials of +neurotomized horses. The opponents of neurotomy were, probably, not aware +that there is in progression a _muscular_ as well as a _tactile sense_.' + +This latter contention is supported by numerous cases, reported at the time +when the operation of neurectomy was at the heyday of its popularity. Two I +select from writings of a later period: + +_Recorded Cases_.--1. 'Two of the finest among the many fine horses in the +Second Life Guards were so lame from navicular disease, when I joined the +regiment, that they were unsafe and unsightly to ride, and were therefore +entered on the list to be cast off and sold. One was so crippled that it +could scarcely be moved out of its stable. Peeling sorry at having to get +rid of such good horses, and anxious to give another blow to the mistaken +theory that unnerved animals were unsafe, I obtained the consent of my +commanding officer, who patronizes practical conclusions, to perform +neurotomy. This was carried out on both horses about eighteen months ago. +Within a fortnight they were at their duty, absolutely free from lameness, +and with first-rate action, and one of them, from being troublesome and +unsteady in the ranks--probably from the pain in its feet--had become quite +steady and tractable. Instead of being lame, blundering, and unsafe, both +were sound, free in movement, and secure, and, the pain being abolished, +they looked improved in condition. + +'During the month of July the regiment attended the summer drills at +Aldershot, and five days every week for a month these horses carried a +weight of about 22 stones each over the roughest and most dangerous ground, +nearly always at a fast pace, and for four, five, or six hours each day; +and yet they never fell or blundered, and the troopers who rode them had +unbounded confidence in their sure-footedness. They returned to Windsor, at +the end of the month's severe test, as sound in their paces as when they +left, and certainly now offer no indication whatever that they are less +safe to ride than any other horse in the regiment. The effects of the +relief from pain are also most marked, not only in the altered gait out of +doors, but also in the stable.'[A] + +[Footnote A: _Veterinary Journal, vol_. ix., p. 178 (George Fleming, +F.B.C.V.S.).] + +2. 'Some years ago I operated upon a valuable hunter, the property of a +gentleman in Kildare, the animal having shown unmistakable symptoms +of navicular disease for some months previously, and which had been +unsuccessfully combated by the milder forms of treatment for the disease +without any benefit. Although the horse went sound, the owner feared to +ride him, and sent him to be sold in Dublin, where he was disposed of for a +small price, and I then lost sight of him. The following Punchestown +Races, to my surprise, amongst a group of horses walking round the paddock +previous to saddling for an important race, I recognised my old patient, +bandaged, clothed, and trained, ready to take his part in the cross-country +contest, and surrounded by a host of admirers willing to back him at any +price. + +'Having satisfied myself that it was no other than the same animal, my +first impulse was at once to find out the jockey who was to ride him, and +warn him of his danger by telling him his mount was devoid of feeling +in both fore-feet; but the saddling-bell had already rung, and in a few +moments more the jockey emerged from the weighing-room and the next view of +the horse was his tearing up the course in the preliminary, and "pulling +double." I was sorry for the jockey if he felt as I did at that moment, for +if he did I fear he and his horse would have parted company at the first +fence, as I was certain there would be a smash before the end of the long +and difficult three miles of the Kildare Hunt Cup course. It was not until +I saw him again in the front rank passing the stand, in the first round, +that I breathed freely, and even then I felt very guilty, and, had he come +to grief badly, I don't think I should ever have operated on another horse +except in such a way as would have left unmistakable traces after it. + +'"The old horse wins!" screamed a thousand voices as the competitors safely +cleared the last bank (now taken away for a gorse fence) the last time +round, and from that moment the operation went up in my estimation a +hundredfold, and I almost lost all interest in the finish (and it was a +close one, with my patient a good third), resolving I would operate for the +future on every animal, young and old, which showed symptoms of navicular +disease. + +'Neither owner nor jockey knew the horse had been operated on, and he was +soon after, on the strength of his performance, sold for a good price to +come to England. It is idle to think that all cases are as successful as +this was, as experience soon told me; but I consider that, in careful +hands, the advantages well outweigh the disadvantages of the operation, and +I have selected this instance merely as a practical example.'[A] + +[Footnote A: _Veterinary Journal_, vol. iii., p. 254 (W. Pallin, +M.B.C.V.S.).] + +It is solely with the object of ventilating both sides of the question +that we quote the last two cases. In our opinion, the colours in which +the results of the operation are there painted are far too rosy. The +practitioner who has before him the task of satisfying a client as to what +will or what will not be the results of an operation he has suggested will +do well to weigh each side of the argument carefully, and endeavour in his +explanation to strike the happy mean. + +We hold, further, that the animal who has previously been accustomed to +fast work, and to work entailing a large call upon the sense of touch when +passing over rough and uneven ground, will be far more likely, in his +neurectomized condition, to give satisfaction to his owner if put to a +slower and a more suitable means of earning his living. + + + +CHAPTER VI + +FAULTY CONFORMATION + + +Under this heading we shall deal with such formations of the feet as depart +sufficiently from the normal to render them serious. Faulty conformation +may be either congenital or acquired, and acquired gradually as the result +of slowly operating causes, or suddenly as the sequel to previous acute +disease. Whether congenital or acquired, serious in its nature or +comparatively of no account, the veterinary surgeon will often find that +the matter of conformation is one which will have a direct bearing on many +of his 'foot' cases, and, furthermore, that it is one upon which he will +often be called to give advice. + + +A. WEAK HEELS. + +_Definition_.--That condition of the wall in which, owing to the softness +of the horn and the oblique direction of the horn fibres, the heels are +unable properly to bear the body-weight, and, as a consequence, curve in +beneath the sole. We give the condition first mention, not because of its +greater importance, but for the reason that it is frequently the forerunner +of the condition to be next described--namely, contracted feet. + +_Symptoms_.--The extreme point of the heel is not affected unless the foot +has been greatly neglected, and the condition allowed to develop. Where, +however, the foot has been uncared for, curving in of the wall takes place +to an alarming degree, and the heels curl underneath the foot to such an +extent as to grow over the sole and the bars. By the pressure they exert on +the sole corns result, and the animal is lamed. + +_Causes_.--In the main this defect is hereditary. It is seen commonly in +connection with flat-foot, and where the horn of the wall is thin and +shelly. + +_Treatment_.--In the case of weak or 'turned in' heels no suitable bearing +is offered for the shoe in the posterior half of the foot. Any attempt to +induce the heels to bear weight is immediately followed by their bending +in. It follows from this that the best shoe to be used here is one in which +the bearing is confined to the anterior half of the wall, the heels being +relieved by being sufficiently pared. As might be expected, this bearing on +the anterior half only of the foot is insufficient; pressure must be given +the frog. This latter end is best gained by a bar shoe (Fig. 68). With it +the anterior portions of the wall, the whole of the bars, and the whole +of the frog may be in contact, and the heels only so pared as to take no +bearing at all. A few such shoeings sees the defect remedied. In every +instance paring of the sole should be discouraged, as it serves but to +increase the deformity. + + +B. CONTRACTED FOOT. + +_(a)_ GENERAL CONTRACTION--CONTRACTED HEELS. + +_Definition_. By the term contracted foot, otherwise known as hoof-bound, +is indicated a condition in which the foot, more especially the posterior +half of it, is, or becomes, narrower from side to side than is normal. + +It must be borne in mind, however, that certain breeds of horses have +normally a foot which nearer approaches the oval than the circular in form, +and that a narrow foot is not necessarily a contracted foot. + +The contraction may be bilateral when affecting both heels of the same foot +and extending to the quarters, or unilateral when the inside or outside +heel only is affected. + +In some cases contraction is confined to one foot, while in others it may +be noticed equally bad in both. It is a matter of common knowledge that +contraction is usually seen in the fore-feet, while the hind seldom or +never suffer from it, a fact which, to our minds, seems difficult of +adequate explanation. Zundel explains this by stating that contraction is +principally _observed_ in the fore-feet, by reason of the fact that when +lameness arises from it alteration in action will more readily be detected +in front than behind. Percival, on the other hand, suggests that the +greater expansive powers of the hind-foot, by reason of the impetus of its +action, is able to overcome any influence operating towards contraction. It +may be, however, that given a cause for contraction, such as the removal of +the frog's counter-pressure with the ground by faulty shoeing or excessive +paring, the fore-feet, by reason of their being called upon to bear the +greater part of the body-weight, are the first to suffer. + +Flat feet with weak heels are those most frequently affected, and, as we +have already intimated, the condition may exist with or without other +disease of the foot. + +Depending upon its degree, contracted foot may vary from a simple +abnormality, non-inflammatory and painless, to a condition in which it +becomes a veritable disease, giving rise to a bad form of lameness, and +bringing about a withered and sometimes discharging and cankerous affection +of the frog. + +_Symptoms_.--In its early stages contraction is difficult of detection, and +where both feet are affected may for some time go unsuspected. With only +one foot undergoing change, the early stages may the more readily be +marked, for in this case comparison with the other and sound foot will at +once reveal the alteration in shape. If lameness in the suspected foot is +present, then any lingering doubt will be quickly dispelled. + +When far advanced, contraction offers signs that cannot well be missed. The +converging of the heels narrows the V-shaped indentation in the sole for +the reception of the frog. As a consequence of this, the frog itself +becomes atrophied by reason of the _continual_ pressure exerted upon it by +the ingrowing horn of the wall and the bars. The median and lateral lacunae +of this organ, from being fairly broad and open channels, become pressed +into mere crack-like openings (see the commencing of this condition in Fig. +80, and a badly wasted frog in Fig. 74A). As the case goes on, the lateral +branches of the frog entirely disappear, and all that is left of the organ +is a remnant of its body or cushion, now wedged in tightly between the +bars. Following upon the disappearance of the frog, we find that the bars +are in contact, or, in some cases, actually overlapping each other at their +posterior extremities. + +At this stage, perhaps, the whole condition has become aggravated by a foul +discharge from the place originally occupied by the frog, and the foot, +especially in the region of the heels, has become hot and tender--really a +form of local and subacute laminitis. + +The long-continued inflammation, although only of a low type, renders the +horn of the hoof hard and dry, and only with difficulty will the ordinary +foot instruments cut it. This in its turn leads to cracks and fissures in +various places, but more especially in the bars and what is left of the +frog. Often, too, cracks will appear in the horn of the quarters, and a +troublesome and incurable form of sand-crack results. + +An animal with contraction advanced as far as this, especially if confined +to one foot, goes unmistakably lame. With both feet affected, he ordinarily +starts out from the stable in a manner that is commonly called 'groggy.' In +other words, the gait is uncertain, and feeling; and stumbling is frequent. +Anyone who has had the misfortune to drive an animal with feet in this +condition knows full well that every little irregularity in the road at +once makes itself felt to the feet, and that the animal, as time goes on, +learns to carefully avoid any suspicious-looking group of stones he may +see. To drive an animal like this is to keep one's self continually on +tenter-hooks, for, sooner or later, the inevitable happens, and the animal +comes down. + +Up to now we have described the changes of form in the hoof as seen when +the contracted foot is viewed from the solar surface. With those changes as +evident as we have depicted them, there will be no difficulty in detecting +the alterations in the form of the wall. + +In addition to a narrowing from side to side there will be noticed an +abnormal straightness of the quarters, with a turning in, more or less +sudden, of the heels. This effect is given in these cases by the smith +maintaining the shoe of a length and width that should normally fit a foot +of that particular animal's size and substance. This is probably done with +the idea of deceiving anyone examining the solar surface. Viewed from this +position, the width of the shoe at the heels gives the impression that it +is attached to a foot of normal breadth. This deception is heightened if +at the same time has been practised the process of 'opening up the heels.' +That expression indicates that the bars have been removed, and the lateral +lacunae of the frog made to continue the concavity of the sole. The arch of +the latter is thus made to appear of much greater extent than it really is, +and the heels, by reason of their being abruptly cut off when removing the +bars, also convey the false impression of being wide apart. + +The practitioner unversed in the tricks of the forge will best guard +against this by viewing the foot, while on the ground, from behind. From +that position he will be able to detect the lowness of the quarters, and +the projecting portion of the shoe, that the hoof, by reason of its sudden +bending inwards, does not touch. + +The 'feeling' manner of the gait before alluded to, together with the +disinclination to put the foot firmly and squarely forward, will sometimes +lead the examiner to over-look the contraction, and diagnose his case as +one of shoulder lameness. In many cases, too, such consequent conditions +as 'thrushy frogs' and 'suppurating corns' are often treated with utter +disregard of the contraction that has really brought them about. But above +all, the disease most likely to be confounded with simple contraction is +navicular disease. More than probable it is that many cases of so-called +'navicular' have in reality been nothing more than contraction brought +about by one or other of the causes we shall afterwards enumerate--cases +where a due attention to the prime cause of the mischief would, in all +likelihood, have remedied the lameness. + +_Changes in the Internal Structures_.--It follows as a matter of course +that the changes we have described in the form of the hoof itself carry +with them alterations in the bones and sensitive structures beneath it. The +tissues, as a whole, become atrophied. The os pedis becomes deformed, loses +its circular shape, and gradually becomes more or less oval in contour. +At the same time, its structure becomes more compact, the cribriform +appearance of its anterior and lateral faces more or less destroyed, and +the few remaining openings apparently increased in size. This atrophy of +the os pedis is best noted at the wings. + +In the plantar cushion the effects of the atrophy are noted in the +smallness of the organ, in its becoming whiter in colour than normal, and +more resistant to pressure. + +The coronary cushion is also affected in the same way, where the changes +are noted most in its posterior portions. + +A further effect of the narrowing of the heels, and their consequent +tendency to drop downwards, is the exertion of a continual pressure on the +sensitive sole. In course of time, and especially in flat feet, this leads +to the appearance of corns. + +The navicular bone and bursa and the tendon of the perforans also suffer +from the effects of compression. The movement of the tendon is restricted, +and arterial supply to the adjacent structures rendered deficient. The +tissues of the bone and bursa are insufficiently nourished, and the +secretion of synovia lessened. In this way it is conceivable that navicular +disease may follow the condition of simple contracted heels. + +In common with the other structures, the lateral cartilages also suffer +from the continual pressure. Their blood-supply is lessened, their +functions interfered with, and side-bones result. + +_Causes_.--Upon the causation of contraction a very great deal has been +written, both by early veterinarians and by those of the present day. Many +and widely differing opinions have been advanced, but a careful resume of +only a few will lead one to certain fixed conclusions. + +We may consider the causes of contraction under two headings--predisposing +and exciting. + +_Predisposing Causes of Contraction_.--Among these we will first mention +heredity, although it is possible it should not be deemed of so great +account as it is by some. That the shape of certain feet, especially those +with low heels and abnormally sloping walls, predisposes to contraction no +one will deny. So long, however, as the animal goes unshod, so long does +the foot maintain a normal condition of the heels. In other words, it +is not until the tendency to contraction already there is aggravated by +careless shoeing and the effects of work that it operates to any noticeable +extent. + +The degree of contraction will also be very largely governed by the amount +of the development of the frog. With a frog of good size, low down, and +taking part in the pressure of the foot on the ground, contraction will +be prevented. On the other hand, an ill-developed frog, one wasted by +long-continued and spreading thrush, or one robbed of its normal function +by excessive paring in the forge, is a common starting-point of the +condition we are considering. We have already referred to this in Chapter +III., when considering the experiments of Lungwitz in this connection. What +we have to bear in mind in these experiments is that the application of +a pad to the frog, in such a manner that effective ground-pressure is +obtained, results always in a marked expansion of the heels, and that, with +counter-pressure with the ground absent, expansion occurs to little or +no extent. This is proof positive of the enormous part the frog plays in +maintaining an open and elastic condition of the heels--a fact so insisted +on by Coleman. + +It is worthy of mention, however, that loss of the frog's function does not +operate to nearly so serious an extent in horses with high, upright heels +as in those with the heels low and excessively sloping. + +In illustrating this, Mr. Dollar, in his work on shoeing, mentions the case +of a pair of trotting horses of similar age, size, and weight, each having +weak fore-heels. In one case the hoofs were flat, in the other upright. The +horse with the flat hoofs suffered from contraction, while the other did +not. + +The reason appears to be that in the animal with upright hoofs the +proportion of body-weight borne by the heels is considerably less than in +those with the hoofs flat and sloping. + +Certain conditions of the horn-producing membranes also predispose to +contraction. For example, in horses reared on marshy soils, and afterwards +transferred to standing in town stables, we find that a dry and brittle +condition of the horn supervenes. This we may regard as a low form of +laminitis, brought about by the heat of the material upon which the animal +is standing, and the congestion of the feet engendered by his enforced +standing for long periods in one position, as opposed to the more or less +continuous exercise when at pasture. With the hoof in this condition it +loses by evaporation the moisture that normally it should contain, and, as +we might expect, a certain degree of contraction of its structure is the +inevitable result. + +We thus see that contraction brought about in this way is not so much +caused by the heat of the stable, as it is by the decreased ability of the +horn to retain its own moisture. + +On the other hand, it cannot be denied that excessive warmth and dryness +combined tend also to an undue abstraction of moisture, even from the horn +of the healthy foot; and this explains in great measure how it is that +lameness, as a rule, and especially that proceeding from contracted heels, +is far more frequent and of greater intensity in the hot, dry months of +summer, than in the cooler and more humid atmosphere of winter. It is +interesting to note, too, that an alternation of humidity and dryness +is far more liable to injure the quality of the horn and tend to its +contraction than the long-continued effects of dryness alone. A common +illustration of this is to be found in the effects of the ordinary +poultice. Everyone knows that when, after a few days' application, they are +discontinued, we get as a result an abnormally dry and brittle state of +the horn. This is doubtless due to the poultice removing the thin, +varnish-like, and protective pellicle known as the periople, and thereby +allowing the process of evaporation to act on the water normally contained +in the hoof. + +_Exciting Causes of Contraction_.--Among these, first place must +undoubtedly be given to shoeing. This does not necessarily imply shoeing +more than ordinarily faulty, nor a faulty preparation of the foot, but +shoeing as it is generally practised. No ordinary shoe, except a few +devised for the purpose, such as the Charlier or the tip, allows the frog +to come in contact with the ground. This we take to be the main factor in +the causation of contracted heels, especially with a predisposition already +present in the foot itself. In the words of Lungwitz: 'Regarded from this +point of view, there is no greater evil than shoeing. It abolishes the +necessary counter-pressure, and thus interferes with expansion. Bars, sole, +and frog cannot perform the functions that naturally belong to them as they +would do without the shoe.' + +In addition to the evil of the shoe itself, errors of practice in the forge +contribute to the causation of contraction. Taking first the preparation of +the foot, we find that often the heels are lowered far too much, and the +toe allowed to remain too long. This can have but one effect--that of +throwing a greater proportion of the animal's weight upon the heels than +properly they should bear, with, what we now know to be the consequence of +that, a corresponding pushing inwards and downwards of the horn; in other +words, contraction. + +Excessive paring of the bars, to which we have already partly alluded, is +also an active agent in bringing about an inward growth of the horn of the +heels and quarters. The bar, or inflexion of the wall at the heel, by means +of its close contact with the frog, communicates the outward movements +of that organ to the wall of the hoof. With the bar removed, the outward +movements of the frog under pressure are naturally rendered of no account, +and a proper and intermittent expansion of the wall denied it. The same +evil follows, though to a less extent, excessive paring of the sole. + +The shape of the bearing surface of the shoe is often to be blamed. Where +this is concave--'seated'--and the 'seating' is carried back to the +heels, it is easy to see that, when weight is on the foot, there is an +ever-present tendency for the bearing edge of the wall to slide down +towards the inner edge of the shoe. This tendency, operating on both the +inner and outer wall simultaneously, must strongly favour contraction. + +A further wrong practice is that of continuing the nailing too far towards +the heels. In our opinion this is not now often met with. When it occurs +its effect is, of course, to prevent those movements of expansion of the +wall which we now know to be normal and most marked at the heels. + +It may be remarked of the build of the shoe, or of errors in the +preparation of the foot, that neither are of much moment. Neither are +they. But when one stays to consider that errors of this description are +practised not only once, but each time the horse goes to the forge, and +that with some of them--those relating to the build of the shoe--the injury +thereby brought about is inflicted not only once, but every day that +particular shoe is worn, then it is not to be wondered at that, sooner or +later, ill consequences more or less grave result. + +_Prognosis_.--This will depend to a very large extent upon the conformation +of the limb, and upon the previous duration of the contraction. Contraction +of long standing, where atrophy of the sub-lying, soft structures and the +pedal bone may be expected, will prove obstinate to treatment. Especially +will this be so if the lateral cartilages have become ossified. Neither may +we look for much benefit from treatment if the contraction has occurred in +animals with an oblique foot axis and flat hoofs. + +On the other hand, if the case is comparatively recent, if the limb +is straight and the form of the hoof is upright, and if matters are +uncomplicated by side-bones, or other serious alteration in the internal +structures, then treatment may be rewarded with some measure of success. + +[Illustration: FIG. 63.--TIP SHOE. The dotted portions represent the length +of the branches removed.] + +_Treatment_.--The greater part of the treatment of contracted foot will +almost suggest itself as a corollary of the causes we have enumerated. The +normal width of the heels may be renewed, and development of the wasted +frog brought about by one of three methods: + +1. By restoring the pressure from below to the frog. + +2. By the use of an expansion shoe. + +3. By operative measures upon the horn of the wall. + +1. _By Restoring the Pressure from Below to the Frog_. + +This may be accomplished as follows: + +_(a) By Shoeing with Tips_.--This method is advocated by Percival, by A.A. +Holcombe, D.V.S., Inspector. Bureau of Animal Industry, U.S.A., by Dollar +in his work on horseshoeing, and by many others. + +Though requiring more care than in fitting the ordinary shoe, the +application of a tip is simple. In reality, the tip is just an ordinary +shoe shortened by truncating the heels. + +Before applying the tip, the horn of the wall at the toe should be +shortened sufficiently to prevent any undue obliquity of the hoof, and the +foot should be so prepared as to allow the heels of the tip to sink flush +with the bearing edge of the wall behind it. + +When the foot does not allow of the removal of much horn at the toe, what +is termed a 'thinned' tip is to be preferred. Its shape is sufficiently +shown by the accompanying figure (Fig. 65). + +With the tip the posterior half of the foot is allowed to come into contact +with the ground, and the object we are striving for--namely, frog pressure, +and greater facilities for alternate expansion and contraction of the +heels--is thus brought about. + +[Illustration: FIG. 64.--THE TIP SHOE 'LET IN THE FOOT.] + +[Illustration: FIG. 65.--THE THINNED TIP.] + +_(b) By Shoeing with the Charlier_.--The results brought about by the use +of a tip may be arrived at by the application of a Charlier or preplantar +shoe, or by a modified Charlier or Charlier tip. + +Briefly described, a Charlier is a shoe that allows the sole and the frog +to come to the ground exactly as in the unshod foot. This is accomplished +by running a groove round the inferior edge of the hoof by removing +a portion of the bearing edge of the wall with a specially devised +drawing-knife. Into this groove is fitted a narrow and somewhat deep shoe, +made, preferably, of a mixture of iron and steel, and forged in such a +manner that its front or outer surface follows the outer slope of the wall. + +The Charlier should have the inner edge of its upper surface very slightly +bevelled, in order to prevent any pressure on the sensitive sole, and +should be provided with from four to six nail-holes. These latter should be +small in size and conical in shape. The nails themselves should be small, +and have a conical head and neck, to fit into the nail-hole of the shoe. + +[Illustration: FIG. 66.--THE SPECIAL DRAWING-KNIFE (FLEMING'S) FOR +PREPARING THE FOOT FOR THE CHARLIER SHOE.] + +The modified Charlier, or Charlier tip, perhaps the better of the two for +the purpose we are describing, is really a shortened Charlier, and bears +the same relation to the Charlier proper as the tip does to the ordinary +shoe. It is let into the solar surface of the foot in exactly the same +manner as its larger fellow, but it does not extend backwards beyond the +commencement of the quarters. By its use greater opportunity for expansion +is given to the heels than is done by the Charlier with heels of full +length. + +[Illustration: FIG. 67.--FOOT PREPARED FOR THE CHARLIER SHOE.] + +We do not here intend to deal at any length with the arguments for and +against the Charlier as regards its adoption for general use. These will be +found fully set out in any good work on shoeing. + +The point that it is correct in theory it would be idle to attempt to +evade; but that it is generally practicable, or that it offers any very +pronounced advantages, as compared with the disadvantages urged against it, +over the shoes in ordinary use, the limited favour it has drawn to itself, +since its introduction in 1865, seems sufficiently to deny. + +_(c) By the Use of a Bar Shoe_.--Where the frog is not excessively wasted +benefit will be derived from the use of a bar shoe. + +[Illustration: FIG. 68.--BAR SHOE.] + +The transverse portion at the back, termed the 'bar,' and which gives +the shoe its name, is instrumental in bringing about from below that +counter-pressure on the frog that we now know to be so necessary a factor +in remedying contraction. When the frog, by wasting or disease, is +so deficient as to be unable to reach the 'bar,' this shoe must be +supplemented by a leather or rubber sole. + +In the event of corn or sand-crack existing with the contraction, the shoe +known as a 'three-quarter bar' is preferable (see Fig. 103). The break here +made in the contour of the shoe allows of dressing the corn, and, in the +case of sand-crack, removes the bearing from that portion of the wall. +_(d) By the Use of a Bar Pad and a Heelless or 'Half' Shoe_.--The bar +pad consists of a shape of rubber composition firmly fixed to a leather +foundation, which shape of rubber takes the place of the 'bar' of the bar +shoe. + +[Illustration: FIG. 69.--RUBBER BAR PAD ON LEATHER.] + +[Illustration: FIG. 70.--THE BAR, PAD APPLIED WITH A HALF-SHOE.] + +For habitual use in such cases as prove obstinate to treatment, or where +a complete cure was never from the commencement expected, the bar pad is +undoubtedly one of the most useful inventions to our hand. The animal's +'going' is improved, the tender frog is protected from injury by loose +stones, and greater comfort given to both the horse and the driver. + +[Illustration: FIG. 71.--FROG PAD.] + +[Illustration: FIG. 72.--FROG PAD APPLIED.] + +_(e) By the Use of a Frog Pad and a Shoe of Ordinary Shape_.--The shape of +rubber on this pad is designed to cover the frog only. Its shape and mode +of application is sufficiently shown in the accompanying illustrations. + +_(f) By turning out to Grass_.--Where the expense of keep is no object, a +return of contracted feet to the normal may be brought about by removing +the shoes and turning the animal out to pasture, thus giving the feet the +advantages to be derived from a more or less continuous operation of the +normal movements of expansion and contraction. In this case the treatment +must extend from three to four, or possibly six months. + +2. _By the Use of Some Form of Expansion Shoe_. + +[Illustration: FIG. 73.--SMITH'S EXPANSION SHOE SEEN FROM ITS GROUND +SURFACE AND FROM THE SIDE. _a_, The screw, with a fine-cut thread; _b_, nut +which travels along it; _c_, a hollow thimble into which the screw passes +at one end, the other being cut out V-shaped to catch into a slot (_d_) on +the shoe; _e, e_, the grip[A] for the bars, the length and direction of +which depend upon the shape of the foot; _f, f_, the counter-sunk rivets +forming the hinge (_f_'); _g_, the counter-sunk rivet of the expanding +piece.] + +[Footnote A: The inventor of this shoe uses the word 'grip' to denote what, +in describing other expansion shoes, we term the 'clip' (H.C.R.).] + +_(a) Smith's_.--For many years past continental writers have been +practising this method. So far as we know, however, Lieutenant-Colonel Fred +Smith was the first English veterinarian to use a shoe of his own devising, +and to report on its effects. This shoe we will, therefore, give first +mention. + +The above figure, with its accompanying letterpress, sufficiently explains +the nature of the shoe. In fitting the shoe, care must be taken to have the +hinges (_f, f_) far enough back, or the shoe will have a tendency to spring +at the heels, and the grips _(e, e)_, which catch on the bars, will have +a difficulty in biting. This trouble will be avoided by having the hinges +about 1-1/2 to 2 inches from the heels. + +After the shoe has been firmly nailed to the foot, the travelling nut _b_ +is driven forward on the screw _a_ so as to cause the grips to just catch +on the inside of the bars of the foot. According to the inventor, the +amount of pressure to be exerted must be learned by experience, and he +says: + +'I screw up very gradually until I see the cleft of the frog just beginning +to open. I now trot the horse up, and if he goes sound it is certain that +the pressure I have exercised will not give rise to trouble. The animal is +sent to work to assist in the expansion of the foot. On examining the shoe +next day, the grip is found to be quite loose, the foot has enlarged, and +the nut is turned once more until the grip on the bars is tightened, the +horse being again trotted to ascertain that no injurious pressure is +exerted. + +'Every day or two I repeat this process, making measurements in all cases +before widening the heels. The increase in width of the foot which results +is astonishing, 1/4 to 3/8 inch during the first week may be safely +predicted, and in a month to six weeks it is impossible to recognise in the +large healthy frog and wide heels, the shrivelled-up organ of a short time +before.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 98.] + +It is pointed out by the writer of the above (and his observations, +doubtless, apply to the use of all other expansion shoes in which the bars +are gripped and forcibly expanded) that the whole secret of success lies +in avoiding injurious pressure by exerting too great an expansion at one +operation. After each manipulation of the expanding apparatus the horse +should trot sound and the frog remain cool. Should the foot become hot, and +lameness supervene, then tension should at once be relaxed. + +_Recorded Cases of the Use of the Shoe_.--The inventor of the shoe relates +two cases of contracted foot treated by these means in which the heels +of one, after thirty-nine days' treatment, had increased in width to the +extent of 1 inch, and the heels of the other, after twenty-four days', had +enlarged 5/8 inch. Of the first case he gives the drawings in Fig. 74. + +A represents the foot before treatment; B the same foot after nine days' +treatment, when the heels had widened 3/4 inch; and C the same foot at +the end of the thirty-nine days' treatment, at which date the frog was an +excellent-looking one, and the foot had increased an inch in width.[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 100] + +[Illustration: FIG. 74.--THE CHANGES IN FORM OF A CONTRACTED FOOT TREATED +WITH SMITH'S EXPANSION SHOE] + +In 1893, at a meeting of the Midland Counties Veterinary Medical +Association, the late Mr. Olver said he had applied this shoe to a valuable +hunter that had gone so lame that he could scarcely put his foot to the +ground. After a fortnight's application, and by the assistance of the +double screw in the shoe, the heel was forced out. Then the horse was put +to work with the shoe on, and he had hunted the whole of the last season in +a perfectly sound condition.[A] + +[Footnote A: _Veterinary Record_, vol. vi., p. 143] + +F.D. McLaren, M.R.C.V.S., writes:[A] 'I resolved to try one of Captain +Smith's shoes in a case where the hoof was badly contracted, and where the +frog had entirely disappeared, there being also slight lameness. The roof +rapidly expanded, and every other day the nut was moved on a bit to keep +the cross-piece tight. I then had the cross-piece bent downwards a little +_to prevent the nut pressing on the rapidly-growing frog_.[B] After another +fortnight or so, I had a shoe made with clips resting against the inside of +the bars,[C] and the next time he was shod these were also dispensed with. +It is now a year ago since the animal recovered his frog, and he still has +the largest frog in the stable, and the hoof shows no sign of contraction.' + +[Footnote A: _Ibid_., vol. vi., p. 183] + +[Footnote B: The italics are mine (H.C.R.).] + +[Footnote C: The expanding shoe itself was here evidently dispensed with, +and an ordinary shoe with bar-clips used in its stead (H.C.R.).] + +_(b) De Fay's_.--Among other shoes of the expansion class may be mentioned +that of De Fay. Like the preceding, it is a shoe with a flat bearing +surface, and provided with bar-clips. It is, however, _un_ hinged. The +requisite degree of periodic expansion is in this case arrived at by a +forcible widening of the heels of the shoe, accomplished by bending +the substance of which it is made, and for this purpose the instrument +illustrated in Fig. 75 is employed. + +The foot is first properly trimmed by levelling the heels and thinning +the sole on each side of the frog. The shoe is then fixed by nails in the +ordinary manner, taking care that the last nails come not too far back, and +that the clips rest evenly and firmly on the inside of the bars. + +The dilator, hoof-spreader, or vice, as it is variously called, is then +applied, its two jaws (_a_ and _b_) fitting against the inner edge of +the shoe at the heels. Careful note is taken of the width of the hoof as +measured on the graduated scale (_e_, _e_), and the double screw (_g_, _h_) +revolved by means of the wrench (k), until the opening of the jaws thus +obtained registers an expansion of 1/12 to 1/8 inch. + +The dilatation is repeated at intervals of from eight to ten days, until, +at the expiration of a month or six weeks, the amount of total expansion of +the heels registers nearly an inch. That the method requires the greatest +care may be gathered from the reports of continental writers. They state +that frequently the pain and consequent lameness keep the patient confined +to the stable for several days. + +Numerous and but slightly differing forms of the dilator are on the market. +As in principle they are all essentially the same, and are to be found +illustrated in any reliable instrument catalogue, they need no description +here. + +[Illustration: FIG. 75.--DE FAY'S VICE.] + +_(c) Hartmann's_.--A further useful expansion shoe is that of Hartmann's +(Fig. 76), in that it may be adapted for either unilateral or bilateral +contraction. This shoe is also provided with bar-clips, and forcibly +expanded at the heels by means of a dilator. The expansion is governed by +saw-cuts through the inner margin of the shoe directed towards its outer +margin, and running only partially through the inner half of the web (see +Fig. 76). + +According as the contraction is confined to the inner or outer heel, the +saw-cuts, one or two in number, are placed to the inner or outer side of +the toe-clip. When the contraction is bilateral, the saw-cuts, one or more +in number, are placed on each side of the toe-clip. + +_(d) Broue's_.--This is one of the forms of so-called 'slipper' shoes (see +Fig. 77). We have already indicated that the shape of the bearing surface +of the ordinary shoe--by its 'seating' or sloping from outside to +inside--is sometimes a cause of contraction. In the 'slipper' of Broue +this bearing is reversed, and the slope is from inside to outside. In +the original form of this shoe the slope to the outside was continued +completely round the shoe. Experience taught that the strain this enforced +upon the junction of the wall with the sole was injurious, and that the +'reversed seating,' if we may so term it, was best confined to the hinder +portions of the shoe's branches. + +[Illustration: FIG. 76. This figure illustrates the principle of the +Hartmann expanding shoe. _a, a_, The clips to catch the inside of the bars; +_b, c_, saw-cuts.] + +The amount of slope should not be excessive. If it is, too rapid and too +forcible an expansion takes place, and pain and severe lameness results. +Dollar gives the requisite degree of incline by saying that the outer +margin of the bearing surface of the shoe should be from 1/12 to 1/8 inch +lower than the inner. + +In the case of the Broue slipper, it is the animal's own weight that brings +about the widening of the heels, the slope or outward incline of the +slipper simply causing the inferior edge of the wall at the heels to spread +itself outwards instead of sliding inwards on the bearing surface of the +shoe. + +[Illustration: FIG. 77.--THE SLIPPER SHOE OF BROUE.] + +_(e) Einsiedel's_.--Like the 'slipper' of Broue, the Einsiedel shoe depends +for its effects upon the slope of the bearing surface. + +It differs from the Broue in being provided with a 'bar-clip.' This, in +addition to gripping the bars like the bar-clips of other expanding +shoes, also assists, under the body-weight, in expanding the heels by the +pronounced slope given to its upper surface. The expanding force exerted +by the body-weight falls thus, through the medium of the bar-clip, clip, +_partly_ upon the bars, instead of, as in the Broue, solely upon the wall. +We say _partly_ advisedly, for, in addition to the slope upon the outer +side of the bar-clips, the bearing surface of the heels of the shoe is +_slightly_ sloped outwards also. The good office served by the bar-clip is +the lessening of any tendency to strain upon the white line. + +[Illustration: FIG. 78.--THE SLIPPER AND BAR-CLIP SHOE OF EINSIEDEL.] + +Those we have described by no means exhaust the number of expansion shoes +that have been devised. There are numerous others, many of which are +composed of three-hinged portions, the two hindermost of which are +gradually separated by a toothed arrangement of their inner margins and +a travelling bar, the disadvantage of which is that it is liable to work +loose. In the majority of this class of shoe the hinges are placed far +forward, one on each side of the toe. They there become exposed to +excessive wear. In fact, against the bulk of this form of shoe it may +be urged that they cannot be worn by the animal at work, that they are +expensive, difficult to make, and easily put out of order. + +3. _By Operations on the Horn of the Wall_. + +_(a) Thinning the Wall in the Region of the Quarters_.--This is best +done by means of an ordinary farrier's rasp. The thinning should lessen +gradually from the heel for 2-1/2 to 3 inches in a forward direction. That +portion of the wall next to the coronary border, about 1/2 inch in breadth, +should not be touched. At this point the thinning should commence, should +be at its greatest, and lessen gradually downwards until at the inferior +margin of the wall the normal thickness of horn is left. The animal is then +shod with a bar shoe and the hoof bound with a bandage soaked in a mixture +of tar and grease, in order to keep the thinned portion of the wall from +cracking. In this condition the animal may remain at light labour. + +When possible, however, it is better to combine the thinning process thus +described with turning out to grass. In this case the ordinary shoe is +first removed, and the foot poulticed for twenty-four hours to render +the horn soft. The foot is then prepared by slightly lowering the +heels--leaving the frog untouched--and thinning the quarters in exactly the +manner described above. + +After this is done, the animal is shod with an ordinary tip, a sharp +cantharides blister applied to the coronet, and then turned out in a damp +pasture. In this case the object of the tip is to throw the weight on +to the heels and quarters. The thinned horn yields to the pressure thus +applied, and a hoof with heels of a wider pattern commences to grow down +from the coronet. Two to three months' rest is necessary before the animal +can again he put to work.[A] + +[Footnote A: This is the treatment strongly advocated by A.A. Holcombe, +D.V.S., Inspector, Bureau of Animal Industry, U.S.A.] + +_(b) Thinning the Wall in the Region of the Toe_.--This is done with +the idea that the tendency of the heels to expand under pressure of the +body-weight is helped by the thinned portion at the toe allowing the heels +to more readily open behind. Seeing that in the case of toe sand-crack the +converse is argued--that contraction of the heels readily takes place and +forces the sand-crack wider open--it is doubtful whether this method is of +any utility in treating contracted heels. + +_(c) Grooving the Wall Vertically or Horizontally, and Shoeing with a Bar +Shoe_.--Marking the wall with a series of grooves, each running in a more +or less vertical direction, was suggested to English veterinarians by +Smith's operation for side-bones. + +The manner of making the grooves, and the instruments necessary, will be +found fully described in Section C of Chapter X. + +That the method is followed by satisfactory results the undermentioned case +will show: + +'A mare, which I have had in my possession since she was a foal, has always +had contracted feet, which were also unnaturally small.... Lately the mare +has been going very "short," and at length her action was quite crippled. +At times she was decidedly lame on the off fore-foot. At no time have I +been able to detect any sign of structural disease. I thereupon concluded +that the lameness was due to mechanical pressure on the sensitive +structures, and I determined to try the effects of the above treatment. As +this was my first experience of the process, I was careful to carry it out +in all its details, as described by Professor Smith. After the bar shoes +had been put on, the mare was very lame. I allowed her two days' rest, then +commenced regular walking exercise, and she daily improved. After fourteen +days there was no lameness, but still short action. I thereupon gave the +mare another week's walking exercise, at the expiration of which I drove +her a short turn of five miles, which she did quite well, and free from +lameness. For three months I kept the saw-cuts open to the coronet, and +continued the bar shoes, keeping the mare at exercise, and giving her +occasionally a drive. She never liked the bar shoes, and I was glad when I +could discontinue them, which I did in the fourth month. When shod with the +usual shoes the complete success of the treatment was shown. I have now had +her going with the ordinary shoes for the past two or three months, and the +improvement in the shape of the feet is very marked; there is no lameness; +the mare is free in movement, fast, and spirited, whereas previously she +was quite the reverse, and almost unfit to drive.'[A] + +[Footnote A: W.S. Adams, M.R.C.V.S., _Veterinary Journal_, vol. xxx., p. +19.] + +This method, though but recently introduced to the English veterinary +surgeon, is by no means new. According to Zundel, it was recently made +known on the Continent by Weber, but was previously known and mentioned by +Lagueriniere, Brognier, and Hurtrel d'Arboval. + +When the grooving is in a horizontal direction, a single incision is +sufficient. This is made 3/4 inch below the coronary margin of the wall, +and parallel with it, extending from the point of the heel for 2 or 3 +inches in a forward direction. As in the previous method, a bar shoe is +applied, and the animal daily exercised. Thus separated from the fixed +and contracted portion of the wall below, the more elastic coronet under +pressure of the body-weight commences to bulge. The bulging is of such +an extent as to cause the new growing hoof from the top to considerably +overhang the contracted portion below, and cure of the condition results +from the newly-expanded wall above growing down in a normal direction. + +This consideration of contracted heels may be concluded by drawing +attention to the advisability of always maintaining the horn of the wall in +as soft and supple a condition as is natural by the application of suitable +hoof dressings. + +A useful one for the purpose is that made with lard, to which has been +added a small quantity of wax or turpentine. + +Especially should a dressing like this be used when the hoof is inclined +to be hard and brittle, and where tendency to contraction has already been +noticed. + +The application of a hoof ointment is also particularly indicated where the +foot is much exposed to dampness, where the animal is compelled to stand +for long periods upon a dry bedding, or where the bedding is of a substance +calculated to have a deleterious effect upon the horn. + +This, in conjunction with correct shoeing, will probably serve to avoid the +necessity for more drastic measures at a later time. + +_(b)_ LOCAL OR CORONARY CONTRACTION. + +_Definition_.--Contraction at the heels, confined to the horn immediately +succeeding that occupied by the coronary cushion. Really, the condition is +but a somewhat arbitrary subdivision of contracted hoof, as we have just +described it in general. For that reason we shall give it but very brief +mention. + +_Symptoms_.--In this case the horn of the heels, instead of running down +in a straight line from the coronary margin to the bearing surface of the +wall, presents a more or less distinct concavity (See Fig. 79, _a_, _a_). + +As is the case with contraction considered as a whole, this deformity may +affect one or both heels; and during its first appearance, which is after +the first few shoeings, the animal may go distinctly lame. + +_Causes_.--Coronary contraction may occur in hoofs of normal shape +immediately shoeing is commenced, and frog pressure with the ground +removed. It is far more likely to ensue, however, if the hoof is flat, +with the heels low, and the wall sloping. And with those predisposing +circumstances it is that the horse goes lame, and not with the hoof of +normal shape. + +Seeing, then, that this condition is largely dependent upon the shape of +the foot, we may, to some extent, regard it as hereditary. Seeing further, +however, that it only appears when shoeing is commenced, we may in a +greater degree also regard it as acquired. The lesson, therefore, that this +and other forms of contraction should teach us is the carefulness with +which the shoeing should be superintended in a large stud, or in any case +where the animal is of more than ordinary value. + +[Illustration: FIG. 79.--HOOF WITH LOCAL OR CORONARY CONTRACTION (AS +INDICATED AT THE POINTS _a, a_).] + +The explanation of the restricted nature of this form of contraction +is simple enough. We have only to refer to the lessons taught by the +experiments of Lungwitz, described in Chapter III., and the condition +almost explains itself. We remember that, briefly, the coronary margin of +the wall resembles a closed elastic ring, which yields and expands to +local pressure, no matter how slight. We remember also that removal of the +counter-pressure of the frog with the ground tended to contraction of the +wall's solar edge when weight was applied. Connect these two facts with +the experience that this form of contraction more often than not occurs in +hoofs with sloping heels, and we arrive at the following: + +1. The excessive slope of the heels tends to throw a more than usual part +of the body-weight upon the posterior portion of the coronary margin of +the wall, with a consequent expansion of that part of the coronary margin +implicated. + +2. That the shoeing, in removing the counter-pressure of the frog with the +ground, is at the same time tending to bring about contraction of the lower +portions of the wall at the heels and quarters. + +3. That this tendency to contraction will at first appear in the thinner +portion of the area of wall named--namely, in that immediately below the +bulging coronary margin. + +We thus get the appearance depicted in Fig. 79--a contraction _(a, a)_ of +the heels in the horn below the coronary margin, with the coronary margin +itself bulging above, and a hoof of apparently normal width below. + +We say 'apparently' with a purpose, for, as actual measurements will show, +the wall near the solar edge is really contracting, for reasons which we +have just described connected with shoeing. Its 'appearance' of normal +width is accounted for thus: The contraction at _a, a_ is caused by the +dragging inwards of the coronary cushion brought about by the sinking +downwards of the plantar cushion, with which body it will be remembered the +coronary cushion is continuous. With the constant dragging in and down +of the coronary cushion there is given, to the horn-secreting papillae, +studding both the lower third of its outer face and its lowermost surface, +a distinct 'cant' outwards. Below the lowermost limit of the coronary +cushion, then, by reason of the cant outwards of the coronary papillae +in the situations mentioned, the horn of the wall takes a more outward +direction than normal, a fact which lessens in effect the contraction as a +whole really going on. It is interesting, too, to note that by this outward +cant of the wall below, and the bulging of the coronary margin above it, +the contraction (_a, a_) is heightened in effect, and caused to appear +greater than really it is. + +From what we have said it follows that contraction of the heels, excepting +the extreme coronary margin, is existent generally, and not confined solely +to _a, a_. + +We have, then, in this condition, as we indicated at the commencement, +but a phase in the evolution of ordinary contracted heels, for, with the +progress of the contraction already existing at _a, a_, and below those +points, it is only fair to assume that with it falling in of the at present +bulging coronary margin must sooner or later occur, that, though expanded +when compared with the wall below it, it will be really contracted as +compared with what it was once in that same foot. + +We may therefore conclude this section by remarking that factors tending to +contraction of the heels in general are equally potent in the causation of +contracted coronet alone. + +_Treatment_.--Exactly that described for contracted heels. Bearing in mind +that contracted coronary margin is but the onset of contracted heels, and +that its first exciting cause is that of removal of the ground-pressure +upon the frog, the most careful attention must be paid to the shoeing. The +use of bar shoes, ordinary frog pads, or heelless shoes and bar pads, are +especially indicated, together with abundant exercise. By these means the +normal movements of expansion will be brought into play, and the condition +quickly remedied. + + +C. FLAT-FOOT. + +_Definition_.--By this term is indicated a condition of the foot where the +natural concavity of the sole is absent. + +_Symptoms_.--In the flat-foot the inferior edge of the wall, the sole, +and the frog, all lie more or less in the same plane. It is a condition +observed far more frequently in fore than in hind limbs, and is seen in +connection with low heels, more or less obliquity of the wall, and a +tendency to contraction. The action of the animal with flat feet is heavy, +a result partly of the build of the foot, and partly of the tenderness that +soon comes on through the liability of the sole to constant bruising. + +[Illustration: FIG. 80. This figure represents the lower surface of a +typical flat-foot. It illustrates, too, the commencement of a condition we +referred to in Section B of this chapter--namely, the compression of the +frog by the ingrowing heels (b) and bars (a).] + +_Causes_.--Flat-foot is undoubtedly a congenital defect, and is seen +commonly in horses of a heavy, lymphatic type, and especially in those +bred and reared on low, marshy lands. It is thus a common condition of the +fore-feet of the Lincolnshire shire. + +As might be expected, a foot of this description is far more prone to +suffer from the effects of shoeing than is the foot of normal shape, and +regarded in this light shoeing may be looked upon as, if not an actual +cause, certainly a means of aggravating the condition. Directly the +shoe--or at any rate the ordinary shoe--is applied, mischief commences. The +frog is raised from the ground, and the whole of the weight thrown on to +the wall. The heels, already weak and inclined to turn in, are unable to +bear the strain. They _turn in_, and contraction commences. This 'turning +in' of the heels is favoured by the undue obliquity of the wall. At the +same time, the sole being archless, a certain amount of elasticity is +lost. The weight is thrown more on to the heels, and the os pedis slightly +descends, rendering the flatness of the sole even more marked than before. +With the loss of elasticity of the sole concussion makes itself more felt. +The animal is easily lamed, bruised sole becomes frequent, and corns sooner +or later make their appearance. + +_Treatment_.--Flat-foot is incurable. All that can be done is to pay +careful attention to the shoeing, and so prevent the condition from being +aggravated. In trimming the foot the sole should not be touched; the frog, +too, should be left alone, and the wall pared only so far as regards broken +and jagged pieces. + +The most suitable shoe is one _moderately_ seated. If the seating is +excessive, and bearing allowed only on the wall, there is a tendency for +the wall to be pushed outwards, and for the sole to drop still further. On +the other hand, if the seating is insufficient, or the web of the shoe too +wide, and too great a bearing thus given to the sole, then we get, first, +an undue pressure upon the last-named portion of the foot a bruise, and, +finally, lameness. The correct bearing should take in the whole of the wall +and the whole of the white line, and should _just impinge_ upon the sole. +Above all, the heels of the shoe should be of full length, otherwise, if +the shoe is worn just a little too long, its heels are carried under the +sole of the foot, and by pressure there produce a corn. + +If, with these precautions in shoeing flat-foot, tenderness still persists, +a sole of leather or gutta-percha must be used with the shoe. + + +D. PUMICED-FOOT, DROPPED SOLE, OR CONVEX SOLE. + +_Definition_.--This term is applied to the foot when the shape of the sole +is comparable to the bottom of a saucer. When least marked it is really an +aggravated form of flat-foot. + +_Symptoms_.--In pumiced-foot the sole projects beyond the level of the +wall. The obliquity of the latter is more marked than in the previous +condition, and progression, to a large extent, takes place upon the heels. +In addition to its deformity, the horn is greatly altered in quality, and, +as the name 'pumice' indicates, is more or less porous in appearance, +bulging, and brittle. + +_Causes_.--As a general rule, it may be taken that pumiced-foot is a sequel +of previous disease, although in its least pronounced form it may occur as +the result of accidental or other causes, such as those described in the +causation of flat-foot. + +Occurring in its most marked form, there is no gainsaying the fact that +pumiced-foot is a sequel of either acute or subacute laminitis. As we shall +see when we come to study that disease, the dropping of the sole is brought +about by distinct and easily-understood morbid processes affecting the +sensitive structures. Briefly, these morbid processes in laminitis may be +described thus: The accumulated inflammatory exudate, and in some cases +pus, weakens and destroys the union between the sensitive and insensitive +laminae. This separation, for reasons afterwards to be explained, is +greatest in the region of the toe. The os pedis, loosened from its intimate +attachment with the horny box, is dropped upon the sole, and the sole, +unable to bear the weight, commences to bulge below. + +The altered character of the horn is accounted for by the inflammatory +changes in the sensitive laminae and the papillae of the keratogenous +membrane generally, for it follows as a matter of course that these +tissues, themselves in a diseased condition, must naturally produce a horn +of a greatly altered and inferior quality. + +When following the _subacute_ form of laminitis, the changes characterizing +pumiced-foot are slow in making their appearance. The animal at first goes +short, and the lameness thus indicated gradually becomes more severe, until +the animal is no longer able to work. The feet become hot and dry, the +hoof loses its circular form, and the growth of horn at the heels becomes +excessive. At this stage the appearance of bulging at the sole begins to +make itself seen. Later, the outer surface of the wall becomes 'ringed' or +'ribbed,' the rings being somewhat closely approximated in the region of +the toe, and the distance between them gradually widening towards the +heels. The wall too, especially in the region of the toe, instead of +running in a straight line from the coronary margin to the shoe, becomes +concave. It is this change, together with the appearance of the rings, that +indicates the loosening of the attachment of the os pedis to the wall, and +its afterwards backward and downward direction (see Fig. 124). + +[Illustration: FIG. 81.--HOOF WITH THE RIBS OR RINGS CAUSED BY CHRONIC +LAMINITIS.] + +As a sequel of _acute_ laminitis, these changes make their appearance with +more or less suddenness, and are generally complicated in that they owe +their occurrence to the formation of pus within the horny box. + +_Treatment_.--Pumiced-foot is always a serious condition. The animal is +useless for work upon hard roads or town pavings, and is of only limited +utility for slow work upon soft lands. The more serious form, that +following acute laminitis, and complicated by the presence of pus, we may +regard as beyond hope of treatment. + +With the more simple form of the condition, we may do much to render +greater the animal's usefulness. The same principles as were applied to the +shoeing of flat feet will have to be observed here. Trimming or paring +of any kind, save 'straightening up' of the wall, must be severely +discountenanced. A broad-webbed shoe, one that will give a certain amount +of cover to the sole, is indicated. As in the treatment of flat-foot, +however, direct pressure upon the sole must be avoided, and the shoe +'seated.' The 'seating,' however, should not commence from the absolute +outer margin of the shoe's upper surface. A _flat_ bearing should be given +to the wall and the white line, and the seating commenced at the sole. + +We have already remarked on the increased growth of horn at the heels. It +is in this position, then, that will be found the greatest bearing surface +for the shoe, and it is wise, in this case, to have the heels of the shoe +kept flat. In other words, the 'seating' is not to be continued to the +hindermost portion of the branches of the shoe. By this means there may be +obtained at each heel a good solid bearing of from 2 to 3 inches, which +would otherwise be lost. + +Where the accompanying condition of the horn is bad enough to indicate it, +a leather sole should be used, beneath which has been packed a compress of +tow and grease, rendered more or less antiseptic by being mixed with tar. + +Where the sole is exceedingly thin, and inclined to be easily wounded, and +where the hoof, by its brittleness, has become chipped and ragged at the +lower margin of the wall, it may perhaps be more advantageous to use, in +place of the compress of tow, the _huflederkitt_ of Rotten. This is a +leather-like, dark brown paste. When warmed in hot water, or by itself, it +becomes soft and plastic, and may readily be pressed to the lower surface +of the foot, so as to fill in all little cracks and irregularities, and +furnish a complete covering to the sole and frog, and to the bearing +surface of the wall. When cold it hardens, without losing the shape given +to it, into a hard, leather-like substance. + +Treated in this way, the animal with pumiced feet may yet be capable of +earning his living at light labour or upon a farm. + + +E. 'RINGED' OR 'RIBBED' HOOF. + +_Definition_.--A condition of the hoof in which the wall is marked by a +series of well-defined ridges in the horn, each ridge running parallel with +the coronary margin. They are known commonly as 'grass rings,' and may be +easily distinguished from the more grave condition we have alluded to as +following laminitis, by the mere fact that they do not, as do the laminitic +rings, approximate each other in the region of the toe, but that they run +round the foot, as we have already said, _parallel with each other_. + +[Illustration: FIG. 82.--HOOF SHOWING THE RINGS IN THE HORN BROUGHT ABOUT +BY PHYSIOLOGICAL CAUSES.] + +_Causes_.--This condition is purely a physiological, and not a pathological +one, and the words of its more common name, 'grass rings,' sufficiently +indicate one of the most common causes. Anything tending to an alternate +increase and decrease in the secretion of horn from the coronet will bring +it about. Thus, in an animal at grass, with, according to the weather +conditions, an alternate moistness and dryness of the pasture, with its +consequent influence on the horn secretion, these rings nearly always +appear. The effects of repeated blisters to the coronet make themselves +apparent in the same way, and testify to the efficacy of blisters in this +region in any case where an increased growth of horn is deemed necessary. +From this it is clear that the condition depends primarily upon the +amount and condition of the blood supplied to the coronary cushion. Thus, +fluctuations in temperature during a long-continued fever, or the effects +of alternate heat and cold, or of healthy exercise alternated with +comparative idleness, will each rib the foot in much the same manner. + +_Treatment_.--The condition is so simple that we may almost regard it +as normal. Consequently, treatment of any kind is superfluous. Where +constitutional disturbance is exerting an influence upon either the quality +or quantity of the blood directed to the part, then, of course, attention +must be paid to the disease from which it is arising. + + +F. THE HOOF WITH BAD HORN. + +(_a_) THE BRITTLE HOOF. + +_Definition_.--As the name indicates, we have in this condition an +abnormally dry state of the horn. + +_Symptoms_.--These are obvious. The horn is hard, and when cut by the +farrier's tools gives the impression of being baked hard and stony, the +natural polish of the external layer is wanting, and there is present, +usually, a tendency to contracted heels. With the dryness is a liability to +fracture, especially at points where the shoe is attached by the nails. +As a consequence, the shoes are easily cast, leading to splits in the +direction of the horn fibres. These run dangerously near the sensitive +structures, giving rise in many cases to lameness. Even where pronounced +lameness is absent the action becomes short and 'groggy,' and the utmost +care is required in the shoeing to keep the animal at work. + +_Causes_.--To a very great extent the condition is hereditary, and is +observed frequently in animals of the short, 'cobby' type. In ponies +bred in the Welsh and New Forest droves the condition is not uncommon, +especially in the smaller animals. Animals who have had their feet much +in water--as, for instance, those bred and reared on marshy soils--and +afterwards transferred to the constant dryness of stable bedding, are also +particularly liable to this condition. It is noticed, too, following the +excessive use of unsuitable hoof-dressings, more especially in cases where +coat after coat of the dressing is applied without occasionally removing +the previous applications. + +_Treatment_.--As a prophylactic, a good hoof-dressing is indicated. It +should not consist solely of grease, but should have mixed with it either +wax, turpentine, or tar. + +Above all, careful shoeing should be insisted on, and the owner of an +animal with feet such as these will be well advised if he is recommended to +have the shoeing superintended by one well competent to direct it rightly. +The foot should be trimmed but lightly, always remembering that in a foot +of this description the horn, in addition to being brittle, is generally +abnormally thin. Jagged or partly broken pieces should be removed, and the +bearing surface rendered as level as possible. The foot should be carefully +examined before punching the nail-holes in the shoe, and the nail-holes +afterwards placed so as to come opposite the soundest portions of horn. The +nails themselves should be as thin as is consistent with durability, and +should be driven as high up as possible. + +On the least sign of undue wear the shoes should be removed, never, as is +too often done, allowing them to remain on so long that a portion breaks +away. If, with the laudable idea of not interfering with the horn more than +is possible, this is practised, the portion of the shoe breaking off is +bound to tear away with it more or less of the brittle horn to which it is +attached. + +Where the breaks in the horn are so large as to prevent a level bearing for +the shoe being obtained, the interstices should be filled up with one or +other of the preparations made for this purpose. One of the most suitable +is that discovered by M. Defay. By its means sand-cracks or other fractures +of the horn may be durably cemented up. + +'Even pieces of iron may be securely joined together by its means. The only +precaution for its successful application is the careful removal of all +grease by spirits of sal-ammoniac, sulphide of carbon, or ether. M. Defay +makes no secret of its composition, which is as follows: Take 1 part of +coarsely-powdered gum-ammoniac, and 2 parts of gutta-percha, in pieces the +size of a hazel-nut. Put them in a tin-lined vessel over a slow fire, and +stir constantly until thoroughly mixed. Before the thick, resinous mass +gets cold mould it into sticks like sealing-wax. The cement will keep +for years, and when required for use it is only necessary to cut off a +sufficient quantity, and remelt it immediately before application. We have +frequently used this cement for the repair of seriously broken hoofs. It is +so tenacious that it will retain the nails by which the shoe is attached +without tearing away from the hoof.'[A] + +[Footnote A: _Veterinary Journal_, vol. iii., p.71.] + +Failing this, the bearing surface may be made level, and fractures repaired +by using the _huflederkitt_ described in the treatment of pumiced sole. + +(_b_) THE SPONGY HOOF. + +_Definition_.--This is the opposite condition to the one we have just +described, and is characterized by the soft and non-resistant qualities of +the horn. + +_Symptoms_.--Spongy hoof is quite common in animals that have large, flat, +and spreading feet--in fact, the two appear to run very much together. It +is a common defect in animals reared in marshy districts, and of a heavy, +lymphatic type. The Lincolnshire Shire, for instance, has often feet +of this description, and, the causative factors being in this case +long-continued, render the feet extremely predisposed to canker. The horn +is distinctly soft to the knife, and has an appearance more or less greasy. +Animals with spongy feet are unfit for long journeys on hard roads. When +compelled to travel thus, the feet become hot and tender, and lameness +results. A mild form of laminitis, extending over a period of three or +four days, often follows on this enforced travelling on a hard road, more +especially in cases where the animal is 'heavy topped,' and the usual +food of a highly stimulating nature. In fact, it has been the author's +experience to meet with this condition several times in the case of shire +stallions doing a long walk daily upon hard roads, with the weather hot and +dry. + +_Treatment_.--When a horse with spongy feet is shod for the first time, +care must be taken to avoid excessive paring of the sole, for already the +natural wear of the foot has been sufficient to keep the soft horn in a +state of thinness. For the same reason hot fitting of the shoe must not +be indulged in for too long a time. That common malpractice of the forge, +'opening up the heels,' must, in this case, be especially guarded against, +or the excessive paring of the frog and partial removal of the bars that +this operation consists in will lay the foot open to risk of contraction. +To begin with, the heels are naturally weak, and, once the bars are +removed, there is nothing to prevent them rapidly caving in towards the +frog. Even when carefully shod, a foot of this class is readily prone to +contract directly the animal is brought into the stable, and the horn +commences to dry to excess. An ordinary light shoe should be used, and the +nails should be light and thin. They should be driven carefully home, and +the 'clinching' made as tight and secure as possible. + + +G. CLUB-FOOT. + +_Definition_.--Under this name we indicate all cases in which the horn +of the wall become straightened from above to below. It will, therefore, +include all conformations varying from the so-called 'upright hoof,' in +which the toe forms an angle of more than 60 degrees with the ground, to +the badly 'clubbed' foot, in which the horn at the toe forms a right angle +with the ground, or is even directed obliquely backwards and downwards, so +that the coronary margin overhangs the solar edge of the wall. + +[Illustration: FIG. 83.--THE CLUB-FOOT.] + +_Symptoms_.--Even in its least pronounced form the condition is apparent at +a glance, the alteration in the angle formed by the hoof with the ground +striking the eye at once, and the heels, as compared with the toe, +appearing much too high. When the condition is slight, the wall of the toe +is about twice as high as that of the heels, while in the most marked form +the toe and the heels may in height be nearly equal (see Fig. 83). When +congenital, but little interference with the action is noticed. Such +animals, by reason of their 'stiltiness,' are unfit for the saddle, but at +ordinary work will perform their duties equally well with the animal of +normal-shaped feet. When acquired as the result of overwork, of contracted +tendons, or other causes, however, the gait becomes stumbling and +uncertain. The body-weight is transferred from the heels to the anterior +parts of the foot, and the shoe shows undue signs of wear at the toe. + +_Causes_.--Upright hoof is undoubtedly hereditary, and is even seen as a +natural conformation in the feet of asses and mules. When hereditary in the +horse, however, it is certainly a defect, and is associated commonly with +an upright limb, and a short, upright pastern (see Fig. 83). + +Among other causes, we may enumerate sprains or wounds of the flexor +tendons, or any disease of the limbs for a long time preventing extension +of the fetlock-joint, such as sprains or injuries of the posterior +ligaments of the limb, splints or ringbones so placed as to interfere with +the movements of the flexor tendons, or, in the hind-limb, spavin, keeping +for some months the fetlock in a state of flexion. In the very young animal +the condition may be induced by an improper paring of the foot--cutting +away too much at the toe, and allowing the heels to remain. + +_Treatment_.--When the condition is congenital, no treatment at all is +indicated. It might, in fact, be said that interference would tend rather +to minimize than enhance the animal's usefulness; for, in this case, the +club-shaped feet are in all probability due to faulty conformation above. +In other words, the upright hoof is in this instance but a natural result +of the animal's build, with which useful interference is impossible. + +Where the upright hoof is a consequence of excessive paring of the toe, +or insufficient removal of the heels, the condition may be remedied by +directing attention to those particulars, and preventing their continuance. +At the same time, a greater obliquity of the limb axis may be given by the +use of a suitable shoe. The shoe indicated is a short one, with thin heels +and a thick toe. In some cases the abnormality may be remedied by the use +of a tip. Whatever method is adopted, care must be taken not to attempt +too positive a change in the direction of the limb at one operation. The +process must be gradual. + +In cases where the abnormality has been brought about by wounds to the +flexor tendons, the alteration in the direction of the limb is often so +great as to produce 'knuckling over' of the fetlock. This, to a very great +extent, may be remedied by the use of a shoe with calkins and an extended +toe-piece (see Fig. 84). + +[Illustration: FIG. 84.--THE SHOE WITH EXTENDED TOE-PIECE AND HIGH +CALKINS.] + +With this shoe a certain amount of forced exercise is advisable, and at +intervals of about two weeks the calkins should be somewhat lowered, until +the heels are brought as close to the ground as is possible. In giving +directions for this shoe to be made the veterinary surgeon must, when +referring to the length of the toe-piece, be guided entirely by the +condition of the case. Ordinarily, a suitable length is from 3 to 4 inches. +It is necessary also to warn the owner that, by reason of the length +projecting, the shoe is liable to be torn off. + +Should the 'knuckling over' have become complicated by bony deposits round +the seat of the original injury, then a favourable modification of the +condition is not so likely to result. + +The benefit to be derived from the shoe with an extended toe-piece in a +case of excessive knuckling is admirably shown in a brief report of a case, +under the title of 'Hooked Foot,' in vol. xiv. of the _Veterinary Record_, +p. 716: + +'An eighteen months' old filly showed a deformity of the third phalanx, +resulting in her walking with the front face of the hoof on the ground. The +flexors were apparently all right, and the bending back seemed to be due to +contraction of the ligaments of the joint and the sheath of the perforans. + +'On the ground of absence of contraction of the flexors, or atrophy and +paralysis of the extensors, the surgeon considered the lesion curable by +simple orthopaedic measures. By means of an elongated toe-piece to the +shoe and calkins, which were shortened every fifteen days, the filly was +completely cured in seventy days.' + + +H. THE CROOKED FOOT. + +(_a_) THE FOOT WITH UNEQUAL SIDES. + +_Definition_.--The foot thus affected has one side of the wall higher than +the other. + +_Symptoms_.--This deformity is the better recognised when the foot on the +floor is viewed from behind. In addition to the difference between the +height of the inner and outer heel is seen at once a deviation in the +normal direction of the horn. That of the higher side is distinctly more +upright than that of the lower, and runs from above downwards and inwards +towards the axis of the foot, while the horn of the lower side maintains +its normal direction of downwards and outwards. + +From what we have said before on contracted foot, this bending in of +the wall of the upright side will at once be recognised as a form of +contraction. It is, in fact, contraction confined to one-half of the foot +only, and, as a result, the upright side of the crooked foot is prone to +the troubles arising from that condition. Corns are frequent, and atrophy +of that half of the frog on the affected side supervenes. With the +inflammatory changes accompanying these conditions we find the horn of the +affected side deteriorating in quality. It becomes dry and brittle, and +extremely liable to sand-crack. At the same time, thrush of the contracted +frog begins to make its appearance. + +_Causes_.--More often than not this condition is a result of the +conformation of the limb. According as the build above inclines the animal +to 'turned in' or 'turned out' toes, so shall we have feet with a wall +crooked inwards or crooked outwards; and it may be mentioned here that the +evil results inflicted on the foot by ill-shaped limbs above will make +themselves the more readily noticed when the animal comes to be shod for +any length of time. So long as a natural wear of the foot is allowed, +so long does it accommodate itself to the form of limb above. So soon, +however, as the shoe is applied, and a more or less equal (and in this case +harmful) wear by that means insisted on, so soon does this abnormal change +in the height and direction of the horn fibres begin to make itself seen. + +While arising in the majority of instances from faulty conformation of the +limb, crooked feet may also be brought about by bad shoeing, or by unequal +paring of the foot, and, in a few cases, from unequal wear of the foot in a +state of nature. + +_Treatment_.--Although it may be taken as a rule that lowering of the +higher wall, even if persisted in at every shoeing, will do nothing towards +remedying the primary cause (viz., the evil conformation of the limb), yet +it will serve to keep the condition within reasonable limits. In this case, +while removing so much of the wall as is deemed necessary, care must be +taken to leave uncut the sole and the bar. Leaving these intact gives us +two natural and very potent protections against the contraction already +mentioned as impending. + +Where, by reason of the thinness of the horn or other causes, sufficient +paring to equalize the tread cannot be practised, then the same end may be +arrived at by the use of special shoes. That branch of the shoe applied to +the half of the foot with the lower wall should be thickened from above +downwards. Or, on the same branch, may be turned up a calkin of sufficient +height for the purpose. Of the two methods the first is preferable. + +In any case, whether depending upon paring, or upon the use of a special +shoe, the animal should be sent to the forge quite often, for it is only by +a well-directed, and therefore constant, application of the principles here +laid down that improvement may be brought about. + +When marked contraction of one-half of the foot is present, it will be +best treated with the expanding shoe of Hartmann, already described in the +section of this chapter dealing with contracted heels (see Fig. 76). + +(_b_) THE CURVED HOOF. + +_Definition_.--The hoof with the wall of one side convex, and that of the +opposite side concave. Fig. 85, showing the foot in section from side to +side, gives an exact idea of this malformation. + +_Causes_.--As was the case with the condition previously described, this +abnormality finds its primary cause in an unequal distribution of weight +due to vice of conformation in the limb above, causing one side of the +hoof to be higher than the other. As a result of this, the wall that is +inordinately increasing in height commences to bulge outwardly (Fig. 85, +_a_), while the opposite (Fig. 85, _b_) becomes concave. + +The same state of affairs may be occasioned in the forge by leaving one +side of the foot too high, and subjecting the other to excessive paring for +several consecutive shoeings. + +_Treatment_.--In the main this condition may be regarded as a long-standing +and aggravated form of the foot with unequal sides. We may say at once, +therefore, that it is not so easily remedied as that simpler defect; that, +although identical principles will be followed in its treatment, cure must +be a matter of some considerable time. + +[Illustration: FIG. 85.--SECTION THROUGH A CROOKED FOOT. _a_, The higher +and convex side of the wall; _b_, the lower and concave side of the wall] + +Again, we must look to successive parings of the wall of the higher side to +bring about a gradual return to the normal. At the same time, the tendency +to contraction of that side is counteracted by shoeing wide, and, if +necessary, giving to the upper surface of that branch of the shoe what we +have termed elsewhere a 'reversed seating'--viz., an incline of its upper +surface from within outwards. + + + +CHAPTER VII + +DISEASES ARISING FROM FAULTY CONFORMATION + + +A. SAND-CRACK. + +_Definition_.--A solution of continuity of the horn of the foot, occurring +usually in the wall, and following the direction of the horn fibres. + +_Classification_.--It is usual to classify sand-cracks according to-- + +_(a) Their Position_.--_Toe-crack_ when occurring in the middle line of the +horn of the toe, and _quarter-crack_ when occurring in the horn of the +quarters. + +Sand-crack of the frog and sand-crack of the sole may also each be met +with. They are, however, of rare occurrence, and are seldom serious enough +to merit special attention. + +The toe-crack is met with more often in the hind-foot than in the fore, +while the quarter-crack more often than not makes its appearance in the +fore-foot, and is there, as a rule, confined to the inner side. The reasons +for these positions being so affected we shall deal with when treating of +the causes of sand-crack in general. It is interesting to note that the +portions of wall known as inside and outside toe are seldom affected. + +_(b) Their Length_.--_Complete_ when they extend from the coronary margin +of the wall to its wearing edge; _Incomplete_ when not so extensive. + +_(c) Their Severity_.--_Simple_ when they occur in the horn only, and do +not implicate the sensitive structures beneath; _Complicated_ when +deep enough to allow of laceration and subsequent inflammation of +the keratogenous membrane. Such complications may vary from a simple +inflammation set up by laceration and irritation of the sensitive +structures by particles of dirt and grit that have gained entrance through +the crack, to other and more serious changes in the shape of the formation +of pus, haemorrhage from the laminal vessels, caries of the os pedis, or the +development of a tumour-like growth of horn on the inner surface of the +wall known as a keraphyllocele. + +_(d) Their Duration_.--_Recent_ when newly formed; _old_ when of long +standing. + +_(e) Their Starting-point_.--This last distinction we make ourselves, +and, referring to cracks of the wall, term them _high_ when commencing from +the coronary margin, _low_ when starting from the bearing surface. + +_Causes_.--We have already classified sand-crack as a disease arising from +faulty conformation. Thus, in just so far as a predisposing build of body +may be handed down from parent to offspring, we may regard sand-crack as +hereditary. If we do so, however, we must afterwards make up our minds +to sharply distinguish between the sand-crack plainly brought about by +accidental cause, and that occurring as a result of hereditary evil +conformation. + +With regard to the latter, we need hardly say that feet with abnormally +brittle horn are extremely liable. But with this, as with many other +affections of the feet, we shall find it necessary to consider several +causes acting in cooperation. In this case, for instance, given the brittle +horn, it becomes necessary to further look for exciting causes of its +fracture. + +We will take conformation first. In the animal with turned-out toes a more +than fair share of the body-weight is imposed on the horn of the inner +quarter. Here, then, three causes exert their influence together: The horn +is brittle; the wall of the inner quarter is thinner than that of the +outer; additional weight is imposed upon it. Fracture results. + +Take, again, the vice of contracted heels. Here, in the first place, we +have a variety of causes tending to bring about the contraction. With the +contraction, and its consequent pressure upon the sensitive structures +in the region of the quarters and the frog, has arisen a low type of +inflammation. The horn of the part has become dry and brittle. The exciting +cause of its fracture is found in an excessive day's work upon a hard, dry +road, with, perhaps, a suddenly-imposed improper distribution of weight, +due to treading upon a loose stone, or a succession of such evil transfers +of weight due to travelling upon a road that is rough in its whole extent. + +In their turn, too, such defects of the feet as we have mentioned in the +last chapter--as, for example, the foot with the pumiced horn, the foot +with abnormally upright heels, or that which is upright on one side only, +or crooked--each offers a condition which is predisposing to the formation +of a sand-crack. In each case it wants but the uneven distribution of +the body-weight, which, as a matter of fact, some of these conditions +themselves give, to bring about a fracture. + +Apart from the predisposition conferred by conformation, must be remembered +the simpler predisposing causes leading to brittleness of the hoof. We +refer to the after-effects of poulticing, the moving from pasture to +stable, the emigration from a damp to a dry climate, or the alternate +changes from damp to dry in a temperate region. Each may have a +deteriorating influence upon the horn, rendering it liable to the condition +we are describing. Excessive dampness alone, especially when the animal is +called upon to labour at the drawing of heavy loads upon a rough road, is +not infrequently a cause. In this case the wet, together with the constant +friction of the sharp materials of which the road is made, serves to +destroy the varnish-like periople. The wet gains access to the inner +structures of the wall, the agglutination of the horn fibres is weakened, +and fissures begin to appear. + +Other causes of sand-crack are purely accidental. An animal at fast work +over-reaches. The secretion of horn at the injured coronet is interfered +with, a diminished supply at an isolated spot being the result. From this +point grows down a fissure in the wall. + +An injury of the same character may also be sustained in various other +ways--treads from other animals when working in pairs, accidental wounding +with the stable-fork, blows of any kind, or a self-inflicted tread with the +calkin of an opposite foot--each with the same result. + +So far as causation is concerned, toe-crack stands in a class almost by +itself. It is met with nearly always in a heavy animal in the hind-foot, +and is directly attributable to the force exerted in starting a heavy load. + +Unskilful shoeing also plays a part in the causation of sand-crack. Removal +of the periople by excessive rasping of the wall is most certainly a +predisposing cause. Cracks, or their starting-points, may also be caused by +using too wide a shoe, or by the use of nails too large in the shank. Also, +they may arise from unskilful fitting of the toe-clip, especially in the +hind-foot of a heavy animal. It must be admitted, however, that the part +shoeing plays in the causation of sand-crack is not a large one; far more +depends upon the state of the horn and the animal's conformation than upon +the exciting cause. + +So far, our observations on the causes of sand-crack have referred to that +form occurring in the wall. Sand-crack of the sole or frog we have already +said is but seldom met with, and then it is always in connection with some +exceptionally deteriorated quality of the horn, as in the case of badly +pumiced feet, or occurs as a result of direct injury. Extensive slit-like +cuts in this region, when deep enough to lacerate the keratogenous +membrane, are sometimes followed by the growth of a fissure in the horn, +and what might almost be termed a permanent sand-crack results. Such cuts +may be occasioned by sharp flints, broken glass, or other sharp objects +picked up on the road, or may result from the animal treading on the +toe-clip of a partially cast shoe. + +_Symptoms_.--In every case the fissure, or evidence of its commencement, +is a diagnostic symptom. It is well to remember, however, that this may +be easily overlooked, especially when the crack is one commencing at the +coronary margin. The reason is this: Sand-cracks in this position often +commence in the wall proper, and not in the periople. They may, in fact, be +first observed as a fine separation of the horn fibres immediately +beneath the perioplic covering. A crack of this description may even show +haemorrhage, and have been in existence for some time, without the periople +itself showing any lesion whatever. Thus, unless lameness is present, or a +more than specially keen search is directed to the parts in question, the +sand-crack goes undiscovered, until of greater dimensions. + +Further, the fissure may be hidden, either accidentally or of set purpose. +It may be covered by the hair, filled in and covered over with mud, or +intentionally concealed by being 'stopped' with an artificial horn, with +wax, or with gutta-percha, or, as is more common, be hidden by the lavish +application of a greasy hoof-dressing. + +In this latter connection it is well to warn the veterinary surgeon, +especially the beginner, when examining for soundness, to be keenly +critical before passing an animal who is presented with feet smothered with +tar and grease or any other dressing. More especially should this warning +be heeded when examining any of the heavier breeds of animal with an +abundance of hair about the coronet. + +Referring again to the search for the crack, it is well to know that with +toe-crack the fissure is the more readily seen when the foot is lifted from +the ground. With quarter-crack, on the other hand, the fissure is wider, +and consequently the easier detected with the foot bearing weight. + +Although commencing in the insidious manner we have described, the lesion +is not thus often seen by the veterinary surgeon. Usually, the animal with +sand-crack is brought for his inspection when lameness has arisen from it. +In this case the cause for the lameness will reveal itself in the crack, +which is now too large to escape observation. The coronet is hot and tender +to the touch, and a sensation of warmth is sometimes conveyed to the hand +by the horn of the surrounding parts of the wall. It is hardly necessary to +say that, with accompanying conditions such as these, the sand-crack is a +_deep_ one. + +Where the lameness is but slight, we may attribute it almost solely to the +pain occasioned by the mere wounding of the keratogenous membrane, and to +no very extensive inflammatory changes therein. By some authorities this +is said to be due to the pinching of the sensitive structures between +the edges of the fissure in the horny covering. In our opinion, however, +pinching does not occur unless inflammatory exudation into the sensitive +structures adjoining the crack has led to sufficient swelling to cause them +to protrude. In other words, the movements of the horny box, communicating +themselves to the structures beneath, and so occasioning movement in the +wounded keratogenous membrane, are quite sufficient to give rise to the +lameness without actual pinching of the structures implicated. + +The severity of the lameness will vary with the rapidity of the gait, and +with the character of the road upon which the animal is made to travel. For +instance, many animals in which the lameness is imperceptible at a walk +become 'dead' lame at a fast trot. It is sufficiently explained when +one remembers the greater movements of expansion and contraction of the +posterior parts of the wall brought about by the increase in the rate of +progression. The same animal, too, will go distinctly more lame upon a hard +than upon a soft surface. + +In like manner the lameness from toe-crack also varies in degree with the +rate of progression and the character of the travelling, though not to +such a noticeable extent as in the lameness from quarter-crack. A greater +variation may in this case be brought about by moving the animal on +ascending and descending ground. Descending an incline, with a more than +ordinary share of the body-weight thus thrown upon the heels, the lameness +is most marked. The reason would appear to be that the greater expansion +of the wall of the heels thus brought about leads to a proportionate +contraction of the wall at the toe, especially at the edges of the crack, +thus causing undue pressure upon the exact spot of the wound in the +sensitive structures. Ascending--the weight in this case transferred from +the posterior to the anterior portion of the foot--the expansion of +the heels becomes a contraction, with a corresponding lessening of the +contraction at the toe and a distinct decrease in the lameness. + +In the case of a deep but recent crack there is always more or less +haemorrhage. This favours risk of infection of the lesion with pus-forming +organisms, and so leads to a more or less pronounced lameness, a degree of +swelling, heat and tenderness in the coronet above, and a certain amount of +surgical fever. + +The acute symptoms subdued, but the fissure still remaining, gives us the +crack we have classified as 'old.' This may in every case be distinguished +from a more recent lesion by the amount of thickening of the overhanging +coronet, and the presence of an increased quantity of sub-coronary horn in +the region immediately about the crack. The previous inflammatory changes +in the adjoining sensitive structures have here led to an increased +secretion of horn, and a greater or less deposition of inflammatory +connective tissue in the wounded coronary cushion. + +Sand-crack of the toe always follows the direction of the horn fibres. That +of the quarter, however, may on occasion run a course that is somewhat +zigzag, first following the direction of the horn fibres for a short +distance, then travelling in a horizontal direction, and finally continuing +its course again in a line with the horn fibres, commonly at a point +posterior to that at which it commenced. + +In a quarter-crack that is old, and when contraction of the heels exists +(which in this case it usually does), then will often be found overlapping +of the edges of the crack. The expansion of the wall brought about when the +body-weight is on the heels, cannot, by reason of the break in it, continue +itself anterior to the crack. As a consequence, repeated expansion of the +wall posterior to the crack, with the portions anterior to it in a state +of enforced quiescence, leads in time to the posterior edge of the crack +coming to lie over that of the anterior. + +_Complications_.--The first complication likely to arise in a case of +sand-crack is that attending simple laceration of the sensitive structures +in a _deep_ lesion. With the laceration all the phenomena of a repairing +inflammation make their appearance. As a result, there is more or less heat +according to the degree of inflammatory hyperaemia, swelling according to +the amount of inflammatory exudate, and pain according to the amount of +pressure the two foregoing bring to bear on the nerves in the inflamed +area. + +A second and more serious complication is the greater inflammation set up +by the introduction into the crack of foreign substances. Small portions of +gravel and flint, both by the irritation set up by their friction and by +the infection they carry in with the dirt surrounding them, are responsible +for the mischief. + +When, from direct communication with the blood-stream, due to extensive +haemorrhage, bacteria from the outside gain entrance, this simple +inflammation is further complicated by the formation of pus, or a limited +gangrene of the keratogenous membrane. + +In cases of great severity the gangrene of the keratogenous membrane +spreads until the deeper structures are involved. We then get a necrosis +(in the case of toe-crack) of the extensor pedis, and sometimes caries of +the os pedis. + +In like manner the necrotic changes occurring under these circumstances may +invade the deeper structures in the region of quarter-crack. As a result of +this, we may have the starting-point of suppurating corn, or necrosis of +the lateral cartilage--in other words, cartilaginous quittor. + +Commonly accompanying quarter-crack is the condition of contracted heels +and atrophied frog. Sometimes described as a complication of sand-crack, it +appears to us more rational to rather regard the sand-crack as a result or +complication of the vice of contraction. + +The overlapping of the edges of the crack before referred to occasionally +gives rise to the condition known as false quittor. A probe or a director +passed beneath the overhanging ledge of horn reveals sometimes a fissure of +1 inch or considerably more in depth, and quittor is diagnosed. A careful +paring away of the overhanging horn, however, reveals the true state of +affairs, and exposes to view the original cause of the mischief--a simple +fissure in the wall. + +A serious complication--one fortunately met with but rarely--is that of +keraphyllocele. This is a tumour-like growth of horn, varying in size from +the thickness of an ordinary quill pen to that of one's middle finger, +growing down from the coronary cushion, and attached to the inner side of +the wall of the hoof. With this lameness is always present, and more or +less deformity of the hoof results. This condition will be found described +at greater length in Chapter IX. + +_Prognosis_.--In the case of sand-crack this should always be guarded. It +may be taken as a general rule that cracks commencing from the coronary +margin are more troublesome to deal with than those originating below. The +reason is not far to seek. They here affect the wall just where the bevel +in it for the accommodation of the coronary cushion has rendered it +weakest. Not only is it weakest, but being more resilient than the portions +below it, it suffers more from the alternate movements of expansion and +contraction of the foot than does the horn below. + +Although in many cases a cure of the existing crack may be easily +accomplished, regard should be paid to the possibility of its recurrence, +either in the same position or elsewhere. Really, in offering an opinion +as to the future usefulness of an animal so affected, a greater attention +should be directed to the animal's conformation than to the crack itself. +Where the vice of conformation giving rise to it (as, for example, +contracted heels or upright hoof) gives hope of being remedied, then +naturally it may be safely said that the liability to sand-crack goes with +it. + +A like favourable prognosis may be given in the case of cracks occasioned +by purely accidental causes. + +Ordinarily, however, cracks once commenced tend rather to increase than +decrease in size and severity. From being superficial and incomplete, they +become complete and deep, with every unfavourable circumstance that an +increase in size and depth brings with it. + +This much, however, may be promised to the owner. A simple crack, even +though originating from the coronary margin, is, in the vast majority of +cases, curable. Under a rational treatment its increase in size may be +prevented, and a sound wall caused to grow down from the coronet. + +_Treatment_.--The principles governing the treatment of sand-crack are +simple enough in themselves, if not always followed by success. + +1. _Preventive_. + +This, as a rule, does not suggest itself until a crack of greater or less +extent has made its appearance. Then, simultaneously with the treatment +proper of the lesion, preventive measures should be adopted, to aid both in +the healing of the fissure already present, and to ward off the occurrence +of others that might be likely to form. The hoof, if abnormally brittle, +should be regularly dressed with a suitable ointment (one containing +glycerine for preference), and its horn kept as nearly as possible in +a normal condition. When the condition of the horn predisposing to its +fracture is brought about by excessive wet, then the appropriate preventive +measures to be adopted suggest themselves. + +With regard to the lesion itself, we may term 'preventive treatment' all +those measures having for their object the prevention of increase in the +size of the crack. They are as follows: + +_(a) Blistering the Coronet_.--In a simple case, where the crack is +superficial and close under the coronary margin of the wall, a sharp +cantharides blister to the coronet immediately above it will have the +desired effect. An increased secretion of horn is brought about, and by +this simple means the crack prevented from becoming longer. Very often this +is all that is necessary. In fact, we may say here that, no matter what +other treatment is adopted, the simultaneous application of a blister to +the coronet is always beneficial. To derive full advantages therefrom, +the blistering should be repeated several times at intervals of about a +fortnight. + +_(b) Clamping the Crack_.--When the services of a skilled smith are at +hand, one of the readiest methods of performing this is to draw the edges +of the crack together with an ordinary horse-nail. + +On each side of the crack a small horizontal furrow is burned or cut into +the wall, leaving the horn for about 1/4 inch on each side of the crack +intact. This provides a groove for the ends of the clamping-nail to rest +in, and brings them flush with the outer surface of the wall. The nail is +then driven carefully home through the crack, and the pointed end grasped +by the farrier's pincers. The edges of the crack are then drawn tightly +together, and the nail firmly clenched. + +[Illustration: FIG. 86.--THE SAND-CRACK FIRING-IRON.] + +'The horse-nails are prepared in the ordinary way as for driving, with the +exception that each is pointed on the reverse side, to prevent puncturing +the sensitive structures. Before being used the nails are put in a vice, +and the head hammered to form a shoulder, to prevent their being driven too +far into the wall, and breaking out the hold.'[A] + +[Footnote A: _Veterinarian_, vol. xlviii., p. 100.] + +Before driving the nail some operators burn or bore a hole for it. Opinion +seems to differ as to whether this is at all necessary. + +A method of clamping which, on account of its simplicity, has become +greatly popular, is that of Vachette. For this operation is needed the +outfit depicted in Figs. 86 and 87. + +[Illustration: FIG. 87.--THE SAND-CRACK FORCEPS AND CLAMP.] + +With the special firing-iron (Fig. 86) an indentation, sufficiently large +to admit the points of the clamp (Fig. 87), is made on each side of the +crack. The clamp is then adjusted, and pressed home tight by means of the +sand-crack forceps (Fig. 87). According to the length of the crack, one, +two, or three clamps may be necessary. Another useful clamp, though far +more complicated in its structure, is that of Professor McGill (Fig. 88). + +[Illustration: FIG. 88.--MCGILL's SAND-CRACK CLAMP.] + +'The object of this invention is to arrange on a spindle, which is +screw-threaded at one end with a right-hand thread and at the other with a +left-hand thread, two clips or clamps, free to travel on the thread, there +being a nut between the two which can be turned by a spanner. The clips +are placed on the hoof, one on each side of the sand-crack, the hoof being +prepared to receive the instrument by filing a groove or notch for the +clamps to fit into, and by turning the nut on the screw the clamps +are brought towards each other, and the crack thus prevented from +spreading.'[A] + +[Footnote A: _Veterinarian_, vol. lxi., p. 141.] + +Still a further useful clamp is that of Koster. This is considerably +broader than the clamp of Vachette, and its gripping edges are provided +with teeth (see Fig. 89). + +As with the clamp of Vachette so with this, a groove is burned into the +wall on each side of the crack for the accommodation of the jaws of the +instrument, and the clamp itself pressed home by means of a special pair of +forceps. This form of clamp holds well, and has the advantage of securing a +wider area of horn than that of Vachette or McGill. + +[Illustration: FIG. 89.--KOSTER'S SAND-CRACK CLAMP.] + +Clamping by any method should be advised or undertaken only under certain +conditions. The horn should be moderately strong, and the wall should be +thick. This practically restricts the use of the clamp to cracks of the +toe, and it is there, as a fact, they are found of most benefit. While +burning the grooves for the clamp, and while tightening the clamp itself, +the animal's foot should be on the ground and bearing weight at the heels, +thus insuring the greatest possible approximation of the edges of the +crack. + +With all methods of clamping an untoward result is sometimes the formation +of a fresh crack at the point of insertion of the clamps. + +(c) _By the Use of Thin Metal Plates_.--These are of use when the horn of +the wall is too thin to allow of clamping, and are therefore of especial +use in cracks of the quarters. The plates are made so as to cover the +greater part of the length of the lesion, and are fastened to the wall +by two or more screws on either side of the crack. It is an advantage to +slightly let the plate into the wall by means of fitting it hot. In a +complicated crack the plate serves the further useful purpose of holding in +position antiseptic pledgets, and so keeping the lesion free from dirt and +grit. + +_(d) By Various Methods of bandaging the whole Circumference of the +Wall_.--In our opinion this method of attempting to secure immobility of +the crack, and so prevent its extension, is not often followed by success. +The main objection to the method is that it subjects the whole of the wall +to the same pressure, and does not restrict the operation to the point at +which it is required. As in the case of the metal plate, however, this +method has the advantage that antiseptic dressings may be kept in position +in the case of a complicated crack. + +[Illustration: FIG. 90.--SAND-CRACK BELT.] + +The binding of the wall may be accomplished in two ways. The simpler of the +two is to merely apply the sand-crack belt depicted in Fig. 90. Beneath +this should be applied a compress of tar and tow or other material, and the +whole tightened up and kept in position by means of the buckle and strap. +This method of binding admits of after-tightening should it unfortunately +work loose. + +The older method of binding the wall, and one now often practised by the +smith, is to use a quantity of so-called 'tar-band' or other stout cord. +With this the foot is neatly bound after the manner of a cricket-bat +handle, and all movement of the crack apparently restricted. There is +always a tendency, however, for such a dressing to work loose, and in the +case of a complicated crack it has the disadvantage of permanently hiding +from view the changes taking place in the discharge from the fissure. + +_(e) By wedging the Crack_.--This is the exact opposite of clamping. +Whereas in clamping we obtain immobility of the crack by keeping it fixed +in the position of greatest approximation of its edges, in wedging, the +crack is rendered free from movement by maintaining it in that position +where its edges are most widely separated. In this case the edges of the +crack are pared smooth, the cavity thoroughly cleansed, and a wedge of hard +wood firmly driven in so as to fit exactly the fissure. + +On the face of it it appears that this procedure would really tend to force +open and so lengthen the crack, especially at its coronary extremity. What +one should really remember, however, is that the crack _is not made wider_ +than before, but that it is simply maintained in a position occurring with +every contraction of the heels of the foot, when it is normally at +its widest. Movement of the edges is thereby stopped, the immediately +surrounding structures are rested, and a new growth of horn, free from +crack, induced to grow down from the coronet. + +This method of treatment only serves to emphasize the fact that, with a +sand-crack once formed, it is the constant movement of the parts that tends +most to keep it in existence, and not any particularly marked exertion of +force. + +Some practitioners, with the wedge, apply also a clamp, thus assuring +additional firmness and solidity to that portion of the wall under +treatment. + +The method of wedging is undoubtedly successful, if neatly performed. + +_(f) By Surgical Shoeing_.--A partial rest is given to the affected parts +by easing the bearing of the shoe at the point required. This may be done +either by removal of part of the wall at the spot indicated, or by thinning +the web of the shoe in the same position. The former is the method usually +practised. Cessation of movement given in this way is, as we have already +said, only partial; for, while the effects of pressure and concussion from +below are minimized, the crack is still able to suffer from the movements +of expansion and contraction of the foot. Still, as an auxiliary to other +treatments, 'easing' of the wall under the affected part should always be +practised. + +[Illustration: FIG. 91.---THE BEARING 'EASED' BY REMOVAL OF THE WALL.] + +[Illustration: FIG. 92.--THE BEARING 'EASED' BY THINNING THE WEB OF THE +SHOE.] + +Figs. 91 and 92 show respectively the manner of 'easing' by removal of +the wall, and by thinning the web of the shoe. In this connection it is +necessary to point out that on no account should 'springing' of the heels +of the shoe be allowed. Fig. 93 illustrates the ill-practice. + +In this case, when the entire weight is thrown on to the heels, the portion +of wall posterior to the crack is bound to participate unduly in the +downward movement, and so tend to widening of the crack at its highest +point. + +[Illustration: FIG. 93.--THE BEARING 'EASED' BY 'SPRINGING' THE HEEL OF THE +SHOE.] + +We have already referred to the matter of 'clips.' In no case, whether the +crack be at the toe or in the quarters, should a clip be placed immediately +below it. If the crack is at the toe, the usual clip should be dispensed +with, and a clip at each side made to take its place. At the same time care +should be taken to avoid throwing the weight far forward. For that reason +a shoe with calkins or with very high heels should be removed, and a shoe +with an ordinary flat web substituted. + +In the case of quarter-crack, where the constant movement of the parts +under expansion and contraction of the foot makes itself most felt, it is +wise to apply a shoe with clips fitting moderately tight against the +inside of the bars. By this means movement will to a very large extent be +curtailed. + +Where a marked tendency to contraction is found, as is often the case with +quarter-crack, then the shoe with the clips may be rendered more marked in +its operation by giving to the outer face of each clip--that face applied +to the bar--a slope from above downwards and outwards. In other words, a +slipper shoe should be applied and the contraction given equally as much +attention as the sand-crack itself. + +Where the crack is situated far back in the quarter, and easing of the +bearing cannot be accomplished without tending to spring the heels, then +the most suitable shoe is a bar shoe. With it the bearing may, of course, +be eased in exactly the position required, and the heels still allowed +to take their fair share in bearing the body-weight, and thus assist in +closing the crack. The bar shoe, if properly fitted, gives us also a +bearing on the frog, and aids greatly in counteracting contraction. + +2. _Curative_. + +_(a) The Application of Dressings to the Lesion_.--In the case of a recent +crack, deep, and attended with haemorrhage, the foot should be thoroughly +cleansed. Where possible, a constant flow of cold water from a hose-pipe +should be allowed to run over the foot. By this means the inflammatory +symptoms will be held in check and pain prevented. Later the shoe may be +eased at the required place, and a blister applied to the coronet. This, +with rest, will sometimes prove all that is needed. + +Should a crack be of old standing, and complicated by the presence of pus, +a course of hot poulticing will often prove of benefit. The poultice should +be medicated with any reliable disinfectant, and should be renewed, or at +any rate reheated, two or three times daily. The crack itself should be +thoroughly cleaned after the removal of each poultice, and a concentrated +antiseptic solution--such as Tuson's spts. hydrarg. perchlor., carbolic +acid, and water, (1 in 10) or liquor zinci chlor.--poured into it. On +discontinuing the poulticing, the strength of the antiseptic solutions may +be decreased, the parts rested by correct shoeing, and a blister applied to +the coronet as before. + +If these measures alone should prove insufficient, then the surgeon will +either fall back on those we have just related, or proceed to methods next +to be described. + +_(b) Immobilizing the Crack by Means of grooving the Wall_.--To our +minds, this is as ready and withal as successful a method of dealing with +sand-crack as has yet been devised. It may be done in a variety of ways: +(1) By two grooves arranged about the crack in the form of a V, as Fig. 94; +(2) by a perpendicular groove on either side of the crack, about 1 inch in +distance from it, and parallel with the horn fibres, as Fig. 95; (3) by a +single horizontal groove at the extreme upper limit of the crack; (4) by +drawing two horizontal grooves, one at its upper and one at its lower end +(see Fig. 96). + +[Illustration: FIG. 94, FIG. 95, FIG. 96. In Figs. 94, 95, and 96 the thick +black lines illustrate the positions of the various grooves made with the +firing-iron for the purpose of immobilizing a quarter sand-crack.] + +The points to be observed in carrying out this line of treatment are simple +enough. In all cases see that the crack is rendered as clean as possible +by the use of suitable dressings, and if an excess of horn is present +immediately around it, as in the case of a long-standing and complicated +lesion, have it thinned down by rasping. + +All that is then needed is one or two moderately sharp, flat firing-irons. +The groove is then burned into the horn in the positions indicated, and +that portion of the wall containing the sand-crack thus prevented from +participating in the movements of the foot. For our own part, we consider +the V-shaped incision, or either of the horizontal methods of grooving, +preferable to lines running in the direction of the horn fibres. With the +latter there is certainly a greater tendency to the formation of new cracks +than with either of those we advocate. The V-shaped incision we consider +most suitable of all, for the reason that by its means a greater degree of +immobility is conferred upon the necessary portion of the wall. + +Whichever method is adopted, care should be taken to carry the grooves deep +enough into the horn, taking them down as near as possible to the sensitive +structures. At the same time, especial care should be exercised in not +carrying them too deep at their extreme upper limit, or in that case the +liability to the formation of fresh cracks in those positions will be +greatly increased. + +After grooving, a sharp blister should be applied to the coronet every +three or four weeks, and the animal, if free from lameness, put to work. + +_(c) By stripping away a V-shaped Portion of the Wall around the +Crack_.--This method is only indicated when the crack is greatly +complicated by the presence of pus, or by the growth of adventitious horn +on the inner surface of the wall. A radical cure is thus obtained, but the +animal for a longer time incapacitated from work. + +The operation is best performed by first grooving a line to connect the +points _a_ and _c_ (Fig. 97). This should run immediately under the +coronary margin of the wall, and should stop short of injuring the coronary +cushion beneath. Grooves forming the sides _ab_ and _bc_ of the triangular +piece of horn are next made, and the horn contained within the lines _ab, +bc_, and _ca_, carefully removed. The grooves are the easiest made by a +cautious use of the firing-iron. The greater thickness of the horn may +thus be penetrated, and the grooves afterwards carried to their full and +requisite depth by the use of the drawing-knife. + +With the removal of the horn the diseased structures are exposed to view. +All such should be removed by a free use of the scalpel, and a suitable +dressing afterwards applied. A necessary factor in the treatment is the +employment of pledgets of antiseptic tow. With these the exposed tissues +are covered, and the successive turns of a bandage run tightly over +them, so as to exert a moderate degree of pressure. When haemorrhage has +accompanied the operation, this dressing should be removed on the following +day, the wound dressed, and the pledgets of tow and the bandage renewed. +Any after-dressing need only then be practised at intervals of a week. +Repair after this operation is rapid, and takes place both from the exposed +podophyllus membrane and from the coronary cushion. + +[Illustration: FIG. 97. The dotted lines outline the V-shaped portion of +wall to be removed in the treatment of complicated toe-crack.] + +[Illustration: Fig. 98. The dotted lines indicate the portion of wall to be +removed in the complete operation for complicated toe-crack.] + +_(d) By stripping the Wall from the Coronary Margin to its wearing Edge on +Either Side of the Crack_.--This is merely a more extensive application +of the method just described, and is only indicated in a _complete_ and +_complicated_ crack that has refused to yield to other modes of treatment +(see Fig. 98). + +As in the previous case, a groove is run from _a_ to _c_. The grooves _ab_ +and _de_ are then continued to the lowermost edge of the wall, and the +whole of the wall within these points removed. To facilitate removal, +the white line should be grooved between the points _b_ and _d_. +After-treatment is exactly the same as that just referred to. + + +B. CORNS. + +_Definition_.--In veterinary surgery the term 'corn' is used to indicate +the changes following upon a bruise to that portion of the sensitive sole +between the wall and the bar. Usually they occur in the fore-feet, and are +there found more often in the inner than in the outer heel. + +The changes are those depending upon the amount of haemorrhage and the +accompanying inflammatory phenomena occasioned by the injury. + +Thus, with the haemorrhage we get ecchymosis, and consequent red staining +of the surrounding structures. As is the case with extravasations of blood +elsewhere, the haemoglobin of the escaped corpuscles later undergoes a +series of changes, giving rise to a succession of brown, blue, greenish and +yellowish coloration. + +With the inflammation thereby set up we get swelling of the surrounding +bloodvessels, pain from the compression of the swollen structures within +the non-yielding hoof, and moistness as a result of the inflammatory +exudate. + +In a severe case the inflammation is complicated by the presence of pus. + +_Classification_.--Putting on one side the classification of Lafosse +_(natural_ and _accidental_), as perhaps wanting in correctness, seeing +that all are accidental, and disregarding the suggested divisions of Zundel +_(corn_ of the _sole_ and _corn_ of the _wall_) as serving no practical +use, we believe, with Girard, that it is better to classify corns according +to the changes just described. + +Following his system, we shall recognise three forms: (1) _Dry_, (2) +_moist_, (3) _suppurating_. + +The _dry_ corn is one in which the injury has fortunately been unattended +with excessive inflammatory changes, and where nothing but the coloration +imparted to the horn by the extravasated blood remains to indicate what has +happened. + +The _moist_ corn is that in which a great amount of inflammatory exudate is +the most prominent symptom. It indicates an injury of comparatively recent +infliction. + +The _suppurating_ corn, as the name indicates, is a corn in which the +inflammatory changes are complicated by the presence of pus. + +_Causes_.--The causes of corns we may consider under two headings--namely, +_predisposing_ and _exciting_. + +_Predisposing Causes_.--By the heading of this chapter we have already +intimated that corns are due to faulty conformation of the foot. It is, +therefore, merely a description of such shapes of foot as favour their +formation that will need mention here. + +The wide, flat foot, with low heels, may be first considered. Here the +posterior portions of the sole, those portions between the wall and the +bars, fall very largely in the same plane as the wearing surface of the +bars and the wall. As a consequence, these portions of the sole are more +prone to receive injury from stones and rough roads and from the pressure +of the shoe. + +The low heels, too, favour a more than due proportion of the body-weight +being thrown on to the posterior parts of the foot. Two evils, both +inclining to the production of corn, result from this. In the first +place, the sensitive structures of the posterior portions of the foot are +subjected to undue pressure from above; secondly, the posterior half of +the foot, by reason of the extra weight thrown upon it, is exposed also to +greater effects of concussion than normally it should meet. Added to this +we find that the abnormally flat condition of the sole has resulted in +a great loss of resiliency. With undue pressure above, and a loss of +resiliency and added effects of concussion below, the sensitive structures +included between the opposing pedal-bone and the horny sole are bound +to suffer more or less bruising each time the foot comes to the ground, +especially if the animal is moved at a rapid pace. + +Writing here of the effects of pressure and concussion affords a fitting +occasion to mention the fact that corns occurring in feet affected with +side-bones are always worse than in feet with normal elastic cartilages. +The explanation of this is simple, for there can be no doubt that the +loss of resiliency in the diseased cartilage is only another aid to undue +pressure and concussion. The sensitive structures are pinched between +unyielding bone above and practically unyielding horn below. + +Feet with high and contracted heels are also predisposed to corn. The +contraction in this case interferes with the downward movements of the os +pedis during progression, while in a state of rest there is a more or +less constant pressure upon the sensitive structures, due to the correct +downward displacement of the pedal-bone being opposed by the amount of +contraction present. In the contracted foot, too, the nutrition of the +vessels supplying the secretory apparatus of the horn is largely interfered +with. The horn loses its natural elasticity, fails to respond to the normal +movements of the parts within, and aids in the compression and laceration +of the sensitive structures. + +Weak feet, with horn too thin to withstand the expansive movements +continually going on--in other words, feet with weak, spreading heels--are +also prone to suffer from corns. In this case the flatness induced by the +spreading, and the insufficient protection afforded by the thin horn, +both combine to lay the sole open to the effects of concussion and direct +injury. + +Brittle feet--feet with horn of undue dryness, by reason of the contraction +thus brought about--are, again, particularly subject to corn. + +So also with long feet. Whether occurring as a natural deformity, or as the +result of insufficient paring, bruises of the sole in feet thus shaped are +common. The reason for this will be better understood when we come to deal +with the shoeing. + +Other and minor predisposing causes are those mainly referring to an +unnatural dryness of the hoof when animals reared in the country are put +to work in large towns. We here really get several predisposing causes +combining. A sudden change is made from a more or less moist condition +underfoot to one excessively dry. The character of the travelling is wholly +altered from occasional work upon soft lands to continual labour upon +hard-paved roads. The horn is often exposed to the vicious influences +of unsuitable litter, the application of unsuitable dressings, and the +deleterious effects of the street mud of our cities. All these play their +part in determining a condition of the horn, rendering it open to receive +the effects of the more exciting causes which we shall next consider. + +_Exciting Causes_.--Than the shoeing, no more frequent and exciting cause +of corn exists. Whatever the predisposing influences may be, it is the +shoeing that in nearly every case completes the list, and finally inflicts +the injury. + +The evils in this connection we shall consider under two headings--viz., +(1) the manner in which the foot is pared; (2) the make and fitting of the +shoe. + +First among the faulty preparations of the foot comes that of excessive +thinning of the sole, especially in the regions subject to corn. The +farrier addicted to this is not as a rule content to confine his operations +to the sole alone. In addition, the frog and the bars also suffer from the +too lavish use of his knife. His main object is doubtless that of giving +a broad and open appearance to the foot. It follows from this that his +operations are confined more to the posterior than the anterior parts of +the foot, and that the toe is therefore left too long. This gives us a +combination of causes leading to pressure and bruises upon the sensitive +structures at the seat of corn. + +By this unequal paring of the toe and the heels greater weight is thrown +upon the posterior half of the foot. What then happens to the structures +thinned as we have described is this: the pared frog, lessened in volume, +does not meet the ground. It therefore fails to expand laterally with +weight, and cannot assist, as normally it should, in aiding the heels +generally in their movements of expansion. The weakened bars and the +thinned sole, meeting with no opposition from the frog, give downwards and +inwards with the body-weight at the precise moment these movements should +be directed mainly outwards. As a further result of non-resistance on the +part of the frog, this time in a lateral direction, the bars, the sole, and +the wall at the heels all contract at the exact time they should expand. +The end result must mean abnormal pressure and bruising of the sensitive +structures in that particular region. Naturally, also, the excessive +thinning of the horn renders direct injury to the sole from stones or other +objects in the road far more probable. + +For this one reason alone--the manner in which it favours the production of +corn--too great a condemnation cannot be placed upon excessive paring of +the sole, the bars, and the frog. + +When corns are already present, as they may be from other causes, the same +remarks will again apply to excessive paring. It is the custom with many +smiths to carefully pare down the discoloured horn in every case of corn +they meet with, and at the same time to again weaken the bars and even part +of the wall at the heels, with the laudable idea of relieving pressure on +the part diseased. After what has gone before, we need hardly say that +their well-meant efforts have a precisely opposite effect to the one they +intend. + +The fitting of the shoe is, perhaps, to a greater extent responsible for +the causation of corn than is the paring we have just described. + +A few of the evils connected with the shoe may, however, be justly +described as unavoidable. We _must_ shoe; we cannot shoe and leave a normal +foot! + +A shoe excessively seated, especially from the last nail-hole backwards, +may be regarded as dangerous. In this case, with every application of the +body-weight, there is given to the foot a tendency to contract, especially +at its lower margin. Result: undue pressure upon the tissues around and the +production of corn. + +On the other hand, varying with the form of foot, the seating may be +insufficient. In the case of flat-foot, or dropped sole, for instance, +insufficient seating will lead to undue pressure of the web of the shoe +upon the sole, and in that way bring about bruising of the sensitive sole +beneath. + +Shoes with heels or calks too high, by destroying the counter-pressure of +the frog with the ground, serve to bring about a series of changes we have +described under contraction, and again result in pinching and bruising of +the sensitive structures. + +The opposite excess--a shoe thick at the toe and thin at the heels--is +blamed by Zundel for causing a like injury. In our opinion, the reason this +author gives--namely, that the throwing of greater weight upon the heels +leads to bruising of the sensitive structures--can only correctly apply to +a _wrongly-applied_ shoe of this type, and not to the shoe itself. True, a +shoe with a thick toe and thinned heels will throw an undue proportion of +the body-weight upon the heels if the foot is not properly prepared for +it. A wise man, however, will most certainly so cut down the toe for the +reception of this shoe that, with the shoe in position, there will still be +maintained a tread that is normal. To our minds harm is far more likely to +arise from a shoe of this class through the thinned iron heels of the shoe +becoming attenuated under wear to the point of bending, and so inflicting +an injury upon the adjoining sole. + +Similarly, this last remark with regard to the thinning of the heels of the +shoe will apply to a shoe with too broad a web. As the thinning of the shoe +proceeds with wear, the inner portion of the thinned branch is bent up on +to the sole, and again inflicts the injury. + +The matter of bearing is also of importance when considering the causation +of corn. In a previous chapter we have already described the correct +bearing as that which includes the whole of the lower margin of the wall +and the white line, and just impinges on the sole. Any marked deviation +from that will, if long continued, be followed by injury to the foot. + +With the bearing surface of the shoe too narrow--in contact with the +wall solely, or perhaps only a portion of it--it is evident that a large +proportion of the foot that should properly bear weight is thrown out of +action. A heavy strain is imposed on the white line, and undue descent of +the sole and contraction of the heels brought about. Again the result of +this is compression and bruising of the tissues around the seat of corn. + +With its bearing surface too wide, the shoe immediately exerts direct +pressure upon the sole with every movement of the animal. The sole normally +is not made to receive this, and harm is bound to result. + +Among other ill-fitting shoes we may mention the one with branches too +short, and the one with the extremities of the branches too pointed. In +the first case, as wear of the shoe proceeds, the thinned end is far more +likely to turn in under the seat of corn than is a shoe with branches +of ordinarily correct length. It is evident in the second case that the +pointed branch, when thinned, is a more dangerous agent than the branch +which is nearer the square at its end. + +The matter contained in the first half of the foregoing paragraph explains +in a large measure the rarity of corns in the hind-feet. Here there is +nothing to prevent a shoe with branches of full length being used. The +correct bearing is thus maintained, even with a shoe excessively thinned +with wear, and the liability to injury from it decreased. An exception is +to be found in the case of a feather-edged shoe, such as is used to prevent +cutting or brushing. The thinning by wear from above to below of the branch +already purposely thinned from side to side leads to the formation of a +thin and narrow piece of iron admirably calculated to bend over and injure +the sole. + +Even with a shoe of correct length, with a flat-bearing surface at the +heels, and other conditions favourable to correct application, evil may +still result from the shoe itself being made too narrow. As a result +of this, the branch of _each_ side is set too far under the foot, with +consequent injury to the sole. This is, of course, sheer carelessness +on the part of the smith. When practised, however, it is not easy of +detection, as in all cases the foot is rasped down to cover what has been +done. In other words, the foot is made to fit the shoe and not the shoe the +foot. + +Recognising this close fitting of the shoe as a cause, we are able to +explain in some measure how it is that corns should occur with greater +frequency in the inner than in the outer heel. There is no doubt that the +inner branch of the shoe is nearly always fitted closer than is the outer. +In the fore-foot it is also often shorter. Take these two evils and add +to them the fact that the inner heel is called upon to bear more of the +body-weight than is the outer, and the frequency of corns in the inner heel +will no longer be wondered at. + +Indirectly, the shoe may still be a cause of corn by reason of the +irritation set up by gravel and small pieces of flint becoming firmly fixed +between the sole and the web of the shoe. In nearly every case of this +description the part to be injured is the white line. + +Corns may also result from the animal picking up a stone. The stone becomes +firmly wedged in between the inner border of the branch of the shoe and the +bar or the frog. With every step the animal takes it becomes wedged more +tightly into position. Projecting below the level of the lower surface of +the shoe, it imparts the concussion it thus obtains directly to the sole. A +bruise--and a bad bruise--is the result. + +Finally, it cannot be denied that the work the horse is put to is largely +responsible for the causation of corn. In country animals corns are +comparatively rare, while in animals in town, almost constantly upon hard +paving, they are common. This seems to point strongly to the fact that +concussion through constant work upon unyielding roads is a great factor in +their production. + +_Symptoms_.--Unless the discoloration of the horn is accidentally +discovered by the smith, the simple, dry corn may go undetected. The +disturbance excited by it is so small, and the pain occasioned so slight, +that the patient may offer no indication of its existence. + +Ordinarily, however, the first symptom is that of pain. The animal goes +feelingly with one or both feet, in some cases even showing decided +lameness. The lameness, however, is in no way diagnostic, and the lesion +itself must be discovered before an exact opinion can be pronounced. + +As an aside, it is well to observe in this connection that a negative +opinion as to the existence of corn should never be given unless the +superficial layers of horn have first been removed with the knife. + +When standing at rest the animal exhibits signs more or less common to all +foot lamenesses. He 'points' the foot--in other words, the limb is slightly +advanced, the fetlock partly flexed, and the heels from off the ground. +When both feet are affected they are pointed alternately, and the animal +often manifests his uneasiness by repeated pawing movements, and by +scraping his bedding behind him. + +Should the injury run on to suppuration, the lameness becomes most +acute. The pawing movements become more pronounced, and there is evident +disinclination on the part of the animal to place the foot squarely on the +ground. One is then led to manipulate the foot. The hoof is hot to the +touch. Percussion causes the animal to flinch, and to flinch particularly +when that portion of the wall adjoining the corn is struck. Finally, +exploration with the knife reveals the serious extent to which the injury +has developed. In a neglected case of this description it is even possible +to detect the presence of pus by the amount of swelling and fluctuating +condition of the coronet. The suppurative process has advanced in the +direction of least resistance, and is on the point of breaking through the +tissues immediately above the horn. + +Lameness due to corn is oftentimes intermittent. With a simple corn, dry or +moist, this intermission is largely dependent on the degree of dryness of +the hoof or the road, and also on the character of the road surface. With a +neglected, suppurating corn, on the other hand, variation in the degree +of lameness, in addition to depending on circumstances such as these, +is dependent to a larger extent upon the changes occurring with the +suppuration. In this case the time of greatest lameness is immediately +before the pus gains outlet. Immediately after its exit at the coronet the +animal will go almost sound. Soundness continues so long as the opening at +the coronet remains clear. The tendency, however, is for the opening thus +made to quickly close again. Pus again accumulates, lameness arises as +before, and disappears again with the second discharge of the contents of +the sinus now formed. + +_Pathological Anatomy_.--When dealing with their classification we gave in +outline the main pathological changes to be met with in corns. It now only +remains to give the same matter in slightly greater detail. + +_In dry corn_ the changes we meet with are those accompanying blood +extravasation. From excessive compression of the parts, or from the effects +of direct injury, a portion of the sensitive sole has become lacerated. +The escaping blood stains the surrounding soft tissues after the manner +of blood extravasation elsewhere. If the escape of blood is sufficiently +large, the horn fibres in the immediate vicinity also are stained. It is +this stain in the horn that is the direct evidence of the injury, and is +itself popularly known as the corn. It may vary in size from quite a small +spot to a broad patch as large as half a crown, while its colour may be a +uniform red, or a mottled red and white. The microscopic changes in this +connection are illustrated in Fig. 99. + +[Illustration: FIG. 99.--HORIZONTAL SECTION OF A CORN. The section cut at +about the base of the papillae of the sensitive sole. _a_, papillae, with +horn-cells surrounding them; _b_, interpapillary or intertubular horn; +_c_, hollow spaces in the intertubular material filled with blood; _d_, a +papilla and its surrounding horn-cells filled with blood.] + +Ordinarily, this ecchymosis of the horny sole is due to injury of the +sensitive sole _immediately beneath_ it. It may, however, proceed from +injury to the vessels of the laminae either of the bars or of the wall. In +this case the ecchymosis of the horny sole may be explained by the fact +that the escaped blood tends to _gravitate_ to that position. + +When the corn is of long standing, or is due to _repeated_ injuries on the +same spot, the horn adjacent to the lesion becomes hard and dry, and often +abnormally brittle, simply on account of the inflammatory changes thus kept +in continuation. This is often seen when attempts are made to _pare out_ +the corn with the knife. + +Should the injury be seated in the sensitive laminae, then the brittle +nature of the horn secreted by the injured tissues makes itself apparent by +the appearance of cracks in the wall of the quarter. Why this should occur +will be readily understood by a reference to Fig. 100. + +[Illustration: FIG. 100.--INNER SURFACE OF THE WALL OF THE QUARTER, SHOWING +CHANGES IN THE HORNY LAMINAE BROUGHT ABOUT BY CHRONIC CORN.] + +It will here be seen that the injury to the keratogenous membrane has led +to great interference with the secretion of horn from the sensitive laminae. +As a result, the regularly leaf-like arrangement of the horny laminae has +been largely broken up. Certain of the laminae are altogether wanting, +while others are broken in their length and rendered incomplete. With this +condition there is always more or less contraction of the quarter. + +Microscopic examination of the structures involved in such a case reveals +the fact that with the contraction is an alteration in the normal direction +of the horny and sensitive laminae. + +They become bent backward, and, instead of the regular and normal +arrangement depicted in Fig. 32, show the distorted appearance given in +Fig. 101. + +From the appearances and characters of the blood-stain in the horny sole +we are able to deduce evidence relative to the duration and nature of the +injury. + +[ILLUSTRATION: FIG. 101.--PERPENDICULAR SECTION OF THE WALL OF A CONTRACTED +QUARTER IN A CASE OF CHRONIC CORN. Both the sensitive and horny laminae +are bent backwards, and haemorrhages have taken place at the base of the +sensitive laminae.] + +When, for instance, the stain is not to be found in the superficial layers +of the sole, but is only discoverable by deep paring, then the injury is a +recent one. + +Where the stain _is_ met with in the superficial layers of horn, and is +quickly pared out, then the injury has been inflicted some time before, and +has not been repeated. When, as is sometimes the case, layers of horn that +are stained are found alternated with layers that are healthy, then we have +evidence that the cause of the corn, whatever it may be, is not in constant +operation. + +Similar indication of the age of the injury is also afforded by the colour +of the lesion. + +A stain that is deep red is proof that the injury is comparatively recent. + +A distinct yellow or greenish tinge, on the other hand, is evidence that +the injury is an old one. + +_In the Moist Corn_ we have, in addition to the blood extravasation, the +outpouring of the inflammatory exudate. In the most superficial layer of +the horn this may not be noticeable. As one cuts deeper into the sole with +the knife, however, it will be found that the lower layers of horn are +more or less infiltrated with the discharge. This gives to the horn a soft +consistence, a yellow appearance, and a touch that is moist to the fingers. + +With the accompanying inflammation the cells in the neighbourhood of the +injury are enfeebled and their normal functions interfered with. We may +thus expect a corresponding interference with the growth of horn. This is +exactly what happens, and as one cuts deeper still into the horn a point is +finally reached when a well-marked cavity is encountered. A pale yellow +and usually watery exudate fills it. This cavity points out the exact spot +where the force of the injury has been greatest, where death of certain +cells of the keratogenous membrane has resulted, and where the natural +formation of horn has for a time been suspended. + +_In the Suppurating Corn_, as in moist corn, we have pathological changes +due to the tissue reaction to the injury, _plus_ the addition of pus +organisms. Confined within the horny box we have a discharge that, by +reason of the living and constantly multiplying elements it contains--the +pus organisms--is always increasing in bulk. This must be at the expense +of the softer structures of the foot. Accordingly, as the formation of pus +increases, we get pressure upon and final gangrene of the sensitive sole +and of the sensitive laminae of the bars and the wall. With no outlet below, +the pus formation increases until finally it finds its way out of the hoof +by emerging at the coronet. + +This in some instances it may do by confining its necrotic influences +solely to the sensitive laminae of the wall, in which case, if a dependent +orifice is quickly made at the sole, the injury to the laminae is soon +repaired by the healthy tissue remaining. + +In other cases, however, the necrosis has spread deeper. Caries of the +os pedis, of the lateral ligaments of the pedal-joint, or of the lateral +cartilages, is a result. When this occurs the exuding discharge from the +coronet becomes thinner and more putrescent, and its feel, when rubbed +between the fingers, sometimes gritty with minute fragments of broken-up +bone. Here, unless operative measures prevent it, necrosis soon spreads +deeper still. The deeper portions of the os pedis become affected. The +capsular ligament of the joint is penetrated by the suppurative process, +and a condition of septic arthritis results. The cavity of the joint +becomes more or less tensely distended, according to the amount of drainage +present, which in this case is almost nil, with matter in a state of +putrescence. As a consequence, the surrounding ligaments become softened +and yield, and the articular surfaces displaced. The articular cartilages +also suffer, become necrotic in patches, and frequently wholly destroyed. +The end result is one of anchylosis of the joint and permanent lameness. + +_Prognosis_.--With the ordinary dry corn a return to the normal may nearly +always be looked for. Similarly, with moist corn, and even with careful +treatment of the suppurating variety, the same favourable termination may +be looked for and promised. + +What cannot so safely be assured is that a relapse will not occur. In other +words, the extent of the injury, no matter how serious, does not often +offer anything that cannot be overcome by Nature and careful surgery; but +the conformation of the animal does. A vicious predisposing conformation +once there is there always, and although the injury resulting from it may +easily give way to correct treatment, the same injury is bound to re-occur +when the animal is again put to work. + +Although with care suppurating corn, like other cases of suppuration +within the hoof, may yield to treatment, the owner of the animal should, +nevertheless, be warned that the condition is a serious one, especially +should the joint become affected. It may so happen, as sometimes in fact it +does, that the animal may die as a result of the infective fever so set up. +From no surface in the body can absorption take place quicker than from the +synovial membrane of a joint. So soon, therefore, as this membrane comes in +contact with septic material, so soon does a severe septic fever make its +appearance. The septic matter has gained the blood-stream, and the patient +succumbs to septic poisoning. + +Apart from death occurring naturally, the changes taking place in the joint +in the shape of bony growths or of actual anchylosis may be so severe as to +render the animal useless, and slaughter may have to be advised. + +_Treatment_.--We have already said that by far the most active cause in +the production of corn is the shoe. It follows from this that it is to the +shoeing we must largely look for a successful means of their prevention, +and that the treatment of corn in its most simple form is really a matter +for the smith, and not for the veterinary surgeon. + +The faults in connection with the shoeing we have mentioned fully when +treating of the _causes_ of corn. From those we learn that a shoe with a +flat-bearing surface, or one moderately seated but flat at the heels, is +the correct shoe for nearly all feet. The heels of the shoe should not be +too high, should not be too short, and should be wide enough apart from +each other to insure the wall of the foot obtaining a fair share of the +bearing. Finally, even with the present method of shoeing, whenever it is +possible to allow the frog to come to the ground, it should be encouraged +to do so, and excessive paring either of the latter organ or of the bars or +the sole should be strictly discountenanced. Where the sole is thin, or the +frog wasted, use a leather sole or a rubber pad. With these precautions, +corns may be prevented from occuring even in a foot with a predisposing +conformation. + +When corn is present, the first treatment usually adopted is that of +'paring it out.' This is advocated by Percival and by many other writers. +We cannot say, however, that we agree with it--at any rate, not in the case +of simple dry corn. + +'Paring it out,' and by that we mean thinning down the sole until close on +the sensitive structures, can only be advised in the case of suppurating +corn, or in cases where doubt exists as to whether pus is present or not. +In the latter case paring becomes necessary as an exploratory means to +diagnosis. + +When it appears fairly certain, even in the case of a moist corn, that pus +does not exist, then paring is to be discountenanced, for the reason that +it only tends to weakening of the parts and to assist largely in the corn's +recurrence. + +Those who advocate it do so for the reason that it relieves pressure on the +injured parts. + +That it does so directly from below cannot be denied; but that it also +favours contraction and compression from side to side is equally certain. + +A moderate paring may, however, be indulged in, say, to about one-half +the estimated thickness of the sole. Softening of the horn and consequent +lessening of pressure may then be brought about by the use of oil, oil and +glycerine, tincture of creasote, or by poulticing. + +In the case of a moist corn the paring should be stopped immediately the +true nature of the injury has made itself apparent. Warm poultices or hot +baths should then be used in order to soften the surrounding parts, lessen +the pressure, and ease the pain. After a day or two day's poulticing, +should pain still continue with any symptom of severity, the formation +of pus may be expected, and it is then time for the paring to be carried +further, until the question 'pus or no pus?' is definitely settled. + +Should the moisture be due simply to the presence of the inflammatory +exudate, then poulticing alone will have the desired effect, and the +pain will be lessened. With the decrease in pain the poulticing may be +discontinued, and the horn over the seat of the injury dressed with some +antiseptic and hardening solution. Sulphate of zinc, a mixture of sulphate +of zinc and lead acetate, sulphate of copper, or the mixture known as +Villate's solution,[A] may either of them be used. Suitably shod, and with +a leather sole for preference, the animal may then again be put to work. + +[Footnote A: The composition of the escharotic liquid bearing his name was +published by M. Villate in 1829 as under: + + Subacetate of lead liquid ... ... ... 128 grammes. + Sulphate of zinc [=a=a] ... ... ... 64 grammes. + Sulphate of copper, [=a=a] ... ... ... 64 grammes. + Acetic acid ... ... ... ... 1/2 litre. + +Dissolve the salts in the acid, add little by little the subacetate of +lead, and well shake the mixture.] + +When dealing with suppurating corn, then, a considerable paring away of the +horn of the sole becomes a matter of necessity. The freest possible exit +should be given to the pus, and this even when an opening has already +occurred at the coronet. Unless this is done, and done promptly, the +putrescent matter still contained within the hoof will make further inroads +upon the soft structures therein, and later upon the ligaments, and even +bone itself. + +Having given drainage to the lesion by the dependent orifice in the sole, +poulticing should again be resorted to and maintained for at least three +or four days. The poulticing may then be discontinued, and the openings in +the sole injected with a weak solution of Tuson's spts. hydrarg. perchlor., +a 1 in 20 solution of carbolic acid, a solution of copper sulphate, with +Villate's solution, or with any other combined antiseptic and astringent. +The success of the treatment is soon seen in the cessation of pain and in +the decreased amount of discharge from the opening in the sole. + +Should pain unfortunately continue, the discharge remain, and a state of +fever reveal itself, then it may be understood that the suppurative process +has not been checked, that a portion of necrosed ligament, cartilage, +or bone still remains, which, surrounded as it is by pus organisms and +putrefactive germs, is sufficient to excite a constant irritation and +maintain the internal structures in a state of infection. In other words, +we have what is known as a quittor. + +This will call for deeper operation. The horn of the wall must be removed, +and the diseased structures, whether gangrenous keratogenous membrane, +necrosed ligament, or carious bone, carefully excised or curetted. This +will be better understood by a reference to the chapter on Quittor, where +the means for carrying out the necessary operative measures will be found +described in detail. + +_Surgical Shoeing for Corn_.--In the case of an ordinary dry corn, where +the injury has been definitely ascertained to be accidental, no alteration +in the shoeing will be necessary. Where, however, the corn is attended with +a more than ordinary degree of inflammation, or where for some reason or +other excessive paring has been practised, then it will become needful +to shoe with a special shoe. The object to be attained is the removal of +pressure from that portion of the wall next to the seat of corn. + +The most simple shoe for effecting this is the ordinary three-quarter shoe. +The only way in which this differs from the ordinary shoe is that about an +inch and a half of that branch of the shoe adjoining the corn is cut off +(Fig. 102). If at the same time contraction of the heels exists, then, +perhaps, a better shoe is that known as the three-quarter bar (Fig. 103). + +Or, if preferred, a complete bar shoe such as that described for sand-crack +may be used, and the upper portion of the web in contact with the foot at +the seat of corn thinned out so as to avoid pressure on the wall at this +point. With this shoe we shall at the same time supply a certain amount +of pressure to the frog, and aid in the healthy development of the part +indirectly involved in the disease. + +The same pressure may also be given to the frog, and protection afforded +the sole, by the use of a leather sole, or rubber pad on leather, as +described when dealing with contracted feet. + +A further method of relieving pressure on this portion of the wall, without +removing the wall itself (a practice which should never be advised) is to +make certain alterations in the web of the shoe. This may be done in one of +two ways. + +[Illustration: FIG. 102.--THREE-QUARTER SHOE.] + +[Illustration: FIG. 103.--THREE-QUARTER BAR SHOE.] + +In the first, that portion of the bearing surface of the heel of the shoe +is 'dropped' about 1/8 inch from the plane of the remainder, so that the +shoe at this position does not come into contact with the foot at all (see +Fig. 104). + +In the second case the shoe is what is termed 'set' at the heel. Here it is +the plane of the _wearing_ surface of the shoe that is altered. The hinder +portion of the required heel is thinned so that its lower surface does not +come into contact with the ground. By this means the wall is freed from +concussion and pressure. At the same time the upper surface of the shoe is +in contact with the wall of the foot (see Fig. 105). + +This 'setting' of the shoe is preferable to the method first described. It +affords a greater protection to the foot, and does not allow of fragments +of stone and flint getting in between the foot and the shoe, and so giving +rise to further mischief. + +The 'set' portion should be fitted full and long. It is obvious, too, that +the animal should not be allowed to carry the shoe too long; otherwise, as +the other portion of the shoe wears down to the level of the 'set' heel, +pressure on the tender part of the foot will again result. + +[Illustration: FIG. 104.--SHOE WITH A 'DROPPED' HEEL.] + +[Illustration: FIG. 105.--SHOE WITH A 'SET' HEEL.] + +In applying surgical shoes for corn of long standing, it must be remembered +that the protection so afforded must be continued for some time. It is not +sufficient to see the lesion itself disappear. In addition to that there +is also, in the majority of cases, a certain amount of contraction to be +overcome. This can only be done by continuing the use of a leather sole +or some form of frog or bar-pad as recommended for the relief of that +condition. + + +C. CHRONIC BRUISED SOLE. + +A similar condition to that of corn may be met with in other positions on +the sole. It is described by Rogerson as sand-crack of the sole[A], and is +invariably met with around that portion of the sole in contact with the +shoe. + +[Footnote A: _Veterinarian_, vol. lxiii., p. 51.] + +The animal is lame, and the shoe is removed in order to ascertain the +cause. Nothing at first is noticeable except that the animal flinches when +pressure is applied to the spot with the pincers, or the sole is tapped +with the hammer. + +On removing the sole with the knife, however, a distinct black mark is +discovered, which, when followed up by careful paring, is often found to +have pus at the bottom. + +In this case the injury has resulted, as we have already intimated +elsewhere, from causing the animal to wear for too long a time a shoe with +too broad a web or insufficiently seated. Or it may have originated with +the irritation set up by foreign and hard substances between the web of the +shoe and the foot. + +In his description of this condition Mr. Rogerson draws attention to the +fact that the pus found should not be wrongly attributed to accidental +pricking of the foot. He says: + +'Considering that the cracks or splits are always found in the immediate +vicinity of the nail-holes, a certain amount of discretionary skill is +required in order that the lameness may be attributed to its proper cause. +This is an instance in which the presence of the veterinary surgeon +is imperative, in order to prevent undue blame being attached to the +shoeing-smith. Misconception in these cases might very easily arise when +parties concerned are disposed to accept an unskilled opinion, sometimes +resulting in danger to the proprietor of the forge, not only of losing a +shoeing contract, but also of being involved in other ways which would +probably prove even more disastrous. + +'Horses that stand on sawdust or moss litter are sometimes found with +extensive discoloration of the horny sole in front of the frog. Their +bedding material collects in the shoe as snow does, and forms a mass, which +keeps a continued and uneven pressure upon the sole. A sound foot is not +injuriously affected, but a very thin sole is, and so also is a sole which +has been bruised by a picked up stone. Even a slight bruise becomes serious +if pressure is allowed to remain active over the injured part. Lameness +increases, serous fluid is effused between the horn and sensitive part, or +even haemorrhage may take place.'[A] + +[Footnote A: Hunting, _Veterinary Record_, vol. xiv., p. 593.] + +_The Treatment of Chronic Bruised Sole_ offers no special difficulty. +Removal of the cause (in nearly every case incorrect bearing of the shoe) +is the first consideration. That done, the lesion may be searched for and +treated in the ordinary manner as described for corn. When pus is present +it must, of course, be given exit, and an antiseptic solution applied to +the wound. Should the sensitive structures be laid bare when allowing the +pus to escape, then the wound so made should afterwards be protected with a +leather sole and antiseptic stopping. + + + +CHAPTER VIII + +WOUNDS OF THE KERATOGENOUS MEMBRANE + + +A. NAIL-BOUND--BIND OR TIGHT-NAILING. + +_Definition_.--By the term 'nail-bound' is indicated that accident +occurring in the forge in which the nail of the shoe is driven too near the +sensitive structures. Although involving no actual wound, it is important +to consider the condition under the heading of this chapter, in order that +it may be distinguished from the graver accident of a 'prick.' + +_Causes_.--Very largely the whole matter of causation turns on the correct +fitting of the shoe. The points especially to be noticed in this connection +are (1) the position of the nail-holes in the web of the shoe, (2) the +'pitch' of the nail-holes. + +Regarding the position of the nails, it goes without saying that the first +consideration when 'holing' the shoe should be to punch the holes opposite +to sound horn. This remark applies especially to shelly and brittle feet, +the type of feet in which tight-nailing most often occurs. The next +consideration in this connection is that of punching the holes so that the +nail emerges from the upper surface of the web at exactly its correct point +of entrance on the bearing surface of the foot. This should be on the white +line immediately where it joins the wall. From this position any marked +deviation inwards ('fine-nailing,' as it is termed) is bound to give to the +nail a direction dangerously near the sensitive structures. + +The 'pitch' of the nail-holes should be such that the nail is guided more +or less nearly to follow the line of inclination of the wall. Accordingly, +the nail-holes at the toe should be 'pitched' distinctly inwards, the +inward pitch lessening as the quarters are reached, until the hindermost +nail-hole or two is pitched in a direction that is almost perpendicular. + +Too great an inward inclination of the nail will, however, give rise to a +bind. + +It is probable that 'tight-nailing' results more often from fine punching +of the shoe than from any fault in the pitch of the hole. Inattention to +either detail, however, is apt to bring the mischief about. + +Even with a correctly fitted shoe, and with a normal foot, tight-nailing +may occur as a result of sheer carelessness on the part of the smith. + +_Symptoms_.--Possibly the animal returns from the forge sound. It is on +the following day, as a rule, that evidence of the injury is given by the +animal coming out from the stable lame. In a well-marked case the foot +is warmer to the hand than its fellow, and percussion over the wall will +sometimes reveal the particular nail that is the cause of the trouble. +Should the shoe be removed, then the fact that the hole the nail has made +is far too close to the sole often points out at once the seat of the +mischief. + +_Treatment_. As to whether or not the shoe should be removed is very much a +matter for careful discretion on the part of the veterinary surgeon. Where +the foot is shelly and brittle even a good smith sometimes finds himself +unable to firmly attach the shoe without verging closely on causing the +condition we are now describing. The author has known cases where animals +with feet of this description have almost invariably returned from the +forge, or rather been found the next day, with a suspicion of tenderness. +After the lapse of a day or two this has quite often disappeared, and +nothing in the meantime been done with the foot. Seeing, therefore, that +removal and refitting of the shoe is in this case attended with risk of +breaking away portions of the brittle horn, and so rendering the foot in an +even worse condition than it was before, it is policy to decline to have +the shoes removed unless worse symptoms make their appearance. + +In coming to this decision the veterinary surgeon must be guided by noting +in the wall the points of exit of the nails. Should the nail adjoining the +position already pronounced to be tender have come out at a higher point +than the others, it may be assumed that at a lower position in its course +through the horn it has gone near the sensitive structures without actually +penetrating the horny box, and that in the course of a day or two the +sensitive structures involved will accommodate themselves to the pressure +thus inflicted. + +If, on the other hand, symptoms of tight-nailing show themselves in an +animal with good sound feet, then there is no objection to be raised +against having the shoe at once removed. Should the offending nail be +definitely detected, then the shoe may again be put on, and that particular +nail omitted from the set. + + +B. PUNCTURED FOOT. + +(_Pricked Foot_--_Nail-tread_--_Gathered Nail_.) + +_Definition_.--Under this heading we propose describing wounds of the +foot occurring in the sole or in the frog, and penetrating the sensitive +structures beneath. + +_Causes_.--These we shall consider under two headings: + +1. Wounds resulting from the animal himself 'picking-up' or 'treading' on +the offending object. + +2. Cases of pricking in the forge. + +Those occurring under the first heading are, of course, purely accidental. +In the majority of cases, the object picked up is a nail; but similar +injury may result from the animal treading on sharp pieces of wood or +iron, on pieces of umbrella wire, on pointed pieces of bones, broken-off +stable-fork points, sharp pieces of flint, etc. The same accident may also +occur in the forge as a result of the animal treading on the stumps of +nails, from treading on an upturned shoe with the stumps of nails _in +situ_, or from treading on an upturned toe-clip. It may also occur from an +accidental prick with the stable-fork when 'bedding up,' or from casting +part of a shoe when on the road and treading on the nails, in this case +left sometimes partly in and partly out of the horn. + +'Serious wounds of this description are also met with in animals engaged in +carting timber from plantations in which brushwood has recently been cut +down. This is, of course, from treading on the stake-like points that are +left close to the ground. Hunters also meet with the same class of injury +when passing through plantations or over hedge banks, where the hedge has +just been laid low or cut down. + +'Agricultural horses also meet with severe wounds of this class from +treading on an upturned harrow.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv., +p. 2.] + +It has been remarked how strange it is that nails should so readily +penetrate the comparatively hard covering of the foot. The matter, however, +admits of explanation. One knows from common observation how easy it is to +tilt a nail with its point upwards by exerting a pressure in a more or less +slanting direction upon its head. This is exactly the form of pressure that +is no doubt put upon the nail if the animal treads upon it when moving at +any pace out of a walk. The foot in its movement forward tilts the nail +up, and almost simultaneously puts weight upon it. The great weight of the +animal is then quite sufficient to account for its ready penetration. + +In purely country districts cases of punctured foot are of far less +frequent occurrence than in large towns. In the latter, animals labouring +in yards where a quantity of packing is done, or engaged in carting +refuse containing such objects as we have mentioned, or broken pieces of +earthenware or glass bottles, meet with it constantly. + +For the manner of causation of those wounds to the foot occurring in +the forge the reader may be referred to the matter under the heading of +'nail-bound.' As in that case so in this the nail may be wrongly directed +by improper fitting of the shoe, by the 'pitch' of the hole, or by the +position of the hole. The nails may also be wrongly directed as a result of +faulty pointing, or by meeting with the stump of a nail that has carelessly +been allowed to remain in the substance of the horn. + +Often pricking is a result of carelessness engendered by a rush of work. +Often it is almost unavoidable on account of the character of the foot that +is brought to be shod. Feet with thin horn, especially a thin sole, feet +with horn shelly and brittle, each in their way are difficult to shoe. + +Sometimes pricking is purely accidental, as in the case of a 'split' nail. +The nail as it is driven splits at its point, and continues to split down +its centre, one half emerging at the correct spot on the wall, the other +half bending inwards, and penetrating the sensitive structures. + +_Common Situations of the Wound_.--In a case of picked-up nail the common +seat of puncture is about the point of the frog, either in one of the +lateral lacunae, in the median lacuna, or the apex of the frog itself. In +comparison with this puncture of the sole is rare. + +Prick sustained at the hands of the smith may, of course, run in either of +the following directions: (1) Directly into the position where the horny +and sensitive laminae interleave; (2) between the sensitive laminae and the +os pedis; (3) into the os pedis itself; (4) the nail may bend excessively +immediately after entering the horn, and so pass either between the horny +and sensitive sole; or (5) between the sensitive sole and the bone. + +_Classification_.--Punctured wounds of the foot may be classified as +follows: + +_Simple or superficial_ when penetrating no structure of great importance. +For instance, a prick that penetrates to the sensitive sole and is not +driven with sufficient force to seriously injure the os pedis we may regard +as simple. In the same manner a prick to the frog that, although deep, is +mainly concerned with penetrating the plantar cushion may also be classed +as simple. + +_Deep or penetrating_ when driven with sufficient force or in such a +direction as to injure structures whose penetration is calculated to give +rise either to serious constitutional disturbance or to permanent lameness. +In this category we may place injuries to the terminal portion of the +perforans, puncture of the navicular bursa, fracture of the navicular bone +and penetration of the pedal articulation, and splintering of the os pedis. + +_Symptoms and Diagnosis_.--While discussing the symptoms and diagnosis, we +will still continue to consider our subject under the two headings of (1) +accidental 'gathering' of some foreign body, and (2) pricks inflicted in +the forge. + +In a few cases belonging to the former class the veterinary surgeon is +fortunate in obtaining a direct history of the injury. The driver has seen +the animal go suddenly lame, and has examined the foot for the cause. +Either the nail has been found embedded in the horn, or the puncture it has +made detected, and the matter has been reported. The foot is then explored +and the full extent of the injury ascertained. + +In many cases, however, it so happens that no evidence of the infliction of +the injury is forthcoming. The momentary lameness occurring at the time of +the prick is unreported at the time by the attendant, and the horse for +a time goes sound. It is not until the changes set up by the subsequent +inflammatory phenomena make their appearance, and lameness results, that +attention is called to the foot. When this happens there has, as a rule, +been time for pus to form around the seat of puncture--a matter of about +forty-eight hours. + +The horse is now brought out for the veterinary surgeon's examination, +going distinctly lame. If the case is well marked there may then be noted +by the man of experience many little signs pointing to the foot as the seat +of the lameness. These, though well enough known to the practitioner, are +nevertheless difficult to describe. It is, in fact, hard to say exactly in +what they really consist, appearing to be as much a matter of intuition as +of actual observation. + +There is a peculiar 'feeling' characteristic in the gait. The affected foot +is put forward fearlessly enough, but is not nearly so rapidly put to the +ground. When at rest the foot is almost immediately pointed, and the pain +at intervals manifested by pawing movements. It is this extreme liberty of +the rest of the limb, as evinced during the pawing movements, that really +strikes one. Shoulder, elbow, knee, and fetlock are all easily and +painlessly flexed and extended. There is nothing wrong with them; it must +be the foot. The short manipulation necessary to test the lameness--viz., +the walk and slow trot--is sufficient to raise the animal's pulse and +quicken the breathing. + +All this is enough, and more than enough, to lead the veterinary surgeon +to examine the foot. It is hot to the touch, and at the coronet tender to +pressure, possibly in a neglected case fluctuating at the heel. Pain is +evinced by the animal withdrawing his foot when percussion takes place over +the affected spot. In a bad case one gentle tap is all that is needed. The +animal at once snatches away his foot, holds it high from the ground, and +makes pawing movements in the air. At that moment, too, his countenance is +highly expressive of the pain he is suffering. Again the foot is explored, +the injury found, and the pus liberated. + +Regarding the manner of exploration of the foot we will take first that +case in which the veterinary surgeon is called in early, and in which pus +has not yet had time to form. Sometimes the merest cleaning up of the +inferior surface of the foot then reveals a distinct stab either in the +sole or the frog. + +If the accident be recent only a little blood will be found, either liquid, +or coagulated about the wound. Later there exudes from the stab a flow of +yellow, serous fluid. The opening thus found should be carefully probed, +and its depth and situation noted. + +At other times the prick is not so readily apparent. The nail or other +object has penetrated and afterwards withdrawn itself. The natural +elasticity of the horn, especially that of the frog, causes it to contract +upon the puncture, and to largely obliterate the hole made. What, +therefore, may look to be but a simple injury to the horn alone may +in reality be the only evidence of a stab complicating the sensitive +structures. It thus behoves the veterinary surgeon to follow up and +carefully cut out any unnatural-looking mark in the horn, more especially +if the horn is discoloured, or if blood is extravasated into its fibres, or +there is moisture exuding from the part. + +In some cases of this description the knife in the act of paring comes into +contact with the cause of the trouble. Sometimes this is a nail, sometimes +a sharp and small piece of flint, so deeply penetrated as to have become +quite buried. When met with in this manner, however, the foreign body is +more often than not a splinter of wood deeply embedded in the cleft of the +frog or in the frog itself. + +The fact that multiple punctures may occur should here be remembered, and +the remainder of the inferior surface of the foot thinly pared. + +On withdrawal of the foreign object blood may immediately follow. Should +the former have been fixed in position for some time, however, pus is +nearly always found at the bottom of the wound. As a rule, its removal is +comparatively easy, but one case recalls itself to the author's mind in +which the extraction was a matter of considerable difficulty. The offending +object was a large, flat-headed nail, some 2 inches long. This was driven +fast into the os pedis, and necessitated the employment of a pair of +pincers and the exertion of some amount of force to move it from its +position. + +In this connection it must be remembered that the penetrating object +sometimes breaks off after entering the foot. The fact that this +occasionally happens only serves to give point to the advice we have +previously rendered--that every stab should be carefully probed, and its +exact condition and depth ascertained. + +In those cases where percussion has led to the positive opinion that pus +really exists, then the exploration must be most searching. There may, or +may not, be a suspicious-looking mark to work on. In the latter case, the +veterinary surgeon must not be content with confining his paring operations +to one spot. The sole should be carefully thinned all round, and the +thinning cautiously proceeded with until either small, pin-point +haemorrhages denote that healthy sensitive structures have been reached, or +a sudden flow of pus indicates that the injury has been definitely located. + +While the symptoms remain much about the same, the diagnosis of pricks +received in the forge, as compared with those occurring in the natural +manner, is easy. The animal starts to the forge quite sound, and returns, +perhaps, with a slight limp. The slight limp in two days' time becomes a +decided lameness, and no doubt remains as to what has occurred. The mere +fact of the lameness arising immediately after a visit to the forge should +be sufficient in the majority of cases to lead one to a correct diagnosis. + +Where the opinion has been formed that a prick has been received, then the +shoe should be removed. + +This operation should always be superintended by the veterinary surgeon +himself. After the removal of the clinches, the nails should be drawn one +at a time with the pincers, and carefully examined. Often the offending +nail may thus be picked out by observing upon it blood-stains, or the +moisture from inflammatory exudate or from pus. Further inflammation will +also be gathered by occasionally meeting with a nail that has split. + +At this stage, too, the veterinary surgeon should have noticed whether or +not the smith has previously sent the animal home with what is known as a +'draw back.' He has discovered, immediately after he has done it, that he +has pricked the animal. He has then withdrawn the nail, and either sent the +animal back with that nail altogether missing from the set in the shoe, or +with the hole filled up with a stump. + +The shoe once off, the holes made by the nails in the horn should be +minutely examined for the presence of haemorrhage, inflammatory fluid, or +pus exuding from them, and also for evidence of their correct placing in +the foot. Should fluid matter issue from any one of them, or should it be +deemed that one has approached too near the inner margin of the white +line, more especially if tenderness exists around it, that hole should be +followed up with a 'searcher' or small drawing-knife until diagnosis is +certain. + +_Complications_.--Before proceeding to discuss the complications that may +arise in the case of pricked foot, we may call to mind that the anatomy of +the parts teaches us that the most serious position in which a punctured +wound can occur is at the centre of the foot. Here the plantar aponeurosis, +the navicular bursa, the navicular bone itself, or the pedal articulation +may be injured. + +Anterior to this position the most serious mischief that can ordinarily +result is stabbing of the os pedis. + +Posterior to the position we have named, the only structure to be injured +is the plantar cushion. + +Anatomically, then, the inferior surface of the foot may be divided into +three zones, as follows: + +_A. Anterior_, extending from the toe to the point of the frog. + +_B. Middle_, extending from the point of the frog to the commencement of +its median lacuna. + +_C. Posterior_, including everything posterior to the middle zone. + +This division of the inferior surface of the foot into zones will be +somewhat of a guide also when describing the complications next to follow: + +_(a) Suppuration_.--This is the common complication of most wounds of the +foot. When detected, it calls for immediate surgical interference in the +shape of removal of the horn of the sole or the frog, as the case may be. +This we shall consider further under the treatment. + +_(b) Separation of the Horny Frog_.--This is a sequel to pus formation in +the sensitive structures immediately beneath it, and the condition makes +itself apparent by a line of separation between the horn and the skin of +the heel of the injured side. + +_(c) Wounding of the Plantar Aponeurosis_.--This occurs when a +moderately-deep penetration of the horn of the middle zone has taken place. +It is always most painful, especially when complicated by necrosis. The +heel is then persistently elevated, and lameness is extreme, in some cases +so severe as to cause the leg to be carried altogether. + +In favourable cases the necrosed piece of tendon is sloughed off by the +process of suppuration, and escapes with the discharges from the wound. +There is then an abatement in the symptoms, and recovery is rapid. + +Commonly, however, on account of the non-vascularity of the structure of +the tendon, the necrotic spot in it tends to spread. The wound is thus led +to become fistulous in character, and the pus forming within it prevented +from escaping from the original opening. As a result, lameness and fever +persist. There is a gradual increase in the severity of the symptoms, and +later fistulous openings appear in the hollow of the heel. + +_(d) Puncture of the Navicular Bursa_.--This results from a prick in +exactly the same position as that last described, and means that the +penetrating object has gone deeper, It may be distinguished from puncture +of the plantar aponeurosis alone by the fact that there is an excessive +discharge of synovia from the wound. This, as it escapes, is at first clear +and straw-coloured. Later it becomes cloudy and flaked with pus, and shows +a tendency to coagulate in yellowish clots. + +Pain and accompanying fever is most marked, much more so than when the +plantar aponeurosis alone is injured. + +Should the original wound be insufficiently enlarged, or should its opening +become occluded by the solid matters of the discharge, then this condition, +like the last, ends in the formation of fistulous openings in the heel. +These make their appearance as hot, painful, and fluctuating swellings in +that position. Later they break, discharge their contents, and leave a +fistulous track behind. + +_(e) Fracture of the Navicular Bone_.--Penetration of the substance of +the navicular bone, _without_ its fracture, adds nothing to the symptoms we +have described under puncture of the bursa. That the bone has been reached +by the penetrating object may be detected by probing. This, however, +must be performed with care, especially if a flow of synovia is absent. +Otherwise, the wound, as yet, perhaps, superficial enough to avoid +penetrating even the bursa, is made a penetrating one by the probe itself. + +Fracture of the navicular bone is fortunately rare. + +_(f) Penetration of the Pedal Articulation and Arthritis_.--This we shall +consider in greater detail in Chapter XII. It is sufficient here to state +that the condition may be suspected when a hot and painful swelling of the +whole coronet makes its appearance. There is at the same time a diffused +oedema of the fetlock and the region of the cannon, sometimes extending +upwards to the whole of the limb. + +Of all the complications to be met with in punctured foot this is the one +most to be dreaded. The intense pain and the high fever render the animal +weak and thin in the extreme. The appetite becomes impaired, sometimes +altogether lost, and the patient in many cases appears to die from sheer +exhaustion. Added to this is always the extreme probability of the wound +becoming purulent, and later the dread of general septic infection of the +blood-stream ensuing, and death resulting from that. Even with the happier +ending of resolution, anchylosis of the joint and incurable lameness is +more often than not left behind. (See Suppurative or Purulent Arthritis, +Chapter XII.) + +_(g) Ostitis and Caries of the Os Pedis_.--Injuries to the os pedis are +met with in the anterior zone of the foot. Evidence that the bone has been +injured is not usually forthcoming until after the lapse of some days. +One is led to suspect it by the fact that there is no indication of the +suppurative process extending further upwards, coupled with the facts that +great pain, high fever, and extreme lameness persist, and that there is a +continuous discharge from the wound of a copious blood-stained and foetid +pus. Used now, the probe reveals the fact that the bone is bared, and +conveys to the hand that is holding it a sensation of crumbling fragility. + +_(h) Wounding of the Lateral Cartilage and Quittor_.--This occurs as the +result of a deep stab in the posterior zone. Ordinarily, wounds in this +position are unattended with serious consequences, and the prick has to be +a deep and a severe one before the cartilage is reached. What then happens +is that a spot of necrosis is formed round the seat of puncture in the +cartilage. This, unless met with surgical interference, is sufficient +to maintain the wound in a septic condition; it takes on a fistulous +character, and a quittor is formed. (See Chapter X.) + +_(i) Septic Infection of the Limb_.--This we have already once or twice +referred to. It simply means that the septic matters from the wound have +gained the lymphatics, and finally the blood-vessels of the limb, and set +up local lesions elsewhere than in the foot. Although dismissed here with +these few words, the condition is a most serious one. Usually, it has +resulted from penetration of the pedal articulation and septic infection of +the joint. In the vast majority of these cases slaughter is both humane and +economical. + +_Prognosis_.--The first consideration in giving a prognosis in punctured +foot should be the position of the wound. When occurring in the middle +zone, the surgeon's statements should be most guarded, and the dangers +attending a wound in that particular position fully explained to the owner. +A wound in the anterior position is, as we have said, far less serious, and +one in the posterior region of the foot even less serious still. + +Whenever possible, the nail or other object causing the prick should be +examined. Much of the prognosis may be based upon the estimated depth of +the wound, and this, in many cases, it is far safer to calculate from the +length of the offending body than from the use of the probe. We need hardly +say that in the middle zone the deeper the prick, the more serious the +case, and the less favourable the prognosis. As in succession the sensitive +sole, the plantar aponeurosis, the navicular bursa, the navicular bone, or +the pedal articulation is injured, so with each step deeper of the prick is +the severity of the case increased. + +The shape of the penetrating object may also be considered. One excessively +blunt, and calculated to bruise and crush the tissues, will inflict a more +serious wound than one of equal length that is pointed and sharp. + +The conformation of the foot should also be regarded. Wounds in well-shaped +feet are less serious than in feet with soles that are flat or convex, or +in which the horn is pumiced or otherwise deteriorated in quality. + +Although unaffecting the prognosis so far as the actual termination of the +case is concerned, it may be mentioned that punctured foot is far more +serious in a nag than in a heavy draught animal. With an equal degree of +lameness resulting in each case, the former will be well-nigh useless, but +the latter still capable of performing much of his usual labour. + +The temperament and condition of the patient will also in many cases +largely influence the prognosis. An animal of excitable and nervous +disposition is far more likely to succumb to the effects of pain and +exhaustion than the horse of a more lymphatic type. In the case of a +patient suffering from a prick to a hind-foot while heavily pregnant, the +attempted forecast of the termination should be cautious. More especially +does this apply to the case of a heavy cart-mare. Ordinarily, the +heavier the breed, the greater the tendency to lymphatic swelling of the +hind-limbs. With pregnancy this tendency is enormously increased, and it is +no uncommon thing to find a cart-mare in this condition, with legs, as the +owner terms it, 'as thick as gate-posts.' A prick to the foot, with the +lymphatics of the limb in this state, is extremely likely to end in septic +infection of the leg, for there appears to be no doubt but that invasion of +the lymphatics with septic matter is favoured by a sluggish stream. Also, +in the case of a patient in the advanced stages of pregnancy, it must be +remembered that, no matter how great may be the need, one is debarred, for +obvious reasons, from using the slings. + +_Treatment_.--_In a simple_ case--and by 'simple' here we mean the case +in which the injury is discovered early, and pus has not yet commenced to +form--our first duties are to give the wound free drainage, and to maintain +it in an aseptic condition. The first of these objects is to be arrived at +by paring down the horn in a funnel-shaped fashion over the seat of the +prick. It is, perhaps, even better to thin the horn down to the sensitive +structures for some little distance round the injury. By this latter method +pressure from inflammatory exudate is lessened, and the after-formation of +pus, if unfortunate enough to occur, the more readily detected, and the +less likely to spread upwards. The matter of asepsis may then be attended +to. + +When the puncture is sufficiently large to admit of it, the antiseptic +dressing is best applied by means of the probe. This instrument is thinly +wrapped with tow, or other absorbent material, so as to form a small swab. +Dipped in a suitable solution (as, for example, Zinc Chloride, Spts. +Hydrarg. Perchlor., Carbolic Acid, or any other that suggests itself), the +swab is inserted into the prick, and the wound conveniently mopped clean. +A further portion of the medicated tow is then pushed partially into the +wound, and allowed to remain in position. The foot is subsequently wrapped +in a clean bag, and kept free from dirt. This dressing should be repeated +twice daily. + +If the prick is in a dangerous position, and deep enough to occasion alarm, +our precautions to prevent the formation of septic matters within it may be +more elaborate. The thinning of the horn and the swabbing of the wound +may, as before, be proceeded with. In addition, the whole foot may then be +immersed for some hours daily in a cold bath, which bath should be strongly +impregnated with one or other of the following salts: Iron Sulphate, Zinc +Sulphate, Copper Sulphate, Aluminium Sulphate, Lead Acetate, or Sodium +Chloride--better still, a mixture of the various sulphates here mentioned. +If preferred, one of the more commonly accepted antiseptics--such as +Carbolic Acid, Lysol, Boracic Acid, or Perchloride of Mercury--may be +substituted. + +By the cold of the bath inflammatory phenomena are held in check, while its +added antiseptic prevents the formation of septic discharges. The lameness +gradually diminishes, and resolution is rapid. In this way deep and +serious, wounds are sometimes easily and successfully treated. + +_When suppuration has occurred_--and this, by-the-by, is by far the most +frequent condition in which we find punctured foot--treatment must be +prompt and decided. Careful search must at once be made by thinning down +the sole, and carefully trimming the frog. On no account should the +veterinary attendant rest content with 'digging' in one place, and upon +that basing a negative opinion as to the existence of pus. The paring +should be carried on, until either pus or haemorrhage shows itself, in at +least three positions--namely, at the most anterior portion of the sole, +and in the sole at each side of the frog. In addition to this, the frog +itself should be minutely examined for evidence of puncture, or for leaking +of pus at the spot where the horn of the heels joins the skin. + +In many of our cases, however, this careful search is not so necessary. +The accompanying symptoms are so decided as to leave no doubt as to the +condition of the case. In such instances paring may often be commenced over +the exact position of suppuration as previously ascertained by percussion. + +When met with, the track formed by the suppurative process should be +followed up in whichever direction it has spread. This will often +necessitate the removal of the greater part, if not the whole, of the horny +sole. + +Having given vent to the pus, and opened up the cavity made by its +formation, the foot should be placed in a hot poultice or, preferably, in a +hot antiseptic bath.[A] + +[Footnote A: At the time of writing this, a certain amount of discussion is +going on in our veterinary journals as to whether a hot or a cold bath is +the one indicated. It is urged against the application of heat that it +favours organismal growth and reproduction, and tends rather to induce the +spread of the suppurative process than to overcome it. Those who hold this +opinion urge in support of it that cold applications are inimical to the +life of the pus organism. At the same time, it must be remembered that in +just so far as cold inhibits the growth of the invading germ, so in just +the same degree does it adversely influence the functions of the tissues +that are to fight against it. To our minds the question thus set up must +always remain more or less a moot-point, and while we fully agree that cold +undoubtedly checks the growth of septic material, we just as fully believe +that warmth serves to place the healthy surrounding structures in a far +better condition to maintain a vigorous phagocytosis against it. We +thus continue to advise a hot antiseptic poultice, or, better still, a +bath.--THE AUTHOR.] + +At the end of the third or fourth day the poultice or the bath may be +discontinued, and the opening in the sole dressed with any suitable +astringent and antiseptic. + +The most serious complication arising from this method of treatment is +one of excessive granulation of the sensitive sole. This we find to be +successfully held in check by a daily application of undiluted Spts. +Hydrarg. Perchlor. (Tuson). Should the granulations become very exuberant, +then the knife must be called to our aid, and the wound so made afterwards +dressed with an astringent. + +When the suppuration has under-run the horny frog there should be no +hesitation in at once removing all the horn that is visibly separated from +the sensitive structures beneath. + +_When the os pedis is splintered and carious_, a portion of the sole round +the wound is removed, and the bone exposed. The diseased portion is scraped +away either with a curette or with the point of the drawing-knife. In this +case the only after-treatment called for is the application of suitable +antiseptic dressings. + +_When necrosis of the plantar aponeurosis has occurred_. We have already +pointed out the tendency there is in this case for the wound to maintain a +fistulous character, and lead to the formation of abscesses in the hollow +of the heel. With a wound in this position, as with a wound in any other, +the only method of avoiding this termination consists in removing all that +is visibly diseased, whether it be soft structures, bone, ligament, or +tendon, and giving the wound free drainage. + +This can only be done by removing the horny sole and frog, and cutting +boldly down upon the structures beneath. The operation is known as +resection of the plantar aponeurosis, or the complete operation for +gathered nail. + +Practised for some years on the Continent, this operation, on account of +its gravity, has been avoided by English veterinarians. From reported +cases, however, it appears often to be followed by success. + +That there is a large element of risk in the operation is quite evident, if +only from the two facts mentioned beneath: + +1. That the close attachment of the plantar aponeurosis to the navicular +bursa, and the nearness of both to the pedal articulation, render +penetration of a synovial sac or a joint cavity extremely likely. + +2. That there is always great difficulty in maintaining strict asepsis of +the foot, more especially if it is a hind one. + +On the other hand, it may be argued that equal risk to the patient is run +in allowing him to remain with a disease (and that disease a progressive +one) of the structures so closely antiguous to the navicular bursa and the +pedal articulation. + +If only for that reason we give the operation brief mention here. + +The animal is prepared in the usual way for the operating bed; the foot +soaked for a day or two previously in a strong antiseptic solution, the +patient cast and chloroformed, and the operation proceeded with. + +[Illustration: FIG. 106.--'CURETTE,' OR VOLKMANN'S SPOON.] + +An Esmarch's bandage should be first applied, and a tourniquet afterwards +placed higher up on the limb. The foot is then secured as described in an +earlier chapter, and the whole of the horny structures of the lower surface +of the foot (the sole, the frog, and the bars) pared until quite near the +sensitive structures, or, if under-run with pus, stripped off entirely. An +incision is then made in each lateral lacuna of the frog, the two meeting +at the frog's point. Each incision thus made should be carried deep enough +to cut through the substance of the plantar cushion. A tape is then passed +through the point of the frog, tied in a loop, and given to an assistant to +draw backwards. The plantar cushion itself is then incised in a direction +from before backwards, and pulled on by the assistant, so as to expose the +plantar aponeurosis. + +Should this be found at all necrotic, it may be taken that purulent +inflammation of the navicular bursa and of the navicular bone itself +exists. The operator must then proceed to resection of the tendon in order +to treat the deeper structures thus affected. At its point of insertion +into the semilunar crest the tendon is severed and afterwards reflected. +This exposes the inferior face of the navicular bone. Instead of the +glistening and clear appearance it ordinarily presents, its glenoid +cartilage is found to be showing haemorrhagic or even purulent spots of +necrosis. The terminal portion of the tendon must then be excised. + +To effect this a clean transverse incision is made at the extreme upper +border of the navicular bone. Here we are in close contact with the pedal +articulation, and great care is necessary in making this last incision, in +order that the synovial sac may not be penetrated. + +All structures showing spots of necrosis should now be carefully removed, +either with the knife or with the curette. The knives most suitable for the +last stages of this operation are those depicted in Fig. 45 (_c_, _d_, and +_e_). The curette, or Volkmann's spoon, we show in Fig. 106. + +[Illustration: FIG. 107.--RESECTION OF TERMINAL PORTION OF THE PERFORANS. +The horny sole and the horny frog stripped from off the sensitive +structures. _a_, The plantar cushion; _b, b_, the plantar aponeurosis, or +terminal portion of perforans; _c_, the navicular bone; _d_, interosseous +ligaments of the pedal articulation; _e, e_, semilunar crest of the os +pedis; _f_, inferior surface of os pedis; _g, g_, the sensitive laminae of +the bars; _h, h_, bearing surface of the wall; _i, i_, the sensitive sole; +_k_, the sensitive frog.] + +When at all diseased the glenoidal surface of the navicular bone should be +curetted, even to the extent of the removal of the whole of the cartilage. +A healthy, granulating surface is thus insured. + +The above figure from Gutenacker's 'Hufkrankheiten' explains shortly the +position of the operation wound and the structures involved, rendering +further description unnecessary here. + +The operation ended, the dressing follows. Upon this depends very largely +the ultimate recovery of the patient, for it is only by careful attention +and suitable dressings that effectual repair of the injured structures may +be brought about. + +A light shoe is first tacked on to the foot, and those portions of the +horny sole that have been allowed to remain dressed with Venice turpentine, +tar, or other thickly-adherent antiseptic. + +The exposed soft tissues are then dressed with pledgets of tow[A] soaked +in alcohol and carbolic acid. This dressing must be allowed to remain in +position, and is kept there by means of a bandage, or the shoe with plates +(Fig. 55) and a bandage over it. No pressure is needed; consequently, the +pledgets of tow must not be too thick. + +[Footnote A: When using tow in the form of a pad, it is well to remember +that many small balls of the material rolled lightly in the palm of the +hand and afterwards massed together are far better than one large pad of +the tow taken without this preparation. The irregularities of the wound are +better fitted, and the whole dressing easier remains _in situ_ (H.C.R.).] + +In the after-dressing of the wound careful attention must be paid to the +granulating surface. Where tending to become too vigorous in growth it +should be held in check by suitable caustic dressings. At the same time it +must be remembered that the granulating process of repair is always more +rapid upon the plantar cushion and fleshy sole than upon the bone, or upon +tendinous or cartilaginous structures. As a result of this we have a wound +showing various aspects of cicatrization. Healthy granulation may be +profuse in one spot, while in another it may be checked either by a flow +of synovia from the still open bursa, or by fragments of bone or of tendon +still acting as foreign bodies in the wound. These latter may be readily +detected by their standing out as dark and uncovered spots in the healthy +granulation around, and should be at once removed. + +The time that an operation wound of this description takes to heal--and +that without complication--is from one to two or three months. Continuation +of pain and intensity of lameness are not to be taken as indications of +failure. The reparative inflammation in the synovial membrane is quite +sufficient to induce pain severe enough to prevent the animal from placing +his foot to the ground for some weeks, even though the progress of the +case, all unknown, may be all that is desired. So long as a great amount of +pain is absent, and so long as appetite remains and swellings in the hollow +of the heel fail to make their appearance, so long may the progress of the +case be deemed satisfactory. + +_Recorded Case of the Treatment_.--A cart-horse, aged six years, was sent +to the Alfort School by a veterinary surgeon for having picked up a nail +in the hind-foot. Professor Cadiot, judging the necessity for the complete +operation, performed it on January 14, and spared the plantar cushion +as much as possible. In consequence of the plantar aponeurosis being +extensively necrosed, it was advisable to scrape the navicular bone and +a part of the semilunar crest. The wound having been washed with a 1 per +cent. solution of perchloride of mercury, it was dusted with iodoform +and packed with gauze, and covered with a cotton-wool dressing, kept in +position by means of a suitable shoe. + +On January 16 there was no snatching up of the limb when the horse was made +to put weight upon it; he ate his food well, and his condition improved +every day. On January 21 the dressing was removed; the wound appeared pinky +and granular, and there was no suppuration. The clot remaining from the +haemorrhage after the operation was removed, the wound was irrigated with a +hot solution of sublimate, and then dusted with iodoform and covered with a +dressing of iodoform gauze and absorbent wool. At this date the horse could +stand on the injured limb. On January 31 a second dressing was made, and +the animal almost walked sound. On February 7 the wound had almost closed +up, save in its central part, where there was a small cavity, and the +lameness had disappeared. On February 15 the wound had completely healed, +and its borders were covered by a layer of thin horn. As the animal was +sound it was sent to work. + +The author directs attention to the rapidity with which a large and +complete wound cicatrizes after the operation for gathered nail.[A] + +[Footnote A: _Veterinary Record_, vol. XV., p. 226 (Jourdan).] + +_In the case of Penetrated Navicular Bursa_, unaccompanied by the formation +of any large quantity of pus, and uncomplicated by necrosis of the +aponeurosis, our aim must be to maintain the wound in that happy condition. +This is doubtless best done by keeping the foot continually in a cold bath, +rendered strongly antiseptic by the addition of sulphate of copper and +perchloride of mercury. Should there be intervals when the bath must be +neglected, the foot in the meantime must be kept clean by antiseptic +packing and bandaging, and a clean bag over all. This treatment should be +continued so long as the character of the discharge denotes that synovia is +running. If, in spite of our precautions, the discharge becomes purulent, +then the track made by the penetrating object should be syringed twice +daily with a 1 in 1,000 solution of perchloride of mercury. + +During the treatment it will be wise to shoe the animal with a high-heeled +shoe. We do not know as yet the full extent of the injury. The navicular +bone may be tending to caries; or necrosis of the plantar aponeurosis, all +unknown, gradually becoming pronounced. This calls for a relief of tension +on the perforans, and is only to be brought about by the high-heeled shoe. + +The result of the inflammatory changes in the tendon, aided possibly by +the use of the high-heeled shoe, is to afterwards bring about contraction. +Where this has occurred, and the animal walks continuously on his toe, the +shoe with the projecting toe-piece (Fig. 84) must be applied. When the +continual use of the toe-piece appears inadvisable, the shoe devised by +Colonel Nunn may be used in its stead (see Fig. 108). + +The toe-piece is screwed into the toe of the shoe when the horse is about +to be exercised, and forms a powerful point of leverage with which to +stretch the contracted tendon, and the shoe, being thin at the heels, +admits of this. The advantage of this form of toe-piece over the ordinary +form of fixed toe-lever is that it can be removed when the horse is in the +stable; while the curved point diminishes the danger of the horse hurting +itself--a danger always present if it is on a hind-foot. (See also +Treatment of Purulent Arthritis in Chapter XII.) + +[Illustration: FIG. 108.--COLONEL NUNN'S SHOE WITH DETACHABLE TOE +EXTENSION.] + +_Should a Sinuous Wound remain in the region of the Lateral Cartilage_, +it should be explored, and its depth and likely number of branches +ascertained. Should this exploration denote that the cartilage itself is +diseased, or that the wound is not able to be sufficiently drained from +the sole, then we know that we have on our hands a case of quittor. The +treatment necessary in such a case will be found described in Chapter X. + +_When the Complication of Purulent Arthritis has arisen_, the surgeon has +to admit to himself, reluctantly no doubt, that the case is often beyond +hope of aid from him. Nothing can be done save to order continuous +antiseptic baths and antiseptic irrigation of the wounds with a quittor +syringe, and to attend to the general health and condition of the patient. +At the best it is but a sorry look-out both for the veterinary attendant +and the owner of the animal. Even with resolution incurable lameness +results, and the animal is afterwards more or less a walking exhibition of +the limitations of surgery, while the owner, unless the animal is valuable +for the purpose of breeding, finds himself encumbered with a life that is +practically useless. (See Treatment of Purulent Arthritis, Chapter XII.) + +_In the case of Lameness Persisting after the healing of all appreciable +lesions_, then neurectomy is followed by good results. The animal, +apparently recovered, is for a long time useless. Lameness persists for +several months, as if the nail had at the moment of its penetration caused +lesions, which doubtless it sometimes does, similar to those of navicular +disease. Examination of the foot in this case reveals no lesion, and the +pain has evidently a deep origin. The lameness caused by it is subject to +variation. Frequently it becomes lessened during rest, and increased by +hard work, while sometimes it is very much more pronounced at starting than +after exercise. + +It is here that neurectomy is called for. The operation does nothing to +impede the work of healing going on, and allows free movement of the foot +and pastern to take place. At the same time suffering and emaciation cease, +and the animal is rendered workable.[A] + +[Footnote A: _Veterinary Record_, vol. ii., p. 371.] + + +C. CORONITIS (SIMPLE). + +TREAD, OVERREACH, ETC. + +1. _Acute_. + +_Definition_.--Under the heading of simple coronitis in its acute form we +intend to describe those inflammatory conditions of the skin and underlying +structures of the coronet occurring without specific cause. Specific +coronitis will be found described in Chapter IX. + +_Causes_.--This condition is almost invariably set up by an injury--either +a bruise or an actual wound--to the coronet. By far the most common among +such injuries are those inflicted by the animal himself by means of the +shoes. + +That known as 'tread' is caused by the shoe on the opposite foot, and may +happen in a variety of ways. More often than not it is met with in the feet +of heavy draught animals, and is there caused by the calkin, either when +being violently backed or suddenly turned round. It may also occur in +horses with itchy legs, as a result of the animal rubbing the leg with the +shoe of the opposite limb. The irritation in this case is nearly always +due to parasitic infection (_Symbiotes equi_), and becomes sometimes so +unbearable as to render the animal unmindful of the injury he may be +inflicting so long as he experiences the relief obtained by the rubbing. + +Self-inflicted tread is also sometimes met with when horses are worked +abreast at plough. The animal in the furrow, with one foot sometimes in and +sometimes out of the hollow, is caused to make a false step, and so brings +the injury about. + +Animals worked in pairs are further liable to receive a tread from the foot +of their companion. This is commonly seen in heavy animals at agricultural +labour in fields, where the walking is uneven, and abrupt turning constant. +It is not uncommon either in animals at work in vans in town, and is +occasionally met with in the feet of carriage-horses. + +'Overreach' is the term used to indicate the injury inflicted on the +coronary portion of the heel of the fore-foot by the shoe of the hind. +Ordinarily, overreach occurs when the animal is at a gallop, and is thus +met with in its severest form in hunters and steeplechasers. It can only +occur when the fore-foot is raised from the ground and the hind-foot of the +same side reached right forward. When the feet separate the injury takes +place. In its movement backwards the inner border of the shoe of the +hind-foot catches the coronet of the fore, and tears it backwards with it. +Quite frequently a portion of the skin is removed entirely, but often it +hangs as a triangular flap. The flap in such a case is always attached by +its hindermost edge, and indicates plainly enough that the direction of the +blow that cut it must have been from before backwards. + +Although ordinarily inflicted at the gallop, the same injury may, +nevertheless, be caused by allowing a fast trotter, and one with extreme +freedom of action behind, to push forward at the utmost limit of his pace. +The outside heel is the one most subject to the injury. + +While the common form of injury to the coronet is, as we have described, +that occasioned by the animal's own shoe, or that of a companion, it is +evident that the foot is also open to similar injuries from quite outside +sources. Falls of the shafts when unyoking animals from a heavy cart, blows +or wounds from the stable fork, wounds resulting from the foot becoming +fixed in a gate or a fence, either may equally well set up the mischief. + +Apart from severe injury, a particularly troublesome form of coronitis may +arise from the condition of the roads. We refer to the conditions attendant +on a thaw after snow. The animal is called upon to labour in, or perhaps +stand for long periods in, a mixture of snow and water, or snow and mud. +That this must have a prejudicial effect upon the structure of the coronet +is plain. The circulation of the part, already predisposed to sluggishness +by reason of its distance from the heart, is farther impeded by the +action of the cold. Small abrasions of the skin, so small as to scarce +be noticeable, are in this case freely open to infection with the septic +matter the mud contains. Necrosis and consequent sloughing of the skin +is bound to follow, and an extensive ulcerous wound, or a spreading +suppuration of the coronary cushion is the result. + +_Symptoms_.--We will take first the case in which no actual wound is +observable. Here the first indication of the trouble is the appearance +of an inflammatory swelling, confined usually to one side, but extending +sometimes to the whole of the coronet. Always the part is hot and tender, +and with it the patient is lame--so much so, in many cases, as to be unable +to put the foot to the ground, the toe alone being used. + +In a mild case, uncomplicated by septic infection, these symptoms rapidly +subside, and resolution occurs. + +Always, however, the presence of septic infection must be suspected and +looked for. When this has occurred, the inflammatory swelling becomes +larger and more diffuse, and the animal fevered. This is then followed by +a slough of the injured part. A portion of the skin first becomes gray, or +even black, in appearance, and around it oozes an inflammatory exudate, or +even pus. The skin immediately adjoining the spot of necrosis is swollen +and hyperaaemic, and extremely painful and sensitive. Later, the necrosed +portion becomes cast off, and an open wound remains. This as a rule marks +the turning-point in the case. The pain and other symptoms rapidly abate, +and the wound, with proper attention, is not more than ordinarily difficult +to treat. + +In the case of an actual wound the symptoms are probably less severe. The +injury is, in this instance, the sooner detected, and remedial measures put +into operation. In this manner the formation of septic material is often +checked, and nothing but the treatment of a simple wound demands attention. + +There are, however, complications. + +_Complications--(a) Diffuse Purulent Inflammation of the Sub-coronary +Tissue_.--This condition is brought about by the spread into the loose +tissue of the coronary cushion of the septic material introduced by the +tread. The whole coronet in this instance becomes excessively swollen, hot, +and painful, and the dangerous nature of the complication is evident enough +when the structure and situation of the parts involved is considered. The +amount of tendinous and ligamentous material in the neighbourhood offers +a strong predisposition to necrosis, and the necrosis, with its attendant +formation of pus, offers a further danger when the close proximity of +the pedal articulation and the unyielding character of the horny box is +considered with it. + +The pus formed in this condition may remain confined to the coronet and +break through the skin as an ordinary abscess, or it may, before so doing, +burrow beneath the wall, and invade the sensitive laminae. In this case, +whenever portions of the secreting layer of the keratogenous membrane are +destroyed, or perhaps only temporarily prevented from fulfilling their +horn-producing functions, then corresponding cavities in the horn are the +result (see Fig. 109). + +_(b) Purulent Arthritis_.--Only too readily the pus so formed tends to +penetration of the articulation and the causation of an incurable arthritis +(see Chapter XII.). + +[Illustration: FIG. 109.--MESIAL SECTION OF A HOOF ILLUSTRATING THE +CONDITIONS FOLLOWING UPON CORONITIS. _a_, Cavity in the horn of the +wall; _b_, enlargement of the coronet and the horn of the wall following +subcoronary suppuration; _c_, cavity in the wall following purulent +inflammation of the sensitive laminae; _d_, hollow in the horn of the sole +consequent upon suppuration of the sensitive sole.] + +_(c) Necrosis of the Extensor Pedis_.--This may arise either as a result +of spreading purulent infection of the coronary cushion, or as a result +of direct injury immediately over it. The close relation of the terminal +portion of this tendon with the pedal articulation, and the incomplete +protection from outside injuries here afforded to the joint by the horny +box, sufficiently points out the gravity of the condition. + +_(d) Penetration of the Articulation_.--This also may be a result either +of the inroads made by pus, or of an actual wound. When occurring from the +latter, it is seen more often than not in the hind-foot, being there caused +by the calkin of the opposite foot. Where a wound in this position is +characterized by an excessive flow of synovia, the condition should be +suspected, and, if the wound be large enough, the little finger should be +introduced in order to ascertain. Needless to say, the injury is a grave +one. + +_(e) Sand-crack_.--Sand-crack is likely to result from tread when an injury +is inflicted in the region of the quarter by a severe overreach. Treads, +too, especially with the calkin of the hind-shoe, are especially apt to end +in this way. In this latter instance the sand-crack usually has its origin +in a nasty jagged tear at the top of the wall of the toe. + +_(f) Quittor_.--In one respect any suppurating wound at the coronet may be +deemed a quittor. By indicating quittor as a complication of coronitis, +however, we denote the more serious form of this disease, in which the +wound has taken on a sinuous character, and conducted pus to invasion of +the lateral cartilage. It is one of the worst complications we are likely +to meet with in this condition, and will be found fully described in +Chapter X. + +_(g) False Quarter_.--This complication of coronitis occurs when the injury +or after-effect of the formation of pus has been severe enough to destroy +outright a comparatively large portion of the papillary layer of the +coronary cushion. To this condition we devote Section D of this chapter. + +_Prognosis_.--In giving a prognosis in a case of coronitis, attention +should be paid to the manner in which the condition originated, and the +extent, when present, of the wound. + +When the inflammatory swelling has arisen from bruising alone, without +actual division of the skin, when the weather is that of winter, and the +swelling showing a marked tendency to spread, then the prognosis must be +guarded. As we have seen, this state of affairs is probably ushering in +a condition of spreading suppuration of the coronary cushion, and +considerable gangrene and sloughing of the skin. We have here no intimation +as yet of how far the suppurative process may run, nor what important +structures it may involve. Consequently, the guarded prognosis we have +mentioned is imperative. + +Where an actual wound is to be seen, and where advice is sought early, +then a more favourable opinion may be advanced. In this case antiseptic +measures, commenced early and persisted in, may prevent the rise of further +mischief. + +It goes without saying that, should there arise any other of the +complications we have mentioned (viz., Arthritis, Necrosis of the Extensor +Pedis, Sand-crack, Quittor, and False Quarter), the fact should be pointed +out to the owner, and the prognosis regulated thereby. + +_Treatment--Preventive_.--Seeing that at any rate the majority of cases of +coronitis result from injuries inflicted by the shoes, we may look at once +to that particular for a means of prevention. + +Take first the case of 'treads'. There is no doubt that they are most +common in animals shod with heavy shoes and with high and sharp calkins. +This suggests at once that a preventive is to be found in substituting a +calkin that is low and square. + +Where the injury is an overreach, and where, on account of the animal's +pace and manner of gait it is in risk of being constantly inflicted, the +shoeing should be seen to at once. + +We have already pointed out that it is the inner border of the lower +surface of the toe of the hind-shoe which, in the act of being drawn +backwards, inflicts the injury. (See Fig. 110). + +In this case prevention may be brought about either by shoeing with a shoe +whose ground surface is wholly concave, or by bevelling off the sharp +border (see Fig. 110, _a_, p. 236). When the tendency to overreach is not +excessive, prevention may in many cases be effected by simply placing the +shoe of the hind-foot a trifle further backwards than would ordinarily be +correct, thus allowing the horn of the toe to project beyond the shoe. This +at the same time does away with the annoyance of 'forging' or 'clacking,' +which, as a rule, accompanies this condition. + +While recognising the value of shoeing in these cases, we must not forget +that a great deal may be brought about by careful horsemanship. The animal +should be held together and kept well up to the bit, but should _not_ be +allowed to push forward at the top of his pace. With many animals of fast +pace and free action overreach is more an indiscretion of youth than any +defect in action or conformation, and his powers should therefore be +husbanded by the driver until the animal has settled down into a convenient +and steady manner of going. + +[Illustration: FIG. 110.--UNDER SURFACE OF THE TOE OF A HIND-SHOE. _a_, +Marks the portion of the inner margin that inflicts overreach.] + +[Illustration: FIG. 111.--THE INNER MARGIN OF THE INFERIOR SURFACE OF THE +HIND-SHOE BEVELLED TO PREVENT OVERREACH.] + +_Curative_.--Although in some cases it is so small as to go undetected, +we may take it that in all cases of coronitis there is a wound, with +consequent danger of septic infection of the surrounding parts. Therefore, +after attention to the shoeing and removal of the cause, the first +indication in the treatment will be to render the parts aseptic. This is +best done by removing the hair from the coronet and soaking the whole foot +in a cold antiseptic solution. After removal from the bath, the coronet +may be dressed with a moderately strong solution of carbolic acid or +perchloride of mercury. When the injury is slight and recent, such is +sufficient to effect resolution. + +When marked swelling persists, however, and the increase in heat and +tenderness denotes the formation of pus, recovery is not so easily +obtained. In this case the application of hot poultices or hot baths is +called for. By these means suppuration is promoted and induced to early +break through in the most favourable position--namely, the softened skin of +the coronet. The pus so escaping is always more or less blood-stained, and +contains both large and small pieces of broken down and decomposed tissue. +After discharge of the pus, the cavity remaining should be mopped out with +an antiseptic solution, and a pledget of antiseptic tow or other material +left in position. All that is then needed is constant dressing in a +suitable manner. We prefer in this instance washing some three or four +times a day with hot water until a perfectly clean wound is obtained, and, +after the washing, painting the raw surface with a strong solution (1 in +200, or 1 in 100) of perchloride of mercury. + +When the abscess we have described as forming is extremely large, or where +it is more than ordinarily slow in 'pointing,' the likelihood of its having +burrowed for some distance below the upper margin of the wall must be +suspected. Here it is sometimes wise to thin the wall with the rasp +immediately below the point of greatest swelling of the coronet. This will +serve to lessen pressure on the sensitive structures beneath. + +Immediately the abscess contents have found exit at the coronet, the cavity +formerly occupied by the pus should be explored. If to any extent it is +found then to have 'pocketed' beneath the upper border of the wall, a +counter-opening should be made where the horn of the wall has been thinned +with the rasp. + +When it so happens, either from extensive bruising or from the action of +excessive cold, that we have or suspect the condition of sloughing, then +the first indication is to aid the live tissues to throw off the necrosed +portion. In spite of what is sometimes urged to the contrary, a hot +poultice is, perhaps, the best means of bringing this about. Directly the +necrosed piece is shed, a wound remains which, so far as treatment is +concerned, may be regarded exactly as that left by the formation of pus. +Hot water applications, some three or four times daily, will serve both to +cleanse the wound and also to maintain vitality in the tissues immediately +surrounding it. After each washing, the use of a strong antiseptic solution +to the wound is again beneficial. + +In the case of an actual wound, whether, as in overreach, affecting the +coronet alone or involving destruction of part of the wall, or, as in the +case of toe-tread, penetrating the pedal articulation, the treatment to be +followed is simple enough, in theory, if not always easy to carry out. It +consists solely in maintaining a rigid asepsis of the parts until healing +is well advanced or complete. The whole foot, including the coronet, should +first be thoroughly washed in warm water. At the same time there should be +used some agent that will tend to remove the natural grease of the parts. +In this manner cleansing will be rendered more thorough, and penetration of +the antiseptic solution to be afterwards applied made the more certain. +The most ready way of effecting this is to use the ordinary stable +'water'-brush, and plenty of a freely-lathering soap. + +This done, the foot should be rinsed in cold water, and afterwards +constantly soaked in a cold antiseptic bath. Where it is inconvenient or +impossible to have the constant bathing carried out, a dry antiseptic +dressing may be tried in its stead. In this case the foot should first be +thoroughly washed and dressed as before. Afterwards an antiseptic powder in +the shape of a mixture of iodoform 1 part, boracic acid 10 parts, should +be freely dusted on the wound, a pledget of carbolized tow or cotton-wool +placed over it, and the whole maintained in position with a bandage +previously soaked in a 1 in 500 solution of perchloride of mercury. Once +on, this dressing should be allowed to remain until healing is complete. +Should the animal manifest pain, however, by constantly pawing, or should +swelling and heat of the parts be suspected, the bandage should be removed, +and the condition of the wound ascertained. + +An excellent example of the value of this method of treatment is that given +below: + +'I call to mind a valuable hunter in my practice a few seasons since, who, +whilst hunting, we suppose, struck himself in the way we suggest. He not +only removed the superior portion of the inner heel, but tore about 3 +inches of the hoof from the top nearly to the bottom. This was clapped back +by the owner, tied with a handkerchief, and the horse removed home. When +the handkerchief was removed, I confess I did not think the horse looked at +all like hunting again. The heel was fairly pulled down, the portion of the +hoof that was hanging to it I could easily have wrenched off. The parts +were fomented, however, with warm water which was slightly carbolized. I +then removed a great portion of the heel and the lateral cartilage, which +was split; placed the portion of hoof again on the laminae, smothered the +wound with iodoform pulv., covered it with cotton-wool packing, and all +the boracic acid I could get it to hold. A piece of linen bandage was +then tightly wrapped a few times round, and the lot enclosed in a +plaster-of-Paris bandage. I did not undo it for a fortnight, when, to +my great pleasure, the heel and hoof presented a highly satisfactory +appearance. I did it up in much the same way for another ten days, then put +the sand-crack clamps into the hoof and fixed it to the sound part. The +hoof remained in position while the new horn grew from the top, and the +horse hunted again the same season.'[A] + +[Footnote A: _Veterinary Record_, vol. ix., p. 501 (Bower).] + +_Sequels_.--Either of the complications we have mentioned--as, for +instance, Arthritis, Sand-crack, or Quittor--may persist and remain as +sequels to the case. In addition to these, there may be left behind +a cavity in the horn of the wall (see Fig. 109), or a loss of the +horn-substance of the wall proper, as that depicted in Fig. 112, or +described under the heading of False Quarter. + +[Illustration: Fig. 112.--HOOF WITH A CAVITY IN THE SUBSTANCE OF THE WALL +FOLLOWING UPON 'TREAD' TO THE CORONET.] + +The treatment of Arthritis, Sand-crack, Quittor, False Quarter, and +Seedy-toe, will be found in the chapters devoted to their consideration. + +2. _Chronic_. + +_Definition_.--Coronitis in which, owing to the persistence of the cause, +inflammatory phenomena continue, resulting in the growth of large fibrous +tumours about the coronet. + +_Causes_.--In many cases it is possible, of course, that abnormal large +growths in this position may have an origin similar to that of neoplasms +elsewhere--that is to say, an origin as yet undiscovered. There is no +doubt, however, that the majority of the huge enlargements about the +coronet have their starting-point in one or other of the diseases to +which the foot is liable, in which the cause remains, and a low type of +inflammation persists. + +In chronic and neglected suppurating corn, in untreated quittor, and in +long-standing complicated sand-crack, for instance, we have conditions in +which pus and other septic matters find ready entrance into the subcoronary +tissues. Should either of these be neglected, or should the pus formation +from the onset take on a slow but gradually spreading form (in other words, +should either of these cases run a chronic rather than an acute course) +then, with the persistence of the inflammatory phenomena so caused, is +bound to result a steady and increasing growth of inflammatory fibrous +connective tissue. This, as it grows, becomes in its turn penetrated by the +ever-invading pus, and, under the stimulus thus caused, itself throws out +new tissue. And so, constantly excited, the tumour-like mass tends to +steady increase in size, until enlargements are formed which one may +sometimes truly term enormous. + +_Symptoms_.--The appearance of the growth is, of course, immediately +evident. Usually these swellings are slow in forming, so that the size +of the enlargement depends entirely upon its age. We may thus meet with +growths of this description, varying in weight from 4 or 5 pounds to +the almost incredible size of 33-1/2 pounds. In the majority of cases a +discharging sore is to be found upon it--in some cases several. Explored, +these sores reveal their true nature. Their lip-like openings, and the +ready manner in which they may be searched by the probe, show them to be +sinuses. + +In a few cases, however, the outer surface of these tumours is intact. When +this is the case, it is possible that the growth is a true fibroma--that is +to say, a non-inflammatory new growth of fibrous connective tissue. On the +other hand, it may have resulted from one or other of the causes we have +enumerated, and its exact diagnosis have been impossible until operative +measures had been proceeded with. In this case, small and encysted foci of +inspissated pus scattered more or less throughout the growth indicate its +true nature. + +Pain as a rule is absent, and, unless the growth, on account of its size, +interferes with progress, the animal walks perfectly sound. Here the +patient may, without offending the dictates of humanity, be put to slow +work. + +_Treatment_.--In very many cases, possibly on account of the decreased +circulation and vitality of the parts, these growths occur in aged animals. +Here treatment is not economic, and may for that reason be put out of the +question. Further, the growths are more common in heavy cart animals of a +lymphatic type than in those of a lighter breed. Couple this with the fact +that the tumour is often unattended with pain, and we see that the animal +is still able to perform his accustomed labour. Here, again, treatment is +contra-indicated. + +For still another reason surgical treatment, which is the only treatment +likely to be of benefit, must not be undertaken rashly. A large and open +wound is bound to be left behind. So large is it in many cases that the +complete covering of the exposed surface with epidermal growths from the +circumference cannot possibly be looked for. There is then left a large and +horny-looking scar, which is an even worse eyesore than was the original +enlargement. + +When the patient is a young and otherwise valuable animal, however, and +when the case, judged either by the size of the swelling or its outside +appearance, promises a fair measure of success, operative measures may be +determined on. + +In this case the author's practice has been, after casting the animal, to +apply a tourniquet to the limb and proceed to excision. A lozenge-shaped +incision, extending to near but not quite the circumference of the +swelling, should be made with a large knife right through the skin and +deeply into the growth. The whole is then removed, proceeding in an +excavating manner under the thickened skin at the margin. Haemorrhage, +though proceeding from several apparently large vessels in the structure of +the tumour, and oozing generally over the whole of the outer surface, +is rarely profuse enough to interfere with the operation, and is easily +controlled by cold water douches and the application of the artery forceps +to one or more of the larger vessels. The operation completed, the larger +bleeding-points should be secured by exerting torsion with the artery +forceps, and the surface oozing stayed by frequent dashing with cold water. + +When the haemorrhage has sufficiently ceased, an ordinary flat firing-iron +should be passed over the whole of the cut surface, and an effectual eschar +formed. + +Following this, and _before removing the tourniquet_, the wound should be +filled with pledgets of carbolized tow, and the whole tightly secured by a +stout and broad linen bandage of not less than 6 yards in length. + +_Reported Case_.--'The patient, a middle-aged cart mare, had a pair of +fore-feet the like of which I never saw. As the result of long-standing and +imperfectly-treated quittor all over the seat of side-bone on the outer +side of each fore-foot, beginning pretty far forward, and extending to the +heel on the inner side, filling up the hollow and reaching nearly to the +fetlock, was a big, bulging, hard, calloused enlargement or tumour standing +out 3 or 4 inches all round, covered with thick horny skin and stubby hair, +and having on its surface the small openings of several sinuses leading +deeply down to the ossified and diseased cartilage underneath. And yet +with all this diseased undergrowth the mare, strangely enough, walked and +trotted sound. I was told that this mare had been troubled with suppurating +corns and quittor, that many unsuccessful attempts had been made at cure, +but that, getting worse instead of better, these tumours had formed. + +'After casting and anaesthetizing, a strong rubber tourniquet was placed +above the knee and the operation commenced. With a surgeon's amputating +knife all the big fibrous mass which I could safely remove was cut and +sliced off, and the coronet and pastern reduced as nearly as possible to +its natural dimensions. The diseased cartilage, or side-bone, gave some +trouble, a considerable portion having to be cut and scraped, and the sinus +in it gouged out; but its complete removal did not appear to be called for. + +'There was little if any haemorrhage until release of the tourniquet, when +the whole broad surface became deluged with blood, three or four small +arteries spurting and veins flowing in all directions, so much so that I +was glad to reafix the clasp, and with the firing-iron seal up the vessels, +searing gently all over the surface. + +[Illustration: FIG. 113.--CHRONIC CORONITIS FOLLOWING 'TREAD.'] + +'A good dusting with antiseptic powder, a thick pad of carbolized wool, and +two long calico bandages wound tightly round, completed the work. + +'The other, the near-leg, was then dealt with in the same way. + +'The mass removed weighed a little over 9-1/2 pounds--5 pounds from the +off-foot and 4-1/2 pounds from the near. Its structure was fibrous tissue, +almost as firm and hard as cartilage, and with no appearance of malignancy. + +'The after-treatment consisted simply of fresh dry dressings--copper, +sulphate, zinc sulphate, and calamine, equal parts--applied every third +or fourth day, after first bathing the feet in a shallow tub of warm +antiseptic water. + +'At the end of eight or ten weeks a fairly presentable appearance existed. +The greater part of what had been raw surface was covered with healthy +skin, and the remainder had become dry and horny.'[A] + +[Footnote A: _Veterinary Record_, vol. xiv., p. 201 (C. Cunningham, +M.R.C.V.S.).] + +A further form of chronic coronitis is that shown in Fig. 113. + +This condition is commonly the result of a severe and jagged tread with +the calkin, and takes the form of an ulcerous and excessively granulating +wound. As time goes on the granulations become hard and horny-looking, and +their fibrous tissue as hard and unyielding as tendon or cartilage. + +These if treated in the early stages with repeated dressings of caustic, +or, if very exuberant, the use of the knife, usually yield to treatment. If +neglected until the condition depicted in the figure is arrived at, then +treatment, as a rule, is of no avail. Neither is treatment of any use if +any great loss of the coronary cushion has occurred. + + +D. FALSE QUARTER. + +_Definition_.--False quarter is the term applied to that condition of the +horn of the quarter in which, owing to disease or injury of the coronet, +the wall is grown in a manner that is incomplete. + +_Symptoms_.--This condition of the foot appears as a gap or shallow +indentation, narrow or wide, in the thickness of the wall, with its length +in the direction of the horn fibres. By this we do not mean that the +sensitive laminae are bared and exposed. Horn of a sort there is, and with +this the sensitive structures are covered. Running down the centre of the +incomplete horn is usually a narrow fissure marking the line of separation +in the papillary layer of the coronary cushion, which, as we shall later +see, is responsible for the malformation. + +On either side of the indentation, as if wishing to aid further than +ordinarily it should in bearing the body-weight, the horn takes on an +increased growth, and stands above the level of the horn surrounding it. It +may, as perhaps it really is, be regarded as a form of hypertrophy, brought +about by the increased work that the loss of substance in the region of the +false quarter puts upon it. + +So long as the sensitive structures are protected the animal remains sound. +Sometimes, however, from the effects of concussion or of the body-weight, a +fissure appears in the narrow veneer of horn that covers them. Into this, +which, of course, is but a form of sand-crack, gravel and dirt penetrate, +and so set up inflammatory changes in the keratogenous membrane. As a +result suppuration ensues, and the animal is lame. + +_Causes_.--False quarter may result from any disease of the foot that +involves destruction of a portion of the coronary cushion. As we may see +from a reference to Chapter III., it is from the papillae of this body that +the horn tubules of the wall are secreted. Destruction of any portion of it +necessarily results in a corresponding loss of horn in that position. The +disease occasioning this more often than any other is perhaps quittor. It +may also result from suppurating corn, from a severe tread or overreach, or +from the effects of a slowly progressing suppurating coronitis. + +_Treatment_.--A radical treatment of false quarter is not to be found. Once +destruction of the secreting layer of the coronary cushion has occurred, +the appearance of the fissure in the wall will always have to be reckoned +with. A false quarter, therefore, not only renders the horse liable to +occasional lameness, but also renders weaker that side of the hoof in which +it occurs. + +The only method of treatment that can be practised, therefore, is that of +palliation. Seeing that the trouble the veterinary attendant will have to +deal with is loss of a portion of the weight-bearing surface, his attention +is immediately directed to the shoeing. As with sand-crack, so with false +quarter, the frog and the bars must be called upon to take more of the +body-weight than commonly they do with the ordinary shoe. The indication, +then, is a bar shoe. At the same time, the bearing of the wall on the shoe +on either side of the fissure should be eased by slightly paring it, and +the hypertrophied horn on the outer surface of the wall removed with the +rasp. + +In cases where penetration of the sensitive structures has occurred, +complicated with the formation of pus, the same treatment as for +complicated crack is to be followed. The foot should be poulticed for +several days with hot antiseptic dressings, and thorough cleansing of the +infected parted brought about. Afterwards strong solutions of suitable +antiseptics should be applied daily until such time as the horny covering +has renewed itself. This done and the bar shoe applied, the fissure may be +plugged with any effectual stopping. Either a mixture, such as Percival's, +of pitch 2 parts, tar 1 part, and resin 1 part, melted and mixed together, +or one of the artificial hoof-horns may either be used with advantage. + + +E. ACCIDENTAL TEARING OFF OF THE ENTIRE HOOF. + +_Causes_.--Seeing that this accident to, and consequent severe wounding of, +the keratogenous membrane nearly always occurs in but one way, it is worthy +of special mention. So far as we are able to ascertain, it is an accident +peculiar to horses continually engaged in shunting operations either in +pits or station-yards. At the moment the animal is released from the waggon +he has been pulling, and should turn to the right or the left in order +to allow it to pass him, the shoe either becomes wedged in between two +converging rails, or is trapped by the wheel of the waggon. Either the +approaching waggon with the added weight its impetus gives it then pushes +the animal suddenly away, leaving a part of his foot still fixed to the +rails, or the animal himself, feeling securely held, makes a sudden effort +to release himself, and draws his foot cleanly out of the imprisoned horny +box. + +The author calls to mind a case in which entire removal of the horn of +the foot of an ox occurred through the passing over it of the wheel of +a heavily-laden cart. It is therefore quite conceivable that the same +accident might occur to the horse. As a matter of fact, we find one case on +record where one-half of the horny box was thus removed.[A] + +[Footnote A: _Veterinary Record_, vol. xiii., p. 129.] + +So far as we are able to gather, it is more a result of imprisonment of the +shoe than of the foot. It appears, further, to be always a result of the +animal being newly shod, and the clinches firmly secured; so much so that +it would be probable, with imperfectly secured clinches, that the animal +would draw the hoof from the clinches and the shoe rather than the foot +from its horny covering. + +Therefore, as the author of one of the cases we shall afterwards relate +suggests, it should be proposed as a preventive that the shoe-nails of +animals regularly engaged in work on the metals should not be clinched in +the regulation manner, but should have their points merely screwed off, and +the nails afterwards rasped level with the wall. + +These cases are particularly interesting as illustrating the rapid manner +in which a new hoof is afterwards formed, and the way in which the exposed +sensitive laminae take their share in adding to, though not forming the bulk +of, the horn of the wall. + +From the cases we are able to record it will be seen that this accident +need not be looked upon as fatal, nor the injury itself beyond hope of +repair. Dependent largely upon the temperament of the animal, the amount of +pain that is caused, and the way in which the animal bears it, recovery may +be looked for. Even from the very commencement of the accident, however, +the pain may be so acute and the animal so violent with it that slaughter +becomes necessary. + +_Treatment_.--This consists in applying an antiseptic and sedative dressing +to the injured parts (for example, Carbolized Oil and Tincture of Opium, +equal parts) and afterwards bandaging. + +From the only data we are able to work on, it appears that this dressing +should be repeated daily, the bandage being removed, each time, the +foot well bathed in warm water, and the dressing and bandage afterwards +replaced. On first sight, it would appear that once cleansed and bandaged +the dressings might be left _in situ_ for several days. Seeing, however, +that suppuration, if once set up, would add further to the intense pain the +animal is already suffering, and considering the always constant exposure +of the foot to infection, it is perhaps wise to persist in daily changing +of the dressings. + +At the same time, the general health of the animal should be attended to. +Suitable febrifuges should be administered, either in the shape of a +dose of physic, or salines and liq. ammonia. acetatis; and the pain, if +appearing unbearable, allayed by doses of choral and hypodermic injections +of morphia. + +_Recorded Cases_.--1. 'A short time ago I was called to see a horse which +had had his hoof torn off in a railway "point." When I arrived at the +stable the injury had been done two hours, and the horse had been led from +the railway to a loose-box nearly half-a-mile off. On going to this box I +was surprised and horrified to find the poor animal mad with pain, rolling +and dashing himself about. When on his back he would struggle and kick the +walls with the injured foot, as though unconscious of pain. Not one moment +was he still, and as I could see that the sensitive structures were much +damaged by his violence, I obtained a gun and put him out of his pain. + +'The accident happened in this way. The horse was employed in shunting +coal-waggons, and had just drawn four loaded trucks up to a point at which +they diverged to the left, and the horse, being unhooked, ought to have +turned to the right. Here, unfortunately, the near fore-foot became wedged +in between two converging railway plates, one of which formed a part of the +waggon-way, on which the trucks were running. The horse was a big animal, +and freshly shod with heavy shoes, on which a toe-piece and calkins were +used. The shoe was roughly but strongly nailed on with eight nails, the +clinches of which were all firm. This shoe was fitted wide at the heels, +and when the foot was fixed in the points (toe downwards) it protruded over +the face of the rail. When the trucks reached it they pressed it down, and, +the horse leaning forward, the hoof was drawn off like a glove. The hoof +was almost as clean inside as if taken off by maceration--only towards the +toe was a small portion of the coffin-bone and some torn laminae left inside +the hoof. + +'As soon as possible after the accident, so I was told, the foot was bound +up with tow and a bandage; then a sack was cut up and placed over all, and +the horse slowly led to his loose-box. He "carried" the leg all the way, +limping along on the three sound ones. Almost immediately after reaching +the box he lay down, but only for a short time. The standing position was +not long maintained--profuse perspiration set in, and the alternations of +position became more rapid and violent, till plunging and rolling were +added to the other signs of excruciating pain. I was also told that the +groaning of the poor animal was almost constant, and at times so loud and +prolonged as to amount to a shriek. + +'I have no experience of a similar case, and I should not have supposed +that this accident would have caused such acute suffering and violent +symptoms. I think I have heard of such cases making a complete recovery; +but I feel sure that, in this case, I only anticipated death by, at most, a +few hours.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 127.] + +2. 'The case I am about to give you an account of, being one of rare +occurrence, I thought would not prove uninteresting to the members of the +Veterinary Medical Association. It is an instance of complete removal of +the hoof by mechanical force. + +'Our patient was a brown mare, five years old, the property of Messrs. +Crawshaw and Co., railway contractors on the Sheffield and Manchester line. + +'On June 20 the mare was, as usual, working on the line, drawing one of the +waggons for the removal of soil from one place to another, and, as was the +custom, the pace is generally increased at about the distance of from sixty +to eighty yards from where the unloading takes place, in order to add to +the velocity, so that the contents of the waggons might roll down so great +a precipice. It was at this increased action, when the mare was being +removed from the waggon, that she stepped between the ends of two iron +rails, sufficiently apart to admit the foot only, when one end of the rail +inserted itself between the sole and toe of the shoe, the other at the top +and in front of the crust. + +'The mare, finding herself fixed, endeavoured to disengage herself, and, in +doing so, got in front of the waggon, which, coming at a great pace, forced +her down into the pit, leaving behind the off fore-hoof, which was only +removed from its situation between the two rails by a large hammer, it +being so firmly wedged in. The shoe and hoof were bent in a very peculiar +manner, as the accompanying cuts will show, the inside heel being +completely raised from above the level of the frog, not one of the nails +being unclenched, or in the slightest degree having given way to so large +an amount of force imposed upon them, although the toe of the shoe was +raised from the sole by the rail being immediately under it (see Fig. 114). +The mare had been shod the day before, and, having a good sound foot, the +shoe was firmly put on. + +'Being a mile from home, she was with some difficulty made to travel that +distance. On her arrival, my preceptor, Mr. Taylor, was immediately sent +for, who found her, as I have before stated, with the off fore-foot +hoofless. + +'Proceeding to examine the foot, he ascertained that it had bled +considerably, which, however, was stopped by bandages to the foot and a +ligature round the coronet. The laminae on one side and a small portion of +the sensitive sole, though not to any great extent, were lacerated. The +coffin-bone was not at all injured. The bleeding having nearly ceased, +she was put into slings, the foot carefully washed with warm water, and +immediately bound up with pledgets of tow saturated with the simple +tincture of myrrh and tincture of opium, of each equal parts. + +[Illustration: FIG. 114.--HOOF TORN FROM THE FOOT BY ACCIDENT.] + +'The dressing was ordered to be allowed to remain on all night, and on the +following morning to be removed. The foot was then bathed, as before, +in warm water, and the application of the tinctures repeated night and +morning. The medicine internally given was castor oil, with tinct. opium, +and this, in a diminished dose, was ordered the next morning. Blood was +also abstracted from the jugular vein, to the amount of 6 quarts, so as +to allay the inflammatory fever set up. The food consisted of bran and +linseed, with small portions of hay and water. The mare being in a highly +excited state, and suffering such severe pain, the opinion Mr. Taylor gave +was that, should she get over the first four days (which appeared quite +uncertain), he had no doubt of her ultimately getting well, and also that +she would have a perfect hoof formed. It was now left for the owners' +consideration, whether they thought the mare worth her keep till such took +place, the time mentioned by Mr. Taylor being four or five months. She was +seen again the fourth day after the accident, and was then found to be +perfectly tranquil and feeding well; her pulse, which at the first visit +could not be counted, was now not more than 65 beats in the minute. On +removing the dressings, the foot presented a very favourable appearance, +the treatment therefore varied only in the application of a linseed-meal +poultice over the former dressings of tinctures of opium and myrrh, +confining the whole in a soft leather boot. Diet as before, in addition to +which give a few oats. Should the bowels become constipated, repeat the +castor oil without the opium. + +'_June_ 28.--The animal was again seen, and appeared to be going on very +favourably. The poultices were directed to be discontinued, and the parts +dressed every other day with sol. sulph. cupri, as the granulations were +getting rather luxuriant. + +'_July_ 6.--To-day she was found to have gone on so well, having two days +before been removed from the slings, that it was thought justifiable to +turn her out, protecting the foot with a boot, and ordering the dressings +to be repeated. + +'_July_ 23.--She was seen by me in the field, where I had the boot removed, +and so much had she improved, that not less than 2 inches of crust, +proceeding from the coronary ring, had been formed, and the foot looked +remarkably healthy. + +'It will be seen that the accident occurred on June 20, a fortnight after +which time I observed the horny crust to be forming from the coronet, +and the insensitive laminae at the same time, in which on every visit an +increase of growth was perceptible, and it soon attained a thickness +exceeding that of the other hoof, but which at the same time presented a +more upright appearance. It was not until three weeks after our first visit +that any formation of new sole or frog was to be seen. Of the two the sole +was the first, being secreted by the sensitive sole, the growth proceeding +from the heels. In like manner the insensitive frog was being produced by +the sensitive. + +[Illustration: FIG. 115.--HOOF TORN FROM THE FOOT BY ACCIDENT.] + +'During the last week in October the mare, having her foot protected with a +bar shoe plated at the bottom, and so formed as to open without necessity +of removing the shoe, in order to facilitate the applications of the +tinctures, was put to light work, which has since been gradually increased, +and she now performs her usual labour equal to any other horse. + +'The growth of the wall or crust and insensitive laminae is not yet quite +complete, nor is the sole, there being wanting about an inch of the horny +substance of it, the entire completion of which I should rather doubt, as I +mentioned in my former communication that the sensitive laminae and a small +portion of the sole were lacerated, and it is in these parts that the +imperfections exist. + +'The yet imperfectly-formed wall not admitting of the insertion of nails +all around it, the shoe is held on partly by nails and partly by a strap +attached to it bound round the coronet.'[A] + +[Footnote A: _Veterinary Record_, vol. iv., p. 182 (B. Cartledge).] + +3. 'This case is related by Mr. A. Rogerson, F.R.C.V.S. It occurred to an +animal regularly engaged in shunting, and happened through the corner of +the shoe becoming "trapped" between a line of metal and the wheel of +a truck. It is particularly interesting on account of the photograph +accompanying it, and which we here reproduce in Fig. 115. + +'The photograph shows plainly the manner in which the holding of the +"clinches" on the left side of the hoof has resulted in drawing it off +from the foot. Had these clinches, as Mr. Rogerson suggests, been left +unfastened, then the accident in all probability would not have occurred. +The animal was destroyed.'[A] + +[Footnote A: _Ibid_., vol. xiii., p. 2.] + + + +CHAPTER IX + +INFLAMMATORY AFFECTIONS OF THE KERATOGENOUS APPARATUS + + +A. ACUTE. + +ACUTE LAMINITIS. + +_Definition_.--The term 'laminitis' is used to indicate a spontaneous and +diffuse inflammation of the whole of the sensitive structures of the foot, +more particularly the sensitive laminae. Usually it occurs in the two front +feet, often in all four, and occasionally in the hind alone. + +_Causes_.--In dealing with the causes of laminitis, we will first dispose +of those coming under the heading of _traumatic_. Correctly speaking, +however, lesions of the laminae thus occurring do not present the same +symptoms, nor run an identical course with the disease we now purpose +describing, and for which we would prefer to entirely reserve the term +'laminitis.' The fact, however, that traumatic causes are detailed in other +works on the same subject compels us to give them mention here. + +Strictly traumatic causes giving rise to a limited inflammation of the +sensitive laminae are violent blows upon the foot, either purely accidental, +or self-inflicted by violent kicking. + +A similar limited laminitis is to be found in the conditions we have +described under 'Nail-bound and Punctured Foot.' It is met with also in +the injuries resulting from tread and overreach, and in the tissue-changes +accompanying corn. + +The tenderness following upon excessive hammering in the forge, or of too +long an application of the shoe in hot-fitting has also been described as +laminitis. + +With either of the conditions we have mentioned, it goes without saying +that there is either a simple congestion or an actual inflammation, +localized or general, of the laminae of the injured foot. In neither case, +however, can the resulting mischief be closely compared with the lesions +attending an attack of laminitis proper, a disease which appears to have an +almost specific cause, and to run a course peculiarly its own. + +The specific cause we have indicated as existing can, in the present state +of our knowledge, be only vaguely described as a poisoned state of the +blood-stream. This, as clinical evidence teaches us, may result from a +variety of causes. + +Among these, by far the most common is that state of the circulation +induced by excessive feeding with too stimulating or too irritating a diet. +In any case, where the use of old oats as a staple diet is departed from, +and where the quantity and manner of using the substitute is left to the +discretion of careless or unskilled attendants, trouble is likely to ensue. +The food more prone, perhaps, than any other to bring about an attack is +wheat improperly prepared--that is, uncooked or unground. So much so is +this the case that one full meal of this provender to an animal unused to +it is sufficient to lead to a train of symptoms often ending fatally. + +Beans, peas, barley, rye, new maize, or even new oats, are all liable, if +carelessly used, to have the same effect. + +It is the laminitis following feeding on new oats that has caused us to +apply to the food the adjective 'irritating.' Here, more often than not, +the peristaltic action of the bowels is found to be abnormally in evidence, +and the excessive use of the diet is always accompanied by a more or less +fluid discharge of the intestinal contents. + +In addition to the foods we have mentioned, many others might be +enumerated, more especially the numerous 'made-up' feeding materials now +on the market. Many are composed of substances that may be regarded as +absolutely opposed to the correct feeding of a horse, and their use can +only be followed by this and other evil results. + +Another most fruitful cause of laminitis is a severe and continued +inflammatory condition of the system elsewhere. It is the laminitis known +to veterinary surgeons as 'metastatic,' and perhaps the two most notable +examples of it are the laminitis following a prolonged attack of pneumonia, +and the 'Parturient Laminitis' occurring as a concomitant of septic +metritis. + +Parturient laminitis it is that offers us the most striking illustration of +the truth that a poisoned state of the blood-stream is a sure factor in the +causation of an attack. From the direct evidence of our senses (namely, +manual exploration of the infected womb, and the stench of the exuding +discharge) we know that we have in the interior of the womb matter in a +state of putrescence. From the experience of previous post-mortems we +know, further, that the putrescent matter thus originating often gains the +blood-stream, and forms foci of septic lesions elsewhere--liver or lung. +When, therefore, during an attack of septic metritis a condition of +laminitis supervenes, we are justified in attributing it to the escape of +septic matter from the already infected uterus. + +In the same category of laminitis from metastasis may also be placed the +laminitis occurring as a result of an overdose of aloes. The enteritis thus +set up is often followed by laminitis, and that of a serious type. + +Prolonged and excessive work upon a hard road is also apt to induce an +attack. When this occurs it in many cases resolves itself into a case of +cruelty. (See reported case, No. 1, p. 279.) + +Laminitis from this cause was frequent among coach and carriage horses in +the pre-railroad period, and resulted from attempting to obtain from the +animal a faster pace and a greater number of miles than he was physically +capable of giving. + +In our day, however, it is more often a result of gross feeding, combined +with only that amount of work which the horse, if ordinarily fed, would +be easily able to perform. An excellent example of this is the laminitis +occurring in the Shire stallion when commencing his rounds of service in +the spring and early summer. At this season these animals are constantly +supplied with a more than sufficient supply of a highly stimulating and +nutritious diet. In this case the blood is already in that state in which +it is predisposed to the disease. Add to this the unwonted exercise--for +during all the winter the animals are idle--and congestion of the venous +apparatus of the extremities is not to be wondered at. + +Passing from these, the more common, we may consider other and less +frequent causes of the disease. Congestion of the laminal blood-vessels and +consequent laminitis occurs when animals are made to maintain a standing +position for prolonged periods, as, for instance, when making sea voyages. +A long and painful disease of one foot, necessitating the whole of the +weight being borne by the other, ends often in laminitis of the second +member. It may thus occur as a sequel to quittor, complicated sand-crack, +suppurating corn, and punctured wounds of the feet. + +Laminitis has also been known to occur as a result of septic infection of +the blood-stream consequent on the operation of castration. (See recorded +case, No. 2, p. 281.) + +A sudden lowering of the surface circulation at a time when the animal is +excessively perspiring is also said to favour an attack, as also is the +giving to drink of cold water to an animal just in from a long and tiring +journey. Also, according to Zundel, 'the influence of the season cannot be +denied, and it is during the summer months that laminitis is more frequent, +while it is rare in winter, as well as in the spring and autumn.' + +Further, laminitis has been described as occurring when the animal is at +grass, and when all causes--at any rate, active ones--have appeared to be +absent. (See reported case, No. 3, p. 282.) + +Regarding heredity, we may safely say that, as a cause of laminitis, it may +be almost totally disregarded. That a bad form of foot, either a flat-foot +or a foot with heels contracted, and already thus affected with a mild type +of inflammation, did not offer a certain predisposition, we should not like +to assert. There must, however, be an exciting cause--namely, a poisoned +condition of the blood-stream. This latter cannot, of course, be in any way +regarded as hereditary. + +In short, the dietetic cause is by far the most common, and, in prosecuting +inquiries as to the starting-point of an attack, the veterinarian's +attention should be directed in the main to that particular. + +_Symptoms_.--Laminitis is always ushered in by a set of symptoms indicative +of a high state of fever. The pulse is raised from the normal to as many as +80 or 90 a minute, muscular tremors are in evidence, the respirations are +short and hurried, and the temperature rises to 105 deg., 106 deg., or 107 deg. F. The +visible mucous membranes are injected, that of the eye, in addition to the +hyperaemia, often tinged a dirty yellow. The mouth is dry and hot, the urine +scanty, and the bowels frequently torpid. As yet, however, the walk is +sound. + +Called in during this early stage, the veterinarian is often puzzled as +to the exact significance of the symptoms. Enteritis, lymphangitis, or +pneumonia he knows to be often heralded in the same manner. In this +connection, Zundel says: 'Laminitis, in most instances, is preceded by +certain general symptoms, such as are premonitory of the invasions of +ordinary inflammatory diseases, but of an uncertain significance.' + +So far we agree with him, but to what we have already said we would add +that, even in this early stage, there is an additional symptom, unmentioned +by Zundel, which often leads one to an exact diagnosis. The feet are in +turn lifted a short distance from the ground, and almost immediately +replaced. This movement ('paddling,' we may term it) is constant, the +animal appearing to obtain ease in no one position for more than a few +moments at a time. + +Seen but a few hours later, when the swelling caused by the hyperaemia +and outpouring of the inflammatory exudate has led to compression of the +sensitive structures within the horny box, the symptoms presented admit of +no misreading, save by the most casual and careless observer. The patient +now stands as though fixed to the ground. The pulse is hard and frequent, +the respirations tremendously increased in number, the body wet with a +patchy perspiration, and the countenance indicative of the most acute +suffering. Only with difficulty, and often only at the instigation of the +whip, can the animal be induced to move. This he does by throwing his +weight, so far as he is able, on to the heels of the feet affected, and +putting the feet slowly forward in a shuffling and feeling manner. The feet +themselves give to the hand a sensation of abnormal heat, percussion upon +them with the hammer is followed by painful attempts at withdrawal, while +any effort we may make to remove one foot from the ground is useless, so +great an aversion does the animal show to placing a greater weight upon the +opposite foot. + +According as the front-feet alone, the hind-feet alone, or all four feet +are affected, the symptoms will vary. + +With all four feet diseased, the animal stands with the two front-feet +extended in front of him, while the hind-limbs are at the same time propped +as far beneath him as is possible. The horse is, in fact, standing upon the +extreme hindermost portions of the feet. + +Why the animal should thus distribute his weight is easily explained. +Standing in the normal position, the body-weight is borne by the sensitive +laminae, the sole, of course, sharing in the burden, but the laminae taking +by far the greater part of the pressure thus exerted. With the vessels of +the laminae gorged with blood, and the laminal connective tissue infiltrated +with a profuse inflammatory exudate, the most excruciating pain is bound +to result by reason of the compression of the diseased tissues within the +non-yielding structures. In some little measure the suffering animal may +afford himself relief by partly removing pressure from the fore-parts of +the hoof. When placing the body-weight behind, the pressure, instead of +falling upon the highly sensitive laminae, is directed to the follicular and +fatty tissues of the plantar cushion: from there, with only a small portion +of the sensitive sole intervening, to the horny frog, and from thence to +the ground. + +The same distribution of weight also places the foot in a position of +greatest expansion, thus, by giving greater room to the diseased parts, +again affording relief of pressure on the inflamed lamina, while it at the +same time relieves of weight the foremost portions of the sensitive sole. + +With the fore-feet alone attacked, the animal affects exactly the same +position of standing as that just described. The fore-feet are again +extended, and the hind propped far beneath him. The fore extended, in order +to obtain the relief occasioned by standing on the heels; the hind in this +case carried forward in order to take a greater share of the body-weight, +and thus relieve the congested members in front. + +With the hind only attacked, then the fore and the hind feet are more +closely approximated than in the normal position. The reason, of course, +is that the hind-feet are carried forward in order to be placed upon the +heels, while the fore are taken backwards to relieve the hind of the +body-weight. + +In like manner the movements of the animal will vary with the feet +affected. With only the front-feet diseased the animal is, comparatively +speaking, comfortable. The hind-feet take the weight, and the animal stands +for long periods together, resting alternately first one fore-foot and then +the other, moving often in a circle of which his body is the radius, and +his hind-limbs the centre. If urged to move forward, then immediately his +countenance and movements manifest the pain to which he is put. Only with +reluctance does he cause the fore-feet to take weight. They are shuffled +forward quickly one after the other, so that weight may not be placed +upon them for one instant longer than is necessary, and the hind-limbs +immediately brought again with two short, awkward movements beneath the +body. Progress thus takes place in a succession of movements 'half hobble,' +'half jump.' + +Painful though this may appear, progress is still more difficult when the +hind-feet alone are diseased. Afraid that, in placing his fore-members +freely forward, he will add to the pain in his hind, the walk takes place +in a series of extremely short steps, with the feet more or less closely +approximated. The gait is thus rendered extremely awkward, and Zundel, by +saying that 'the animal appears as if treading on sharp needles,' most +fitly describes it. + +Movement with all four feet affected, though less awkward in appearance, +is doubtless more painful than in either of the other conditions. Here +the animal can hardly be induced to shift his position at all. Only by +flogging, and that severe, can he be made to go forward. When so induced to +move, the agonizing pain to which the patient is subjected may be gathered +by noting his countenance and manner of progression. + +With each movement forward, muscular tremors affect the limbs; each step +is short, jerky, and convulsive; the respirations and pulse are almost +immediately greatly quickened, and the lower lip is hung pendulous, and +moved almost unconsciously up and down with a flapping noise against the +upper. A patchy perspiration breaks out about the body and quarters, and +the tail is outstretched and quivering. At the same time the lines of the +face become drawn, the commissures of the lips pulled upwards, the eyes +staring and haggard, the eyelids puckered, the nostrils extended, and +the whole expression indicative of the intense and agonizing pain of the +disease. + +One can perhaps better give one's client some vague idea of the patient's +suffering by likening the pain to the throbbing sensation of a festered +finger-nail. Tell him that each hoof of the horse is similarly, or, if +anything, more delicately, constructed, that in each foot the same process +of 'festering' is going on, and that upon them the animal has perforce to +stand. + +As one might expect, the position of greatest ease is the decumbent. +Strange to say, though, in many cases of laminitis the animal persists in +maintaining a standing posture. Once down, however, one has sometimes the +greatest difficulty in persuading him again to rise. The lying position is +so long maintained that bedsores begin to make their appearance, and the +animal rapidly loses flesh, not only by reason of the fever and the pain, +but by giving to rest the time he should normally give to feeding. + +Difficulty in rising is greatest when all four feet are affected; is +_nearly_ as great when the hind-limbs only are in trouble, but is least +when the disease exists alone in the two fore-feet. + +THE COURSE OF THE DISEASE AND ITS PATHOLOGICAL ANATOMY.--As with +most inflammations of any severity, so with this we may consider the +pathological changes taking place in the foot under three headings: (a) +The period of Congestion; (b) the period of Exudation; (c) the period of +Suppuration. + +(a) _Congestion_.--In the early stages of laminitis there is a state of +engorgement of the vessels of the keratogenous apparatus generally, but +more particularly the laminal portion of it. With the hoof removed at this +stage the sensitive laminae are found to be swollen, dark red in colour, and +affording a distinct feeling of increased thickness when pressed between +the fingers, Incised, there escapes from the cut surface a large flow of +dark venous-looking blood. At this stage haemorrhages of the laminal vessels +occur. The escaping blood infiltrates the surrounding connective tissue, +and in many cases destroys the union between the horny and sensitive +laminae. This change is most noticeable in the region of the toe and the +commencement of the quarters, the os pedis appearing as though pushed +backwards by the escaping fluid collected between the wall and the bone. In +severe cases, fortunately but rarely seen, the blood so escaping continues +to infiltrate, and separate the tissues until it is seen to be freely +oozing at the region of the coronet. (See reported case, No. 1, p. 279.) + +(b) _Exudation_.--The period of exudation marks the outpouring of the +inflammatory fluid. This, even more than the haemorrhages attending the +stage of congestion, tends to destroy the intimacy between the sensitive +and the horny laminae, leading finally to their complete separation at +the region of the toe. Fig. 116 illustrates this state of affairs after +laminitis has existed for a week. The sensitive and horny laminae are here +shown to be distinctly separated from each other, a well-marked cavity +existing between them, which cavity is greatest in extent at the toe of the +os pedis. With the sensitive structures thus detached from the wall, it is +evident that very much that formerly held the os pedis in normal position +has been destroyed. What then happens is that the whole of the body-weight +is placed upon the sole. Never intended to bear the strain thus imposed, +it naturally sinks. With the sinking is a corresponding 'dropping' of the +pedal bone--in fact, of the whole of the bony column. Seeing that the +structures _above_ the hoof are still normally adherent to the bones, it +follows that they must, as the os pedis sinks, be carried with it. As a +consequence we get a marked depression at the coronet (see Fig. 117, _a_), +which depression may be often noticed after the second or third week of a +severe attack of the disease. + +[Illustration: FIG. 116.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +EIGHT DAYS' STANDING. The separation between the sensitive structures and +the hoof is indicated by a dark line. The cavity is filled with exudate. It +will be noted that as yet there is little change in the position of the os +pedis.] + +Here, again, though to a greater extent than that caused by the haemorrhage +alone, the os pedis appears to be pushed backwards, the space at the toe +between the bone and the horny box being closely filled with the yellow, +slightly blood-stained exudate. This condition is well depicted in Fig. +117. + +[Illustration: FIG. 117.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +FOURTEEN DAYS' STANDING. _a_, The depression at the coronet caused by the +dropping of the bony column within the horny-box: _b_, a portion of the +sensitive sole pushed downwards and forwards by the descending os pedis.] + +With the descent of the os pedis we get in many cases a penetration of the +horny sole (see Fig. 117), leading always to serious displacement of the +sensitive sole (see Fig. 117, _b_), and often to caries of the exposed +bone. + +The backward displacement of the os pedis may be accounted for in two ways. +Firstly, the greater vascularity of the membrane covering its front leads +to a greater outpouring of inflammatory fluid in that particular position. +Here, therefore, loss of adhesion with the wall is greatest, while into the +cavity so formed is poured a large quantity of a fluid that is practically +incompressible. The os pedis _must_ be pushed backwards. Secondly, the +manner in which the animal distributes his weight--namely, upon the +heels--is calculated to aid in the bone's backward movement, for with his +feet in this position tension upon the extensor pedis is relaxed, while +that upon the flexor perforans is greatly increased. + +(c) _Suppuration_.--Should the animal survive the pain and exhausting calls +made upon his system by the accompanying fever of the foregoing conditions, +the case ends either in resolution or suppuration. When suppuration occurs +it is found, as a rule, at the sole, leading to almost entire separation of +the sensitive and horny structures. The pain, if possible, is even worse +than in either of the foregoing stages, and relief for the suffering +patient is only obtainable by the natural exit of the pus at the coronet, +or by giving it escape with the knife at the sole. As a rule, suppuration +in laminitis is rare, and then only occurs when the disease has been of +some several days' duration. It has been the author's experience, however, +to meet with it in a case but three days' old. This particular animal had +laminitis restricted to the hind-feet. The condition was diagnosed and pus +liberated at the sole of one foot during the third day of the lameness. The +animal was cast on the fourth day, and pus obtained from the sole of the +opposite foot. + +_Complications_.--In a moderate case, carefully treated, laminitis +terminates at the end of three or four days in resolution. The general +symptoms of fever gradually subside, the appetite returns, and the walk +becomes easier. Cases thus terminating fortunately leave behind them no +change of serious importance, either in the sensitive tissues or in the +horny envelope. Should resolution, however, be longer delayed, then the +case, although eventually terminating successfully so far as soundness in +gait is concerned, leaves more or less evidence behind in the shape of +rings about the wall and alterations in the build of the sole. + +When the happy ending of rapid resolution is denied us, then, in addition +to the condition we have described as suppuration, we may meet with one or +other of the following complications: + +_(a) Metastatic Pneumonia_.--This complication is not uncommon, and, +when occurring, more often than not ends fatally. It may be accounted for +indirectly by the greater work the lungs are called upon to perform in +carrying out the increased number of respirations occasioned by the general +fever and pain, and directly by the poisonous materials circulating in the +blood-stream. + +_(b) Metastatic Colic_.--This may be either a subacute obstruction of the +bowel or an enteritis accompanied by an offensive purge. + +A striking case of the former is related in the _Veterinary Journal_ (vol. +xvi., p. 180) by H. Thompson, of Aspatria. Here no evacuation of the bowels +occurred for three days, and the pains of laminitis were added to by the +usual pains of intestinal obstruction. + +The colic of enteritis is in some cases caused by the nature of the food, +giving rise to laminitis. In our opinion, however, it is more often +occasioned by the drastic action of the aloes nearly always resorted to in +the treatment of the disorder. As does the pneumonia, the enteritis thus +brought about nearly always has a fatal termination. + +_(c) Gangrene of the Structures within the Hoof_.--This complication is +the one most to be dreaded. It occurs as a result of the great pressure +exerted by an excessive exudation, and doubtless affects first the laminae +and softer structures. Once commenced, however, it rapidly extends to death +of the other structures (ligament, tendon, and even bone), and gives a +fatal ending to the case. + +That gangrene of the tissues ("mortification" as our older writers called +it) has occurred is soon made evident to the veterinarian by the symptoms +shown by the patient. The agonizingly acute pains suddenly subside, the +feet are placed firmly and squarely to the ground, and the animal walks +with ease. Perhaps but the night before the patient is seen racked with +excruciating pain; the morning sees the astounding change of apparent +absolute recovery. Too well, however, the eye of the experienced veterinary +surgeon sees that such is not the case. Even before proceeding to take a +record of the other symptoms, he knows that it is but the commencement of +the end. Methodically, however, he notes the other conditions. The pulse +he finds small and imperceptible, save at the radial. The thermometer +registers a subnormal temperature, the extremities are cold, and cold +sweats bedew the body. To the same experienced eye the countenance of the +animal is almost suggestive of what has occurred. The drawn and haggard +expression, to which we have previously referred, becomes more marked, and +the angles of the lips are drawn back in what has been described by some +writers as a 'sardonic' grin. + +We can best express what the whole look of the animal's countenance +indicates to us by saying that it gives us the impression that the animal +himself knows that some serious change, and a change fatally inimical to +his chances of life, has taken place in his feet. + +It may be that in some odd cases, although it has not yet been our lot to +meet with them, gangrene may terminate in the casting off of one or more +hoofs. Needless to say, there can still be but one termination to the case. + +_(d) Periostitis and Ostitis_.--This complication is referred to by other +writers under the term of 'Peditis.' It signifies, of course, that the +periosteum and the bone have become invaded by the inflammatory process. +It is our opinion that these two conditions, even including an actual +arthritis, always exist, even in an attack of laminitis that ends +favourably. We do not claim, however, to be able to relate any means, save +that of post-mortem examination, by which it may be singled out from the +other changes occurring in the foot. The high fever and pain occasioned by +the inroads of the inflammation into the other sensitive structures serves +to effectually mask whatever evidence of it we might otherwise obtain. +It may be sometimes only small in degree, but we feel confident that +inflammation, at any rate of the _outer_ layer of the periosteum, is in +laminitis constant even, we repeat, in a mild case. + +[Illustration: FIG. 118.--SHOWING CHANGES IN THE OS PEDIS WITH LAMINITIS OF +LONG STANDING, (_a_, Viewed from the front; _b_, viewed from the side.) +The porous condition of the bone, which is here shown, is a result of a +rarefying or rarefactive ostitis. This specimen also illustrated (what the +photograph cannot show) an accompanying condition of condensation of bone, +or osteoplastic ostitis. (For a fuller description of the changes occurring +in these forms of ostitis, see Chapter XI.)] + +When the case is a serious one we have ample evidence to show that ostitis +exists, and exists in a severe form. The bones become vastly altered in +shape, a process of absorption leads to the formation of large, irregular +cavities within their substance, and what of the bone is left is rendered +hard and ivory-like (condensed) near what was the original centre, while +the edges and other portions show often a tendency to become brittle and +porous. + +Fig. 118 illustrates the effects of a severe ostitis in pedal bones removed +from hoofs with laminitis of several weeks' standing. + +_(e) Chronic Laminitis_.--The most common complication--or, perhaps, +rather we should term it 'sequel'--to acute laminitis is the chronic form +of the disease. For this condition we have reserved a separate section of +our work. It will be found described in Section B 1 of this chapter. + +_Diagnosis and Prognosis_.--One is almost tempted to state that the +diagnosis of laminitis offers no difficulty. In the very early stages, +however, it may, as we have already indicated, be mistaken for the oncoming +of Enteritis, Lymphangitis, or even Pneumonia. The paddling of the feet +may help us. If this is absent, however, nothing but a most careful +examination, or, if necessary, the withholding of our opinion until the +following visit will prevent a blunder being made. + +Even when well established, laminitis has been mistaken for paralysis, +for tetanus, for rheumatic affections of the loins, or even for some +undiscovered affection of the muscles of the arms and chest. This latter is +no doubt suggested to the uninitiated by the reluctance the animal shows to +move the muscles _apparently_ of that region, and led the older writers to +give to the disease its name of 'Chest-founder.' It is only fair to add, +however, that these blunders in diagnosis are nearly always committed by +persons without a veterinary training. + +Thus warned, the veterinary surgeon of average ability should have no +difficulty in establishing a distinction between the diseases we have +enumerated as likely to be confounded with it, and the one this chapter is +describing. + +The prognosis in laminitis should, in our opinion, always be guarded. No +advice given in a work of this description can be of any real use, for +every case must be judged entirely on its merits. The severity of +the symptoms, the cause of the attack, the complications, and the +idiosyncrasies of the patient, have all to be taken into account. These the +veterinarian must be left to judge for himself. + +_Treatment_.--The treatment of acute laminitis in its early stage must be +based upon the fact that we have to deal with a congested state of the +circulatory apparatus of the whole of the keratogenous membrane. This fact +was well enough known to the older veterinarians. It is not surprising, +therefore, to learn that jugular phlebotomy was at once resorted to as the +readiest means of relieving the overcharged vessels of their blood. As a +matter of fact, bleeding from the jugular is still advocated by modern +authorities. We cannot say, however, that we unhesitatingly recommend it. +Mechanically, of course, the removal of a large quantity of blood is +bound to result in a lowering of the pressure in the vessels. The effect, +however, is but transient. Blood removed in this way is again quickly +returned to the vessels so far as its fluid matter is concerned, and the +pressure, removed for a time, is again as great as before. With the +other and more vital constituents of the blood-stream--namely, the +corpuscles--restoration is not so rapid. We have, in fact, a weakened state +of the system, in which it is probable it will not so successfully combat +the adverse conditions the disease may induce. + +With these prefatory remarks, we may advise bleeding under certain +conditions. The quantity removed must be moderate (7 to 8 pints), and the +pulse and other conditions must show no signs of weakness or collapse. + +Local bleeding, either from the toe or the coronet, is also advised. In +the former situation the sole is thinned down until a sufficient flow +is obtained, while at the coronet scarification is the method adopted. +Bleeding locally, however, is far less effectual than the jugular +operation. Neither must it be forgotten that wounds in these situations, +more particularly at the toe, are extremely liable, especially with +the existing poisoned state of the blood-current, to take on a septic +character. What might possibly have remained a comparatively simple +inflammation is induced by the operation itself to terminate in the more +complicated and serious condition of suppuration. + +Other means of combating the congested state of the membrane are +principally those of local applications. With many veterinary surgeons warm +poulticing is still largely advocated and practised. We do not believe in +it. Warmth, as a means of removing local congestion, can only be successful +when applied _widely_ round the congested area, and so dilating surrounding +bloodvessels and lymphatics. Applied to the congested area itself, and to +that alone, it is almost worse than useless. + +With the foot, both around and below it, a surrounding area is denied us. +The only vessels we are able to dilate with the warmth, and so enable them +to carry off the fluid from the congested foot, are those in the +limb above. That poulticing cannot be successfully there applied is +self-evident. Apart from that, it is an open question whether poultices may +not do actual harm in inducing suppuration in cases where, probably, it +would not otherwise occur. + +For these reasons we hold to the opinion that when a local application is +determined on it should be a cold one. Various methods of applying cold are +in vogue. Cold swabs are perhaps most in favour. They must, however, be +_kept_ cold. When a suitable water-course, pond, or other expanse of +shallow water is at hand, then the animal may be kept standing therein, or +preferably walked about in it. When suitable apparatus is obtainable, a +constant stream over each foot from a rubber hosepipe is most beneficial. + +Astringent baths, containing solutions of alum, of copper sulphate, of iron +sulphate, or of common salt, or composed of a mixture of two or more of the +salts mentioned, may also be used with advantage. In addition to the fact +that such solutions are for a time below the temperature of simple water, +we have the advantage that they have also a more or less antiseptic +property. + +While on the subject of the relief of the congestion, we must not forget +to mention a treatment which we ourselves have practised with considerable +success--namely, that of forced exercise. It appears to have been first +brought into prominence by Mr. Broad, of Bath, and the two terms 'Forced +Exercise and Rocker Shoes' and 'Broad's Treatment' have come to be +synonymous. + +The Broad shoe is a shoe with a web of quite twice the thickness of the +animal's ordinary shoe, and has this web gradually thinned from the toe +backwards until at the heels the shoe is at its thinnest (see Fig. 119). + +The excessive thickness of the shoe serves two purposes. It allows of the +requisite amount of slope being given to the web, and so enables the animal +readily to throw himself back on to his heels, a position in which, as we +have already indicated, he obtains the greatest ease. It also minimizes to +some extent the effects of concussion. + +[Illustration: FIG. 119.--SEATED ROCKER BAR SHOE (BROAD'S) FOR TREATMENT OF +LAMINITIS.] + +With forced exercise, as practised by Mr. Broad, this shoe is first +applied, and the animal afterwards made to walk upon soft ground, or even +upon the roadway, for a half an hour to an hour and a half three times a +day. + +For our own part, we consider the shoe to be almost if not quite +superfluous, so far as its influence upon the progress of the disease is +concerned. We therefore dispense with it, and have the animal exercised in +his ordinary shoes. To do this, the patient has sometimes to be severely +flogged into taking the first few steps. After that progress gradually +becomes easier. + +It has been said to be cruel. In so far as we knowingly, and of set +purpose, occasion the animal pain, cruel it undoubtedly is; but it is +cruelty with an aim that is truly benevolent, and the object of our +benevolence is the animal upon whom the cruelty is practised. + +One word of advice is needed. The forced exercise must be commenced early. +In the later stages, when the stage of congestion has passed from that +to the acuter stages of the inflammation and the outpouring of the +inflammatory exudate, then forced exercise cannot be safely commenced. The +loss of adhesion between the pedal bone and the horny box, which we know to +be then existent, negatives its advisability. + +By many it is advised to always remove the shoes. From what we have already +said, it will be seen that this is not our practice. But one argument +in favour of so doing appears to us to carry weight, and that is that +'dropping' of the sole is probably prevented from becoming so marked. That +condition, however, is entirely dependent upon the changes occurring within +the horny box. It is bound to occur with the animal shod or unshod, and +to reach a stage when only contact with the ground prevents its further +descent. The complication then sometimes following--namely, penetration of +the sole by the bone, is not prevented by having the shoes removed. It may, +in fact, be thus rendered more likely. + +Internal treatment consists in the exhibition of suitable febrifuges and +the administration of a dose of aloes. + +With regard to the wisdom of the latter proceeding, opinion seems to be +divided. Personally, we hold an open mind concerning it. This much is +certain: in many cases of laminitis--those cases which have their origin +in overfeeding with an irritating food--there is already a strong +predisposition to enteritis. The administration of aloes in this case +is extremely apt to induce a fatal super-purgation. Aloes is, again, +contra-indicated when the laminitis is a result of excessively long +journeys, and the patient is already greatly exhausted. Neither can it be +advocated in the laminitis occurring as a sequel to septic metritis or to +pneumonia. + +On the other hand, when the disease has occurred as a result of long +standing in the stable and an overloaded condition of the bowels, or where +one full meal of some constipating food, such as whole wheat, pea or bean +meal, wheat or barley meal, has occasioned the attack, then a dose of aloes +at the commencement of the treatment is productive of good. + +Suitable febrifuges are found in potassium nitrate, potassium chlorate, +sodium sulphate, or magnesium sulphate, either of which or a mixture of two +or more of them, the animal will readily take in his drinking-water. + +The administration of sedatives is also indicated. In this connection +aconite will be found most useful. More especially in the early stages of +the disease, when pain is excessive and the temperature high, will its +good effects be noticed. This also the animal will often take in his +drinking-water. We have been in the habit of so prescribing the B.P. +tincture in 1/2-dram doses three times daily. By its use the temperature is +rapidly lowered, the pulse reduced in number and in fulness, and the pain +in some instances perceptibly diminished. With others hypodermic injections +of morphia and atropine have given equally satisfactory results. + +Needless to say, good nursing is a _sine qua non_. During the first +stages of the fever a light and easily digested diet should be +allowed--bran-mashes, roots and grass when obtainable, and a carefully +regulated supply of water. The animal should be warmly clothed and the box +well ventilated, even to the opening of the doors and windows. Only in this +way is pneumonia as a sequel sometimes prevented. The patient's comfort +should be attended to in providing him with a suitable bed. Anything in +the shape of long litter should be avoided. When nothing else is at hand, +litter that has already been broken and shortened by previous use is best. +With this the box floor should be thickly covered, and matting of the +material prevented by constant turning. A good bed for the horse with +laminitis is peat-moss mixed with short straw. This, without being +dragged into irregular heaps, remains springy and elastic with but little +attention. Better than all, however, especially with good weather, is an +open crewyard. Here the animal has an abundance of fresh air, has a bed +that is always soft, and has plenty of room in which to get up and down +with some degree of ease. + +Leaving the dietetic and medicinal, we may consider other treatments of +laminitis that come more particularly under the heading of operative. + +The first matter that here demands our attention is that of allowing the +exudate to escape at the sole. If after the expiration of three or four +days pain and other symptoms of distress continue, then it may be judged +that the inflammatory exudate has made its appearance. Operative measures +allowing of its escape, though not giving absolute ease, do undoubtedly +relieve the more marked expressions of suffering, and should be at once +determined on. To do this completely it is necessary to cast the animal. +The sole is then thinned at the toe with the drawing-knife until the +sensitive structures are reached. A flow of yellow and sometimes +blood-stained discharge is immediately obtained, and the sole itself found +to be underrun to a considerable extent. An opening sufficiently large to +admit of free drainage (about the size of a half a crown-piece) is made, +the wounds antiseptically dressed, and the hobbles removed. + +If showing an inclination to do so, the animal should then be allowed +to remain and rest. In one instance in which we so operated (a case of +laminitis in the hind-feet alone), the relief given was at once manifested. +For three days previously the animal had remained standing in agonizing +pain. On the fourth he was cast, and the discharge--partly inflammatory +exudate, and partly a sanious foetid pus--liberated. The hobbles were +removed, and the animal allowed to remain down while our attention was +drawn to another case. This attended to, we walked back to the field +where, our first patient was lying. His breathing, but a short time before +distressedly short and catching, was now so slow and deeply regular that +for one brief moment the thought flashed across our mind that he was dead. +He was in a _profound_ sleep. + +Other operators sometimes give the exudate escape while making the grooves +in what is now known as 'Smith's Operation.' + +In this operation the hoof is so grooved as to allow of its expansion, so +relieving the pressure on the sensitive structures within it. Incidentally, +the inflammatory exudate is given exit. + +[Illustration: FIG. 120.--DIAGRAM OF HOOF SHOWING THE POSITION OF THE THREE +GROOVES MADE IN THE TREATMENT OF LAMINITIS.] + +The animal is cast, the shoes removed, and three vertical grooves made +in the wall. The first is cut down the centre of toe, extending from the +coronet to the ground surface. The second is made to the right of this, and +the third to the left, each following the direction of the horn fibres, and +each distant about 2 inches from the first (see 1, 2, and 3, Fig. 120). + +Each of the grooves must run completely from the coronary margin to the +ground surface, and each should be carried through the substance of the +horn until the horny laminae are reached. This done, the underneath surface +of the foot is grooved at the white line (see curved groove 4, Fig. 121) +in such a manner as to entirely isolate the two pieces of horn _a_ and _b_ +from the remainder of the hoof. + +Expansion of the horny box is thus brought about, while at the same time +the semicircular groove at the toe is made deep enough to allow of the +escape of the exudate. + +If thought wise by the operator, the two pieces of horn _a_ and _b_ may be +isolated, and the exudate given exit by making the fourth groove in the +position of the dotted lines in Fig. 120--that is to say, at the lowermost +portion of the sensitive structures. By this means the sole will be left +intact. + +[Illustration: FIG. 121.--LOWER SURFACE OF FOOT SHOWING POSITION OF THE +GROOVES MADE IN THE TREATMENT OF LAMINITIS.] + +Fuller instruction for making the grooves and the instruments required will +be found described in Section C of Chapter X. + +The animal should be afterwards shod, and the bearing on the portions +_a_ and _b_ of the wall removed. Almost immediate relief is afforded the +patient. + +_Recorded Cases_.--1. 'On the evening of September 28 last, I was called +rather hurriedly to attend a posting-horse which had just arrived from a +twenty-one miles' journey, and was said to be "very ill." I lost no time in +proceeding to the spot, and found my patient "very ill" indeed. No need for +long consideration as to diagnosis; the symptoms showed at once that I had +an uncommonly severe case of acute founder before me. On examination I +found the pulse was 120, the respirations 100, and the thermometer 106 deg. F. +The poor brute could not move, the fore-legs were well out before, and the +hind-legs thrown back behind; in fact, he was, as one might say, propping +himself up with his four legs! + +'On examining his feet, I discovered what I had never either seen or heard +of before--namely, _blood freely oozing out_ at the coronet of all four +feet; if anything, the hind-feet were the worst, and, showing that this +bloody discharge at coronets had commenced during progression and before +he was stabled, the inside of the thighs were all shotted over with blood, +which had been thrown up by his feet while he was trotting or walking. He +was completely soaked all over with perspiration. + +'My prognosis could not well be otherwise than unsatisfactory. I resolved, +however, to do all I could to relieve the poor suffering brute. As a matter +of course, jugular phlebotomy was utterly impracticable; so, to relieve the +pressure in the feet, I had him (after, with extreme difficulty, removing +the shoes) bled, or rather opened, at all four toes, and hot poultices +applied. On opening the off-side toe, in both hind and fore feet, I found +an escape of very dark-coloured blood, with a great many bubbles of gas, +thus showing that the destructive process was fairly established in the +two bony extremities mentioned. The near fore and near hind feet showed no +signs of gas-bubbles on being opened at the toe. + +'I gave a laxative in combination with a diffusible stimulant, and ordered +doses of aconite and potassium iodide; I also applied strong sinapisms to +each side, immediately behind the shoulders. After three hours I found my +patient rather easier; respiration about 90, and temperature 104 deg.; willing +to take a little water, and even attempted to take some hay. Ordered +continued applications of hot water to the poultices at feet, and +clothed him up for the night. Next morning there was little improvement; +respirations over 80, and temperature 103.5 deg.. Continue same treatment. +Second morning, horse apparently easier; temperature 102.5 deg., but very +difficult respiration; laxative had operated during the night; ordered +diffusible stimulants. About two hours and a half after my last visit, the +horse turned round in his stall and dropped down dead! + +'_History of the Horse_.--He belonged to an extensive horse-hiring +establishment; was purchased a short time before for L60--a long price for +a post-horse--had recently suffered and been off work from some "severe +cold"; was taken out, and did forty-seven miles of a journey the day +_before_ I saw him; on forenoon of the day on which he was attacked he did +two or three short turns, and then twenty-one miles of a journey in the +afternoon, during which he became so ill as scarcely to be able to conclude +the twenty-one miles; this was the last turn he was to do. He was a grand +stepper, and no doubt was pushed a little during this final journey, as +the driver intended, after a short rest, to finish off with the twenty-six +miles between this and home. With the short turns on the second forenoon, +this would have been over 100 miles in less than two days, with a horse +just out of a _severe cold_.'[A] + +[Footnote A: _Veterinary Journal_, vol. xvii., p. 314 (A.E. Macgillivray).] + +2. 'Whilst attending a patient on a farm on September 5 last my attention +was called to a cart-horse, five years of age, that had been castrated in +the standing position by a travelling castrator about ten days previously. + +'I found the animal presenting the following symptoms: Head down, blowing +hard, very dull, and disinclined to move, temperature 105 deg. F., hard, rapid, +slightly irregular pulse, membranes injected, appetite lost; scrotum, +sheath, and penis tremendously swollen, castration wounds unhealthy, and +exuding a thin, reddish-brown discharge of a most foetid odour. + +'The next day well-marked symptoms of laminitis were present. I finally +ceased attending him about the middle of October, and at the end of that +month he was turned out for the winter.'[A] + +[Footnote A: _Veterinary Record_, vol. xiv., p. 649 (Charles A. Powell).] + +3. 'On July 8 an interesting case of laminitis came under my notice. The +subject was a mare, eight years old, which had been running on the common +here for some months, and was taken up on the night of July 2 by a boy, +who did not observe anything amiss with her. The following morning, on the +owner going to the stable, he found the animal in great pain, and at once +sent for me. I discovered her to be suffering from laminitis, and saw her +again in the evening, when she was much worse. The attack proved to be a +most severe one. + +'The owner informed me that she had not been allowed any corn for two +months, and that she had no distance to travel on the road from the common. + +'Though on such a poor pasture, the mare was very fat; she had never been +unwell before this attack. + +'This is the first case I have seen of laminitis occurring when the animal +was on grass.'[A] + +[Footnote A: _Veterinary Journal_, vol. ix., p. 176 (W. Stanley Carless).] + + +B. CHRONIC. + +1. CHRONIC LAMINITIS. + +_Definition_.--A low and persisting type of inflammation of the sensitive +structures of the foot, characterized by changes in the form of the hoof, +and incurable pathological alterations within it. + +_Causes_.--Chronic laminitis more often than not is a sequel to the acute +form we have just described. With an attack of acute laminitis that defies +treatment, and does not end in resolution in from ten days to a fortnight, +then the chronic form may be expected. + +The brittle horn, convex sole, and other changes we have described under +Pumiced Foot may, however, be regarded as a chronic laminitis, and this +condition, as we have already indicated in Chapter VI., may run a course +slow and insidious from the onset. + +_Symptoms_.--When the disease arises without previous acute symptoms, the +first thing noticeable is an alteration in the gait. The animal begins to +go feelingly, especially when first moved out from the stable. Our opinion +is asked as to the cause of the lameness, and an inspection is made. With +the changes in the form of the hoof as yet wanting, we have nothing to +guide us, and other causes for the lameness suggest themselves, probably +corns. Evidence of these is not forthcoming, and we in all probability +withhold our opinion until a later visit. On the second or a subsequent +call we are perhaps lucky enough to find our patient down. Diagnosis is +then rendered easier. Made to rise, the animal stands in the attitude we +have described as indicative of laminitis. We have him walked and trotted +out. The symptoms of tenderness disappear, and the animal soon goes fairly +sound. He is, in fact, workable--that is, by anyone who is careless as to +the comfort of his beast. + +When following an acute attack, we have the most marked symptoms of pain +and distress, somewhat abating after the second or third week. The walk, +however, is still painful, and, for a short time after rising from the +ground, even difficult. + +In short, in both cases we have the horse going on his heels, with a walk +that is painful, and with symptoms of pain that are most apparent when +moved on after a rest. + +Later, the changes in the form of the hoof begin to appear. It seems to +have lost its elasticity, and is seen to be dry and chippy, and to have +become denuded of its varnish-like outer covering. + +In addition, it is of largely altered shape. The toe, by reason of the +animal walking on his heels, and by reason of an increased growth of horn, +becomes elevated, so that the front of the wall, instead of forming an +obtuse angle with the ground, comes to run very nearly horizontal with +it. The horn of the heels, as compared with that of the toe, takes on an +increased growth. The same thing we have already indicated as happening at +the toe, though in lesser degree. Taken together, this increased growth of +horn at the toe and at the heels has the result of lengthening the diameter +of the foot from before backwards, the transverse diameter remaining more +or less normal. The hoof thus loses its circular build, and comes to +approach nearer an elongated oval. + +[FIG. 122.--FOOT BADLY DEFORMED AS A RESULT OF CHRONIC LAMINITIS.] + +At this stage, too, the pathological 'ribbing' of the hoof is observable. +The outer surface of the wall becomes marked with a series of ridges +encircling the hoof from heel to heel (see Fig. 81, which illustrates a +moderate deformity of the hoof occurring after laminitis). In the badly +laminitic hoof, however, this deformity is largely increased, until in some +cases the shapeless mass can hardly be likened to a foot at all (see Fig. +122). + +The inferior or solar surface of the foot also offers certain changes for +our consideration. The first thing that strikes one is the convexity of the +sole. This, as we have already pointed out, is due to descent of the os +pedis, and the highest point of the convex portion is that immediately in +front of the apex of the frog. Here the horn is sometimes found to be quite +yielding to the finger, is excessively thin, and is more or less granular +and inclined to break up under manipulation. As a consequence, any rough +use of the drawing-knife, or an accidental wounding with sharp flints or +stones, leads to exposure of the sensitive structures and local gangrene. + +With the horn of the sole thus deteriorated by reason of excessive and +continued pressure upon the parts secreting it, it is not surprising to +find that, in many cases, actual penetration of it with the os pedis +occurs. It is the anterior portion of the inferior margin of the bone that +makes its appearance, and shows itself as a small semicircular white or +dark gray line on the sole. + +[Illustration: FIG. 123.--SOLAR ASPECT OF FOOT WITH CHRONIC LAMINITIS, +SHOWING ITS ABNORMAL OVAL SHAPE FROM BEFORE BACKWARDS, AND THE EXCESS OF +HORN GROWING FROM THE WHITE LINE IN THE REGION OF THE TOE.] + +Exposure of the bone is soon followed by its necrosis, in which case the +wound takes on an ulcerating character. From it there is a discharge of +pus, black in colour and offensive in smell, and, protruding from the +opening, are excessive granulations of the remains of the sensitive sole. + +The 'white line,' so apparent when a normal foot is cleaned with the knife, +can no longer be sharply distinguished from the surrounding horn, while in +some cases the horn composing it takes on an abnormal growth at the toe +(see Fig. 123). This adds still further to the abnormal lengthening of the +antero-posterior diameter of the foot already mentioned. + +In other cases horn in this position is altogether wanting, and in its +place is a well-defined cavity, into which the blade of a knife can be +readily passed. This cavity is bounded in front by the original wall of the +hoof, and is here lined by a degenerated and hypertrophied growth of the +horny laminae. Posteriorly the cavity is bounded by the front of the os +pedis, and is lined by a thin growth of horn secreted by the keratogenous +membrane covering the bone. Superiorly the cavity is quite narrow, +and extends to near the lower surface of the coronary cushion, while +inferiorly, at its open portion, it is often 1/2 inch to 1 inch wide. +Laterally it extends on each side of the toe to the commencement of the +quarters. + +[Illustration: FIG. 124.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +THREE WEEKS' STANDING. On the anterior face of the cavity, in front of +the os pedis, are thickened horny laminae. Due to the sinking of the bony +column, the os pedis has perforated the horny sole.] + +Exploration with a director, or with the blade of a scalpel, removes from +the opening a dry detritus. This is composed of the solid constituents +of the escaped blood, the dried remains of the inflammatory exudate, and +broken-down fragments of cheesy-looking horn. The size to which the cavity +may sometimes extend is illustrated in Fig. 124. The thickened horny laminae +forming the anterior boundary of the cavity are here depicted, together +with commencing perforation of the horny sole by the os pedis. It is this +cavity which, when opened at the bottom and discharging its mealy-looking +contents, is known as seedy-toe, for a further description of which see p. +293. + +The lameness occurring with chronic laminitis does not always persist. As +time goes on the sensitive structures accommodate themselves to the altered +form and conditions of the horny box. In certain situations--namely, where +pressure is greatest--the softer structures become atrophied, and sometimes +even wholly destroyed; while in other positions the changes in form of the +hoof tend to increase in size of its interior, with a consequent diminution +of pressure upon, and increased growth of the structures within it. + +_Pathological Anatomy_.--In detailing the changes to be observed in chronic +laminitis, we take up the description where we left it when dealing with +the pathological anatomy of the acute form. The alterations to be met +with are best observed by taking a foot so diseased and making of it two +sections--one longitudinal, from before backwards; the other horizontal, +and in such a position as to cut the os pedis through at its centre. + +These sections will expose to view the cavity formed by the pouring out of +the exudate, and its full extent may be noticed by examining the sections +alternately. Taking the horizontal section first, it will be seen that +the hollow space extends wholly round the toe, and as far back as the +commencement of the quarters. In the latter position one is able to observe +laminae still in their normal positions and condition. At the toe, however, +the horny and secretive laminae are widely separated, and the space between +them filled with a yellow, semi-solid material, the remains of the +inflammatory exudate and new horn secreted by the keratogenous membrane. +The laminae, both horny and sensitive, are greatly enlarged. This is a +hypertrophy, resulting from the continued effects of the inflammation, and +leads in time to the formation of laminae quite three or four times their +normal size. It is this hypertrophy of the laminae and the pressure of the +exudate that causes the bulging and increased growth of the horn at the toe +(see Fig. 125), and contributes towards the oval formation of the foot we +have mentioned before. + +[Illustration: FIG. 125.--LONGITUDINAL SECTION OF A FOOT WITH LAMINITIS OF +SEVERAL YEARS' DURATION.] + +In the longitudinal section the first thing noticeable is the change +in position of the bones, more especially in that of the os pedis. The +circumstances we have mentioned before--pressure of the exudate upon it in +front and tension of the perforans on it behind--have caused it to assume +a more upright position than is normal, so much so that in a bad case the +front of the bone becomes quite vertical. This vicious direction the other +bones of the digit follow (see Fig. 125). + +Consequent upon the displacement of the bone, the plantar cushion, by +reason of the continued pressure thus put upon it, becomes atrophied, while +its hinder half is, as it were, squeezed into taking up a position +more posterior and higher in the digit than normally it should. The +horn-secreting papillae covering its inferior face thus become directed +backwards sooner than downwards, in which way we account in some measure +for the noticeable increase of horn at the heels. + +_Treatment_.--Chronic laminitis is incurable. Treatment must therefore be +directed towards the palliation of such conditions as are present, with +the object of rendering the the animal better able to perform work. When +perforation of the sole has occurred, with the attendant formation of pus +and necrosis of the os pedis, it is doubtful whether treatment of any kind +is advisable. There are on record cases of this description, where careful +curetting of the exposed and necrotic portions and the after application of +antiseptic dressings, held in position by a plate shoe or a leather sole, +has been followed by good results, and the animal restored for a time to +labour. In our opinion, however, early slaughter is the most economical +course to adopt, and certainly the wisest advice to give to the ordinary +client. + +When perforation of the sole is absent, and when serious alteration in the +shape of the horny box has not occurred, then the most simple treatment is +to put the animal straight away to slow work, with the feet protected by +suitable shoes. + +Here, again, the most useful shoe is the Rocker Bar (Fig. 119). The broad +web and deep seating gives ample protection to the convex sole, and with +the ease in distributing his weight that this shoe affords the animal is +able to perform slow work on soft lands with some degree of comfort. + +Should the growth of the horn at the toe and at the heels be unduly +excessive, then our attention may be directed towards reducing it to some +approach to the normal. This is accomplished by removing with the rasp and +the knife those portions indicated by the dotted lines in Fig. 127. Here it +will be seen that the bulk of the horn removed is that protruding at +the toe. After this the animal should again be suitably shod. In this +connection it should be noted that the fact of the animal walking largely +on the heels tends to a forward displacement of the shoe. This must be +prevented by providing each heel of the shoe with a clip, after the manner +shown in Fig. 128; or, in the case of a bar shoe, supplying it with a clip +at the centre of the bar. + +[Illustration: FIG. 126.--DIAGRAM ILLUSTRATING THE ABNORMAL GROWTH OF HORN +AT THE TOE AND HEELS OF THE FOOT WITH CHRONIC LAMINITIS.] + +[Illustration: FIG. 127.--THE SAME FOOT AS IN FIG. 126. The dotted lines +show the excess of horn removed preparatory to shoeing.] + +Among other treatments to be noted we may mention one or two to be found +chiefly in Continental works on this subject. + +The method of Gross consists in thinning down with a rasp about 1-1/2 +inches of the horn of the wall immediately below the coronet, the thinned +portion extending from heel to heel. The groove made is filled with +basilicon ointment,[A] and the coronet stimulated with a cantharides +ointment, In this way there is induced to grow from the coronet a new wall +of nearly normal dimensions. + +[Footnote A: Basilicon ointment is made by heating together resin 8 parts, +beeswax 8 parts, olive oil 8 parts, and lard 6 parts. Allow to cool without +stirring.] + +By other operators (Bayer, Imminger, Meyer, and Gunther) this treatment +has been modified by enlarging upon it and removing the whole of the +adventitious horn. + +[Illustration: FIG. 128.--THE SHOE WITH HEEL-CLIP.] + +This is done by means of the drawing-knife and the rasp, the ugly-looking +pumiced foot being carefully cut and trimmed until, so far as outward +appearances are concerned, it is perfectly normal. This done, the whole +foot is treated with a suitable hoof ointment, and a shoe applied that +affords protection to the sole without imposing pressure upon it. The +shoe indicated is either an ordinary shoe with an unusually broad and +well-seated web, or the seated Rocker Bar of Broad. With either it is well +to additionally protect the sole by means of a leather or rubber pad and +tar stopping, or by using the Huflederkitt described on p. 148. In every +case the nails must be kept well back in order to avoid the weakened and +degenerated horn at the toe, and to take advantage of the greater growth of +horn at the heels. + +The wisdom of thus removing the whole of the adventitious horn may be +questioned. Although a foot of a nearly normal shape is obtained, it must +be remembered that the grave alterations within it are unchanged, and +that in certain positions the operation must have carried us nearer the +sensitive structures than is advisable. + +All other treatments failing, the operation of neurectomy has been advised. +This we do not think wise. One would imagine that, with degenerative +processes already going on in the foot, the tendency to gelatinous +degeneration, always to be looked for in neurectomy, would be increased. +This, as a matter of fact, is the case, and is borne out by the statements +of those who have tried this method of treatment. In many cases the +lameness even is not got rid of. Even where it is, the operation is +afterwards followed by a great tendency to stumble, by sloughing of the +hoof, or by a marked increase in the adventitious horn, and a consequent +greater deformity of the foot. + +Sooner than risk neurectomy, it seems to us wiser to give a trial to the +operation advocated by M.G. Joly, namely, that of ligaturing one of the +digital arteries on each affected foot. This operation is performed in the +same position as is the higher operation of plantar neurectomy, and may be +either internal or external. The vessel is exposed, and a double ligature, +preferably of silk, placed on it. The artery is then divided between +the two ligatures. The immediate effect of the operation is to cause +a considerable diminution in the arterial pressure, and so lessen the +intensity of the ostitis in the os pedis. Its consequences are not so +serious as those of neurectomy, and it decongests tissues which neurectomy +congests. + +In cases related by M. Joly this operation, practised both in conjunction +with removal of the excess of horn and without it, has resulted in a marked +improvement in the gait, the animal going to work one month after the +treatment, and remaining sound for some time afterwards. + +2. SEEDY-TOE. + +_Definition_.--A defect in the horn of the wall, usually at the toe, but +occurring elsewhere, resulting in loss of its substance in either its +internal or external layers (see Figs. 129, 130, and 131). + +_Causes_.--The most common factor in the causation of this defect is +undoubtedly disease of the sensitive laminae. We have, in fact, just given +an excellent example of the formation of a seedy-toe in the sections of +this chapter devoted to laminitis (see pp. 265 and 286). The cavity here +formed by the outpouring of the inflammatory exudate and the separation of +the sensitive and horny laminae persists. It becomes filled with the +dried remains of the exudate and perverted secretions from the horny and +sensitive laminae (see p. 287). As yet, however, the cavity is closed below, +and its existence only surmised. Later, with successive visits to the +forge, the layer of solar horn forming its floor is cut away, and the +cavity exposed to view. Its mealy-looking contents are removed, and the +case reported by the smith. + +Although occurring in this way with an acute attack of laminitis, it must +be remembered that seedy-toe may arise without previous noticeable cause. +The first intimation the owner has is a report from the forge that +seedy-toe is in existence. To refer to cases so arising a probable cause is +far from easy. At one time it was believed to be due to parasitic infection +of the horn. Others have blamed the pressure of the toe-clip, excessive +hammering of the wall, or pressure from nails too large or driven too +close. Others, again, say that seedy-toe may result from a prick in the +forge, from hot-fitting of the shoe, from standing on a dry and sandy soil, +or from the use of high calkins on the front shoes. In these cases--cases +with an insidious onset--we are inclined to the opinion that the disease +of the horn commences from below, and that the sensitive laminae become +implicated later. Holding this view, one must account for the commencing +disease of the horn by giving, as causes, firstly, those factors (as, +for instance, alternate excessive dampness and dryness) leading to +disintegration of the horn tubules; secondly, the penetrating into and +between the degenerated tubules of parasitic matter from the ground; and, +thirdly, the final breaking up of the horn, and spread of the lesion under +the invasion thus started. + +[Illustration: FIG. 129.--DIAGRAM ILLUSTRATING POSITION OF SEEDY-TOE +(INTERNAL). 1, The horn of the wall; 2, the horn of the sole; 3, the cavity +of the seedy-toe; 4, the os pedis; 5, the keratogenous membrane.] + +_Symptoms_.--Lameness sometimes attends seedy-toe, and sometimes does not. +This is an important point to be carried in mind by the veterinary surgeon +who is accustomed in his practice to have many animals pass through his +hands for examination as to soundness. An animal with advanced seedy-toe--a +condition constituting serious unsoundness--may walk and trot absolutely +sound, and may give no indication, either in the shape of the wall or the +condition of the sole, that anything abnormal is in existence. Later, +however, after the veterinary surgeon has passed him, the purchaser lodges +the complaint that the horse has a bad seedy-toe, which, so he is told, +must have been there for some time. In this case, culpable though he may +appear, there is every excuse for the veterinary surgeon. + +Once the cavity is opened at the toe in the neighbourhood of the white +line, then diagnosis is easy. A blunt piece of wood, the farrier's knife, +or a director may be easily passed into it, sometimes as far up as +the coronary cushion (see Fig. 129). Issuing from the opening is seen +occasionally a little inspissated pus; more often, however, the dry, +mealy-looking detritus to which we have before referred. This form of the +disease we may term 'Internal Seedy-Toe.' for, plainly enough, it has had +its origin in chronic inflammatory changes in the keratogenous membrane. + +[Illustration: FIG. 130.--EXTERNAL SEEDY-TOE COMMENCING AT THE PLANTAR +BORDER OF THE WALL.] + +[Illustration: FIG. 131.--EXTERNAL SEEDY-TOE COMMENCING ON THE ANTERIOR +FACE OF THE WALL.] + +Disease of the horn and loss of its substance may, however, also commence +from without. A report on this condition, under the title of 'External +Seedy-Toe,' is to be found in vol. xxix. of the _Veterinary Journal_, from +which we borrow Figs. 130 and 131. + +In Fig. 130 it will be seen that the disease commences at the plantar +surface of the toe, and extends upwards and inwards. The same condition +may also appear anywhere between the coronet and the ground, gradually +extending into the substance of the wall, as shown in Fig. 131. According +to the writer, Colonel Nunn, the progress of the disease in this latter +case appears to be faster in a downward than in an upward direction. This, +however, is more apparent than real, as the rate of growth of the horn +downwards detracts from the progress of the disease upwards, although it +spreads over the horn at the same rate. + +Before concluding the symptoms, we may again allude to the fact that, +although usually occurring at the toe, the same condition may be met with +in other positions--namely, at either of the quarters. In appearance and in +other respects it is identical with that occurring at the toe. + +When the animal is lame and the existence of seedy-toe is surmised, or when +the cause of the lameness is altogether obscure, a little information may +perhaps be gathered from noting the wear of the shoe. If the animal has +been going lame for any length of time as a result of disease in the +sensitive laminae, then the shoe will be greatly thinned at the heels, and +the toe but little worn. + +_Treatment_.--As with diseased structures elsewhere, the most rational +treatment, when possible, is that of excision. The entire portion of the +wall forming the anterior boundary of the cavity is thinned down with +the rasp and afterwards removed with the knife, wholly exposing the +hypertrophied, but usually soft layer of horn covering the sensitive +structures. These hypertrophied portions are also removed, and every +particle of the dust-like detritus cleaned away. After-treatment consists +in dressing the parts with a good hoof ointment, protecting them, if +necessary, with a pad of tow and a stout bandage. It may be that the +removal of a large portion of the wall may for some time throw the animal +out of work. Acting on Colonel Fred Smith's suggestion, this may be avoided +by having made a thin plate of sheet-iron, slightly larger in circumference +than the portion of horn removed, and shaped to follow the contour of the +foot. This made, it is sunk flush with the wall by hot-fitting it, and kept +in position by several small steel screws fixed into the sound horn, just +as in the treatment for sand-crack (see p. 174). This will serve the +useful purpose of maintaining in position any dressing that may be thought +necessary, of acting as a support to the horn left on each side of the +portion removed, and of keeping the exposed structures free from dirt and +grit. + +Practical points to be remembered in fitting plates of this description +to the feet are: The plate must never quite reach the shoe, or it will +participate in the concussion of progression, and so loosen the screws that +hold it in place. For the same reason, that portion of the sole adjoining +the piece of horn removed must have its bearing on the shoe relieved. The +screws holding the plate should be oiled to prevent rusting, and should +take an oblique direction in order to obtain as great a hold as possible on +the wall. + +When excision is deemed unwise or unnecessary, treatment should be directed +towards maintaining the cavity in a state of asepsis. To this end it +should be thoroughly cleaned of its contents, and afterwards dressed with +medicated tow. The ordinary tar and grease stopping is as suitable as any. +This, together with the tow, is tightly plugged into the opening and kept +in position by a wide-webbed shoe. Instead of the tar stopping and the tow, +there may be used with advantage the artificial hoof-horn of Defay (see p. +152). Before using this the cavity should again be thoroughly cleaned out, +and should in addition be mopped out with ether. The latter injunction is +important, as unless the grease is thus first removed, the composition will +fail to adhere to the horn. With the cavity thus cleaned and prepared, the +artificial horn, melted ready to hand, is poured into it and allowed to +set. + +In every case, no matter what else the treatment, the bearing of the horn +adjacent to the lesion should be removed from the shoe. + +Whether practising the method of plugging the cavity or that of excision of +the wall external to it, attempts to quickly obtain a new growth of horn +from the coronet should be made. To further that, frequent stimulant +applications should be used. Ointment of Biniodide of Mercury 1 in 8, of +Cantharides 1 in 8, or the ordinary Oil of Cantharides, either will serve. + +3. KERAPHYLLOCELE. + +_Definition_.--By this term is indicated an enlargement forming on the +inner surface of the wall. In shape and extent these enlargements vary. +Usually they are rounded and extend from the coronary cushion to the sole, +sometimes only as thick as an ordinary goose-quill, at other times reaching +the size of one's finger. Often they are irregular in formation and +flattened from side to side. + +[Illustration: FIG. 132.--A PORTION OF THE HORN OF THE WALL AT THE TOE +REMOVED IN ORDER TO SHOW A KERAPHYLLOCELE ON ITS INNER SURFACE.] + +_Causes_.--Keraphyllocele is very often a sequel to the changes occurring +at the toe in laminitis. Probably, however, the most common cause is an +injury upon, or a crack through, the wall. It may thus occur from excessive +hammering of the foot, from violent kicking against a wall or the stable +fittings, and from the injury to the coronet known as 'tread.' It may also +occur as a sequel to complicated sand-crack, and to chronic corn. + +That fissures in the wall are undoubtedly a cause has been placed on record +by the late Professor Walley, who noticed the appearance of these horny +growths following upon the operation of grooving the wall.[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iii, +p. 170.] + +This gentleman had a large Clydesdale horse under his care for a bad +sand-crack in front of the near hind-foot, and, as the lameness +was extreme, he adopted his usual method of treatment--viz., rest, +fomentations, poulticing, and the making of the V-shaped section through +the wall, and subsequently the application of an appropriate bar shoe +to the foot, and repeated blisters to the coronet. In a short time the +lameness passed off, and the horse was put to work. A few days later the +animal met with an accident, and was killed. + +On examining a section of the hoof it was found that a vertical horny ridge +corresponding to the external fissure had been formed on the internal +surface of the wall, and that a well-marked cicatrix extended upwards +through the structure of the hoof at the part forming the cutigeral groove; +furthermore, _a similar ingrowth had been taking place in the line of the +oblique incisions made for the relief of the sand-crack_. + +This case has an important bearing on the operation of grooving the wall, +which operation we have several times in this work advocated for the relief +of other diseases. It teaches us that the incisions should not be carried +so completely through the horn as to interfere with and irritate the +sensitive laminae, and so set up the chronic inflammatory condition leading +to hypertrophy of the horn. + +From the position on the os pedis of the indentation made in it by the +keraphyllocele (see Fig. 133) it has been argued that pressure of the +toe-clip is a cause of the new growth. This, we should say, cannot be a +very strong factor in the causation, for, while we admit that the continual +pressure of the clip, and the heavy hammering that sometimes fits it into +position, is likely to set up a chronic inflammatory condition of the +sensitive laminae in that region, we must still point out that the rarity +of keraphyllocele, as compared with the fact that clips are on every shoe, +does not allow of the argument carrying any great weight. + +_Symptoms_.--Except under certain conditions this defect is difficult +of detection. As a rule, lameness is not produced by it. In making that +statement we are led largely by the conclusion arrived at by Professor +Walley. This observer noted the fact that ingrowths of horn such as we are +describing nearly always take place in false quarter, or after a sand-crack +has been repaired, and that they commonly occur after the operation of +grooving the wall in the manner we have just shown. + +Now, we know that quite often under these circumstances the horse goes +perfectly sound. Thus, while we know that in all probability keraphyllocele +is in existence, we have ocular demonstration that the animal is quite +unaffected by it. + +In some cases, however, lameness is present. During the early stages of +the growth's formation it is but slight, increasing as the keraphyllocele +enlarges. Should this be the case, other symptoms present themselves. +The coronet is hot, and tender to the touch, sometimes even perceptibly +swollen, and percussion over the wail is met with flinching on the part +of the animal. In other cases one is led to suspect the condition by +the prominence of the horn of the wall of the toe. This is distinctly +ridge-like from the coronet to the ground, while on either side of it the +quarters appear to have sunk to less than their normal dimensions. We +believe this to be an illusion, as a ridge of any size at the toe readily +gives one the impression of atrophy behind it, without this latter +condition being actually present. + +Should this ridge-like formation and the accompanying symptoms of pain and +lameness occur after repair of a sand-crack, then keraphyllocele may, with +tolerable certainty, be diagnosed. When these outward signs are wanting, +however, and the true nature of our case is a matter of mere conjecture, a +positive diagnosis may still be made at a later stage--that is, when the +abnormal growth of horn reaches the sole. In this case either there is +met with when paring the sole a small portion of horn, circular in form, +distinctly harder than normal, and indenting in a semicircular fashion the +front of the white line at the toe, or solution of continuity between the +tumour and the edge of the sole and the os pedis takes place, and the +lameness resulting from the ingress of dirt and grit thus allowed draws +attention to the case. + +_Pathological Anatomy_.--With the sensitive structures removed from the +hoof by maceration or other means, these growths are at once apparent. They +may occur in any position, but are usually seen at the toe, and they may +extend from the coronary cushion to the sole, or they may occupy only +the lower or the upper half of the wall. In places the tumour (or 'horny +pillar' as the Germans term it) is roughened by offshoots from it, and does +not always exhibit the smooth surface depicted in Fig. 132. Commonly, the +horn composing the new growth is hard and dense. Sometimes, however, it is +soft to the knife, and is then found to be itself fistulous in character, +a distinct cavity running up its centre, from which issues a black and +offensive pus. + +In a few cases the sensitive laminae in the immediate neighbourhood are +found to be enlarged, but in the majority of cases atrophy is the condition +to be observed. Not only are the sensitive structures found to be shrunken +and absorbed, but the atrophy and absorption extends even to the bone +itself (see Fig. 133). This latter is a result of the continued pressure of +the horny growth, in a well-marked case ending in a sharply-defined groove +in the os pedis in which the keraphyllocele rests. The fact that the softer +structures, and even the bone, thus accommodate themselves to the altered +conditions is, no doubt, the reason that lameness in many of these cases is +absent. + +_Treatment_.--It is doubtful whether anything satisfactory can be +recommended. When we have suspected this condition ourselves, it has been +our practice to groove the hoof on either side of the toe, after the manner +illustrated in Fig. 120, and, at the same time, point-firing the coronet +and applying a smart cantharides blister. Certainly, after this operation, +lameness has often disappeared--whether, however, as a result of the +treatment adopted or by reason of the structures within accommodating +themselves to the condition, we would not care to say. + +[Illustration: FIG. 133.--OS PEDIS SHOWING THE GROOVE IN IT CAUSED BY +ATROPHY AND ABSORPTION INDUCED BY PRESSURE OF A KERAPHYLLOCELE.] + +Other writers advocate the removal of that portion of the wall to which the +tumour is attached, after the manner described on p. 182, and illustrated +in Fig. 98. This, however, should be a last resource, and should be adopted +only when weighty reasons, such as excessive and otherwise incurable +lameness, appear to demand it. + +4. KERATOMA. + +In our nomenclature the terms 'Keratoma' and 'Keraphyllocele' are both used +to indicate the condition we have just described. There are some, however, +who reserve the term 'Keratoma' for horny tumours occurring only on the +sole, and for that reason we draw special attention to the word here. +Keratoma may thus be used to describe what we have called keraphyllocele +directly that growth makes its appearance at the sole, and is there able +to be cut with the knife. Similar hard and condensed growths may, however, +make their appearance on the sole in other positions quite removed from the +white line, plainly being secreted by the villous tissue of the sensitive +sole, and having no connection whatever with the sensitive laminae. +They appear as circular patches, varying in size from a shilling to a +two-shilling piece. Compared with the surrounding horn, they stand out +white and glistening, while in structure they are dense and hard, and +offer a certain amount of resistance to the knife. They are of quite minor +importance, and, beyond keeping them well pared down, need no attention. +Keratoma probably offers us the best analogy we have to corn of the human +subject. + +5. THRUSH. + +_Definition_.--A disease of the frog characterized by a discharge from it +of a black and offensive pus, and accompanied by more or less wasting of +the organ. + +_Causes_.--The primary cause of this affection is doubtless the infection +of the horn, and later the sensitive structures, with matter from the +ground. Those factors, therefore, leading to deterioration of the horn, and +so exposing it to infection, may be considered here. Such will be changes +from excessive dampness to dryness, or _vice versa_; work upon hard and +stony roads; prolonged standing in the accumulated wet and filth of +insanitary stables, or long standing upon a bedding which, although dry, is +of unsuitable material. + +In this latter connection may be mentioned the harm resulting from the use +of certain varieties of moss litter. This we find pointed out by J. Roalfe +Cox, F.R.C.V.S.[A] Tenderness in the foot was first noticed, and, on +examination, the horn of the sole and of the frog was found to be +peculiarly softened. It afforded a yielding sensation to the finger, not +unlike that which is imparted by indiarubber, and on cutting the altered +horn it was almost as easily sliced as cheese-rind. The outer surface +being in this way slightly pared off, the deeper substance of the horn was +discoloured by a pinkish stain. The horn of the frog was in many instances +found detaching from the vascular surface, which was very disposed to take +on a diseased action, somewhat allied to canker, and became extremely +difficult to treat. + +[Footnote A: _Veterinary Journal_, vol. xvi., p. 243.] + +Conditions such as these, although not constituting the disease itself, +certainly lay the frog open to infection, especially if afterwards the +animal is called upon to work in the mud of the streets of a large town, or +to stand in a badly drained and damp stable. + +A further cause of thrush is to be found in the condition of the frog, +brought about by contraction of the heels (see p. 118). We have already +seen that one of the most prominent factors in the causation of contraction +is the removal of the frog from the ground by shoeing, with its consequent +diminution in size and deterioration in quality of horn. This leads to +fissures in the horny covering, and favours infection of the sensitive +structures beneath. Thrush is, in fact, nearly always present in the later +stages of contracted foot. + +By some thrush is believed to be but the commencement of canker. With this, +however, we do not hold. We believe both to be due to specific causes as +yet undiscovered, but that the cause of thrush is not the one operating in +canker. In arriving at this conclusion we are guided by clinical evidence. +The two conditions are quite dissimilar, even in appearance, and, while +one is readily amenable to treatment, the other is just as obstinately +resistant. + +_Symptoms_.--The symptoms of thrush are always very evident. Probably the +first thing that draws one's attention to it is the stench of the puriform +discharge. The foot is then picked up and the characteristic putrescent +matter found to be accumulated in the median, and often in the lateral, +lacunae. The organ is wasted and fissured, the horn in the depths of the +lacunae softened and easily detachable, and portions of the sensitive frog +often laid bare. + +With a bad thrush lameness is present, the frog itself is tender to +pressure, and often there is considerable heat and tenderness of the heels +and the coronet immediately above. More especially is this noticeable after +a journey. + +It is, perhaps, more common in the hind-feet than in the fore, and more +often met with in heavy draught animals than in nags. The hind-feet are, of +course, more open to infection by reason of their being constantly called +upon to stand in the animal discharges in the rear of stable standings, +while it is a well-known fact that heavy animals have their stables kept +far less clean, and their feet less assiduously cared for, than do animals +of a lighter type. + +In a nag-horse with thrush of both fore-feet lameness becomes sometimes +very great. The gait when first moved out from the stable is feeling +and suggestive of corns, while progress on a road with loose stones is +sometimes positively dangerous to the driver. + +_Treatment_.--When this condition has arisen, as it often does, from want +of counter-pressure of the frog with the ground, this pressure must be +restored after the manner described when dealing with the treatment of +contracted foot (see p. 125) either by the use of tip or bar shoes, or by +suitable pads and stopping. + +So far as direct treatment of the lesion itself is concerned, the first +step is to carefully trim away all diseased horn and freely open up the +lacunae in which the discharge has accumulated. Good results are then often +arrived at by poulticing, afterwards followed up by suitable antiseptic +dressings. With us a favourite one is the Sol. Hydrarg. Perchlor. of Tuson, +used without dilution. Others use a dry dressing, and dust with Calomel, +with a mixture of Sulphate of Copper, Sulphate of Zinc and Alum, or with +Subacetate of Copper and Tannin. + +With restoration, so far as is possible, of the frog functions, and with +careful dressing, a cure is nearly always obtained. + +6. CANKER. + +_Definition_.--Under this unscientific, yet expressive term, is indicated a +chronic diseased condition of the keratogenous membrane, commencing always +at the frog, and slowly extending to the sole and wall, characterized by a +loss of normal function of the horn secreting cells, and the discharge of a +serous exudate in the place of normal horn. + +_Causes_.--The exact cause of canker has still to be discovered. Therefore, +before expressing an opinion as to what the _probable_ cause may be, we may +state here that such opinion can only be based upon clinical observation. +Such being the case, we are almost duty bound to give the views of older +authors before those of more modern writers. + +From the mass of material ready to hand we may select the following as +serving our purpose. + +The earliest opinion appears to have been that canker, as the name +indicates, was of a cancerous or cancroid nature. This was also believed by +Hurtrel D'Arboval, who looked upon canker as carcinoma of the recticular +structure of the foot. The same theory we find enunciated in the +_Veterinary Journal_ so late as 1890. Although the word 'cancer' or +'carcinoma' is not there used, the author employs the terms 'Papilloma' and +'Epithelioma' with the evident intention of expressing his belief in the +malignant nature of the disease. + +Another early opinion was that the disease was a _spreading ulcer_, +gradually extending and changing the tissues which it invaded. + +A further early theory, and one which if not still believed in, has died a +hard death, is the constitutional theory. This was believed in by nearly +all the older writers, and is mentioned so late as 1872 by the late +Professor Williams. In his 'Principles and Practice of Veterinary Surgery,' +he says: 'Canker is a constitutional disease due to a cachexia or habit +of body, grossness of constitution, and lymphatic temperament.' This, we +believe, is credited to-day by some, and yet, quite 100 years before the +date of the 1872 edition of Williams's work--in 1756, to be exact--we find +a veterinary writer when talking of grease (a disease, by-the-by, very +closely allied to canker) exclaiming against this habit of referring +everything which we do not rightly understand to some ill-humour of the +body. The wisdom his words contain justifies us in giving them mention +here. 'It is a very foolish and absurd Notion,' he says, 'to imagine a +Horse full of Humours when he happens to be troubled with the Grease. But +such Shallow Reasoning will always abound while Peoples' Judgments are +always superficial. Therefore, to convince such unthinking Folks, let them +take a thick Stick and beat a Horse soundly upon his Legs so that they +bruise them in several Places, after which they will swell, I dare say, +and yet be in no danger of Greasing. Now, pray, what were these offending +Humours doing before the Bruises given by the Stick?' + +At the present day it is safe to assert that neither the ulcerative, the +cancerous, nor the constitutional theory is believed in widely, and, among +the mass of contrary opinions as to the cause of this disease, we may find +that even quite early many of the older writers had discarded them. + +Quoting from Zundel, we may say that Dupuy in 1827 considered canker as +a hypertrophy of the fibres of the hoof, admitting at the same time that +these fibres were softened by an altered secretion; while Mercier in 1841 +stated that canker was nothing more than a chronic inflammation of the +reticular tissue of the foot, characterized by diseased secretions of this +apparatus. + +Saving that they make no mention of a likely specific cause, these last two +statements express all that we believe to-day. As early as 1851, however, +the existence of a specific cause was hinted at by Blaine in his +'Veterinary Art.' We find him here describing canker as a _fungoid_ +excrescence, exuding a thin and offensive discharge, which _inoculates_ the +soft parts within its reach, particularly the sensitive frog and sole, and +destroys their connections with the horny covering. + +The use of the word 'fungoid,' and particularly that of 'inoculate,' is +suggestive enough, and is evidence sufficient that either Blaine or his +editor recognised, simply through clinical observation, the working of a +special cause. + +Four years later, Bouley is found holding the opinion that canker was +closely allied to tetter, thus recognising for it a local specific cause. +The same observer also pointed out that the secretion of the keratogenous +membrane instead of being suspended was greatly increased, taking care to +explain, as did Dupuy, that the products of the secretion were perverted +and had lost their normal ability to become transformed into compact horn. + +In 1864 this slowly growing recognition of a specific cause received +further impetus from the statements of Megnier. This observer claimed to +have discovered in the cankerous secretions the existence of a vegetable +parasite (namely, a cryptogam, as in favus), which he termed the +keraphyton, or parasitic plant of the horn. + +Modern research, though failing to substitute anything more definite, has +not confirmed this. The exact and exciting cause of canker is therefore +still an open question, and a matter for research. We may, however, sum the +matter up by briefly discussing the causes, so far as clinical observation +teaches us. This we shall do under two headings--namely, _Predisposing_ and +_Exciting_. + +_Predisposing Causes_.--Starting with the assumption that the disease is +due to local infection, we may relate as predisposing causes anything +having a prejudicial effect upon the horn, disintegrating it, and so laying +the tissues beneath open to attack. The most prominent in this connection +is certainly a continued dampness of the material on which the animal +has to stand. Particularly is this the case when the material is also +excessively foul and dirty, contaminated with the animal discharges, and +presumably swarming with the lower forms of animal and plant life. We +shall therefore find bad cases of canker in stables where the "sets" are +irregular, or where no paving at all is attempted, where the drainage +is defective, and where darkness and want of proper ventilation favours +organismal growth. The fact that with modern drainage and a general +hygienic improvement in stabling, canker has to a large extent died out, +supports this contention. + +Again, as with thrush, anything removing the counter-pressure of the frog +with the ground and throwing that organ out of play, may be looked upon +as a predisposing cause. The atrophy of the frog thus occurring, the +deterioration in the quality of its horn and the fissures in its surface +lay it specially open to infection. That one of the principal factors in +the treatment of canker is a restoration of ground-pressure to the frog and +the sole is sufficient proof of this. + +Further, it is well to note that, although playing no part in the actual +causation, certain constitutional conditions may in some measure predispose +the foot to attack. Clinical observation teaches us that animals of a +lymphatic nature, with thick skins and an abundance of hair, with flat feet +and thick, fleshy frogs, are far more liable to attack than are animals +with reverse points. + +_Exciting Causes_. Those who give this subject careful consideration cannot +fail to arrive at the conclusion that canker is most certainly due to local +infection with a specific poison, and that poison a germicidal one from the +ground. The symptoms arising may be due to the action of a single germ, or +to two or more germs acting in conjunction. As to whether the parasitic +invasion is single or multiple we cannot feel certain, but that it _is_ +parasitic we feel absolutely assured. + +It is simply the light that bacteriological advance has made during the +last two decades that enables us to make the statement with such feelings +of assurance. We arrive at our conclusions by reasoning from analogy. +Here we have a disease always exhibiting the same symptoms, more or less +peculiar to one class of animal, always with a similar characteristic +appearance and smell, always obstinately refractory to treatment, showing +always a tendency to spread to the other feet of the same animal, and often +to the feet of other animals _near enough to become_ infected, and always +cured--when cured it is--by a treatment which may be summed up in two words +as 'rigid antisepsis.' Other diseases, with points in common with this, +have been directly proved to be due to a specific cause. Common regard for +logic compels us to admit the same for canker. + +[Illustration: FIG. 134.--A FOOT, THE SUBJECT OF CANKER, SHOWING +DESTRUCTION OF THE HORNY FROG, AND A FUNGOID-LOOKING HYPERTROPHY OF THE +TISSUES BENEATH.] + +_Symptoms and Pathological Anatomy_.--The symptoms of canker are seldom +noticeable at the commencement of an attack. The disease is slow in its +progress; for some time confines its ravages to the sub-horny tissues +unseen, and is quite unattended with pain. It is not observed, therefore, +until considerable damage has been done, and the disease is far advanced. +What is usually first seen is a peculiar softening and raising of the horn +of the frog. The infective material has set up a chronic inflammation of +the keratogenous membrane, leading to abnormal secretion, and, in place of +the horny cells it should normally secrete, is thrown out an abundance of a +serous fluid. + +This upraised and softened horn once thrown off is not again renewed, and +the whole of the sensitive frog and perhaps a portion of the sensitive sole +is left uncovered. In place of the normal horn, however, is often found a +hypertrophy of the elements of the keratogenous membrane leading to huge +fungoid-looking growths with a papillomatous aspect, damp in appearance and +offensive in smell, and readily bleeding when injured (see Fig. 131). + +The horn immediately surrounding the lesion is loose and non-adherent to +the sensitive structures. This indicates, of course, that the disease has +spread further beneath the horny covering than is at first sight apparent. +Portions of this loose horn removed reveal beneath it a caseous foetid +matter, easily removed by scraping (the perverted secretion of the +keratogenous membrane). When this is carefully scraped away, the sensitive +structures appear to be covered with a thin, smooth membrane, gray in +colour and almost transparent, while beneath it may be seen the red +appearance of normal sensitive structures. + +If the horn surrounding the lesion is not touched with the knife, but +little is seen of the extent of the disease, for that removed by natural +means is often very small in quantity. To all intents and purposes the +disease appears to be confined to the frog. This appearance is misleading, +especially if the disease has been in existence for some time, for it +may have easily spread to the whole of the sole, and even to the greater +portions of the laminae secreting the wall. + +It is, in fact, not until the pressure exerted by the normal horn +is removed by its breaking away that the vascular structures of the +keratogenous membrane begin to swell, and the perverted secretions to +enlarge in size. Once the pressure is removed, however, this quickly +comes about, and the characteristic fungoid growths rapidly make their +appearance. + +This tendency to spread is highly indicative of canker. The serous matter +exuding from the diseased keratogenous membrane appears, in fact, to be +highly infective. Once its flow is commenced, it slowly, but surely, +invades the sensitive structures near it, appearing, as Elaine has put it, +to 'inoculate' them. What is really the case, of course, is not that the +discharge itself is infective, but that it is contaminated with infective +material. + +The fungoid-looking growths to which we have before referred are, in +reality, nothing more than the villi of the sensitive frog and sole greatly +hypertrophied and irregular in shape. At times the hypertrophy is as a huge +and compact enlargement occupying the position of the frog. Sometimes, +however, it occurs as numerous elongated and twisted fibrous bundles, +separated from each other by deep clefts, and the clefts filled with the +offensive cankerous discharge (see Fig. 134). + +[Illustration: FIG. 135.--LOWER ASPECT OF CANKERED FOOT, SHOWING +DESTRUCTION OF WALL.] + +At a very advanced stage canker leads to destruction of much of the horny +sole and frog; or even parts of the wall may become separated from the +tissues beneath, and break away from the foot (see Fig. 135). At other +times the disease brings about a deformity of the whole of the foot. Its +longitudinal and transverse diameters become enormously increased, and the +whole foot apparently flattened from above to below (see Fig. 136). This +indicates that not only has the horny sole been entirely destroyed, but +that the destructive process has also extended to the greater part of the +lower half of the wall, with a consequent hypertrophy of exposed soft +structures, and a sinking of the bony column, similar to that which occurs +in laminitis, but not so pronounced. + +[Illustration: FIG. 136.--FOOT WITH ADVANCED CANKER.] + +A further aspect of the badly-cankered foot is to be found in an apparently +enormous increase in the length of the wall. This we have seen protruding +for quite 5 inches beyond the plane of the sole. It simply indicates that, +in order to keep the animal at work, the smith has at every shoeing spared +the wall, so that the diseased structures might be kept from contact with +the ground. + +As we have said before, pain and other symptoms of distress are quite +absent. Animals affected with canker for a long time maintain their +condition, feed well, and are quite capable of performing work under +ordinary conditions. + +_Differential Diagnosis and Prognosis_.--Perhaps the only disease with +which canker may be confounded is thrush. They should, however, be easily +distinguishable. The discharge from thrush is not so profuse, and is +thicker and darker in colour, while the loosening of the horn is almost +entirely absent. Furthermore, thrush shows no tendency to spread, and, even +when left untreated, may remain confined to the frog for months, and even +years. Canker, on the other hand, is slowly progressive, and soon shows the +characteristic fungoid excresences, which growths are in thrush never seen. +A further point of difference is discovered when treatment is commenced. +Canker is found to be refractory to a point that is absolutely +disheartening, while thrush, with careful attention, is soon got under +hand, and a permanent cure effected. + +The prognosis must be guarded. By many canker has been said to be +incurable. This, however, has been clearly shown to be wrong. When the +animal is young, and treatment may reasonably be judged to be economical, +then a favourable prognosis may be indulged in, provided the veterinary +surgeon intends to put into that treatment a more than ordinary amount of +individual care and attendance. Even then, however, he will have to be very +largely guided by the condition of his case. He should see that it is +not too far advanced, and that a great deformity of the hoof, or actual +exploration, does not indicate disease of the greater part of the wall. + +_Treatment_.--From what has gone before, it will be seen that the +eradication of canker is no easy task, that it is, in fact, a most +difficult matter, and one not to be lightly undertaken. At the risk of +recapitulating what we have said before, we may mention here the two points +which the veterinarian must bear in mind. (1) That there is no actual +disease or alteration in structure of the deep layers of the keratogenous +apparatus. It is only the superficial, or horn-secreting, layer that +concerns us. (2) That the disease of this superficial layer is infection +with a material that may reasonably be presumed to be infective. + +Put thus, treatment of canker would at first sight appear to be easy. One +would imagine that a simple and long-continued soaking of the entire foot +in a strong enough antiseptic would be all that was needed. Clinical +observation, however, shows that this is not so, and for this there must be +reasons. + +The reasons are these: (1) Between us and the diseased layer upon which our +attention must be directed is often a layer of normal horn, effectually +protecting the tissues beneath from any dressing which we might consider +beneficial. (2) Anything applied with the object of destroying septic +material, but strong enough, or caustic enough, to injure the membrane upon +which we are working, only makes the case worse. The superficial layer of +the keratogenous membrane in which we have judged the disease to exist is, +after all, but a delicate structure. When attacked by the application of +too potent a drug its horn-secreting layer is easily destroyed, and thus, +although we may succeed in establishing asepsis, we cannot expect at the +point of injury a growth of horn. In its place we are confronted with large +outgrowths of inflammatory fibrous tissue. (3) Shedding of the diseased +horn and removal of the pressure exerted by the hoof faces us with +hypertrophy of the exposed villi. The difficulty of meeting this with an +adequate and evenly-distributed pressure is well enough known, and we find +in that a further reason that the treatment of canker is superlatively +difficult. (4) The material on which the animal has to stand is a distinct +bar to the maintaining of a strict asepsis. + +When we have said this, it is easy to understand that canker is not to be +successfully met with any so-called specific--that it makes but little +difference what the application may be so long as it is antiseptic, and is +used by a man thoroughly conversant with the difficulties he has to contend +with, and with his mind firmly set upon surmounting them. + +With this point established, we will not devote more of our space to a +consideration of the various dressings that have at different times been +highly advocated in the treatment of the disease. It is interesting, +however, to note that intensely irritating and caustic applications have +been greatly in favour. Nitric acid, sulphuric acid (either alone or its +action reduced by the addition of alcohol, oil, or turpentine), arsenic, +butter of antimony, creasote, chromic acid, carbolic acid, arsenite of +soda, and the actual cautery, have all been used. + +Without dwelling further on that, we may say at once that a correct +treatment consists in (1) the removal of all horn overlying infected +portions of the keratogenous membrane, (2) the application of an antiseptic +not too powerfully caustic in its action, (3) frequent changes of the +dressings in order to insure a maintenance of antisepsis, and (4) the +application of an adequate pressure to the exposed soft structures. Thus +combated, canker is curable. + +The man who, at the expense of much time and trouble, has demonstrated the +truth of these axioms is Mr. Malcolm, of Birmingham. The determination with +which he clung to his point that canker was, with correct treatment, in +every case curable, was some years ago provocative of much discussion in +veterinary circles. That he was successful in proving his contention is +more to our point here. It is his method of treatment, therefore, that we +shall give, and this we shall do by liberal extracts from Mr. Malcolm's own +writings. + +'On the first occasion of operating upon and dressing the cankered foot, +it is usually necessary to cast the horse, and this may have to be done +at intervals for a second or even third time; but in most cases once is +sufficient, subsequent dressing being usually accomplished without much +difficulty, frequently even without the aid of a twitch. After the horse +has been secured, the drawing-knife is first employed; and if the frog +alone is affected, it is unnecessary even to pare the sole, the removal of +all frog horn not intimately adherent to its secreting surface being all +that is required. But if both sole and frog be involved, the whole of the +sound horn should be first thinned until it springs under the thumb, +and then, using a sharp knife, every particle of diseased horn must be +carefully removed from both sole and frog, a process much more easily, and +with far greater certainty, secured by the previous thinning of the horn. + +'The removal of diseased horn should always commence at the most dependent +part of the foot, so that any haemorrhage produced may be below the parts +still to be operated on, a matter of considerable moment for effective +treatment. But with due care there will be little haemorrhage, as, except in +the initial stage, there is no real union between the diseased horn and the +diseased vascular secreting surface. + +'After all apparently diseased horn has been removed by the knife, any +still remaining should be at once destroyed by the actual cautery, by +which it can be identified. All the diseased secreting surface should be +_carefully scraped with a thin hot iron_,[A] fungoid growths excised and +cauterized, and, indeed, every particle of cankered tissue should, if +possible, be eradicated. In securing this more reliance can be placed on +the actual cautery than on any other, whether liquid or solid: it is more +under control in application, more decisive in effect, and its results can +be anticipated with a far greater certainty. Moreover, its aid in diagnosis +is of immense value; applied to the thinned horn or secreting surface it +unmistakably demonstrates the presence or absence of canker. Healthy tissue +chars black; cankered tissue, on the contrary, bubbles up white under the +hot iron, and presents an appearance not unlike roasted cheese. + +'Although this test is certain for horn thinned to the quick, it is not to +be relied upon with thick horn, the outside of which may be practically +healthy and char black, while its underlying surface may be cankered. With +this exception the test is an infallible one, as by it the demarcation +between cankered and healthy tissue can be clearly traced, and as a result +we can with equal confidence radically _remove_[A] all cankered tissue, and +conserve all healthy. As the object of that abominably cruel and barbarous +operation of stripping the sole is the exposure of all canker, and as this +can be done with equal certainty with the aid of the hot iron, there can be +no necessity for performing it. The pain of cauterizing cankered tissue, +which is a necessary operation, is infinitesimal (canker largely destroying +sensation), compared with the pain produced in the totally unnecessary +process of tearing healthy horn from a highly sensitive tissue. + +[Footnote A: The words in italics are alterations in the original article +made by Mr. Malcolm in a private letter to the author (H.C.K.).] + +'Having by means of the knife and cautery removed every known particle of +disease, the next procedure is to pack the surface of the sole and frog +thus exposed with a _mild dressing, such as vaseline; but if the cankered +surface has not been efficiently, scraped, than there is required a more_ +[A] powerful astringent or caustic dressing, which may vary considerably +according to the individual fancy. A great favourite of mine consists of +equal parts of sulphates of copper, iron, and zinc, mixed with strong +carbolic acid, a very little vaseline being added to give the mass +cohesion. The dressing, covered by a pledget of tow, is held in position +by a shoe with an iron or leather sole, and the dressing and tow together +should be of sufficient bulk to produce slight pressure on the sole when +the nails of the shoe are drawn up. This insures contact between the +dressing and the exposed surface, as well as any benefit derivable from +pressure. + +[Footnote A: The words in italics are alterations in the original article +made by Mr. Malcolm in a private letter to the author (H.C.E.).] + +'The dressing of the foot and nailing of the shoe can usually be more +expeditiously performed when the horse is on his feet than when prone. If +only the frog, or the frog and a small part of the sole, be involved, the +horse should be kept at work, but if a large part or the whole of the sole +a few days' rest may be necessary; but as soon as the condition of the foot +will allow, work should be resumed, and it is simply marvellous how sound a +horse will walk while minus the greater part of his sole from canker. + +'On the second day following the shoe should be removed, and the foot +redressed. To effect this it is necessary to recast the horse. Commencing +at the edge of the sound horn, at the most dependent part of the foot, +all new horn, no matter what its condition, must be pared to the quick, +especial care being taken to effectually remove any lingering disease. Want +of success is frequently attributable to neglect of this precaution. +A small particle of canker remains undetected, forms a new centre of +infection, and just when success is anticipated, much to your chagrin you +have to deal with a fresh outbreak of canker, instead of a rapidly-healing +foot. Parenthetically, I may here remark that the amount of more or less +imperfect new horn produced by a cankered surface after an effective but +not too destructive cauterization is almost incredible, and one cannot fail +to be struck with the very active proliferation here compared with the +meagre production of new horn by the healthy surface. + +'After all disease has been excised, carefully clean the foot with waste, +thoroughly protect any raw surface resulting from overcauterization by some +mild agent, such as a saturated calomel ointment, reapply an astringent +dressing over the whole affected surface, and nail on the shoe. This method +of procedure should now be thoroughly carried out daily for a time, and +as it is proceeded with a successful issue soon becomes assured in nearly +every case. Where, in spite of these efforts, the disease still persists, +depend upon it the fault is with the operator, who has failed to eradicate +some centre of infection. Under these circumstances it may be necessary +to recast the patient, repare the foot, and by the aid of eye, knife, +and cautery, endeavour to find the cause, and having found it, which can +invariably be done, remove it. The usual treatment will then speedily +become successful. As the case proceeds dressing every other day will +soon be sufficient, then twice a week, and finally, once a week until +sufficiently cured. + +'During this healing process, and after the complete eradication of canker +it may be again repeated, no agent seems to have a more beneficial effect +than calomel, and for this purpose it is best used as a dry powder. Under +this dressing any remaining spot of canker is readily detected by the wet +condition of the calomel when the shoe is removed the next day. In dealing +with such a spot, a very good plan, after all apparently diseased tissue +has been excised, is to touch the cankered part with solid nitrate of +silver, or a feather dipped in one of the strong mineral acids, and +then reapply calomel over the surface. The result of this treatment is +frequently very gratifying. + +'In successful treatment the shoe must be removed each time--an adjustable +plate will not do, as no man can thoroughly pare and examine a foot with +the shoe on, and imperfect dressings are worse than useless. Indeed, it is +better not to pare or thin the horn at all, than to imperfectly pare, since +canker, if undestroyed, develops far more rapidly under thin horn than +under thick. + +'In conclusion, I would again urge the necessity, at the very first +operation, when the horse is down, of removing _every single particle_ of +the diseased tissue, either by excision or effectual cauterization, but at +the same time taking very great care to guard against the latter being +too destructive. The cautery should be laid aside as soon as the tissue +cauterized ceases to _burn white_. The moment at which the canker has +thus been eradicated without destroying sound tissue is indicated by +the appearance of healthy horn, by the intimate union of that with the +secreting surface, and by the healthy aspect of the exuded blood when +paring has been carried to the quick. + +'Should subjacent healthy structures be destroyed during the process, +that is shown by the production of a raw sore, or of a sore to which a +"sit-fast," coextensive to the injury, is firmly attached. This seriously +retards recovery. The secreting surface having been destroyed, no new horn +can be produced directly from the part, and a new secreting surface and new +horn have now to grow inwards from the surrounding undestroyed tissue, and +that is a slow process. At the same time, on the principle of choosing +the least of two evils, practical experience teaches that it is better to +produce a small sore or a "sit-fast" than to leave a part of the canker +undetected; but, on the other hand, it is better to leave a small part +of canker undetected, which can be recognised and removed at the next +examination, than to cause a large slough. The object of the skilful +surgeon is, naturally, to avoid both extremes; and if trouble be taken to +carry out the procedure described, there need be no fear of the result.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. iv., +p. 24.] + +Treated in this way, the horse with cankered feet may be usually kept at +work during the whole time that treatment is carried out, and a cure is +obtainable in periods varying from six weeks to six or even twelve months. + +The same essentials in treatment--namely, removal of diseased horn, +antiseptic dressings, and pressure--are insisted on by other writers. +Bermbach,[A] in 1888, treats canker as follows: The horse having been cast, +the undermined hoof-horn is removed with the knife, and the hypertrophied +sensitive structures, if necessary, reduced in the same manner. The chief +difficulty in removing the latter is experienced in the lateral lacunae of +the frog, where it is most conveniently scraped away with a spoon or sharp +curette. Professors Hoffmann and Imminger also operate in the same way, +applying an Esmarch's haemostatic bandage, and using the knife and curette +freely.[B] + +[Footnote A: _Ibid_., vol. ii., p. 68.] + +[Footnote B: _Veterinary Journal_, vol. xxxv., p. 433.] + +Haemorrhage is afterwards arrested, and a dressing of perchloride of mercury +(a solution, 1/2 per cent., in equal parts of alcohol and water) applied. +The after-dressings succeeding best are those of _slightly_ caustic and +astringent agents, preferably in the form of a powder, and held in position +by carbol-jute pads and linen bandages applied with a certain amount of +pressure. + +The same author draws attention to the fact that caustic agents such as +nitrate of lead, chloride of zinc, etc., act too powerfully if the bleeding +has been arrested and the wound disinfected. They then form a thick crust, +under which profuse suppuration takes place. The same agents are likewise +contra-indicated when haemorrhage is still present. In this latter case +they combine with the blood to form metallic albuminates, which lie as an +impenetrable layer on the surface of the wound, and so hinder the action of +drugs on the tissue below. + +During his after-treatment, Bermbach advocates removal of the dressings +every second day, all cheesy material to be scraped away with the knife, +and the sublimate lotion to be used again. He also insists on the animal +being kept standing in a _dry stable_,--nothing but a stone pavement kept +clean--and put to regular work in a plate shoe after the first or second +week. Cure of advanced cases is said to be obtainable in from four to six +weeks. + +As illustrative of the value of pressure in the treatment of canker, we may +also draw attention to a treatment advocated by Lieutenant Rose.[A] This +observer holds that adequate pressure is unobtainable by packing the foot, +and, to obtain it, removes the wall from heel to heel, much after the +manner of preparing the foot for the Charlier shoe, so that the _whole_ of +the weight is taken by the sole and the frog. Tar and tow is then lightly +applied, the foot placed in a boot, and the patient turned into a +loose-box. The dressing is repeated at intervals of four or five days until +the animal is cured. + +[Footnote A: _Veterinary Record_, vol. xi., p. 435.] + +Those who have followed this method of treatment have modified it by +actually shoeing the animal Charlier fashion, and keeping him at work, +attention, of course, being at the same time given to a proper antiseptic +dressing. + +_Reported Cases_.--1. (Malcolm's Treatment[A]). The subject was a five-year +old horse belonging to a client of Mr. Giver's, of Tamworth. The case was +an exceptionally bad one, for not only was the whole of the frog and sole +of the near hind-foot cankered, but the disease on the outside quarter +extended to within 1/2 inch of the coronet, and on the inside quarter to +within 2 inches of it. As the owner, a farmer, had not proper convenience +for Mr. Olver to treat the case, the latter asked me, while visiting him, +if I would care to undertake the treatment, saying at the time it would +be a very good test-case, as the disease was so far advanced. I readily +agreed, and, after the necessary arrangements, had the horse removed to +Birmingham on July 2. In this case it was found necessary to cast the +animal and cauterize the foot a second time before a healthy granulating +surface was secured; but after this the progress towards recovery was +uninterrupted, although necessarily slow, on account of the large amount of +new secreting surface which had to be formed. + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. v., +p. 48.] + +The horse was finally discharged, after inspection by Mr. Olver, absolutely +cured and free from canker, on January 7. + +The illustration (Fig. 135, p. 312) is from a photograph, and it gives a +somewhat imperfect representation of the state of the foot two months after +it came under my care. + +2. (Rose's Treatment.[A]) This was a bad case of canker, which had been for +two or three months treated in the ordinary manner, with but little sign +of ultimate success. Commenced in June and carried on until the end of +September, the ordinary treatment consisted in burning down the fungus +growth with the hot iron, and dressing with copper sulphate, zinc sulphate, +and boracic acid. The cauterization was repeated every five days. + +[Footnote A: _Veterinary Record_, vol. xi., p. 435.] + +The treatment of Lieutenant Rose was commenced at about the end of +September, at which date the disease extended from the toe on one side of +the foot right back to the heel, involving the sole, half of the frog, and +the bulb of the heel. One week after treatment the diseased surface was +drier, and granulations were more healthy. At the expiration of a fortnight +the new horn had commenced to grow from the wall, and also from the frog, +right round the diseased surface, the diseased part of the bulb of the heel +being divided from the sole by new horn. + +Three to four weeks later the diseased surface was gradually getting +smaller, while in about six weeks it was quite healed up, the last place to +heal being a strip outside the bar, between it and the wall, and a smaller +spot on the bulb of the heel. These healed up simultaneously, and left the +animal sound. + +3. (Treatment by Pressure, H. Leeney [A]). I was consulted in the early +part of last summer, before the dry weather had begun, as to a farm-horse +with canker in three feet. Her shoes were in the 'disgruntle' condition we +so often find on farms, that, to give her a level bearing until I should +call another day with a farrier to help me to pack the foot up in the +old-fashioned way, I had the remaining shoes pulled off. The case somehow +dropped out of my list, and I neglected to call, until asked one day to see +something else. + +[Footnote A: _Veterinary Records_, vol. xi., p. 447] + +I then found that, under a pressure of work, the animal had been used in +the shafts of a farm-cart on tolerably level ground, and when the dry +weather had already set in. There was a distinct improvement in all the +diseased feet, and as she was badly wanted I contented myself with rasping +off some broken crust, and supplied some caustic dressing for use at night. +Without shoes she worked continuously on the dry and hard meadow-land for +several weeks, and was practically cured in something less than three +months. My astringent or caustic lotion may have had something to do with +the cure of the deep-seated parts, but the bare recital of the case should +be sufficient to show that it is all a question of bearing, or nearly so. + +7. SPECIFIC CORONITIS. + +_Definition_.--In describing this condition under the above heading, we +are following the lead of Mr. Malcolm. We may define it as a chronic +inflammatory condition of the keratogenous membrane, usually confined to +that of the coronary cushion, the ergots and the chestnuts, but sometimes +extending to that of the frog and the sole, characterized by a malsecretion +of the affected membrane similar to that observed in canker. + +_Causes_.--The cause which we have indicated for canker--namely, a local +specific one, is in all probability the one operating here. Apparently +there is a variance of opinion as to whether the condition is actually +canker or not. We think, however, that the character of the secretion of +the affected membranes, the appearance of the growths, the manner in which +they react to the hot iron, the comparative absence of pain, and other +points of similarity, point to the fact that the two conditions are +actually identical. In other words, the cause is precisely the same, and +the only point of difference is the alteration in the point of attack. + +_Symptoms_.--Like canker, the disease is insidious in onset. In precisely +similar manner the horn, and in this case the skin of the coronet, is +underrun. Later there is the partial shedding and fissuring of the +undermined horn and the exuding of the characteristic discharge--in this +case not so watery as that of canker. The caseous material of canker is +also present, as is a disposition to hypertrophy of the exposed sensitive +structures. What horn is left becomes rough and irregularly fissured, and +has been likened by some observers to deeply-wrinkled bark of an old tree. +A peculiar characteristic of this condition is the state of the ergots and +chestnuts. Here the keratogenous membrane participates in the diseased +process, and their horn becomes dry and brittle, and readily splits into +small fibrous bundles very similar to the fibroid growth described in +canker. These excrescences are easily separated from the sensitive +structures beneath, and the exposed surface is seen to be more or less +moist, or even exhibiting a slight oozing of blood. + +Again, as in canker, the deeper layers of the sensitive structures appear +to be normal, the horn-secreting layers being the only ones affected. +According to Malcolm, the disease is in its nature equally as inveterate as +canker, but it is easier to treat, on account of its more exposed position. + +_Treatment_.--This is exactly that as described for canker. + +[Illustration: FIG. 137.--SPECIFIC CORONITIS OF ALL FOUR FEET.] + +[Illustration: FIG. 138.--OFF FORE-FOOT AFFECTED WITH SPECIFIC CORONITIS.] + +_Recorded Case_.--The subject of this case was a young black cart gelding. +The disease is reported as having begun as thrush, and then extended to the +coronet. When I saw him he had been in a similar condition to that depicted +in Fig. 137 for, it was said, two or three months, the driver of the horse +meanwhile endeavouring to effect a cure by some potent drug of his own. The +animal was in good condition, but walked with difficulty owing to the pain. +The coronary bands were swollen to two or three times their natural size, +and this caused the hair immediately above to curl upwards. Just below the +coronary bands there was a line of separation between them and the wall. +They themselves were covered with the cheesy substance typical of canker, +and they bled on friction. Down the wall of the off fore-foot some blood +had trickled, which may be seen in Fig. 138. The frogs of all four feet +bulged backwards, and were badly affected. The soles were covered with +normal horn, but I did not resort to paring to see if they were affected. +One very curious feature about the case was the fact that all the +callosities (ergots and chestnuts) seemed to participate in the morbid +process, and they, too, were covered with a thin layer of soft cheesy horn. +The animal used to bite at his coronets and also the callosities above the +knees and hocks until they bled, which they did quite easily. The owner +would not go to the expense of having him treated, so he was destroyed.[A] + +[Footnote A: Henry Taylor, _Veterinary Record_, vol. xvii., p. 311.] + + + +CHAPTER X + +DISEASES OF THE LATERAL CARTILAGES + + +A. WOUNDS OF THE CARTILAGES. + +To a consideration of this we shall devote but little space. It is +sufficient to say that any wound in the region of the coronet should always +be given the most careful attention. More particularly should this be so +when it is ascertained that the wound has involved one of the lateral +cartilages. Wounds of non-vascular bodies such as these are always slow to +heal, and, by reason of their slowness, invite septic infection. In many +cases, in fact, it happens that they do not heal at all. Instead, the +injured part becomes necrotic, is unable to cast itself off, and remains as +a centre of infection in the depths of the wound, thus constituting what is +known as a quittor. + +Apart from this, it will be remembered that the internal face of the +cartilage is in intimate contact with the pedal articulation, especially +anteriorly. Wounds in this situation are, therefore, likely to penetrate +the joint, giving us as a complication of the injury the conditions of +synovitis and arthritis. + +Immediately a wound is inflicted in this position, attempts should be made +to insure thorough asepsis of the part. When possible, by far the better +way of accomplishing this will be to wholly immerse the foot in a tub of +cold antiseptic solution, and keep it there for an hour three times daily. +During the time the foot is out of the solution the wound should be +protected with a pad of carbolized tow or other suitable dressing, and +wrapped in a linen bandage or clean bag. If unable to use the bath, then +antiseptic solutions of more than moderate strength should be freely +applied to the wound and the adjacent parts, a carbolized or other +antiseptic pad placed over it, and the bandage adjusted as before. Repeated +injuries to the cartilages, even if not attended with an actual wound, +are apt to bring about their ossification and end in the formation of +side-bones. + + +B. QUITTOR. + +_Definition_.--A fistulous wound of the foot, usually opening at the +coronet, and variously complicated according to the structures invaded by +its contained pus. For the reason that quittor is in every-day veterinary +nomenclature _usually_ associated with necrosis or other abnormal condition +of the lateral cartilage, we include its description in this chapter. + +_Classification_.--It has been customary with Continental authors to +classify quittor according to the extent and position of the diseased +process. There were thus distinguished: + +_(a)_ The _Simple_ or _Cutaneous Quittor_, in which had occurred nothing +more than necrosis of a portion of the coronary skin and the structures +immediately underlying it--that is, the superficial portion of the coronary +cushion. + +_(b)_ The _Tendinous Quittor_, in which not only the immediately +subcutaneous tissues were attacked, but also portions of tendon and of +ligament. + +_(c)_ The _Sub-horny Quittor_, in which the diseased process had invaded +the deeper portions of the coronary cushion, and continued a downward +course until the laminal tissue below the upper margin of the wall was +involved, or any other case, no matter what the starting-point, in which +pus existed within the horny box and was discharging itself by a fistulous +opening. + +_(d)_ The _Cartilaginous Quittor_, in which a portion of the lateral +cartilage had become attacked and rendered necrotic. + +We believe that--in this country, at any rate--the word 'quittor' is +usually held to indicate one or other of the two latter conditions, and +probably the last of these; and that the two first are held of small +account, or hardly of sufficient gravity to allow of the word 'quittor' +being applied to them. In fact, by defining quittor as a 'fistula,' or +little pipe, we have ourselves already indirectly restricted the use of the +word to the two latter conditions, for in those varieties known as Simple +or Cutaneous and Tendinous, the wound is generally broad and open, or, +at any rate, superficial, and can scarcely be strictly described as +'fistulous.' In the two latter, however, a true fistula exists. These, +however, have only one essential difference, and that consists simply in +the position of the lesion and the structures it has attacked. In the main +the symptoms will be the same, the disease in each case about equally +serious, and in each the same essentials of treatment will have to be +regarded. + +In our opinion, therefore, a lengthy classification serves no useful end, +and we think matters will be simplified by considering quittor under +two headings only--namely, 'Simple or Cutaneous' and 'Sub-horny,' and +discussing the other varieties as simply complications of either of these +two. + +1. SIMPLE OR CUTANEOUS QUITTOR. + +_Definition_.--This condition is simply a sloughing of a portion of the +skin of the coronet, together with a portion of the immediately underlying +soft structures. + +_Causes_.--This form of quittor has its origin more often than not in +contusions, punctures, or wounds of the region severe enough to cause death +of a small portion of the tissues. In this case the low vitality of the +parts does not allow of the dead portion being removed piecemeal by a +process of phagacytosis, as is usually the case with similar injuries +elsewhere. Instead, the tissues around, aided by a process of suppuration, +cast the offending portion off as a slough. It is the wound remaining after +the slough which we may really regard as a quittor. In this connection may +be considered as causes blows from falling shafts, self-inflicted treads, +or treads from other horses, overreach, etc. On the other hand, simple or +cutaneous quittor may occur without ascertainable cause. In this case we +can only explain its appearance, as we did that of simple coronitis (see p. +231), by attributing it to septic infection through a wound or a blow that +is able to inoculate the skin, yet which is insufficient to cause pain, or +in any other way attract the attendant's notice. Meanwhile, the spot of +infection thus started spreads, and the end result is an abscess in the +coronary region, again accompanied with necrosis and sloughing of more or +less skin and other tissue, which terminates by discharging its contents +and leaving behind a wound which again constitutes a cutaneous quittor. +Thus, as with simple coronitis, anything lowering the vitality of the +parts, and so favouring infection of the skin, may bring about a quittor. +Walking through much water in the winter months, through the dirt and mud +of our streets, through melting ice and snow, or through anything in the +nature of a chemical irritant, may be looked upon as a cause. + +_Symptoms_.--Whether commencing from an ascertainable injury, or beginning +at first unnoticed, cutaneous quittor is characterized sooner or later by +the appearance of an inflammatory swelling, usually confined to the seat of +injury. Heat and tenderness are present, and the animal is lame. + +Later the inflammatory swelling becomes more profuse, the animal is +fevered, and the symptoms of lameness increased. Poulticing is at this +stage perhaps resorted to. By its means the process of suppuration is +aided, and the swelling (at first tense and hard) either becomes gradually +softened, its contents discharged, and a simple abscess cavity left behind, +or the suppuration runs immediately round the necrosed structures, and +casts them off bodily as a slough. This latter condition is always +manifested, where the hair does not hide it, by the colour of the skin. At +first this is only red in colour--the angry red of an inflamed spot. As its +intention to slough away becomes evident, the red gradually gives way to a +gray, or even blue-black appearance, while from around it oozes a slight +discharge of pus, yellow in colour and non-offensive, or blood-stained and +dark in appearance, and foetid to the smell. + +Almost invariably these symptoms are added to by a more or less diffuse and +oedematous swelling of the lower portion of the limb, extending in some +cases to as high as the fetlock or the upper third of the cannon. + +With the casting off of the slough the phenomena of inflammation to a great +extent subside, the pain ceases, and the case under ordinary conditions +commences to mend. + +_Pathological Anatomy_.--In its early stages the condition of simple or +cutaneous quittor is really a condition of acute coronitis (see p. 229), +and consists in an inflammation of the subcutaneous tissue, and the more +superficial portions of the coronary cushion. The tissues implicated are +destroyed outright, become infiltrated with the inflammatory exudate and +escaped blood, and act as a source of irritation to the still living +tissues around. Under the irritation the latter, as we have said before, +cast the necrosed portion away by a process of sloughing. + +Always, however, it is found that the portion to be sloughed off, while +easily separated from the tissues adjacent to its sides, is closely +connected on its lowermost or deeper face with the structures below, and +cannot be torn away without haemorrhage and the causing of acute pain. + +_Prognosis_.--With wounds about the feet our forecast should always be +guarded. Even with this, the most simple form of quittor, no decided +opinion should be given until the progress of the case warrants one in +reasonably assuming that complications are absent. Once this point is +decided, a favourable prognosis may be given. + +_Complications_.--With cutaneous quittor various complications may arise, +according to the extent of the invasion of the septic matter. Necrosis of +tendon, of ligament, or of cartilage, caries of the bone, or a condition of +synovitis and arthritis may be met with. As these complications are equally +common to sub-horny quittor, we shall reserve their description until +dealing with that condition. _Treatment (Preventive)_.--Immediately after +the infliction of an injury in this position, more especially if it is such +as to lead one to judge that necrosis will follow to any large extent, the +patient should be rested. Ill effects may then be probably warded off by +having the foot immersed in a cold antiseptic solution, and afterwards +bound with an antiseptic pad and bandage. + +_Curative_.--When the condition has gone undiscovered until commencing +necrosis and suppuration are plainly discernible, then the wisest course we +can follow is to do all we can to hasten removal of the necrosed portion. + +This is best done by promoting the suppurative process by means of warmth +or stimulant applications. + +To this end hot poultices, or, better still, hot baths, should be resorted +to. Under their influence a greater supply of blood is directed to the +still healthy tissues enabling them to actively continue the inflammatory +processes necessary to the detaching of the portion necrosed, while, at +the same time, the pus organisms, stimulated by the heat, are stirred into +greater activity, and the readier accomplish their purpose of destroying +the adhesion still existing between the necrotic portion and the +surrounding living tissues. + +When prolonged poulticing or bathing cannot be practised, then the swelling +should be stimulated with a sharp cantharides blister, repeated, if the +case demands it, at intervals of a few days. + +Should the swelling show distinct signs of pointing, and an abscess is +plainly the condition to be dealt with, its contents should be liberated by +a free use of the knife. In this connection it is important to insist on +the fact that the opening should be made large enough. One bold incision +from the uppermost limit of the swelling down to the coronary margin of the +wall is usually sufficient. + +Even when pointing is not very evident, and suppuration is plainly more or +less diffuse, benefit may still be derived from the use of the knife. In +this case a deep scarification of the part is indicated. Three, four, or +more vertical incisions are made in the swelling, and from them obtained a +flow of blood mingled with a small quantity of pus from several different +centres. By this means sloughing of the diseased portion is quickly +obtained, and nothing but an ordinary open wound left for treatment. It +should be mentioned, however, that when sloughing can be in any way induced +to take place naturally it is better to allow this to take place. Even when +the necrosed portion is freely movable, and only adherent by its base, it +should not be forcibly removed, but left to the slower but more effectual +action of the tissue reactions. If torn forcibly away, we in all +probability leave in the bottom of the wound remnants of the dead tissue, +which, being small and consequently less productive of inflammatory +phenomena, are not so readily sloughed as the larger portion. These remain +as centres of infection, and prolong the case. + +Once a suitable slough has occurred, the after-treatment is simple. It +consists in dressing the wound with reliable antiseptics, and maintaining +the parts in a healthy condition until Nature completes the cure by +repairing the breach. Solutions of carbolic acid, of perchloride of +mercury, of zinc chloride, or of moderately strong solutions of copper +sulphate, are all of them useful (see also treatment of coronitis on p. +236). + +It is sometimes found that even with careful attention the wound left +by the removal of the slough shows a marked disinclination to heal. The +greater portion of the cavity becomes filled with granulation tissue, and +the epidermis gradually closes round until all is covered except a spot of +perhaps the size of half a crown or a crown piece. Here the regenerative +process stops, and the wound obstinately refuses to effectually close. + +In such cases we have derived excellent results with the actual cautery. +The animal is cast, the foot firmly secured by fastening it upon the cannon +of another limb, and the animal chloroformed. A practical point to be +remembered in this connection is that all necessary fixing of the limb is +easier performed if the chloroform is administered first. With the patient +thus secured we first of all ascertain by means of the probe whether or no +the non-healing of the wound is due to the presence of a fistula. Decided +in the negative, we take an ordinary flat firing-iron, and with it cut away +a portion of the skin immediately around the still open wound, carrying +our incisions deep enough to 'scoop' out a large portion of the new +inflammatory tissue beneath. With the loss of pressure from beneath, +occasioned by the removal of so much of the cicatricial tissue, the +epidermis the more readily closes over the wound. To a large extent also +this new growth of epidermis is helped by the renewal of the inflammatory +phenomena brought into being with the cauterization. + +2. SUB-HORNY QUITTOR. + +_Definition_.--A fistulous wound of the foot in which the lower and blind +end of the fistula is situated below the level of the coronary margin of +the wall. + +_Causes_.--These, again, will be practically the same as those mentioned +in the cause of cutaneous quittor--namely, bruises, punctures, wounds--in +fact, any injury upon the coronet severe enough to cause death of tissue +and a suppurating wound. We may thus expect sub-horny quittor to follow +upon treads, overreach, accidental injuries with the stable-fork, and kicks +from other animals. + +Sub-horny quittor may also arise without original injury at all to the +coronet. Either from a violent blow upon the hoof, or from the animal +himself kicking violently against a wall, death of a portion of the +sensitive structures takes place within the hoof, suppuration ensues, and +the formation of quittor commences. With the escape of the pus at the +coronet the quittor is fully formed. + +Any other diseased condition of the foot in which suppuration is present +may in like manner terminate in quittor. In complicated sand-crack, +suppurating corn, or in ordinary pricked foot quittor may be a sequel. In +these conditions the pus formation either goes unnoticed or is neglected, +and after seriously invading the sensitive structures within the hoof, +breaks out at the coronet. Again, too, as with the simpler form of quittor, +and as with coronitis, we may always regard as a predisposing cause the +action of excessive cold in promoting septic infection of the wound when +occurring at the coronet. + +_Symptoms and Diagnosis_.--Where the fistulous wound has had its +starting-point in an injury to the coronet diagnosis is, of course, easy. +The history of the case explains it. Nothing in this instance remains but +to probe the opening, and ascertain its direction, depth, and extent. + +An animal with the wound thus open at the coronet, and freely discharging +its contents, may, if no serious complications exist, walk tolerably sound. +It is only when put to the trot that symptoms of lameness are apparent. + +It may so happen, however, that we first see the case when the symptoms are +wholly those arising from a painful suppuration within the horny box. +This occurs when the original injury has taken place at a more dependent +position than the coronet. Either from violent blows upon the hoof, +puncture from below, from corn or from sand-crack, or any other causes we +have enumerated, suppuration is occurring deeply within the hoof, with as +yet no opening upon the coronet. + +Even when an opening has already occurred on the coronet, the same +condition of sub-horny suppuration may be met with in cases when the +opening of the fistula has by some means or other become occluded. +Granulation tissue, for instance, may have temporarily closed the mouth of +the fistula. The pus, instead of continuing its discharge thereat, is made +to burrow in other directions. + +In either of these cases pain is excessive, the animal walks on three legs, +the foot is painful to percussion, and grave constitutional disturbance +is noticeable. The presence of pus is immediately suspected, and, in the +absence of any indication of an opening having existed at the coronet, +searched for at the sole. It may or may not be found. If found it is given +exit, and the case ends as one of ordinary pricked foot, of suppurating +corn, or some other condition equally simple when compared with quittor. +In those cases where the pus is not discovered at the sole, one adopts the +expectant treatment of poulticing. This, if pus is present, is followed +by a painful swelling of the coronet. At one point there forms a hot and +tender enlargement, with the hairs on it standing straight up from the +skin, which latter is seen below red and inflamed in appearance. + +Later, the abscess--for abscess it is--discharges its contents, the opening +is explored, and we find that in extent it is not confined to the coronary +region, but that it is deep enough to constitute a true sub-horny quittor. + +This discharge of the abscess contents may take place at a well-defined +spot on the coronet, or it may ooze out at the junction of the wall +with the skin. In appearance the discharged pus varies. When the softer +structures only are attacked it is thick, and yellow or white in colour; +when bone is involved it is ichorous; and when attacking the horn itself +black or gray. It may or may not be extremely foetid, and often it is +mingled with blood. + +When evidence of a previous opening upon the coronet is plain, then it is +not considered wise to attempt a paring of the sole. Instead, poulticing +is at once resorted to, to induce the discharge of the pus through its +original channel. Once this has occurred a fistulous wound remains, which +is open for treatment upon one or other of the lines we shall afterwards +indicate. + +COMPLICATIONS--_(a) Necrosis of the Lateral Cartilage_.--This is the +so-called 'cartilaginous quittor' of other writers. In all probability it +is the condition generally understood when the word 'quittor' is used by +one practitioner to the other. Its tendency to keep the disease existing in +a chronic form renders it of grave importance, and for that reason we give +it first mention among the complications. + +It may occur as a sequel either of cutaneous or of sub-horny quittor, and +may result either from actual wounding and infection of the cartilage, or +from an attack on it of septic matter originating elsewhere. + +Unless there has been discovered a fistula, which on probing is seen to +lead direct to the position in which we know the cartilage to be, we +know of no precise means by which the existence of this condition may be +diagnosed. When free from other complications, the horse with his foot in +this state may travel fairly sound. This is so when the necrosis is situate +in the posterior half of the cartilage, in which case the irritation set up +by the disease is confined to the comparatively non-sensitive tissues of +the cartilage itself and the fibrous mass of the plantar cushion. When +attacking the anterior half of the cartilage, the close contiguity of the +joint renders the disease of a more serious nature. It is then that we have +acute pain, and with it extreme lameness, for in this position it is more +than likely that we have involved either the synovial membrane of the +articulation or the tops of the sensitive laminae. It will be remembered +that here the synovial membrane protrudes as a small sac between the +antero- and postero-lateral ligaments of the joint. More or less easily +then it is bound to come into intimate contact with the septic matter +attending the necrosis of the cartilage, and so share in the inflammatory +processes, afterwards communicating them to the interior of the +articulation. + +With necrosis of the lateral cartilage is always swelling and thickening of +the skin and subcutaneous structures of the coronet. This is the greater +the longer the disease has been in existence. Upon the swelling is seen the +mouth of the fistula, or it may be the mouths of several, and from them all +a discharge of pus. + +The mouth of each fistula is generally filled with a mulberry-like +granulation tissue, standing above the level of the skin, and bleeding +easily if touched. The exuding pus is thin and pale gray in appearance, +gritty to the touch, and generally free from pronounced smell. At other +times its colour is reddened with contained blood, and floating in it are +tiny particles of a pale-green substance, which when picked up and rubbed +between the fingers are seen to be small fragments of the diseased +cartilage. + +Should the mouth of a fistula become occluded with the granulations filling +it, and the discharge prevented from escaping, it soon happens that we have +close to the fistula that has closed a tender fluctuating swelling. This +points and breaks, and pus is again discharged from another opening. In +this manner is accounted for the multiplicity of scars and fistulas seen on +the swelling of an old-standing quittor. + +The continued, inflammation thus kept in existence has the effect of +rendering the skin and subcutaneous tissues in the neighbourhood greatly +thickened and indurated. This in time leads to a tumour-like enlargement, +and causes the structures of the coronet to greatly overhang the hoof. At +the same time the constant inflammation has made its stimulant effects +noted in a great increase in the growth of the horn of the wall. + +Although more abundant, however, the quality of the horn is deteriorated. +The perioplic ring has become obliterated, and the varnish-like appearance +of the healthy wall destroyed. Cracks and fissures in its surface are +numerous, and sometimes deep enough to lead to exposure of the sensitive +structures beneath, complicating the quittor with a sand-crack of a +peculiarly objectionable type. + +_Pathological Anatomy of the Diseased Cartilage_.--The bulk of observers +appear to agree in the statement that in quittor the necrotic cartilage is +pea-green in colour, and recognise it by that characteristic. In size the +necrotic portion thus recognisable varies from the tiniest speck to a +portion the size of a horse-bean. Commonly, however, it is about as large +only as a pea. It is seen to be more or less detached from the rest of +the cartilage, to which it is adherent by one of its extremities only. In +general appearance we can best liken it to the split half of a green pea, +whilst others have compared it with the green sprouting of a seed. The +portions of cartilage nearest the necrotic piece are also slightly green in +colour, thus indicating that here also the diseased process has commenced. +This peculiar change of colour in the affected cartilage is of great +importance to the surgeon. It enables him when operating to distinguish +with some degree of certainty those portions of the cartilage which are +healthy and those which are not. + +_(b) Necrosis of Tendon and of Ligament_.--This complication of quittor +is, as we have said before, treated by other writers as a distinct form of +the disease, and described by them under the heading of Tendinous Quittor. + +This simply means, of course, that the diseased process has extended to +either of the flexor tendons, to the tendon of the extensor pedis, or, +perhaps, to the ligaments of the pedal articulation. + +Of the flexor tendons, the perforans is the one commonly attacked, by +reason, of course, of its more superficial position. At times, however, +especially when its aponeurotic expansion is diseased, the necrosis of the +perforans spreads until the aponeurosis is eaten through and the phalangeal +sheath penetrated. Septic materials gain entrance thereto, and commence to +multiply. In this way the flexor perforatus is invaded, and comes to share +in the diseased process. + +The extensor pedis is usually attacked by extension of the disease from a +necrotic cartilage, or results from the infliction of a severe tread in a +hind-foot. In this case the diseased structure has nothing between it and +the articulation, the synovial membrane in one position actually lining its +inner face. The result is that a condition of synovitis is easily set up, +and the case aggravated by that and by arthritis. + +With the flexor tendons attacked pain is always very great, and lameness is +excessive. This, however, is not sufficiently characteristic to enable us +to determine the precise seat of the necrotic changes. Later, however, a +tender but hard enlargement made its appearance in the hollow of the heel, +which enlargement, later still, became soft and fluctuating. At this stage +there is also considerable swelling along the whole course of the tendons, +as high up as the knee or the hock. The foot is carried forward with all +the phalangeal articulations flexed, and in many cases the limb is unable +to take weight at all. Manipulated after the manner of examining the +tendons for sprain, this swelling is found to be extremely painful. The +animal flinches from the hand, and shows every sign of acute suffering. +This condition may, in fact, be mistaken for sprain, and is only to be +distinguished from it by carefully noting the history of the case--first, +the appearance of the swelling in the hollow of the heel, and, secondly, +the _after_-swelling of the upper portions of the tendons. + +The formation of the abscess, the after-discharge of its contents, and the +final establishing of a fistula, are processes greatly prolonged in this +form of quittor. It will readily be understood why this should be so when +one remembers the depth at which the suppurative process is going on, the +thickness of the metacarpo-phalangeal sheath, and the resistant nature of +the material of which this latter is made, and which must be penetrated +before the condition becomes observable. + +After the opening of the abscess, which usually takes place in the hollow +of the heel, there is left the fistulous wound which obstinately refuses to +heal. Or it may be, again, that there are several of these fistulas, each +opening in the heel, and the mouth of each marked by a small, ulcer-like +projection. The discharge continually oozing from these keeps the heel +constantly wet with a thick purulent discharge, which is nearly always +blood-stained, and very often foetid. + +This constitutes what is known as tendinous quittor in its worst form, +for more often than not there is associated with it inflammation of +the navicular bursa, caries of the bones, or arthritis of the pedal +articulation. + +With the extensor pedis attacked matters are not quite so grave, in spite +of the fact that the articulation is closely situated thereto, for in this +case the more superficial position of the diseased structure allows both +of readier exit of the discharges and of easier removal of the necrosed +portion and after-treatment of the wound. + +_(c) Caries of the Bones_.--Portions of the os pedis, more especially of +its wings, and therefore usually occurring in conjunction with necrosed +cartilage, become carious in quittor. In many cases it is impossible to say +with certainty when this has occurred. In a few instances, however, the +exuding discharge gives evidence of what has happened. It is thin, but +extremely offensive, with the characteristic odour of decayed bone or +tooth, and with a feel that is gritty with contained particles of broken-up +bone. If, with a discharge of this nature present, the probe also conveys +to the fingers the sensation that bone is reached, then diagnosis may be +sure. + +_(d) Ossification of the Cartilage_.--This may take place in part or in +whole. It, of course, constitutes Side-bone, a fuller description of which +will be found in a later portion of this chapter. + +_(e) Penetration of the Articulation_.--This may occur either as a result +of the suppurative changes or as an accident in excision of the diseased +cartilage. Unless it is followed by a severe purulent arthritis, it is not +so grave a complication as at first sight it would appear. + +_(f) Synovitis and Arthritis (Purulent)_.--Should this complication arise, +the case is a most serious one. Beyond here mentioning the fact that it may +occur, we shall not dwell on it. Fuller consideration is given to it in +Chapter XII. + +_Treatment_.--The various treatments adopted for the cure of sub-horny +quittor offer the veterinary surgeon a large number to select from. We +will describe them in the order in which they are, perhaps, most commonly +practised. + +_Poultices and Hot Baths_.--As in cutaneous quittor, and as in coronitis, +when the pus formation is only suspected, and has not yet broken out at the +coronet or elsewhere, then the first indication in treatment is the use +of warm poultices or of hot baths. Their application is in most cases +productive of pointing at the coronet. + +Directly this appears it is a wise plan to thin the wall down with the rasp +immediately below the swelling. To some extent it relieves the pressure of +the inflammatory products within, and at the same time paves the way for +operative measures which may be necessary later on. + +With the breaking of the abscess and the discharging of its contents, we +may in some measure ascertain the condition we have to deal with. The probe +is used, and the abscess cavity explored. The size of the wound, its depth +below the upper margin of the wall, the structures involved, and other +information, may be thus obtained. + +At first, however, the nature of the wound, and the character of the +discharges, must largely guide us as to the treatment we adopt. In many +cases, even where the abscess cavity is far below the upper margin of the +wall, and is presumably in an unfit position to drain and heal, a a regular +application of an astringent and antiseptic dressing is sufficient to bring +about resolution. If, however, the discharge from the wound continues to be +liquid, and the wound itself at one spot refuses to heal, it may be judged +that a portion of necrotic tissue is situated under the wall, and affecting +the laminae, the cartilage, or ligament, as the case may be. If this is so, +then operative measures must be determined on (see Removal of the Wall, p. +349). + +_Blisters_.--Instead of the poultice and hot baths, the pointing of the +abscess and the casting off of the slough may be brought about by the +application of a sharp cantharides blister. We have, in fact, seen many +cases where this treatment was adopted prior to the formation of a fistula, +and also in cases where one or more fistulous openings already existed, +where repeated blisters to the coronet have alone been sufficient to effect +a cure. + +We are bound to admit, however, that the treatments of poulticing and +blistering are only expectant--we might almost say empirical. At any rate, +we admit to ourselves that what we have advised and carried out is not in +itself curative, but only a means of assisting Nature to satisfactorily +work her own ends. Empirical or not, however, we believe that in every +case of quittor it is wise in practice to at first adopt some such simple +measure, for in nearly every instance where operative measures are +practised, the patient must be laid aside for at least several weeks, +whereas in this way he may be kept at work and a cure effected at the same +time. + +_The Actual Cautery_.--Largely of the same empirical nature, yet doing +something a little more calculated to destroy necrotic tissue and bring +about its sloughing is the use of the cautery, both actual and potential. + +The actual cautery may be beneficially employed for the relief of sub-horny +quittor in at least two ways. + +In the first place, it is often used--a blunt 'point-firing' iron being the +instrument--instead of the knife as a means of evacuating the contents of +the coronary abscess. Those who use it for this purpose are able to say +this in its favour: it brings about the opening of the abscess without the +unsightly haemorrhage attending the use of the knife, and at the same time +just as effectually empties it. The opening made is not nearly so likely +to close prematurely--that is, before a proper course of treatment of the +wound has been carried out--and so leave necrotic tissue at its bottom. The +intense tissue reaction it sets up is productive of a large slough, cast +off by highly active inflammatory phenomena, which means that the remaining +wound is one in which no dead tissue is left, and which is more amenable to +treatment. + +We have also seen the actual cautery used in sub-horny quittor, where that +disease has reached a chronic fistulous stage, as a means of cauterizing +the whole length of the lining of each fistulous passage. + +At the present day this method is regarded as barbarous, and savouring +too largely of the methods and practice of the old empirics. There is no +denying the fact, however, that it is at times followed by a speedy and +complete cure of what has for months been an intractable and apparently +incurable quittor; and, honestly speaking, we ourselves can see nothing +very greatly against the operation in certain cases save its appearance. In +that it is certainly rough, and is not calculated to favourably impress the +more critical of our clientele. With the animal chloroformed, however, much +of what can really be urged against it disappears, and on farms and other +places where a skilled and competent dressing of an operation wound cannot +be looked for, it is sometimes wise to advise this method of treatment in +preference to more advanced methods of operating. So far as we can judge, +the after-effects are very little worse than those following other +operative measures, more especially when a suitable case has been chosen. + +This method of treatment is particularly applicable to cases of chronic +sub-horny quittor in the more posterior parts of the foot. Here, if one or +more fistulas exist, their openings are probed and the direction of the +sinuses determined. In all probability they are burrowing down along-side +the wall to the sole, where, for want of outlet, they are invading the +substance of the plantar cushion or the plantar aponeurosis. + +Should this preliminary probing demonstrate that neither of the fistulas +run dangerously near the joint, then the operation may be decided on. + +The animal is cast and chloroformed, the foot firmly fixed, and the horn of +the quarter rasped away quite thin. The sole of the same side is also pared +with the knife until the horn of both the quarter and the sole yields +easily to pressure of the thumb. All that is then needed is three or four +long, round, and pointed irons (about 1/4 to 3/8 inch in diameter) heated +to redness. These are inserted into the fistulas, and the false mucous coat +of these passages thus destroyed. When the iron, on being directed into the +fistulous opening at the coronet, is found to travel alongside the wall, +and to easily reach the sole, it should be made to go further still. The +sole is penetrated, and a dependent opening thus made for the escape of the +discharge that afterwards accumulates. + +What happens now, of course, is that an intense and acute inflammation +is set up along the whole track of the fistula, in which position the +inflammatory changes were heretofore chronic. The whole lining of the +fistula, and with it, we hope, all necrotic tissue, is cast as a slough, +leaving nothing but healthy tissue behind. This, with a suitable dressing, +heals and gives no further trouble. + +The after-treatment consists in the application of hot poultices. These +tend to greatly ease the pain, and at the same time to facilitate the +removal of the slough. The poulticing should be continued, therefore, until +the sloughing comes about, which happens, as a rule, at about the fifth or +seventh day. + +Immediately the slough is cast off, the poultices may be discontinued and +dressing of the wound carried out. This consists of injections of solutions +of zinc chloride 1 in 200, perchloride of mercury 1 in 1,000, carbolic acid +1 in 20, of Villate's solution, or of such other antiseptic as the surgeon +may think fit. The dependent orifice at the sole should be kept open for as +long as possible, being occasionally trimmed round with the drawing-knife, +and scooped out with a sharp-edged director. + +Directly a healthy and pink-looking granulation is observed along the +track of the iron, and the discharge therefrom takes on a thick and yellow +appearance, the strength of the antiseptic solutions should be gradually +diminished. This point, in fact, is of great importance in treating all +wounds of the foot. There is a great temptation, on account of the known +excessive liability of the parts to septic infection, to use an antiseptic +solution unduly strong. What must be remembered is that used _too_ strong +they themselves give rise to dead tissue, or to impermeable layers +consisting of compounds of the discharges with themselves, and so create +substances that prove a source of irritation and subsequent trouble. + +_The Potential Cautery_.--This is employed in the treatment of sub-horny +quittor, either in the solid form (in sticks, in lumps, or in the powder), +or in the liquid form, when it is injected with a quittor syringe. + +In the former method such drugs as perchloride of mercury in the lump, or +nitrate of silver, chloride of zinc, and caustic potash or soda in the +stick, are introduced into each of the sinuses present. This is done by +means of a director or a probe. + +A better method, however, when the dressing lends itself to the purpose, is +to use it in the form of a powder, wrapped in the form of small cubes +in extremely thin paper, such, for instance, as is used for rolling +cigarettes. It is then conveniently inserted into each fistula. Introduced +in this more finely divided form the drug is, perhaps, a little more active +in bringing about the desired result. + +This method of 'plugging,' although practised by many, we cannot recommend +in preference to the use of the hot iron or of liquid injections. Our +reasons are these: the action of the drug is a protracted one. Almost +immediately after its introduction into the fistula there is formed about +it an almost impermeable layer of a metallic albuminate, which effectively +prevents further rapid action of the caustic. In addition to thus +preventing further action of the dressing, this combination of the tissue +albumin with the metal of the salt, together with much necrotic tissue that +it has caused, is extremely hard to remove from the healthy tissues. This +we explain by pointing out that the action of the caustic, prolonged as +it is, sets up a tissue reaction which partakes largely of the type of a +chronic rather than an acute inflammation. With a chronic inflammation +there is sooner a tendency to the production of fibrous tissue (and thus +the firmer attachment of the necrosed portions) rather than an active +phagocytosis and the casting-off of a slough. Again, careful though we may +be with the probe, it is extremely difficult to be certain that we have +discovered the whole extent of any fistula. An equal difficulty, therefore, +exists in being certain that we have placed the caustic in the position +in which it is most wanted--namely, at the furthermost end of the fistula +where the necrotic tissue is to be found. + +When a caustic is used at all, it is far better to employ it in the liquid +form, when either of the drugs we have just mentioned may again be used. In +the first place, the liquid is far more likely to be brought into contact +with the diseased structures than is the solid salt. Also, its action may +be regulated by altering the strength of the solution, and the liability to +form impermeable albuminates thus diminished. + +Probably the best solution for use in this way is the old-fashioned +Villate's solution (see p. 199). + +This liquid should be injected at least every day, and, in a bad case, +even two or three times daily. Practical hints to be borne in mind when +attempting to cure quittor by means of injections are these: + +If the fistulas are numerous, the fluid should be injected into their +various orifices. + +In order to force the fluid to the bottom of each diseased track, it is +necessary, when injecting one opening, to firmly close all others. + +Several injections should be made at each time of injection. In other +words, we must not be content with just forcing fluid in. It must be forced +in, and again forced out by a further syringeful. The fistulous tracks +must, in fact, be washed in the liquid. + +The effect of the injection during the first eight or ten days is to render +suppuration more abundant and whiter. After two weeks of the treatment +sloughing of the inside of the sinuses occurs, and healing of the wound +commences. Signs that this is occurring are--slight haemorrhage at the end +of each injection, and a gradually increasing difficulty in forcing in the +fluid. + +_The Making of Counter-openings to the Fistulas_.--Although Villate's +solution or any other caustic used in the manner we have described +often effects a cure, many practitioners insist on the fact that a +counter-opening to the fistula must also be made. + +The probe is used and the direction and depth of the fistula ascertained. +Through the wall is then made an opening at exactly opposite the lowest +point found by the probe, or through the sole if the probe should there +lead us. This opening is best made with a sharp-pointed iron, and may +afterwards be kept large enough by an occasional trimming with the knife. +Many of the older authors, and with them writers of the present day, +declare that unless this is done the ordinary injection is likely to fail +in a great many instances where it would otherwise have been successful. + +Where a counter-opening is thus made it is found that it very readily +closes with granulation tissue, and the purpose for which it was made +defeated. This may be avoided by the use of a seton. In preference to the +seton, however, we ourselves would advise that the opening be kept free by +the occasional use of a sharp-edged director or a fine scalpel. + +An interesting modification of the practice of making a counter-opening is +that related by Veterinary-Captain S.M. Smith.[A] In point of severity it +runs a middle course between the making of a simple counter-opening and +the removal of a wedge-shaped portion of the coronary band and the wall, a +method which we shall later describe. + +[Footnote A: _Veterinary Record_, vol ii., p. 157.] + +To perform this operation, the animal is cast and chloroformed. The foot is +fixed and the parts thoroughly cleansed. The horn of the wall is then sawed +through in a direct line from the coronary margin to the solar edge, the +saw-line running exactly over the seat of the sinus. + +A strong scalpel is now introduced at the coronary opening, with its +cutting-edge outwards, and is gradually passed down the opening made by the +saw. In this way the sinus is completely destroyed, and from end to end +converted into an open wound. The parts are then washed in a perchloride of +mercury solution, covered with a mixture of powdered iodoform and boracic +acid, over which a pledget of carbolized tow is placed, and then a bandage +over the whole. This dressing should be left on three or four days, after +which the injury should be treated as an ordinary wound. In conclusion, +the author says: 'I can safely recommend this line of treatment to any +practitioner having an obstinate case under treatment.' + +_Removal of the Wall and Excision of the Necrotic Tissue_.--This we +may term the radical operation for sub-horny quittor, for it is often +productive of a successful issue when all other means have failed. No +matter in what position the sinus is, whether at the extreme anterior +portion of the coronet, or whether in the region of the heels, it is to be +thoroughly opened up. To do this, the fistula is carefully explored with +the probe and a knowledge of its exact dimensions arrived at. This is +carefully noted, and the horn of the wall for some little distance around +it then rasped down quite thin. Immediately over the sinus, and for a short +distance on either side of it, the horn is stripped away to the sensitive +structures. The cavity of the fistula is then opened up with a scalpel, and +every particle of diseased tissue removed with this instrument and a pair +of forceps. After-dressing consists simply in the application of suitable +antiseptics. + +_When the Complication of Necrosed Tendon or Ligament exists_.--We may take +it as an axiom that wherever this exists, whether it is in the extensor +pedis, in the lateral ligaments of the joint, or in portions of the +flexors, all diseased structures should, where possible, be removed. This +is done either with a scalpel or with a curette. + +When septic matter has gained the sheath of the perforans, and the +formation of pus therein is indicated by inflammatory swellings in the +hollow of the heel, it is sometimes advisable to lay the sheath open for 1 +to 2 inches along the course of the tendons. This, if a fistula is present, +may be best done with a blunt-pointed bistoury, or with a cannulated +director and a scalpel. With the pus thus given exit, and an antiseptic +dressing regularly applied, the case sometimes ends in rapid resolution. +More often than not, however, it is found that the pus has been liberated +too late, and that it has gravitated in the sheath to the extent of +affecting the plantar aponeurosis. Or it may be, of course, that it was in +the plantar aponeurosis the disease commenced. Whichever may have been the +case, we have in the hollow of the heel one or more fistulous openings, or +an opening we have made ourselves, leading down to a necrosed portion of +the terminal expansion of the perforans. + +In such cases we ourselves have derived benefit from a regular flushing +of the sinuses with a 1 in 2,000 solution of perchloride of mercury, +introduced by means of a glass syringe, followed later by flushing in the +same manner with a 1 in 40 solution of carbolic acid, the hollow of the +heel meanwhile being kept clean with an antiseptic pad and bandage, or by +liberal applications of an antiseptic powder. + +The septic materials are in this way destroyed, and the wound heals without +further complication. We must admit, however, that the cure of the lesion +is generally at the expense of slight lameness, due, in all probability, +to inflammatory tissue adhesions between the flexor perforans and the +perforatus, and to a partial destruction of the synovial membrane of the +sheath. + +If, in spite of the antiseptic irrigations, the fistula persists, then +nothing remains but to resort to excision of the aponeurosis, as described +on p. 222. + +_When Necrosis of the Lateral Cartilage is present_.--In this case we may +at first try the ordinary treatments of poulticing; and blistering, of +antiseptic caustic injections, and of plugging. In some cases a cure is +effected. Should these fail, however, and we intend to see the finish of +our case, then operative measures must be determined on. This means cutting +down upon the diseased cartilage, and either removing the necrosed portion, +or excising the cartilage in its entirety. + +The latter method is seldom practised in this country. As it is the most +radical of the two, however, we shall describe it here first. + +_Extirpation of the Lateral Cartilage_.--The operation of extirpating the +lateral cartilage is by no means a new one, being introduced, according to +Zundel, by the senior Lafosse in 1754. It consisted in removing a portion +of the wall by grooving and stripping it, and of excising the exposed +cartilage by means of a sage-knife. + +As to what portion of, and how much of the horn of, the quarter should +first be removed, and as to what particular direction each groove should +take, opinion among the older writers varied considerably. This we know +now is not an important matter, and it is sufficient to say that the first +preliminary is a thinning down of the horn of the quarter with the rasp +over the position occupied by the cartilage. At the present time there are +two or three modifications of the operation as originally introduced. +In all, however, the preliminary steps are the same. We shall therefore +describe them collectively, as applying correctly to either of the three +methods of operating we are about to show. + +_Preparation of the Subject and Preliminary Steps in the Operation_.--On +the day previous to the operation the horn of the wall immediately over the +cartilage must be so thinned with a rasp as to yield readily to pressure +of the thumb in any position. It should be so thin as to only just avoid +wounding the sensitive structures below. + +The whole of the foot must then be thoroughly cleansed, and rendered as +nearly aseptic as possible. The use of warm water, soap, and a stiff brush +is the readiest means of removing the surface dirt. Afterwards the foot +should be soaked for some time in a reliable antiseptic solution, a 1 in +1,000 solution of perchloride of mercury being the most suitable. When +removed from the solution the foot must be packed round with wool or +tow impregnated with corrosive sublimate, and then bandaged, the whole +afterwards wrapped in a thick cloth, or protected with a boot. + +On the following day the animal is brought out and cast, and the foot +desired to be operated on firmly secured, after the manner described on p. +81. The bandages and sublimate pads are then removed, and the skin of +the coronet over the seat of operation shaved of hair. An Esmarch rubber +bandage is next run up the limb, and the tourniquet applied, thus rendering +the operation a nearly bloodless one. + +This done, the animal is chloroformed, and an antiseptic douche played over +the foot. + +So far, the steps in the operation are common to all methods. There are +now, however, three slightly differing modes of extirpating the cartilage, +which modes vary simply according to the structures severed by the knife. + +_First Method_.--This is the oldest method of the three, and consists in +making (1) a horizontal incision through the sensitive laminae along the +lower border of the cartilage, and (2) a vertical incision through the skin +of the coronet, the coronary cushion, and a portion of the sensitive laminae +(see Fig. 139). + +The flaps (Fig. 139, _a, a_) are now held back by tenaculae, and the whole +of the cartilage, or only the necrosed portion, carefully excised by means +of right- and left-handed sage-knives. Fistulous openings in either of the +flaps _a, a_ must now be carefully curetted and dressed, and the flaps +allowed to fall into position. They are then sutured with carbolized gut, +and the wound finally dressed as to be described later (p. 357). + +[Illustration: FIG. 139.--EXCISION OF THE LATERAL CARTILAGE (OLD METHOD). +The wall covering the lateral cartilage first thinned and stripped off; the +two flaps (_a, a_) of skin and the coronary cushion made by the vertical +incision turned back. _a_, The operation flaps; _b_, the exposed cartilage; +_c_, the sensitive laminae; _d_, the coronary cushion.] + +_Second Method (after Holler and Frick_[A]).--These operators deem it wise +to leave untouched the skin of the coronet and the coronary cushion. They +therefore make their first incision along the lower border of the coronary +cushion (see Fig. 140), afterwards exposing the lower half of the cartilage +by removing a half-moon-shaped portion of the thinned horn and underlying +sensitive laminae (see Fig. 140, _b_). + +[Footnote A: Two cases of quittor successfully treated by this method are +reported by R. Paine, M.R.C.V.S., in the _Journal of Comparative Pathology +and Therapeutics_, vol. xv., p. 81.] + +[Illustration: FIG. 140.--EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER +AND FRICK.) _a_, The thinned horny wall covering the coronary cushion; _b_, +the lateral cartilage exposed by stripping off the thinned wall; _c_, the +sensitive laminae.] + +This done, the external face of the cartilage is separated from the skin +of the coronet. To do this a double sage-knife is run flatwise between the +coronary cushion and the cartilage, with the convex surface of the blade +towards the skin. The knife is then passed backwards and forwards until the +necessary separation is accomplished. During these movements of the knife +a finger of the unoccupied hand should follow the knife, and guard the +coronary cushion against injury. + +Following this, the inner surface of the cartilage must be also separated +from the structures lying beneath it. To this end a sage-knife (right- or +left-handed, according as to whether the anterior or posterior portion of +the cartilage is to be first removed) is again passed into the incision. +With the cutting-edge of the knife forward, it is gradually reached round +and under the hindermost end of the cartilage, and theposterior half of +the cartilage separated from underlying structures, and at the same time +excised by one clean cut forwards. Using the second sage-knife in a similar +manner, the cutting-edge this time backwards, it is reached in front of the +cartilage, whose anterior half is then excised by a careful cut backwards. +Any small portions of cartilage remaining after this are sought for with +the finger, and carefully removed by means of a scalpel and a tenaculum. + +The fistulous opening or openings in the skin of the coronet should now be +thoroughly curetted, and the whole of the wound dressed as to be described +later. + +In removing the anterior half of the cartilage it is highly important to +remember the close contiguity to it of the synovial membrane of the +pedal articulation. This projects as a small sac between the antero- and +postero-lateral ligaments of the joint. Risks of injury to it may be +diminished by having the foot secured with a line, and pulled forward by an +assistant while the cut is being made. + +_Third Method (after Bayer)_.--This operator recommends that, after +stripping a half-moon-shaped piece of horn from the seat of operation, +instead of raising the skin of the coronet and the attached coronary +cushion in two flaps (as Fig. 139, a, a), that the cartilage be exposed +by raising up one flap only (Fig. 141, a), consisting of a portion of +the sensitive laminae, the coronary cushion, and the skin and underlying +structures of the coronet. + +With the horse cast and the preliminary steps over, the thinned horn of +the quarter is incised in a semicircular fashion, and the half-moon-shaped +piece thus separated from its surroundings stripped off. At about 1/4 inch +from the incision in the horn, a second incision of similar shape is made +through the sensitive structures, which incision is also carried up into +the skin and structures of the coronet. This incision severs, from bottom +to the top, (1) the sensitive laminae covering a portion of the pedal bone +and a portion of the lateral cartilage, (2) the coronary cushion, and (3) +the skin of the coronet and such structures as lie between it and the +cartilage. + +[Illustration: FIG. 141.--EXCISION OF THE LATERAL CARTILAGE. (AFTER +BAYER.) The horny wall is stripped off over the seat of operation. _a_, +Semicircular flap of sensitive laminae, coronary cushion, and skin; _b_, the +lateral cartilage; _c_, the sensitive laminae; _d_, the coronary cushion.] + +That this incision of the sensitive structures should be kept at 1/4 inch +from the one in the horn has a reason. It is that when this flap is again +placed into position (as later it will have to be) we have round its +circumference a rim of soft structures into which to place the sutures. And +in this connection it is well to advise the operator that the thinness of +the keratogenous membrane (the laminal portion of it) should warn him that +the portion of it to be turned up--namely, that forming the tip of the +flap--should be _scraped_ away quite close to the os pedis. Unless this is +done, there will not be a sufficient thickness left to afterwards bring +into position and suture. + +The half-moon-shaped piece of tissue incised is now carefully dissected +away from the external face of the cartilage, until it may be turned up as +a flap (see Fig. 141, _a_), and held from off the cartilage by a tenaculum. + +The exposed cartilage is now carefully removed by the aid of a sage-knife +and a stout pair of forceps, the same precaution of holding the foot well +forward being again taken in order to avoid wounding of the articular +capsule. + +At this stage in the operation considerable care is required. The operator +must remember that close beneath him, and more particularly in front, is +the pedal articulation. It is better, therefore, to excise the cartilage +piecemeal, and to do it carefully, than to attempt, at the risk of injury +to the joint, to make the operation 'showy.' + +During removal of the cartilage, the terminal branches of the digital +arteries are wounded, as also are the veins of the coronary plexus. Should +either of these stand out with extra prominence from the others, it should +be picked up with a pair of forceps, and ligatured with either carbolized +gut or silk. + +Attention should then be given to the flap of skin and coronary cushion. +Wherever a sinus has existed in it, it is to be carefully scraped, and all +dead portions of tissue removed. This done, the flap is allowed to fall +into position, and is there carefully sutured, not only at the skin of the +coronet, but along the whole circumference of the incision. + +_Dressing of the Wound and After-Treatment_.--The whole secret of the +success of this operation is in afterwards maintaining a strict asepsis +of the wound. Unless there is reasonable room for belief that this may be +done, the operation had far better not be advised, for if the wound is +afterwards suffered to get into a suppurating and dirty condition, the last +stage of the case may be worse than the first Synovitis and arthritis, with +certain anchylosis of the joint, and a probable loss of our patient, is +almost bound to follow. + +We cannot, therefore, too strongly insist upon the advice that the whole of +the preliminary antisepticising of the foot that we have described, and the +after maintaining of asepsis that we are now about to relate, _must_ be +methodically and thoroughly carried out. It is of even _more_ importance +than little details in the operation itself. + +In the first and second methods of operating, directly the actual operation +is over, the surface of the wound and both surfaces of the skin-flaps +should first be thoroughly douched with a 1 in 1,000 solution of +perchloride of mercury. Bayer prefers a 1 in 5 solution of iodoform in +ether. + +Next, either iodoform or chinosol in the powder should be dusted over the +whole surface, including again both inner and outer faces of the reverted +skin-flaps. This done the flaps are allowed to fall into position and +sutured there with carbolized silk or gut. + +Another liberal application of an antiseptic dressing follows this. +Iodoform, iodoform and boracic acid, or chinosol, is freely dusted over +the wound and for some distance around it. Bayer, however, again prefers a +dressing of the wound, and especially the moistening of the line of sutures +with the 1 in 5 solution of iodoform in ether. + +Over the wound is then placed a protective layer of gauze, impregnated +either with boric acid, with a mercuric salt, or with iodoform. + +Finally, numerous small and lightly-rolled balls of dry carbolized tow +are packed regularly over the whole of the operation wound, and the foot +bandaged. + +Practical points to be remembered in this after-dressing are: (1) The +balls[A] of tow should be numerous enough to exercise pressure upon the +sutured flap when the foot is finally bandaged. (2) The bandage should +be run on from the coronet downwards, in order to insure pressure being +exerted in the exact position over the sutured flap. (3) Bandages should +be used in abundance, commencing always from the coronet, and carefully +applied so as to exert an even and uniform pressure. (4) The bandages +should be of clean, unused linen. + +[Footnote A: Bayer recommends that the tow be rolled into cylindrical +tampons, each long enough to cross the wound. These are placed on the wound +in alternate horizontal and vertical layers, so that when rolled round by a +bandage they are pressed into an even and compact pad.] + +Once the bandages are adjusted, the hobbles may be removed, and the +tourniquet loosened. Directly the tourniquet is removed there is a steady +oozing of blood through the bandages, no matter how many we have put on. +This should occasion no alarm, as experience has taught that the careful +attention to antiseptic measures observed throughout the operation has the +effect of maintaining the lowermost dressings, those next to the wound, in +a state of asepsis. The bandaged foot should now be wrapped in a piece of +thick clean cloth or placed in a boot. + +If our antiseptic precautions have been thorough, the dressings and +bandages so adjusted may be allowed to remain without disturbance for from +eight to fourteen days. In this, however, the veterinary surgeon must be +largely guided by the symptoms of his patient. If, at the end of the +first three or four days, the animal maintains a vigorous appetite, if he +commences to place a little weight on the foot, and if the thermometer +gives no indication of a rise beyond the one or two degrees of ordinary +surgical fever, then the surgeon may know that things are proceeding +satisfactorily. Pawing movements with the foot, inability to place weight +upon it, loss of appetite, an increase in the number of respirations, and +a serious rise of temperature, denote the opposite state of affairs. The +wound is in all probability suppurating. The bandages and dressings should +therefore be removed, and the wound either redressed and bandaged, or +treated as an ordinary open wound. + +Ordinarily, however, if the operation has been properly performed, healing +takes place by first intention, and the wound when the bandages are removed +at the end of the first or second week appears clean and _dry_. + +Having assured ourselves that such is the case, we dress the foot in +exactly the same manner as before, save that so many bandages are not put +on. A similar dressing is repeated weekly until such time as the wound +shows sufficient growth of horn--quite a thin pellicle--to act as a +protective. It may then be left undressed, except for some simple hoof +dressing and a bandage. + +Complete healing of the wound takes from about four to eight weeks, at the +end of which time the animal can be again gradually put into work. The +labour, however, should be light, and quite three or four months should be +allowed to elapse before any attempt is made to put him to heavy work. + +Should the second method of operating have been the one adopted, then there +is one slight difference in the after-dressing that needs attention calling +to it. In this case we have more or less of a _hidden_ cavity left to deal +with rather than the broad and _open_ wound left in either of the other +methods. This cavity, left by the extirpation of the cartilage, must be +thoroughly dressed with iodoform or chinosol, or with Bayer's iodoform +in ether. The packing with carbolized tow and the bandaging may then be +proceeded with as before. + +In conclusion, we may say that the operation is one of some delicacy, and +needs a good surgeon for its successful performance. Furthermore, no one of +the antiseptic precautions we have advised can be omitted. It is, perhaps, +these two considerations (and in justice to the English surgeon we should +say most probably the latter of them) that have prevented this operation +from being generally adopted. + +That it is successful there is no gainsaying. Professor Bayer, of the +Vienna School, with whose name is associated the last of the three methods +of operating we have described, is enthusiastic in praise of the operation, +and says: 'The favourable results that I have got by this operation have +caused me wholly to abandon the medicinal treatment, and to prefer in all +cases the surgical operation as being the best means to the end.' + +_Partial Excision of the Lateral Cartilage_.--Discarding the somewhat +elaborate methods we have just described, there are English operators who +removed the necrosed portion only of the cartilage, and do so in what +appears at first sight a comparatively rough-and-ready manner. + +The apparent roughness is that they do not concern themselves with +conserving the coronary cushion, and hesitate but little in cutting +portions of it bodily away. One would imagine that in this case the quarter +of the side operated on would be always more or less bare of horn. Such, +however, is not the case. + +To perform this operation the animal is again cast and chloroformed. Some +operators, however, use the stocks and dispense with the anaesthetic. The +foot is first well cleaned with soap and water and a stiff brush, and the +hair of the coronet over the seat of operation shaved. Again, too, the horn +of the affected quarter is rasped until it yields easily to pressure of the +thumb, and the whole of the foot washed in an antiseptic solution. + +A probe is now inserted into the opening at the coronet, and the direction +of the fistula noted, after which the foot is firmly secured, and an +Esmarch bandage and tourniquet applied to the limb. + +This done, a triangular or wedge-shaped portion of skin, coronary cushion, +and thinned horn is removed with a strong sage-knife or scalpel. + +The base of the wedge-shaped portion removed contains the opening of the +fistula, and the apex of the wedge should reach to the bottom of the sinus +(see Fig. 142). + +After the horn is removed and the fistula followed up, it is sometimes +found that what we at first thought was its end, it may now be continued in +an altogether different direction. + +It is again followed up with the probe, and the horn and sensitive +structures excised until we are quite certain we have reached its furthest +extent. + +Attention should next be paid to the cartilage. Wherever spots of necrosis +are found, as indicated by the pea-green colour of the affected parts, they +must be _carefully_ excised. Care should be taken in so doing to carry the +line of excision some little distance around the visibly affected parts. +This is done that we may be quite certain nothing at all remains calculated +to give rise to further trouble. + +It goes without saying that, in addition to the necrosed cartilage, all +other diseased and necrotic tissues should also be removed. The os pedis is +occasionally found necrotic just where the cartilage joins it, or it may be +that a small portion of the sensitive laminae, by reason of its _liver-red_ +or even gray coloration, gives evidence of death of the part. + +The former must be well curetted, and the latter cleaned carefully with a +scalpel and forceps. + +[Illustration: FIG. 142.--PARTIAL EXCISION OF THE LATERAL CARTILAGE BY +REMOVING A PORTION OF THE CORONARY CUSHION. The dotted lines show the +outline of the wedge-shaped portion of structures to be removed, including +skin, coronary cushion, horn, and sensitive laminae. _a_, The opening of the +fistula.] + +The operation finished, the foot is again douched in an antiseptic +solution, the wound mopped dry with carbolized tow, dressed with either of +the dressings described on page 358, and finally bandaged. The dressing +should be changed every three days only, unless in the meanwhile pawing +movements and other symptoms of distress indicate their removal. + +The length of coronary cushion removed in this operation is from 1/4 to 1/2 +inch (we ourselves, however, have seen it more), and yet its loss seems to +occasion no serious after-trouble beyond a slight deformity of the parts +beneath. The sensitive structures become sufficiently covered with horn, +and the animal in nearly every case is returned to work, while in a great +many instances he may also trot perfectly sound. + +Simple though the operation may appear, and apparently rough in its method, +it is nevertheless successful in effecting a cure in cases where blisters, +plugging, injections, and other means have failed. + +Mr. W. Dacre, M.R.C.V.S.,[A] after reading an article on the operation +before the members of the Lancashire Veterinary Medical Association, says: +'My observations have not been based on a single case, and having had nine +of them, and all of them successful, I felt it to be my duty to bring this +subject before the Society.' + +[Footnote A: _Veterinary Record_, vol. v., p. 407.] + +Mr. T.W. Thompson, M.R.C.V.S.,[A] says: 'In a great number of cases I have +removed a 1/2 inch of the coronary band.... I have performed the operation +a great number of times, and have never seen a foot that has been damaged +by it.' + +[Footnote A: _Ibid_.] + +Professor Macqueen[A] says: 'I do not spare the coronary band or sensitive +laminae when I find those parts diseased. I do not unnecessarily damage +those structures. At the same time, I am confident that excision of a piece +of the coronary band or removal of a few sensitive laminae has not the +untoward consequences so much dreaded in former days.' + +[Footnote A: _Ibid_., p. 714.] + +Mr. John Davidson, M.E.C.V.S.,[A] says: 'The treatment described, if +carefully carried out and details attended to, will be found a success in +dealing with the majority of cases of quittor. If I may be permitted to say +so, without being considered boastful, I have yet to see the first case +that has resisted the treatment.' + +[Footnote A: _Ibid_., vol. xiv., p. 769.] + +Should our case of quittor be complicated by caries of the bone, this must, +where possible, be scraped or curetted until the whole of the diseased +portion is removed, and a healthy surface is left. After-dressing must then +be carried out as in other cases. + +The treatment of ossified cartilage will be found under treatment of +side-bones, and the methods of dealing with penetrated articulation and +purulent arthritis are treated of in Chapter XII. + +_Surgical Shoeing in Quittor_.--In the case of simple or cutaneous quittor, +no alteration in the shoeing is necessary. + +When the condition becomes sub-horny, however, and particularly when it is +situated in the region of the quarters, ease is afforded to the diseased +parts by removing the bearing of the shoe in that position. + +Should there be no dependent opening at the sole, then the best shoe for +the purpose is an ordinary bar shoe (Fig. 68), with the bearing eased under +the affected quarter. + +If, however, there is a dependent orifice, or one is expected, then it will +be necessary either to leave the animal unshod or to provide him with +a shoe that admits of dressing the lesion. In the latter case the most +suitable shoe will be found to be either a three-quarter shoe (Fig. 102) +or a three-quarter bar shoe (Fig. 103). Many operators, however, keep the +animal unshod. We must say ourselves that we consider a shoe useful after +either of the operations for removal of the cartilage, if only to assist in +maintaining the bandages and dressings in position. + +In this case a very useful shoe will be the three-quarter bar shoe. With a +little manipulation the bandages are easily run under the bar portion of +the shoe, and a few of their turns every now and again wrapped round the +bar in order to keep the whole firmly in position. + +In connection with tendinous quittor, when septic matter has gained the +sheath of the flexor tendons, there is, for a long time after healing of +the fistula, a marked tendency for the animal to go on his toe. To a large +extent we judge this to be due to slight adhesions between the two tendons +brought about by the growth of inflammatory fibrous tissue. In such cases +benefit is sometimes derived from the application of a shoe with an +extended toe-piece (see Figs. 84 and 108). + + +C. OSSIFICATION OF THE LATERAL CARTILAGES, OR SIDE-BONES. + +_Definition_.--An abnormal condition of the lateral cartilages, in which +the substance of the cartilage becomes gradually removed and bone formed in +its place. + +[Illustration: FIG. 143.--OSSIFIED LATERAL CARTILAGES (SIDE-BONES).] + +_Symptoms and Diagnosis_.--Side-bones are nearly always met with in heavy +draught animals, and are rarely seen in the feet of nags. They are, +moreover, nearly always confined to the fore-feet. In the ordinary way +little need be said concerning their characteristics, and the way in which +they may be detected. Neither need any concern be ordinarily manifested +with regard to the effect they may have on the animal's gait and future +usefulness. Seeing, however, that side-bone constitutes one of the +recognised hereditary diseases, and that at the various agricultural and +horse shows its existence or otherwise in a certain animal is a matter of +great importance, some little attention must be given to these two points. + +With a side-bone anywhere approaching full development, diagnosis is easy. +The thumb is pressed into the coronet over the seat of the cartilage, when, +in place of the elasticity we should normally meet with, we have the solid +resistance offered by bone. In some instances diagnosis is even easier +still. We refer to those cases in which the side-bone stands above the +level of the coronet with such prominence as to be readily _seen_ and +recognised without manipulation, and where its growth has caused distinct +enlargement and bulging of the wall of the affected quarter. It seems that +in such cases the bone-forming process does not end with simply depositing +bone in place of the removed cartilage, but that, after that is +accomplished, the bone still continues to be produced, as in the case of an +exostosis elsewhere. + +Although diagnosis in cases such as these is easy, it becomes a very +different matter when we are called upon to give an opinion in cases where +ossification of the cartilage is only just commencing. Whether the result +of our examination is to decide the sale or purchase of an animal, to +determine his fitness or otherwise to enter the show-ring, or to merely +advise a client as to whether or no a side-bone is in course of formation, +our position is equally difficult, and in either case our examination must +be searching. + +Perhaps the best advice we can give is to say that the whole of the +cartilage must be manipulated both with the foot _on_ and _off_ the ground. +What the reason may be we do not pretend to say, but it is a well-known +fact that in many instances the cartilage, with the foot bearing weight, +is so rigid as to at once convey the impression that ossification has +commenced or is even far advanced. And yet that same cartilage, with the +foot removed from the ground, is as pleasantly yielding to pressure of the +thumb as the most exacting of us could wish for. In any case, then, where +doubt exists, the foot should be lifted to the knee, and the cartilage +carefully examined with the foot in that position. If, then, at any spot +above the normal contour of the os pedis we meet with hardness or rigidity, +we are to look upon that foot with suspicion. Nevertheless, providing our +conscience is sufficiently elastic, the animal may be passed _sound_ so far +as the _existence_ of a side-bone is concerned. We know, however, that with +commencing rigidity we may ere long expect one, and if our opinion is asked +with regard to that particular, it must be admitted that with rigidity of +the cartilage once commenced it is usually not long afterwards before a +fully-developed side-bone makes its appearance. + +As is only to be expected, the first noticeable hardening of the cartilage +is to be found near the normal bone. We may thus look for it more +particularly in the lower portions of the cartilage. We think we may say, +too, that in the vast majority of cases the ossification of the cartilage +commences in its anterior half. It is thus brought about that often we +are called upon to examine and report on the condition when we have +_anteriorly_ a side-bone in course of formation, and _posteriorly_ a +perfectly normal cartilage. It is to the latter half of the cartilage that +dealers and others mainly, if not wholly, devote their attention. A horse +with the cartilage in this transition state will therefore pass muster, and +a nice little point of ethics has again to be decided by the veterinary +surgeon before giving his signature to a certificate of examination of an +animal in this condition. + +With regard to alteration in gait, we may say at once that side-bones in +heavy animals are not often the cause of lameness. In fact, where the foot +is well developed, when neither the foot as a whole nor the phalangeal +bones give evidence of disease, and where the pasterns are fairly oblique +and well formed, this alteration of the cartilages may be looked upon as of +no serious import at all. Neither is the side-bone due to blows or other +injuries likely to be productive of lameness--that is, always supposing, of +course, that the foot in other respects is of good shape. If lameness is +met with at all, then it is where we have a foot that is in other respects +unsound, with badly contracted heels and upright 'stumpy' hoof, or where +side-bones have occurred in a young animal, and have already reached a +large size before the horse is put to labour. In this latter case, the +added effects of concussion and the evil influences of shoeing are +sufficient to turn the scale. Directly the animal, previously sound, is +asked to work, lameness is the result. + +It follows, therefore, that side-bone in the feet of young animals is of +far more serious import than when occurring in older horses. In a nag +animal they constitute a positive unsoundness, and lameness in this case is +more often than not an accompanying symptom. + +_Causes_.--To commence with, we may remark that, although met with +sometimes in very early life, side-bones are seldom, if ever, congenital, +and that more often than not they may be looked for in animals of three +years old, or older, seldom earlier. They appear, in fact, only when the +animal is shod and commences work. + +This at once suggests two of the principal factors in their +causation--namely, concussion and loss of normal function. Directly the +horse is put to work he has for a great part of his time to travel upon +roadways--either macadamized roads or town sets--where everything is +calculated to bring concussion about. In addition to that he has the +lateral cartilage itself thrown largely out of action by shoeing. We +explained in Chapter III. (p. 66) that the chief function of the cartilage +was to take concussion received by the plantar cushion and direct the +greater part of it outwards and backwards. Now, with the animal shod, the +plantar cushion does not itself, as normally it should, receive concussion. +By the shoeing the frog is lifted from the ground, and the plantar cushion, +together with the cartilage, taken largely out of active work. In other +words, the normal outward and inward movements of the cartilage are +enormously reduced. + +It is fair, we think, to take it that the mere fact of the lateral +cartilage persisting _as_ cartilage is due in large measure to its constant +movement. Directly, therefore, it is placed in a state of comparative +idleness, then it commences to ossify, more particularly if there should at +the same time be a tendency to a low type of inflammation of the parts. + +Does this latter exist? We may safely say that it does. It is in this way: +The secondary effect of loss of ground-pressure upon the frog and plantar +cushion is to bring about contraction of the heels. With this we get +compression of the parts within, with a certain amount of irritation and +the exact low type of inflammatory phenomena calculated to assist in the +bone-forming process. + +The fact that concussion acts as a cause explains in great measure how it +is that side-bones are more frequent in cart animals than in nags, and also +why they should be more common in the fore-feet than in the hind. Taking, +in both animals, a rough calculation as to the weight of body carried +by feet of a certain size, we notice at once that the cart animal has +proportionately more weight to carry than has the nag. Concussion to the +foot is therefore greater. The greater part of the body-weight is borne by +the fore-limbs. Concussion is therefore greater to the fore-feet than to +the hind. + +This, however, does not explain altogether the comparative immunity of the +nag animal from this defect. He, too, must also be subject to the effects +of concussion, especially when his higher and faster action is taken into +account. To our minds there is only one explanation to be offered here. We +point at once to the years of constant and judicious breeding of the nag. +Compare that with the relatively few minutes that have been devoted to a +more careful selection of the cart animal, and we at once see a possible +explanation. That the explanation holds some amount of truth is borne out +by the fact that, since a greater attention has been paid to the selection +of our cart animals, side-bone has grown a great deal less common. + +Is side-bone hereditary? We can best answer that by saying that, some +several years ago, the Council of the Royal College of Veterinary Surgeons, +at the request of the Royal Commission on Horse Breeding, drew up a list of +those diseases 'which by heredity rendered stallions so affected unfit as +breeding sires,' and that in that list was included side-bone. + +Side-bones, therefore, are hereditary. We think, however, the statement +needs qualifying. It is in this way: side-bones occur only at a certain, +usually well-defined, time after birth, and we might say are _never_ +congenital. They occur only after the animal has been put to work, and are +more or less plainly due to mechanical causes--namely, the ill effects of +shoeing and concussion. The cause of their appearance, in short, is more +plainly extrinsic than intrinsic, and side-bone in the horse is, as +Professor McCall puts it, about as much due to heredity as is corn on the +human foot. + +Between these two opinions--that they are plainly hereditary, and that they +just as plainly are not--it is well to strike a middle course. They are, we +will say, hereditary in this way: So long as a cart animal is bred, to put +it vulgarly, 'top-heavy' (that is, with a body out of reasonable proportion +to the feet that have it to support), so long will the foot be subjected to +a greater concussion, and so long will side-bones in such animals commence +to make their appearance at about middle life. + +In addition to the causes we have now mentioned, side-bones are often +the result of other diseases of the foot. They thus occur as a sequel to +sub-horny quittor, to suppurating corn, to complicated quarter sand-crack, +or to the inflammation of the parts occasioned by a prick. They also arise +in many instances from the effect of a prick or injury to the coronet. +Among the latter we may mention treads from other animals, and treads +inflicted by the animal himself with the calkin of an opposite shoe, or the +repeated injury occasioned by the shafts being carelessly allowed to drop +on to the foot. In severe cases of laminitis, too, the cartilages are +nearly always affected. In this instance the inflammatory phenomena in the +os pedis no doubt give rise to an abnormal activity of bone-forming cells. +The cartilage is invaded, and the side-bone formed (see Fig. 118). + +_Treatment_.--In the ordinary way the 'treatment' of side-bone is a thing +but rarely mentioned. The explanation lies, of course, in the fact that +side-bones are so rarely the cause of lameness. When lameness does occur +with a side-bone, and we have reason to believe that the said side-bone +is the cause of the lameness, it is well before talking of treatment to +question ourselves thus: 'In what way does the side-bone cause lameness?' +The now generally-accepted answer to that query is the explanation put +forward several years ago by Colonel Fred Smith--namely, that the pain, and +therefore the lameness, was due to the compression of the sensitive laminae +between the ossified and enlarged cartilage and the non-yielding and often +contracted wall of the quarters. That, in fact, constitutes the basis upon +which Smith's operation for side-bone (that of grooving the wall of the +quarters) is founded. + +Before describing the operation, however, we may say that we are now able +to understand that older operators who claimed success for other methods of +treatment, were to a very great extent justified in so doing. + +For instance, take the combined treatments of firing and blistering, and +the use of a bar shoe. Here the beneficial action of the cautery and the +blister may be largely problematical. The bar shoe, however, would be +almost certain to give good results. Frog-pressure with the ground would be +again restored, and the contraction of the heels removed. Pinching of the +sensitive structures would be diminished, and the lameness cured. + +Take, again, the treatment of 'unsoling.' It was barbarous, we know +barbarous, because unnecessary and easily avoidable. It was practised, +however, certainly very little more than two decades ago, and practised by +men of standing in the profession. Without dragging the case to light again +by mentioning the names of those concerned, we may mention that not +many years ago a highly respected member of the profession was, at the +instigation of the Royal Society for the Prevention of Cruelty to Animals, +prosecuted for practising unsoling for the relief of side-bone. Practically +only one other member of the profession was able to come forward and defend +the operation on the score of its utility. We see now, however, that--as +does Smith's operation--unsoling does permit of the greater expansion of +the heels. The contraction is done away with, the pressure on the sensitive +laminae again diminished, and the lameness relieved. + +Not that we are attempting to defend the operation--far from it. We simply +mention it as interesting, and quote this and the use of the bar shoe (with +both of which methods older operators have claimed success) merely as +evidence that the operation of Smith is based on a logical foundation. + +When treatment is decided on, therefore, we may first advise blistering and +the use of a bar shoe. After that, should the lameness continue, and should +we still judge the side-bone to be the cause of it, the operation may be +advised. + +As we have said before, the operation consists in so grooving the wall as +to allow of the quarters widening sufficiently to relieve pressure on +the parts within. In one or two previous portions of this work we have +considered operations involving this procedure. Before detailing the +operation here, therefore, we will first describe the instruments +necessary, and the most satisfactory methods of incising the horn. + +To begin with, it must be remembered that all methods of hoof section have +for their object the after-expansion of the horny box, and that this can +only be brought about by making each groove complete from coronary margin +to solar edge of the wall, and carrying it, throughout its length, _deep +enough to reach the commencement of the sensitive structures_. + +To this end, therefore, the operator must bear in mind the comparative +thickness of the various parts of the wall, and must, in particular, +remember the relative thinness of that portion of horn forming the outer +boundary of the cutigeral groove, and accommodating the coronary cushion. + +For the making of the incisions there is the special saw devised for this +operation by Colonel F. Smith, A.V.D., and which we illustrate in Fig. 144. +With this the wall is sawn through _until the depth arrived at is equal to +what is indicated by a previous examination of the thickness of the crust +as viewed from the solar surface_. Here Colonel Smith says: 'I strongly +advise everyone to use a metal gauge (a thin piece of material) to +introduce into the incision made by the saw, and run it up and down to +ascertain whether the wall is properly divided throughout. The depth to +which this should be done we know from the previous measurements of our +gauge on the crust.' + +[Illustration: FIG. 144.--SMITH'S SIDE-BONE SAW (EARLY PATTERN).] + +Should the saw be of a pattern in which the set of its teeth makes only a +narrow incision,[A] it should, while operating, be kept well oiled, and +should be withdrawn every few seconds in order that the horn-dust lying in +its teeth may be examined. If this is getting slightly blood-stained, +we know, of course, that the sensitive structures are reached, and the +incision has been carried far enough. In so judging the depth of the +incision, however, care must be taken to see that the top of the coronary +cushion is not injured with the saw, for if this is done the blood +trickling into the depth of the incision will tinge the horn-dust, and give +the false impression that the incision is sufficiently deep. + +[Footnote A: That is Smith's older pattern. The newer pattern (Fig. 145) +has the teeth so set as to make an incision wide enough to be looked into. +In this case the depth arrived at is to be judged by the appearance of the +bottom of the incision.] + +If the operator has had no previous experience of the use of the saw in +this operation, he must also be careful to avoid placing too great a +pressure on the teeth of its lower third. This is done by keeping the hand +too greatly depressed. Again, this leads to wounding of the sensitive +structures (this time at the lower end of the incision), and again the +operator is confused by the blood thus allowed to run into the groove. + +The only portion of horn difficult to operate on is that immediately under +the coronet. This is best severed with a succession of downward movements, +and is easier performed with Smith's later pattern of side-bone saw (Fig. +145) in which the set of the foremost teeth is reversed. + +[Illustration: FIG. 145.--SMITH'S SIDE-BONE SAW (IMPROVED PATTERN).] + +In making these grooves we must say that we think the use of the special +saw may be dispensed with, and the incisions just as easily, or, at any +rate, just as successfully, made with the knife. Those who select to use +this instrument should choose a narrow-topped and sharp searcher, or a +modern shaped drawing-knife of suitable size, such as those depicted in +Fig. 46, _a_ and _b_, and they will find their work much easier if +they will make the first steps in the incisions with an ordinary flat +firing-iron. By the use of the latter instrument the grooves are made +conveniently open along their tops, and room left for nicely finishing the +more delicate manner of removing with the knife the softer horn near the +sensitive structures. + +Those whose leaning is towards the use of special instruments, but who, at +the same time, do not care to use the saw, will find their wants supplied +in the hoof plane (Smith's), Fig. 146, or the hoof chisel (Hodder's), Fig. +147. With the hoof plane the groove in the wall is made by a succession of +downward scraping movements, while with the chisel the cut in the wall is +made either from below upwards, or from above downwards, according as +the foot is held forward or backward--whichever, in fact, comes most +convenient. + +[Illustration: FIG. 146.--HOOF PLANE (SMITH'S).] + +When using the knife or the hoof plane it is not often that the sensitive +structures are injured. In all cases, however, no matter what the +instrument used, the metal gauge should be employed when the sensitive +structures have been touched, and the operation obscured by blood. + +[Illustration: FIG. 147.--HOOF CHISEL (HODDER'S).] + +Our instruments at hand, the operation may be proceeded with. The first +step is to ascertain the extent of the side-bone, and to determine the +position of the incisions. To do this the coronet is felt with the thumb, +and the anterior extremity of the side-bone noted. This is marked on the +horn with a piece of chalk, and a vertical line dropped from this position +to the inferior margin of the wall (Fig. 148,1). The line crosses the horn +fibres obliquely, and is purposely made in that direction in order that its +inferior end may be far enough back to avoid the last nail-hole. Should the +side-bone reach very far forwards, it may be wise to cause this line to +slant from before backwards (see dotted line _a_, Fig. 148). Unless this is +done, it is found that in some feet so much of the wall is isolated at the +bottom that insufficient is left to nail the shoe to. + +The next line to be made is the rear one. Its correct position is +ascertained by first noting the junction off the wall with the bar (see +groove 2, Fig. 149); and its inferior end must be just anterior to the +inflexion of the wall. This is done that we may avoid cutting the bar. The +position of the lower end of the rear line thus ascertained, it is run +upwards with the chalk in the direction of the horn fibres. + +[Illustration: FIG. 148.--DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES +IN THE WALL IN COLONEL SMITH'S OPERATION FOR SIDE-BONE. 1,2, and 3, mark +the grooves in the order in which they are made; the dotted line _a_ marks +the position taken by the anterior line when the side-bone, is one reaching +far forward, while the dotted lines _b_ and _c_ mark the position of the +additional grooves to be made if thought necessary.] + +The third line is made in such a position as to divide into two equal +portions the wall between lines 1 and 2. Here, however, some operators +prefer to make two, or even three, lines, adding those as at _b_ and +_c_, Fig. 148; and Smith himself says that a multiplicity of lines is an +advantage rather than not. + +In any case, having once determined the position of the lines, they should +be plainly marked out with chalk, and then viewed from a distance with +the foot on the ground, in order to judge of their regularity. If we are +satisfied with them, we then lightly mark them with the saw, with the hot +iron, or with the knife, whichever instrument we may be intending to use. + +Unless the details are methodically carried out as here described, it is +probable that more of the foot will be isolated than is necessary, and that +as a consequence very little is left to which to nail the shoe. + +[Illustration: FIG. 149.--DIAGRAM ILLUSTRATING THE POSITION OF THE GROOVES +MADE IN THE HOOF IN COLONEL SMITH'S OPERATION FOR SIDE-BONES. 1, 2, and 3, +show the grooves in the wall in the order in which they are made; 4 shows +the groove made at the junction of the sole with the wall.] + +The incisions are then made with the saw or the knife, with the foot +held in a convenient position by an assistant. That usually found most +comfortable for the first incision is with the foot held forwards and +placed on an assistant's thigh in the position adopted for 'clenching up' +when shoeing, while that for the rear incision is with the animal's knee +flexed, and the foot held well up to the elbow. In this, however, each +operator will suit himself. + +Should the preliminary steps in making the incisions be performed with the +iron, it will be easiest done with the foot on the ground. + +When the incisions through the wall are complete, our attention must be +given to the sole. A drawing-knife is here used, and a further incision +made over the white line so as to destroy the union of the sole with the +wall between incisions 1 and 2, and so completely isolate the portions of +wall included within the four grooves (see groove 4, Fig. 149). When this +is done it should be found that the portions of the isolated wall spring +readily to pressure of the thumb. + +The inferior or wearing margin of the isolated wall must now be so trimmed +that it takes no bearing on the ground when the opposite limb is held up by +an assistant and full weight placed upon the foot. + +For a day or two after the operation lameness is intense. This is to be +treated with hot poultices or hot baths, and and soon disappears. Three to +four days later a bar shoe is nailed on (taking care that the bearing of +the quarters is still eased), and the hot poultices still continued. Four +days later still walking exercise may be commenced, to be followed +shortly afterwards by trotting. At about the twelfth day some animals may +conveniently be put to work, while in other cases a fortnight, or even a +month, must elapse before this can be done. When put to work early, it is +wise to fill in the fissures made in the wall with hard soap, with wax, or +with a suitable hoof dressing, in order that irritation of the sensitive +structures with outside matter may be prevented. + +This operation is soon followed by remarkable changes in the shape of the +foot. At about the third week the coronet shows signs of bulging, and the +upper part of the wall operated on is often so protruding as to render the +foot wider here than at the ground surface. This is a sign that the case is +doing well. + +Should no improvement be noticed at the end of three weeks or a month, or +should the grooves become filled from the bottom (which they do remarkably +fast), then the incisions must be deepened, the exercise reduced, and the +fomentations or poulticing repeated. So treated, many cases of side-bone +lameness will be relieved, if not entirely cured, and, should the worst +happen, and no alteration in the lameness is noticeable, no harm will have +been done to the foot. In this connection, the originator of the treatment +says: 'I may assure those induced to doubt either their diagnosis or the +value of hoof section that no harm is done to the foot, even should the +operation be of no value. It may do much good; it cannot do harm. The +operation will never succeed until the inherent timidity of sawing or +cutting into the wall is overcome. The _incisions must be deep, and of the +same depth from the coronet to the ground_.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. +iii., p. 313.] + +It is well to remark here that the operation of hoof section cannot be +expected to succeed in every case. The last man in the world to claim that +for it would be its originator. Failure to relieve the lameness may be +accounted for in a variety of ways. First, of course, will come errors in +diagnosis. No one of us is infallible, and the lameness we have judged as +resulting from side-bone may arise from another cause. There are, too, +complications to be reckoned with, the existence or absence of which cannot +always be definitely ascertained. Such are: Ringbone, especially that form +of ringbone known as 'low'; bony deposits on the pedal bone, either on its +laminal or plantar surface, or even changes in the navicular bursa. + + + +CHAPTER XI + +DISEASES OF THE BONES + + +A. PERIOSTITIS AND OSTITIS. + +We head this section, Periostitis _and_ Ostitis, for the reason that in +actual practice it is rare for one of these affections to occur without the +other. The periosteum and the bone are so intimately connected that it is +difficult to conceive of disease of the one failing to communicate itself +in some degree to the other. Pathologically, however, and for purposes of +description, it is more convenient to describe separately the abnormal +changes occurring in these two tissues. + +With the main phenomena of inflammation occurring elsewhere we presume +our readers are aware. Briefly we may put it, that under the action of an +irritant, either actual injury, chemical action, or septic infection, +the healthy tissues around react in order to effect repair of the parts +destroyed. Also that this reaction involves the distribution of a greater +blood-supply to the part, with an abundant migration of leucocytes, and +the outpouring of an inflammatory exudate, together with symptoms of heat, +pain, redness, and swelling of the affected area. And that in chronic +inflammations, owing to persistence of the cause, the process of repair +thus instituted does not stop at mere restoration of lost tissue, but +continues to the extent of forming an abnormal quantity of such tissue as +normally exists in the parts implicated. + +The process of inflammation in bone is essentially the same. It takes place +along the course of the bloodvessels, and is only modified in its attendant +phenomena by the structure of the parts involved. Swelling, for instance, +cannot take place in the centre of compact bone tissue. Otherwise, other +changes occur exactly as in inflammations of other structures. + +When the causal irritant has been excessively severe and the migration of +leucocytes abundant, actual formation of pus may occur, the bony tissue +being broken down and mingled with it, and an abscess cavity formed. In +milder cases, affected and necrotic tissue is removed by a process of +phagocytosis, and new tissue (this time osseous) formed in its place. + +In the periosteum we may take it roughly that inflammation runs a course +similar to that occurring in soft tissues elsewhere. There is but one +exception, and that, as we shall mention shortly, is connected with its +deeper layer. + +As we know, the periosteum consists of two layers, an outer fibrous and +an inner yellow elastic, and is extremely vascular. Numerous bloodvessels +ramify in it, and, with their attendant nerves, break up to enter the +numberless canals of the Haversian system. This extreme vascularity, of +course, favours abundant exudation. The exudate, however, is, as it were, +shut in by the dense fibrous layer of the membrane, and the result is that +in periostitis it collects between the membrane and the bone, causing +swelling and raising of the membrane, and giving rise to excruciating pain +from pressure upon the nerves. + +Should the periostitis be complicated by the formation of pus, then the +vessels entering and supplying the bone are, in the suppurative area, +destroyed. With their destruction it may happen that we get also death of +a portion of the osseous tissue. This, however, when the suppuration is +abundant, cannot commonly occur, as the bloodvessels within the bone--those +of the medulla--commence to supply blood to the affected part. In cases of +trouble with the bones of the foot, these last few remarks have a special +significance. Here we have three bones whose medullary cavity is extremely +small--almost nil, in fact--which explains in some measure how easy it is +when suppuration exists to get necrosis and exfoliation of, say, portions +of the os pedis. Necrosis and sloughing of the periosteum itself may also +happen, but as the extreme vascularity of the membrane is a fairly strong +safeguard against that it is of only rare occurrence. + +In connection with the deep layer of the periosteum, and forming part of +it, are found numerous bone-forming cells (_osteoblasts_). These, under +ordinary conditions, are relatively quiescent. Under the slightest +irritation or stimulation, however, their bone-forming functions are +stirred into abnormal activity, thus explaining how easy it is (especially +with bones so open to receive slight injuries as are those of the foot) to +get ossific deposits, the starting-point of which we are quite unable to +account for. + +With this brief introduction we will now describe such pathological changes +as occur in the separate structures, and which we are likely to encounter +in the various diseases of the foot. While so doing, we shall draw +attention to such diseases as we have previously described in which the +pathological conditions we are considering may be met with. + +1. PERIOSTITIS. + +This we shall consider under _(a)_ Simple Acute Periostitis, _(b)_ +Suppurative Periostitis, _(c)_ Osteoplastic Periostitis. + +_(a) Simple Acute Periostitis_.--This is the periostitis that follows on +the infliction of a slight injury to the membrane--an injury without an +actual wound and free from infective material. It is one, therefore, which +we always judge as existing in those cases where we have distinct evidence +or history of injury, but in which the injury has not been severe enough to +lead to fracture or to the infliction of an actual wound. + +Such cases may be those of lamenesses persisting after violent blows upon +the foot--cases where the animal has been kicking against the stable +fittings, or where the foot has been partially passed over by the wheel of +a waggon. It may be, too, that in a case of 'nail-bound' a great deal of +the pain and lameness is due to a simple periostitis caused by pressure of +the bulged inner-layer of horn upon the sensitive structures. + +Simple acute periostitis may also occur in cases where an actual wound is +in existence, but where such wound, fortunately, remains aseptic. We may +thus have this condition accompanying ordinary cases of pricked foot, of +treads in the anterior region of the coronet, and of accidental injuries of +other kinds. + +In simple acute periostitis the membrane is thicker and redder than normal, +and is easily stripped from the bone. As it is pulled off it is noticed +that there are numerous fibril-like processes hanging to its inner surface, +and which draw out from the substance of the bone. These are simply the +vessels (bloodvessels and nerves) which, loosened by the inflammatory +exudate, are readily detached and drawn from the Haversian canals into +which they normally run. In addition to its increased redness, the membrane +has a swollen and gelatinous appearance owing to its infiltration with the +inflammatory discharges. Simple acute periostitis may and often does end +in resolution. On the other hand, it may end in suppuration or may become +chronic. If the latter, then the osteoblasts of the innermost layer become +active, and abnormal deposits of bone are the result. + +_(b) Suppurative Periostitis_.--This condition simply indicates that +the inflammation is complicated by the presence of pus organisms. It is, +therefore, a common termination of the simple acute form attending the +infliction of a wound. The wound becomes contaminated, and the case of +simple periostitis is soon changed into the suppurative form. Once having +gained entrance to the wound, the pus increases in quantity, and slowly +runs between the membrane and the bone. This, however, it does not do to +any large extent, showing rather a tendency to penetrate the outer fibrous +layer and gain the outside of the membrane. + +Suppurative periostitis is met with in foot cases, commonly in connection +with punctured foot. It occurs, too, as a complication in suppurating corn, +in severe tread, in complicated sand-crack, as a result of the spread of +suppurative matter in acute coronitis, and in sub-horny quittor. + +In ordinary cases of suppurative periostitis the pus formed is yellow +in colour, creamy thick, and free from pronounced odour--the so-called +'laudable' pus of the older writers. It so happens in many cases of foot +trouble, however, that putrefactive organisms gain entrance side by side +with those of pus. In this case the characters of the discharge are +very different. It is distinctly more fluid, is of a pink or even light +chocolate colour, and extremely offensive. In these instances the pus +shows a marked tendency to spread, strips the periosteum from the bone, +perforates the outer layer of the membrane, and finally infiltrates the +surrounding tissues. + +This forms a near approach to what is known in human surgery as an +_infective_ periostitis, and in our subjects is nearly always met with in +cases of severe prick. Its rapidly spreading character makes it always +a dangerous condition, and a punctured foot exuding a discharge of this +nature should always be regarded as serious. The close contiguity of +the joint (it can never be _far_ distant in foot cases), the spreading +character of the disease, and the rapidity with which the horse succumbs to +arthritis, are all factors to be taken into consideration, and to lead to a +warning-note being struck when attending a case of such kind. + +A further instance of infective periostitis is that met with in acute +laminitis. The discharge obtained from the sole in these cases very often +bears the character we have just described, and when one considers the +thinness of the keratogenous membrane, one is bound to admit that changes +so grave occurring in it cannot fail to spread and infect the periosteum. + +_(c) Osteoplastic Periostitis_.--This is more particularly a chronic +process, and is, as the suffix '_plastic_' indicates, associated with +bone-forming changes in the membrane. It may occur as a consequence of +slight but continued irritation, often without ascertainable origin (see +Case 2, p. 392), or it may be the sequel of acute disease. + +In this form of periostitis the membrane is again swollen and more vascular +than in health, and is also easily separable from the bone. The exposed +bone is generally rough, in some cases even spicular, and the inner layer +of the removed membrane is rough and gritty to the touch--characters +imparted to it by numerous minute fragments of bone that have been torn +away with it from the more compact osseous tissue beneath. + +The results of an osteoplastic periostitis are frequently met with in the +bones of the foot, and are described by veterinary writers under +such headings as 'Pedal Exostoses,' 'Ossifying Ostitis,' and 'Pedal +Ossification' (see Figs. 152, 153, 154, and 155). In many of these cases +the disease is purely chronic, and the original cause nearly always +wanting. When the foot has been subjected to laminitis of some weeks' +duration, the same condition is also met with, being at the same time +associated with rarefactive osteoplastic ostitis, conditions which we +shall shortly describe. Cases we have examined have undoubtedly shown this +condition of osteoplastic periostitis, the rarefactive and osteoplastic +changes in the bone itself, met with in older cases, occurring no doubt +as a result of non-expansion of the horny box. So far as we are able to +ascertain, there is every reason to believe that in chronic laminitis the +accompanying periostitis leads to the formation of bone, and would, if it +were possible, lead to increase in the size of the os pedis. If proof were +wanted of this, it is only necessary to point out the increased growth at +points where resistance is nil--namely, along the upper margin of the bone +(see Fig. 118). However, increase in size elsewhere is prevented by the +resistance of the hoof, so that, as the bone-forming process progresses, as +it inevitably _must_ under the inflammatory changes going on, it is, as it +were, compensated for by rarefaction or bone-absorption changes occurring +simultaneously with it. + +2. OSTITIS. + +We shall next deal with the inflammatory changes occurring in the bones +themselves, and shall consider them under (_a_): Rarefying or Rarefactive +Ostitis, (_b_): Osteoplastic Ostitis, and (_c_): Caries and Necrosis. + +Inflammatory changes occurring in the medulla we may pass without +consideration, for in the bones of the foot the medullary cavity is so +small, and the changes taking place in it of such minor importance, that we +may do this without in any way seriously prejudicing our work. + +_(a) Rarefying or Rarefactive Ostitis_.--By this term is indicated an +inflammation of the bone attended by its absorption, the absorption being +due to the action of certain cells, termed _osteoclasts_. This condition +may be due to the pressure of tumours, may occur as the result of injury +when a piece of bone is stripped of periosteum, or may be the result of an +inflammation occurring in the periosteum elsewhere. + +A piece of bone undergoing rarefactive ostitis is redder than normal, and +the openings of the Haversian canals are distinctly increased in size. As a +result a greater number of them become visible. Their increase in size is +due to the inflammatory absorption of the bony tissue forming them, and in +the larger of them may be seen inflammatory granulation tissue surrounding +the bloodvessels. This enlargement of the Haversian canals is well seen +when the bone is macerated, the whole then giving the appearance of a piece +of very rough pumice-stone. + +This process of rarefaction or absorption of bone tissue may be confined +to quite a small portion, or it may be spread over the whole of the bone, +rendering it more porous than is normal, but stopping short of complete +destruction of the bone tissue (a condition which is sometimes known +as inflammatory osteoporosis (see Fig. 118)). In this latter case the +condition is a chronic one, and the bone tissue remaining often appears to +be strengthened by a compensatory process of condensation. For an example +of rarefactive ostitis as met with in cases of disease of the feet, +we refer the reader to laminitis (see Fig. 118). The osteoplastic or +condensing process that appears to exist simultaneously with it explains, +no doubt, how it is that bones so affected do not more commonly fracture. + +A further example of this process is illustrated in Fig. 133. The pressure +of a tumour (in this case a keraphyllocele) has led to rarefactive changes +in the bone, forming a neat indentation in the normal contour of the bone +which serves to accommodate the tumour. + +_(b) Osteoplastic Ostitis, Osteosclerosis, or Condensation of Bone_.--This, +too, is essentially a chronic process. It may occur as a result of, or, as +we have just shown, exist simultaneously with the condition of, diffuse +rarefactive ostitis. In this case there is a formation of new bone in the +connective tissue surrounding the vessels in the Haversian canals. As a +consequence the bone affected is greatly increased in density, and many +of the Haversian canals by this means obliterated. The end result is an +increase in size of the bones in such positions as the horny box admits of +it, and a peculiar ivory-like change in their consistence. + +For an example of this, we again refer the reader to the changes occurring +in chronic laminitis. + +_(c) Caries and Necrosis_.--_Caries_ is a word which appears to be used +with a considerable amount of looseness. In addition to the meaning implied +by necrosis (namely, 'death' of the part), caries is generally used to +indicate that there is also a condition of rottenness, decay, and stench. +It is particularly applied, in fact, when the death of the bone is slowly +progressive, and is due to the inroads made upon it by putrefactive or +septic matter. + +_Necrosis_ of bone may be the result of any injury, such as severe blows, +or pricks and stabs. In such cases it would appear that it is loss of a +portion of periosteum that is the starting-point. With death of a portion +of this membrane the vascular supply to a portion of the bone is cut off, +and necrosis ensues. It may also result from the extension of inflammatory +affections of the structures adjoining it, as, for instance, the spread of +the infective material in severe tread, or the encroaches made by pus in +cases of quittor, suppurating corn, or complicated sand-crack. + +When the necrosed portion of bone is small, and is free from infective +properties, it is quite possible that it may, as is the case with small +spots of necrosis in softer tissues, be removed by a process of absorption. +It must be remembered, however, that where the necrosis has occurred as a +result of septic invasion this cannot be looked for, for in every case such +reparative changes are worked solely by healthy tissue. If the tissues +around the necrosis are engaged in dealing with organismal invasion and +the poisonous products thus poured into their working area, their state of +health is so weakened that they are unable to successfully combat with the +two conditions simultaneously. As a consequence, the necrotic piece of bone +persists, and acts as a permanent source of irritation. + +It must be remembered, too, that if the dead portion of bone--even though +it be free from septic matter--is very large, that it may itself act as a +continual irritant, in which case it again persists, and cannot by natural +means be removed. + +In our cases necrosis of bone may be met with in punctured foot, in severe +cases of tread, in cases of complicated crack, and in suppurating corn. +It is met with, too, in navicular disease, in the extension of irritating +discharges in cases of quittor, and in cases of chronic laminitis where the +solar margin of the os pedis has penetrated the sole. In this latter case +the protruding portion of bone is quickly denuded of its periosteum. Its +blood-supply is destroyed, and necrosis follows. + +_Treatment_.--In simple cases of periostitis, those caused by a blow but +free from an actual wound, the most beneficial treatment is the continued +application of cold by means of a hose-pipe or by swabs. If by these means +we are successful in holding the inflammatory phenomena in check, any large +formation of new bone is prevented, and the case does well. + +When the case is complicated by a wound, then antiseptic measures, such as +those described in the treatment of punctured foot, will at the same time +have to be practised. + +It must be admitted, however, that in all but the most simple cases +ordinary treatment such as this is of very little use; for with only a +slight exostosis in almost any position in the foot, excessive lameness +presents itself and remains. In such cases nothing is left to us but the +operation of neurectomy. + +When the periostitis and ostitis is the result of a wound, and is +complicated by caries or necrosis of the bone, the diseased portion of +bone must in every case be laid bare and removed. It so happens that the +majority of cases of this kind occur in positions where the diseased bone +is easily got at. The lower margin of the os pedis or portions of the wings +are commonly the seat of such changes. We meet with the former in cases +of pricked foot, and with the latter in severe cases of tread, or as a +complication in suppurating corn or in quittor. In such cases the animal +must be cast and the foot secured. The wound is then followed up, the horn +if necessary removed, and the bone curetted with a Volkmann's spoon; or, if +showing itself as a sequestrum, removed with a scalpel and a strong pair +of forceps. Care must be taken that every particle of the diseased bone +is removed, and that no part of it is left to act as an after-source of +irritation. With removal of the diseased portion and a strict attention to +antisepsis healing soon takes place. + +_Reported Cases of Periostitis and Ostitis_.--1. 'Figs. 150 and 151 +represent the phalangeal bones of the off fore-leg of a thoroughbred horse +named Osman, who was well known as a hunt steeplechaser of considerable +merit in the Midland counties some twenty years ago. I may say that this +horse was under my observation pretty regularly during the whole of his +career, and up to the time of his death, from ruptured aorta, when eight +years old. My attention was called to him as a yearling by his owner, who +told me that he sometimes fancied the colt was lame. I went over to see +him, and found that he was unmistakably lame on the off fore-leg. Careful +examination showed no heat or enlargement anywhere. I advised rest and the +colt became pretty sound, though not quite so--in fact, he never did become +quite sound, and sometimes he was very lame indeed. + +[Illustration: FIG. 150.--EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR +BONES.] + +'Every imaginable sort of treatment was tried short of neurectomy, without +avail. The curious part of the case was that there never was much heat or +any apparent change of structure, nor was "pointing" a very noticeable +feature. The foot always remained a good-looking one. As the horse won a +good number of races he was of some value, and was seen by a good many +members of the profession, who were by no means unanimous as to the cause +of lameness. The favourite theory was that it was a sequence of "split +pastern." A post-mortem examination showed that there was no fracture. +There was no adherence of the tendon to the navicular bone nor any +ulceration. The morbid changes consisted entirely of osseous deposit as +shown in the photographs. The under surface of the navicular bone was much +enlarged and roughened by this bony deposit, which extended on to the os +pedis, causing complete anchylosis at each extremity of the navicular. The +lateral cartilages were healthy. The interesting points in connection with +the case are the insidious commencement of osseous disease, its extensive +development, and the entire absence of any external manifestation, through +its being confined entirely within the limits of the hoof. + +[Illustration: FIG. 151.--EFFECTS OF PERIOSTITIS ON THE PEDAL AND NAVICULAR +BONES.] + +'It should also be noted that the animal was able to undergo a severe +course of training for some years, and to gallop successfully over some of +the most trying courses in England. During the whole of this time he walked +and galloped apparently sound, but trotted always lame, and generally dead +lame.'[A] + +[Footnote A: W. E Litt, M.R.C.V.S., _Veterinary Record_, vol. viii., p. +527.] + +[Illustration: FIG. 152.--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +2. 'I herewith send you photographs of three cases of the above disease, +occurring in the internal surfaces of the wings of the os pedis. The photos +were kindly done for me by Dr. A. Lingard, Imperial Bacteriologist to +Government of India. It is a cause of many cases of obscure foot lameness +in India, and frequently accounts for the numerous entries on veterinary +medical history sheets under the heading "Contused Foot." + +'The course of the disease is as follows: The disease makes its appearance +very soon after arrival in India, the animal being admitted to hospital +suffering with undoubted foot lameness, generally slight. One is soon led +to suspect this disease by negative symptoms of other disease being in +existence. No coronary enlargement or flinching on pressure to the coronet, +no shrinkage or wiring in of the heels, neither is the characteristic +pointing of navicular present. In the early stages one has false hopes +of recovery by finding gradual improvement for a time by fomentation and +poultices, followed by irrigation and stimulants to the coronet, and +perhaps the animal is discharged from hospital, to be returned after a +few days worse than ever. The disease then becomes insidious and more +pronounced, the nodding of the head, even at a walk, more exaggerated, and, +in fact, the animal seems afraid to put his foot to the ground, and much +resembles a horse with an abscess in his foot, either from prick or picked +up nail. He absolutely nurses his foot. There is a certain amount of heat +always present. The disease being now well developed, pressure is caused by +the ends of the navicular bone, and they become involved at their points +by bony deposits. The causes of this disease I attribute, firstly, to +hereditary predisposition; and, secondly the exciting cause, standing +confined on board ship, where no doubt pedal congestion takes place. And +perhaps some subjects start it in their marches in mobs down country +in Australia. Concussion may be the cause among older horses, but the +specimens photographed were taken from remounts, that had either done no +work or only very gentle work, in a deeply littered riding school. + +[Illustration: FIG. 153.--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +'_Treatment_.--It is obvious from the position of this disease that +treatment will be of no avail in producing a cure. As already stated, the +disease is insidious and progressive, and it is hopeless to expect to +arrest the growths once they are started. Unnerving would no doubt remove +the symptom (lameness) of the disease, but an unnerved horse is not of much +good for army purposes. I therefore consider that once the disease becomes +firmly established it is an unfortunate and incurable one. + +[Illustration: FIG. 154, 155--EFFECTS OF PERIOSTITIS ON THE OS PEDIS.] + +'Post-mortem reveals the small nodular growths on the inner surfaces of the +wings of the pedal bone, and if long established the ends of the navicular +bone are also involved. Exudation and gradual growth of false material +around the nodules takes place, which also serves to increase pressure.'[A] + +[Footnote A: Captain L.M.Smith, A.V.D., _Veterinary Record_, vol. xi., p. +229.] + +3. 'This case was brought for my opinion. The horse was lame, and walked +similar to one that had had laminitis, putting the heel down first upon +the ground. I ordered the patient to be destroyed. You will note the +ossification of the flexor pedis at its attachment to the pedal bone. +I enclose photos of the ground, also of the articular, surfaces of the +bone.'[A] + +[Footnote A: F.B.Jones, M.R.C.V.S., _Veterinary Record_, vol. xi., p. 230.] + + +B. PYRAMIDAL DISEASE, BUTTRESS FOOT, OR LOW RINGBONE. + +_Definition_.--A condition of periostitis and ostitis in the region of +the pyramidal process of the os pedis, usually preceded, but sometimes +followed, by fracture of the process, and characterized by deformity of the +hoof and an alteration in the normal angle of the joint. + +_Causes_.--In the majority of cases buttress foot is brought about by +fracture of the pyramidal process. Thus, although distinct evidence of such +is nearly always wanting, we may assume that the original cause is violent +injury to the part in question. Properly, therefore, one would say that +this condition should be described under Fractures of the Os Pedis. It +appears, however, that other cases of the kind arise in which fracture is +altogether absent, or in which it is plainly seen to be subsequent to the +diseased processes in the bone. For that reason, and also for the reason +that the condition has come to be known by the name we have given, we give +it special mention. + +_Symptoms and Diagnosis_.--Even when the condition arises as the result +of fracture, the ordinary manifestations of such a lesion are absent. By +reason of the situation of the parts within the hoof we are unable to +detect crepitation, and the resulting lameness is perhaps--in fact, nearly +always is--neglected until such time as any heat or swelling caused by the +injury has disappeared, in which case we are denied what evidence we might +have obtained from that. All that is presented is lameness, and lameness +that is at times excessive. But with the lameness there is nothing +distinctive. The foot is tender on percussion, and the gait suggestive of +foot lameness, that is all. We are unable, therefore, to make an exact +diagnosis, and the condition goes for some time undetected. + +Later, however, changes in the form of the hoof and the coronet begin to +appear. The skin of the coronet, especially in the region of the toe, +becomes more or less thickened and indurated, and the same remark applies +to the subcutaneous tissues. The most marked change, however, is the +alteration in the shape of the hoof. The wall protrudes at the toe in a +manner that has been termed 'buttress-like,' and has given to the condition +one of its names. This, of course, entirely alters the contour of the horny +box. From being more or less U-shaped, it approaches nearer the formation +of the letter V, the point of the V being at the toe. + +In the later stages the coronary enlargement is plainly seen to be due to +an extensive formation of bone. It is, in fact, a reparative callus, and +the reason it reaches so large a size is probably to be accounted for by +the pull of the extensor pedis upon the detached pyramidal process. As +might be expected, this displacement of the fractured portion, with its +effect of giving greater length to the extensor pedis, leads to a backward +displacement of the os coronae upon the pedal bone. As a result there is a +marked depression at the coronet, the depression being heightened in effect +by the exostosis in front. Pyramidal disease is, as a rule, met with in the +hind-feet, but occurs also in the fore. + +_Pathological Anatomy_.--When occurring without fracture, the first +observable change is a thinning of the articular cartilage of the pyramidal +process, through which the bone beneath appears abnormally white. Later +the thinning of the cartilage progresses until at last it becomes entirely +obliterated. This destruction of the cartilage commences first at the +highest point of the articular surface of the pyramid, and gradually +reaches further backward into the joint. While this is taking place the new +bone is being formed on the front of the os pedis, below and around the +process, until, as we have already seen, an exostosis is formed, large +enough to be noticeable at the coronet. This, of course, partly implicates +the joint and the points of the insertion of the extensor tendon. + +Finally, fracture may, or may not, take place. When it does, the exostosis +is larger, and the general deformity of the hoof greater. + +_Treatment_.--Ordinary treatment, such as point or line firing, repeated +blisters, or hoof section, each of which we have tried, appears to be +utterly useless. So far as we have been able to gather from the writings of +other practitioners, however, neurectomy returns the animal for a time to +usefulness. If the fore-limb is the seat of trouble, either plantar or +median neurectomy may be practised; if the hind, then the best results are +obtained by section of the posterior tibial. + +_Reported Cases_.--1. This animal, a mare, had been rested for lameness +behind for two or three weeks, and then sent out to work, going sound. This +was repeated several times, and each time the coachman reported, "Goes very +lame behind after she has been at work about fifteen to twenty minutes." +She always pulled out sound when I saw her in a halter on the following +day, so I had her ridden, and after about seven or eight minutes she began +to go lame in a hind-limb. Her lameness got rapidly worse as she was being +ridden, and within a quarter of mile of her first showing lameness, she +dropped and carried the lame foot in a way that suggested a badly fractured +pastern. There was no recognisable disease in the limb to account for this +lameness. + +'I divided the posterior tibial nerve, and she went back to work moving +sound, and continued to work sound up to her death from one of the +regularly fatal bowel lesions twist or rupture. + +'She worked nearly two years after unnerving, and developed the usual +thickening at the coronet.'[A] + +[Footnote A: W. Willis, M.K.C.V.S., _Journal of Comparative Pathology and +Therapeutics_, vol. xv., p. 366.] + +2. 'The subject of this note was a chestnut mare, nine years old, and used +for omnibus work. + +'_History_.--For about two months the mare was lame on the off fore-leg, +and in spite of treatment the condition became steadily worse. The off +fore-foot was rather long and narrow, and the fetlock-joint was inclined +to be bowed outwards, but the degree of lameness was out of proportion to +these defects, and the diagnosis was obscure. + +'Median neurectomy was performed on May 10, 1902, and reduced the lameness +to about half of what it was before. On June 5 ulnar neurectomy was +performed, with the result that the mare became sound, and went to work +three weeks later. She continued to work soundly and well, being inspected +from time to time. + +'During February of 1903 the coronet began to enlarge in front and slightly +to the outer side, and gradually a ridge of bone grew down from the coronet +to the toe. The case, in fact, became a typical one of so-called "buttress +foot," which my friend Mr. Willis has described as diagnostic of disease +of the pyramidal process of the pedal bone. Meanwhile the swelling of the +coronet, which appeared to be mainly composed of fibrous tissue, increased +in size, until the whole of the front and sides became involved, assuming +the appearance shown in Fig. 156. + +'In spite of the coronary enlargement the mare worked well, and remained +free from lameness till June 8, 1903, on which day the limb became swollen +up to the site of the median operation. The appearance of the limb closely +simulated an attack of lymphangitis. The mare was kept under observation +till the 13th of the same month, during which time the swelling increased, +as did also the lameness to a slight degree. During progression she brought +the heel to the ground and "rocked the toe," as in a case of rupture of the +perforans tendon. The mare was killed on June 13. + +[Illustration: FIG. 156.--A CASE OF BUTTRESS FOOT.] + +[Illustration: FIG. 157.--FRACTURE OF THE PYRAMIDAL PROCESS IN BUTTRESS +FOOT.] + +'_Post-mortem_.--In trying to pull away the hoof from the sensitive +structures with a pair of farrier's pincers, the tendons and ligaments of +the corono-pedal articulation gave way, leaving the pedal bone _in situ_. +The flexor perforans tendon showed inflammatory softening, and was very +nearly ruptured through at the level of the navicular bone. There was +slight evidence of navicular disease. The articular cartilage of the +corono-pedal joint had been almost completely removed, and there was +sclerosis of the opposed bony surfaces, which by unequal wear had brought +about deformity of the os coronae and os pedis. + +There was very old-standing fracture of the pyramidal process (see Fig. +157), with the formation of a false joint between the process and the pedal +bone. There was also a recent fracture of the part of the pedal bone which +carries the articulation for the navicular bone, and this and the tendon +lesions probably accounted for the final symptoms of 'break-down.' + +Neurectomy enabled us to get a year's useful work out of what would +otherwise have been a hopeless cripple.[A] + +[Footnote A: A.R. Routledge, M.R.C.V.S., _Journal of Comparative Pathology +and Therapeutics_, vol. xvi., p. 371.] + + +C. FRACTURES OF THE BONES. + +More or less by reason of the protection afforded them by the hoof +fractures of the bones of the foot are rare. When occurring they are more +often than not the result of direct injury, as, for example, violent blows, +the trapping of the foot in railway points, the running over of the foot +with a heavily-laden waggon, or violent kicking against a gate or a wall. +They occur also as a result of an uneven step upon a loose stone when going +at a fast pace, and as a result of sudden slips and turns, in which latter +case they are met with when animals have been galloping unrestrained in +a field, or when an animal, ridden or driven at a fast pace, is suddenly +pulled up, or just as suddenly turned. + +At other times fractures in this region take place without ascertainable +cause, and cases are on record where animals turned overnight into a +loose box in their usual sound condition have been found in the morning +excessively lame, and fracture afterwards diagnosed. + +1. FRACTURES OF THE OS CORONAE. + +Fractures of the os coronae result from such causes as we have just +enumerated, and are nearly always seen in conjunction with fractured +os suffraginis. When this latter bone is also fractured diagnosis is +comparatively easy, a certain amount of crepitus, even when the suffraginis +is only split, being obtainable. When the os corona alone is fractured +then diagnosis is extremely difficult, the smallness of the bone and the +comparative rigidity of the parts rendering manipulation almost useless, +and effectually preventing the obtaining of crepitus. It is, in fact, only +when the bone is broken into many pieces that crepitus may be detected, and +even then it is slight. + +_Reported Cases_.--1. 'The subject was a four-year old hunter. While at +exercise in the morning of August 10 he bolted, got rid of his rider, and +ran about in a mad fashion, came into contact with a wheelbarrow in a +narrow passage, and finally came into violent contact with a wall, which +had the effect of throwing him down. The rider stated that the animal +suddenly put down his head and managed to get off the bridle; he then +bolted, and the only chance for the rider was to throw himself off. + +'On examination I found the horse unable to place any weight on the off +fore-leg, the pastern was swollen and painful, the hollow of the heel was +also swollen, and there was marked constitutional disturbance. + +'After a short time he would place the heel on the ground and elevate the +toe to a slight degree. On manipulating the pastern slight crepitation +could be discovered, and there was abnormal mobility in the corono-pedal +articulation. On the near fore-leg there were extensive wounds in the +region of the knee, and great laceration of the tissues. The animal was +destroyed. + +'On examining the leg I found the subcutaneous tissues infiltrated from +below the knee to the foot, large masses of gelatinous blood-stained +material being present along the flexor tendons and in the hollow of the +heel. The inferior articular surface of the os suffraginis was denuded +of cartilage anteriorly; the os coronae was fractured into eight moderate +sized, irregular fragments, and ten minute pieces. The surface of the +perforans tendon as it glides over the smooth surface at the back of the os +coronae was lacerated, and minute portions of the bone were found embedded +therein.'[A] + +[Footnote A: E. Wallis Hoare, F.R.C.V.S., _Veterinary Record_, vol. xiv., +p. 133.] + +2. 'Here, again, fracture was the result of the animal bolting with his +rider. Trying to avoid collision with a conveyance coming towards him, the +animal slipped on a wooden pavement, sliding along until his near fore-leg +came in contact with the wheel of a standing cab. There was considerable +swelling from the knee downwards, great pain, and evidence of fracture in +the region of the pastern. + +'Post-mortem revealed the os suffraginis broken into about thirty pieces, +and the os coronae with a piece broken off the inside of its proximal +end.[A] + +[Footnote A: A.F. Appleton, M.R.C.V.S., _Veterinary Journal_, vol. xiii., +p. 411.] + +3. 'The patient was a brown mare used for heavy van work in London. About +January 10 she was lame, and as she had a cracked heel, was treated by +poulticing for a day, and then by antiseptic lotions. In a week she was +sent to work, but the following day lameness returned, and continued till +about February 15. No special symptom was detected which indicated the +exact position of any cause of lameness. Then the lameness increased in +severity, and some swelling around the coronet began to show itself. + +'In consultation with another veterinary surgeon, two possible causes of +this intense lameness were discussed: one, that we had septic infection of +the coronet, and that probably the swelling of this part would soften, and +sloughs occur; the other, that a fracture of the os pedis or os coronae +existed. The enlargement of the coronet was hard and firm, not particularly +sensitive. It was decided to do nothing for a few days. In a week the +pain abated, and the mare would put her foot on the ground, and ceased to +"nurse" the limb as she had done. When moved over in the box she put a +little weight on the foot, but limped very decidedly. + +'Another week passed, and the pain and lameness further abated, but the +swelling around the coronet continued. Perhaps it was a little less in +front, but it had not decreased on the inside. It remained firm, and was +not painful on pressure. It showed no soft places, and the upper part of +the leg remained free from oedema. + +[Illustration: FIG. 158.--FRACTURE IN SITU (OS CORONAE).] + +'The diagnosis was now that a fracture existed, and it was proposed to +send the mare to grass for a few months. The consulting veterinary surgeon +suggested that before doing so a blister might be applied to the coronet. +This was done. The mare was found next day again on three legs. She had +apparently been down during the night. In a few days the coronet increased +again in size, and within a week "broke out" in two places. + +'The opinion now formed was that, with a fracture and this additional cause +of inflammation around the joint, it would be most economical for the owner +to have her killed. This was done, and a post-mortem examination was made +by Mr. Hunting and Mr. Willis. + +[Illustration: FIG. 159.--WITH BROKEN PORTION REMOVED.] + +'_Post-mortem_.--The foot, cut off at the fetlock-joint, showed extensive +swelling all round the coronet. There were two wounds on the skin--one on +the front of the coronet, the other on the inner side. From both pus and +blood had escaped. They both communicated under the skin with a large +abscess cavity. The abscess did not communicate with the joint. The pastern +bone was sound. On separating the pastern from the coronet bone the +articular surfaces were of a healthy colour, but the soft tissues +immediately surrounding them were inflamed. On the centre of the articular +surface of the coronary bone a thin red ring was noticed, and the portion +of cartilage within it seemed raised. With the point of a scalpel this +portion was lifted, and was found to be not only cartilage, but a layer of +bone completely detached from the os coronae. On removing the bones from the +hoof the rest of the bone was quite normal, as was the pedal bone. + +'Fig. 158 shows the articular surface of the coronet with the fracture _in +situ_; and Fig. 159 the surface from which the broken portion is removed +and laid to the side of the foot. + +'Some interesting questions arise. How was the fracture caused? When did it +occur? Between the broken portion and the main bone there was a layer of +granulation tissue, so that it is certain the injury existed before the +blister was applied, and it may possibly have existed from the commencement +of the lameness.'[A] + +[Footnote A: R. Crawford, M.R.C.V.S., _Veterinary Record_, vol. viii., p. +478.] + +2. FRACTURES OF THE OS PEDIS. + +These also are a result of the causes we have before given. The os pedis +is also liable to fractures from pricks, from treads in the region of the +wings, and from the malnutrition and careless use of the foot sometimes +following neurectomy. + +It is interesting to note that, with fracture of this bone, lameness is +nearly always excessive, but that at times it may be entirely absent. +Crepitus is, of course, denied us, and in nearly every instance the case +is only diagnosed when the lameness persists and pus commences to form, or +when grave changes in the normal shape of the foot compel our attention to +the parts. When it is the continued formation of pus that draws our notice +to something more than ordinarily grave, it is in giving exit to the pus +that the fracture is nearly always discovered. + +_Reported Cases_.--Two interesting cases of fractured os pedis are reported +by Mr. Gladstone Mayall, M.R.C.V.S., in the _Veterinary Record_, vol. xiv., +p. 54: + +1. 'The horse was brought in markedly lame on the off hind-foot, knuckling +at the fetlock, and taking a long stride with the injured limb. There was +a punctured wound at the toe. The horn was pared, and antiseptic poultices +applied. Notwithstanding the antiseptic treatment pus continued to form. At +the end of a week sufficient horn was removed to ascertain the cause of +the constant suppuration. A movable object was found at the bottom of the +wound, and a piece of bone as large as a sixpence finally removed. Recovery +was uneventful.' + +[Illustration: FIG. 160.--FRACTURED OS PEDIS.] + +2. 'A filly was attended for a discharging fistula at the coronet. +Externally it had all the appearances of a quittor. At first no history +was given. The filly went scarcely lame at all, and had never been shod. +Treatment with poultices and caustic injections was useless. Finally the +filly was cast and the foot examined. A piece of bone, apparently part of +the wing of the os pedis, was removed, and the case made a good recovery. +Subsequent inquiries elicited the fact that the animal had kicked at and +hit a gate-post, and it was judged that then the injury had occurred.' + +3. 'The subject was a bay horse, nine years old, used for railway shunting. +On August 7 he was found to be intensely lame of the near hind-limb, and, +after inquiries, there was no evidence bearing on the cause, as is often +the case, and at times this comes to light when least expected. + +'I was called in consultation on September 2, and found him suffering +acute pain, with great swelling around the coronet. The foot was examined +thoroughly, and the diagnosis was fracture of the pedal bone, and immediate +slaughter was recommended. However, that was not carried out, and he died +on September 22. + +'The post-mortem inspection revealed a complete fracture of nearly the +whole of the articulating surface and the left wing of the pedal bone (as +shown in Fig. 160).'[A] + +[Footnote A: J. Freeman, M.R.C.V.S., _Veterinary Journal_, vol. xxxi., p. +324.] + +4. A further interesting case is reported by Mr. William Hurrell.[A] Here +the cause was presumably galloping in the field, for the subject, a cart +mare running out at grass with her foal, was suddenly found to be lame. + +[Footnote A: _Ibid_., vol. v., p. 408.] + +As the lameness continued to increase in severity, Mr. Hurrell was called +in on August 1, and diagnosed the case as one of foot lameness. On this +date the foot was pared out, and a large accumulation of pus discovered, +Poulticing and antiseptic dressings were continued until August 16, when a +movable piece of the os pedis was found at the toe. + +On August 25 this detached portion of the bone was removed, and turned out +to be the whole of the anterior margin of the os pedis, measuring 3-1/2 +inches long, and varying in width from 1/2 inch to 1-1/2 inches. On +September 20 the mare was working without lameness. + +3. FRACTURES OF THE NAVICULAR BONE. + +Hidden within the wings of the os pedis, and protected as it is by its +tendinous covering and the yielding substance of the plantar cushion, the +navicular bone is even less liable to fracture than either of the other +bones of the foot. + +The most common cause of fracture of the navicular is that of stabs or deep +pricks in the region of the point of the frog (see p. 216). Following that, +the next most common cause is violent injury. We thus find the navicular +bone fractured, together with one or both of the other bones of the foot, +when the foot is run over by a heavy vehicle. One such case is reported +by Mr. J.H. Carter, F.R.C.V.S., where the horse's foot was run over by a +tram-engine, in which the os pedis and the navicular were fractured in +several places.[A] A further case is on record where a sharp blow on the +front of the hoof was the cause. In this case the os pedis and other +structures were uninjured, but the navicular bone was fractured into three +large, and about half a dozen small, pieces.[B] + +[Footnote A: _Veterinary Journal_, vol. xxxi., p. 246.] + +[Footnote B: _Veterinarian_ for 1857, p. 73.] + +Fractures of the navicular may occur, however, in which history of a prick +or of a violent injury is absent. See reported case below. + +As with fractures of the os pedis and the os coronae, so with this exact +diagnosis is difficult--we may say almost impossible. With a history of +violent injury, however, some little regard may be paid to a continued heat +and tenderness of the foot, and a distinct inclination on the part of the +animal to go on the toe. Even when the fracture is the result of a prick, +and the bone is plainly felt with the probe, we still cannot be positive as +to fracture. + +_Reported Case_.--'The animal was a Hungarian, a troop-horse in the 3rd +Hussars (G. 15). On November 22, 1881, on the march from Norwich to +Aldershot, the horse suddenly made a violent stumble, very nearly coming +on to his knees. The rider declared that he put his foot on a stone. The +accident caused great lameness in the near fore-leg, and the horse had to +be led the remainder of that day's march. On the following day he was also +led; but, after going some sixteen or eighteen miles, he was so lame that +he was left at the nearest billet (in Edmonton). He was here attended by +Mr. Stanley, M.R.C.V.S., of Edmonton, who pronounced it a case of navicular +disease. I first saw the animal on December 1, 1881, and quite agreed with +Mr. Stanley that it was a case of foot lameness, though, from the horse's +former history, I could not think it a case of ordinary navicular disease. +I diagnosed it a case of fracture, without displacement, either of the os +coronae or the navicular bone, but was more inclined to the former than the +latter. This was after a full hour's examination. I failed to find any heat +in, or any flinching by manipulation of, any part of the limb; but, in +walking, the horse was excessively lame, going on the toe, and, indeed, +trying if possible to keep the foot entirely off the ground. + +'On December 6 the horse was sent on to Aldershot by rail. He was then +walking better, though still very lame. My only treatment for a short time +was to apply cold water constantly to the coronet and foot. For two hours +daily this was done by a hose, the remainder of the time by a cold swab. On +December 14 I applied a strong blister over the coronet, reaching up to the +fetlock. This was washed off about the end of December. The horse was then +not nearly so lame. I then resumed the cold-water treatment, and he got +gradually better, and was sent to light duty on February 18, 1882. He, +however, only attended one field-day, and was taken into the Horse +Infirmary again on March 8, very lame. Again, there was an entire absence +of heat or pain on pressure, but the same action, viz., going on the toe. +I forgot to remark that he always pointed the toe of the affected leg when +standing in the stable, and this symptom continued. I put him under the +cold-water treatment for a short time, and about the middle of March again +applied a strong blister over the coronet up to the fetlock. This was +washed off about the end of the month, and was succeeded by the cold water +again. Towards the end of April there was no improvement at all, and I +applied for permission to destroy the horse. This was carried out on April +27, at the recommendation of Mr. Gudgin, I.V.S., Aldershot, and a Board of +veterinary surgeons. + +'On making the post-mortem examination I first thought the bone was only +partly fractured or cracked, but on manipulating it, after its being in hot +water a short time, I saw the fracture was complete.'[A] + +[Footnote A: S.W. Wilson, M.R.C.V.S., A.V.D., _Veterinary Journal_, vol. +xv., p. 12.] + +_Treatment of Fractures of the Bones of the Foot_.--It will be seen at once +that in most cases anything in the way of bandaging is well-nigh useless. +When the os coronae is fractured, however, a little more may be added to the +natural rigidity of the parts by enclosing the region of the pastern and +the foot in a plaster-of-Paris bandage. The main treatment, however, in +every case, will be a continual use of the slings for at least seven to +eight weeks, by that means compelling the animal to give to the injured +parts the necessary amount of rest. + +With fracture of the os pedis, when such is caused by pricks and +complicated by a flow of pus, then attention must be given to removal of +the displaced piece of bone. The pus track is to be followed up with the +searcher, sufficient horn removed with the knife, and the broken piece of +bone removed with a scalpel and a pair of strong forceps, the operation to +be afterwards followed up by antiseptic dressings to the opening. Until +this is done the wound refuses to heal. + +Fracture of the navicular bone, if in any way diagnosed with certainty, +offers us an almost hopeless case, for it appears to be a commonly reported +fact that attempts at reunion are rare. This, in all probability, is due +to the pressure put upon it every now and again, when the animal's weight +presses the bone between the os coronae and the os pedis above and the +perforans tendon below. Even should reunion take place, the resulting +callus, interfering as it does with the movements of the perforans, leaves +us a case of incurable lameness. When the fracture is complicated by +the formation of pus, as in the case of prick, then the case, with the +attendant purulent synovitis and arthritis, is even more hopeless still. + +Diagnosis of fracture of either of the bones of the foot is, as we have +said before, extremely difficult. It so happens, therefore, in those cases +caused by violent blows, that anything approaching an accurate opinion +cannot be given until some months after the injury. After some time we are +met with unmistakable changes in the form of the foot, and are able to +assume that the persisting lameness is due to pressure of a reparative +callus within the hoof. In such cases the only treatment of any use is that +of neurectomy. + + + +CHAPTER XII + +DISEASES OF THE JOINTS[A] + + +[Footnote A: Properly speaking, we have in the foot of the horse but _one_ +joint--namely, the corono-pedal articulation. + +Although not a joint in the strict sense of the word, we, nevertheless, +intend here to consider the navicular bursa as such. In this apparatus, +although we have no articular cartilage proper, and no apposition of bone +to bone, we still have a large synovial cavity, and in close proximity to +it bone. We may, in fact, and do get in it exactly similar changes to those +termed 'synovitis' and 'arthritis' elsewhere. Therefore, we include the +changes occurring in it in this chapter, and hence the plural use of the +word to which this note refers.] + + +A. SYNOVITIS. + +_Definition_.--By the term 'synovitis' is indicated an inflammation of the +synovial membrane. It may be either (_a_) _Simple_ or _Acute_, or it may be +(_b_) _Purulent_ or _Suppurative_. + +In the simple form there is little or no tendency for the affection to +implicate the other structures of the joint, whereas in the suppurative +form the joint capsule, the ligaments, and the bones soon come to +participate in the diseased processes, giving us a condition which we shall +afterwards describe as acute arthritis. + +(_a_) SIMPLE SYNOVITIS. + +1. _Acute--(Causes)_.--Simple or acute synovitis is nearly always brought +about by injury to the joint--by blows or bruises, or by sprains of the +ligaments. At other times it occurs without ascertainable cause, and is +then put down to the influence of cold, or to poisonous materials (as, for +example, that of rheumatism) circulating in the blood-stream. + +_Pathology_.--Uncomplicated acute synovitis never causes death. The +pathological changes in connection with it have therefore been studied in +cases purposely induced, and the animal afterwards slaughtered. It is then +found that, as in inflammation elsewhere, the synovial membrane is showing +the usual inflammatory phenomena--that it is thick and swollen as a result +of the inflammatory hyperaemia and commencing exudation. Later, the synovial +fluid becomes increased in quantity, is thin and serous, and after a time +is seen to be mixed with the inflammatory exudation poured into it. We then +find that it has lost its clear appearance, has become thick and muddy, and +has floating in it flakes of fibrin. + +If the case progresses favourably these materials are soon absorbed and +resolution occurs. In rarer cases the thickening and congestion of the +membrane increases, and the articular capsule becomes so distended with the +increased synovia and accumulated inflammatory discharges that a kind +of chemosis occurs. In other words, there oozes through, without actual +rupture of the membrane, a thin, blood-stained, and purulent-looking +discharge. + +It is an important point to note that in cases of synovitis the fringes of +the synovial membrane become swollen and blood-injected, forming noticeable +red elevations at the margins of the cartilages. It is then that the +diseased condition soon spreads and runs into arthritis. + +Further, it is important, especially with regard to the question of the +degree of pain and lameness likely to be caused, to note that often +granulations are thrown out upon the looser folds of the membrane. As +these increase in size they come to form fringed and villous membranous +projections inserting themselves between the bones forming the +articulation. In such cases there is no doubt that the intense pain +sometimes observed in these cases is due to pinching of these prolongations +of the synovial membrane by the opposing bones of the joint. + +_Symptoms and Diagnosis_.--Acute synovitis of a joint leads to heat of the +parts, pain, distension of the capsule, and, where the joint may be easily +felt, fluctuation. In the articulation with which we are dealing, however, +these last two symptoms are not easily detected, for the surrounding +structures--namely, the lateral and other ligaments of the joint, the +extensor pedis tendon in front, and the perforans behind, together with the +dense and comparatively unyielding nature of the skin of the parts--are +such as to prevent distension and fluctuation becoming marked to a visible +extent. We are able to diagnose the case as one of foot lameness, and, with +a history of a severe blow or other injury, are able to assume that this +condition, perhaps attended with periostitis, is in existence. + +When other symptoms present themselves diagnosis may be more certain. The +animal becomes slightly fevered, throbbing pains in the joint manifest +themselves by irregular pawing movements on the part of the patient. The +animal comes out from the stable stiff, even dead-lame, and the limb is +carried with the lower joints semiflexed. The breathing is hurried and the +pulse firm and frequent, while in a bad case patchy perspiration breaks out +at intervals on various parts of the body. If with this we get a puffy and +tender swelling in the hollow of the heel, our diagnosis may be certain at +any rate as to the existence of joint trouble, although, from reasons we +have given, we may not be able to mark its exact nature. + +2. _Chronic_.--Simple synovitis may in many instances become chronic. In +this case we have simply a pouring into the synovial capsule of serous +fluid, and with it an increased quantity of synovia--this time with an +absence of the usual inflammatory phenomena. Beyond the swelling of the +capsule there is little to be noticed. The joint becomes perhaps a little +weaker, but pain or tenderness and heat are entirely absent. Such a +condition, by reason of the natural rigidity of the parts, is not to be +observed in the foot, although at times it must most certainly occur. +Examples of such a condition are to be found in bog-spavin, in hygroma of +the stifle, and sometimes in the fetlock. From a study of these, we know +that they may be induced by frequent attacks of acute synovitis, from +repeated slight injuries or bruises, or from strains to the ligaments of +the joint; or that they may be chronic from the outset. We know, too, that +in such cases the synovial membrane becomes thickened, and that in places +it may have extended somewhat over the edges of the articular cartilages. +It is only fair to suppose that such changes occur also in the pedal +articulation. In that case we may take it for certain that the natural +rigidity of the surrounding structures has the effect of pushing the +thickened membrane further between the bones of the joint than occurs in a +like condition elsewhere, leading, of course, to a lameness that is marked +in degree but occult as to cause. + +In our minds there is no doubt that many of the occult and chronic forms of +foot-lameness we meet with in practice are in this way to be accounted for. +We may, in fact, explain them by suggesting either a chronic synovitis +alone, or a synovitis complicated with periostitis. + +_Treatment of Synovitis_.--If a joint has been injured, as we have +suggested, by slight blows or other causes--in other words, if the injury +is subcutaneous, and no wound is in existence--then there is no treatment +which offers better results than does the continued application of cold. + +At the same time, the animal should be slung, or, if non-excitable and +inclined to rest, allowed at intervals to lie on a thick and comfortable +straw bed, the cold fomentations during such intervals being discontinued. +When the case is a marked one and the animal valuable, benefit will be +derived from the application of crushed ice. + +The animal's condition must be watched, and the case helped as far as is +possible by the administration of a mild dose of physic, by saline drinks, +and, when necessary, by the giving of small but repeated doses of Fleming's +tincture of Aconite in order to relieve the pain. In a chronic case the +repeated application of a blister is indicated. + +(b) PURULENT OR SUPPURATIVE SYNOVITIS. + +In this condition we have synovitis complicated by the presence of pus. +Unlike the simple form, it shows a marked disposition to spread, and +quickly involves the surrounding structures. Very soon the ligaments of +the joint, the periosteum, the articular cartilages, and the bones are +implicated. This, of course, constitutes a condition of acute purulent +arthritis. Under that heading, therefore, the condition will be later +discussed. + + +B. ARTHRITIS. + +(a) SIMPLE OR SEROUS ARTHRITIS. + +With an attack of simple synovitis it may be always assumed that the +changes commenced in the synovial membrane, communicate themselves more +or less readily to the surrounding tissues, and are not confined to the +synovial membrane alone. We may thus have the inflammatory phenomena +asserting themselves in the surrounding ligaments, in the periosteum, in +the bone, and in the articular cartilages. It depends, in fact, upon the +severity of our case whether we call it synovitis or arthritis. The two +conditions merge so the one into the other that no hard-and-fast rule +may be laid down whereby they may with certainty be differentiated. Such +symptoms, therefore, as we have given for synovitis may be also read as +indicating a condition of simple arthritis. The course of the case will be +very similar, and the treatment to be followed identical with that just +given. + +(b) ACUTE ARTHRITIS. + +_Causes_.--An attack of acute arthritis may commence with the affection of +the synovial membrane, and spread from that to the other structures. In +other cases the disease of the synovial membrane, and after it the disease +of the joint, may be secondary to diseases commencing in the structures +around the joint. This affection may therefore follow on a case of acute +coronitis, a case of suppurating corn, a case of quittor, a severe case of +tread, or may attend a case of laminitis. + +_Symptoms_.--In our cases we get very little beyond a magnification of such +symptoms as we have described under acute synovitis. The heat and the pain +is perhaps greater, and the lameness more marked. It is rather to the +constitutional disturbance we must look, however, for a confirmation of our +opinion that arthritis is in existence. This is always severe, and of +an acute febrile nature. The pulse is fast, thin, and thready, the +respirations enormously increased, and the temperature high. The appetite +is in abeyance, the animal quickly becomes what is termed 'tucked-up,' or +greyhound-like, in the body, and patchy perspirations break out about him. +The limb is held with the joints all semiflexed, and severe and intense +throbbing pains are indicated by the frequent pawing movements the animal +makes in the air. Manipulation of the foot is resented, and the agonizing +intensity of the pain so caused is shown by the drawn and haggard +appearance of the eyes. + +In a favourable case the symptoms from now onwards may gradually subside. +The appetite returns, the breathing and other signs of disturbance show a +return to the normal, weight is placed on the limb, and resolution slowly +but surely takes place. In many of these, our favourable cases, however, +resolution is incomplete, and recovery only takes place at the expense of +anchylosis of the joint, a condition we shall refer to later. + +In unfavourable cases, and these unfortunately are only too common, the +condition terminates in suppuration. + +(c) PURULENT OR SUPPURATIVE ARTHRITIS. + +_Definition_.--By this term we indicate an arthritis complicated by the +formation of pus within the joint. + +_Causes_.--The organisms of pus may infect the joint by extension of a +suppurating process from without. For example, in the case of a suppurating +corn, in quittor, in tread, or in the case of a suppurating wound caused +by a prick, the pus formed may in many instances be very near the capsular +ligament of the articulation. Under such circumstances, unless there is a +free and unhindered flow of the pus from an outside opening, inroads will +be made by it upon the thin capsule. The latter is quickly penetrated, and +pus is admitted to the interior of the joint. + +In other cases infection of the joint may proceed from within, from a +poisoned state of the blood-stream. The condition occurs, for instance, +in bad attacks of laminitis. We ourselves, too, have seen two cases where +suppuration of the pedal articulation occurred in the septic pyaemia of +foals, a disease known commonly as 'joint-ill,' and characterized by an +infected state of the circulation. Cases have also come under our notice +where this condition has resulted from slight injuries in the region of +the insertion of the extensor pedis inflicted by the animal himself when +galloping away. + +Perhaps, however, the most common cause of suppurative arthritis in the +foot is direct penetration of the articulation in the case of pricks. +The penetrating object is nearly always dirty--bacterially dirty, at any +rate--and suppuration only too readily commences. Even should such a wound +be inflicted by an aseptic body, infection would quickly ensue as a result +of the wound gathering dirt from the ground, or even from admission to the +joint of impure and bacilli-laden air. + +_Symptoms and Diagnosis_.--This is one of the most serious conditions we +are called upon to face when dealing with diseases of the foot, for in many +cases it quickly ends in exhaustion and death of the patient, while in even +the most favourable cases nothing better than a condition of complete and +bony anchylosis is to be expected. The owner, therefore, should be warned +accordingly. + +As in the other joint affections, so here, we get all the symptoms of +acute febrile constitutional disturbance. The pulse, the temperature, +the respirations, and the general haggard, 'tucked-up,' and distressed +appearances of the animal all tell too plain a tale. Our patient is in +constant pain, and the seat of the trouble is clearly enough shown by the +constant pawing movements of the affected foot. If he has room to get up +and down in comfort the animal adopts for long periods at a stretch the +recumbent position, and is not upon his legs long enough to take the +necessary amount of food to keep him going. Even when down, it is plain to +see that the animal is not at rest. The pawing movement is still maintained +with the foot, and every now and again the eyes are opened and the headed +lifted to give a troubled look round. The appetite, too, is capricious, and +in many cases almost entirely lost. + +In some slight degree the condition is less to be feared in a fore than in +a hind foot--that is, so far as absolutely fatal results are concerned. +With the condition confined to one fore-foot, the animal is able to get up +and down with a moderate degree of comfort. At intervals, therefore, he +rises to take nourishment, and as soon as his wants are satisfied again +lies down. + +With the disease in a hind-foot matters are not taken so comfortably. The +patient finds that with each day's increasing weakness the difficulty that +at first he had to raise himself with only one sound hind-foot becomes +enormously increased. The consequence is that he fears to go down, and the +standing position is maintained until sheer weakness overcomes him, and he +goes down, not to rise again without assistance. + +If judiciously attended he is, of course, put in slings before this stage +is reached; but there are instances, as in the case of a cart-mare heavy +with foal, where the use of slings is most decidedly contra-indicated. + +If doubt before existed as to the nature of the case, it is at a later +stage dispelled by the appearance, generally in the hollow of the heel, of +a hot and painful swelling. This at first is hard, but later fluctuates. +Finally it breaks at one or more spots, and there exudes from the opening +or openings a purulent and oftentimes sanious discharge, which coagulates +about each fistula after the manner of ordinary synovia. + +With the discharge of the abscess contents there is some slight improvement +in the symptoms. Here, with a suitable treatment, and with a patient of a +particularly robust constitution, the case appears to turn, and slowly but +surely progresses towards the only end we can hope for--namely, a more or +less painless anchylosis of the articulation. + +In less favourable cases the purulent discharge continues, and (always a +bad sign) becomes more or less chocolate-like in colour, distinctly thin, +and stinking. The diseased process spreads until the ligaments of the +joint, both by reason of their infiltration with the inflammatory +discharges, and also on account of the ravages made on them by the invading +pus, either greatly stretch or altogether rupture. + +The joint, after its ligaments have been destroyed in this manner, is +loosened, and the bones are now freely movable. Their manipulation gives +to the touch a sickening, grating sound--in other words, we have crepitus. +This, of course, indicates that the articular cartilages have become +greatly eroded by the inflammatory process, and so left what we may term +'raw' surfaces of bone to rub together. When the animal is put to the walk +the toe of the foot is elevated, and the extreme mobility of the foot gives +one the idea of fracture. With every step there is a peculiar sucking +noise, comparable to that of a foot moving in a boot of water, and +putrescent matter is squeezed from every opening each time the foot is put +to the ground. Although we have seen cases even advanced thus far recover, +it is questionable whether it is now wise to attempt to prolong life. +Slaughter is far more humane, and, in our opinion, except with a valuable +brood animal, more economical. + +If the animal is allowed to linger, other symptoms will nearly always +present themselves before death occurs. Whether in slings or not, a careful +watch should be kept upon the sound limb. For some time the patient stands +upon it incessantly, but sooner or later it happens that a farther visit +show us the animal standing with full weight on the diseased foot, and +making painful pawing movements with what before was the sound. We +immediately jump to the conclusion 'laminitis.' And so it is, but it is a +laminitis brought about by pyaemia. This is indicated by the swollen and +oedematous nature of the lymphatics of the limb. Plainly enough they +indicate the road by which the poison has travelled. It is in this way: Pus +and putrefactive organisms have gained entrance to the lymphatics of +the original diseased limb. From these they have rapidly gained the +blood-stream and set up infection elsewhere. In this particular instance it +is demonstrated by the laminitis and lymphangitis of the previously sound +limb. With the poison thus circulating in the blood-stream, we often +also get spots of infection commenced in one or other of the more vital +organs--notably the lungs or the kidneys. The end of our case is then +either a gangrenous pneumonia or complications induced by a condition of +widespread pyaemia. + +With the animal in slings there are one or two other symptoms that call +for attention. In many cases, especially with animals of a lymphatic and +indolent nature, the use made of them is inordinate. The patient rests +so continually in them that alarming swellings commence to make their +appearance about the rectum, or in the case of a mare about the vulva. The +animal must then be let down at regular intervals and again raised when +rest is obtained. + +A more alarming symptom still is when the animal, instead of resting in the +slings by his buttocks, casts his weight bodily into the belly-rest and +hangs with a heavy head into the head-stall. This indicates complete +exhaustion and a wish for death. Matters should therefore be explained to +the owner, and his consent obtained for immediate destruction. + +_Pathology_.--The pathological changes occurring in suppurative arthritis +we shall pass over briefly. It is almost sufficient, in fact, to say that +the whole of the joint becomes completely disorganized. + +The synovial membrane becomes so tremendously thickened and injected as to +be scarcely recognisable as such, the thickening in the later stages +being due to large growths of granulation tissue which entirely alter the +appearance of the membrane as we know it normally. In the early stages +the contents of the joint are composed of thin pus and synovia. Later, +as destruction of the synovial membrane proceeds, the flow of synovia is +stopped, while the pus formation goes on until finally nothing but pus and +dead tissue products fill the cavity. + +If the suppurative process has commenced from within, the pus that is +formed is, as a rule, thick and creamy, comparatively unstained, and free +from marked odour. If, on the other hand, air has gained access to the +joint, or the suppurative process has started from the materials introduced +by a foreign body, the joint contents are thin, blood-stained, and +stinking. + +The inflammatory changes in the joint soon spread to the ligaments, and to +the soft structures in contact with them. This means that the ligaments +become infiltrated with inflammatory exudate, that the fibrous bundles +composing them become separated, and that the ligaments are weakened and +easily stretched. As a consequence, a certain amount of displacement or +dislocation of the bones is allowed. + +In like manner the inflammatory changes keep spreading until we have the +periosteum next the ends of the bones affected. The periostitis thus set +up invariably takes the osteoplastic form, and as a result of this we have +growths of new bone in the near neighbourhood of the joint. It is in the +later stages of the disease--that is, when the pus has been evacuated and +reparative changes commenced--that this osteoplastic periostitis is most +marked, and it plays a large part in bringing about the condition of +anchylosis, which we shall afterwards describe. + +Grave changes also occur in the articular cartilages. They quickly lose +their peculiar glistening polish, their semitransparency is lost, and the +natural tint of a pearl-like blue gives way to a dirty yellow. Later this +is followed by erosion of the cartilages at such points as they happen to +be in greatest contact. The ends of the bones are thus exposed, and their +medullary cavities exposed to infection. As a result we get in them the +changes we have already described under Ostitis. + +_Treatment_--_(a) Preventive_.--Seeing that many of these cases have their +starting-point in stabs or penetrating wounds of the sole, we shall be +concerned first with a consideration of the correct treatment to be adopted +when we know the wound to have reached the articulation. + +Only too frequently the treatment practised is that of poulticing. In other +portions of this work we have pointed out the advantages that a continued +antiseptic bathing has over the application of a poultice, the greater +readiness with which the solution comes into contact with the deeper parts +of the wound, and the far greater chance there is of maintaining water in +an antiseptic condition than there is of keeping a poultice in the same +state. There is no doubt, that in this case also, the cold or warm +antiseptic bath is to be preferred to the poultice. It is questionable, +however, whether even the bath is sufficient for our purpose here. We have +in this case a deep punctured wound, and a wound that in every probability +is infected with the organisms of pus or of putrefaction. It is a wound, +moreover, which is likely to impede the thorough access to it of the +solution in which the foot is fomented, on account of the flakes of +coagulated fibrin which fill it. + +The most rational treatment, therefore, if we get to the case early enough, +is to irrigate the wound freely with a solution of carbolic acid in water +(1 in 20), or with a solution of perchloride of mercury (1 in 1,000), +injected by means of a glass syringe, or the pattern of syringe devised for +quittor. This injecting should be done thoroughly, and by that we mean that +several syringefuls of the solution should be injected, the joint after +each injection being manipulated so as to distribute the solution as far as +possible over it. When this is done the opening in the sole may be plugged +with a little perchloride of mercury, or, better still, with a little piece +of tow saturated with a concentrated solution of perchloride of mercury +or a solution of iodoform in alcohol and an antiseptic pad of tow or lint +placed over all. The foot should then be bandaged and encased in a boot or +sacking protective. The bandage should be removed daily and the antiseptic +pad changed. At each visit the animal's condition must be carefully +noted. So long as constitutional disturbance is slight, the foot appears +comfortable, is free from marked heat and tenderness, and pawing movements +are absent, and so long as the discharge on the pad appears non-purulent, +free from marked odour, and small in quantity, then this dressing may be +persisted in. + +This treatment of open joint, preventive as it is of arthritis, is also +indicated in the case of open navicular bursa. In several instances we have +practised this treatment for the dressing of wounds implicating the bursae +of tendons and the capsules of joints. It is also spoken of favourably by +Mr. C.H. Flynn in the _American Veterinary Review_ for June, 1888, whose +treatment is as follows: 'Place the patient in a clean, well-ventilated, +and drained stable. Have all the litter removed, and insist on the stall +being kept clean. Either place the animal in slings, or tie the head so as +to prevent lying down. Clip the hair and cleanse the parts well. He prefers +the corrosive sublimate solution (1 in 1,000). Should the wound be of two +or more days' standing, inject the joint with the corrosive sublimate +solution. Now dry the parts with a clean towel and sprinkle the wound with +iodoform. Over this place a thick layer of absorbent cotton-wool, filled +with iodoform, bandage securely, and keep the patient on a moderate diet, +preserving the utmost quietude possible. Should the bandage remain in +position and the animal free from pain, leave the bandage and dressing in +place from five days to a week. Then change it, and should the discharge +be little, do not disturb it, but renew the iodoform and cotton dressing, +leaving it on for another week.' + +Other treatments for the same condition are practised, in which the wound +is dusted with powdered iodoform, with potassium permanganate, or with +corrosive sublimate, or where the wound, instead of being dusted, has +the corrosive sublimate applied in the form of a plug. In each case the +preliminary irrigation with the corrosive sublimate solution is dispensed +with. This, however, should on no account be omitted. In our opinion it +constitutes the very essence of the rationality of the treatment. + +_(b) Curative_.--It may happen, however, and often does, that this first +injection of an antiseptic is unsuccessful in preventing organismal +infection of the wound. In this case grave constitutional disturbance and +other untoward symptoms such as we have already described quickly make +their appearance. + +The animal should now be placed in slings and preparations made for +actively treating the wound with antiseptics. Whether we fail or not, we +have the satisfaction of knowing that we have given to the patient the best +and the only chance of recovery. + +It should be remembered, however, and should be pointed out to the owner, +that with purulent arthritis fully developed, with the grave constitutional +changes it occasions, and with the ever-present danger of a general +septic invasion of the blood-stream, that the human surgeon under such +circumstances offers to his patient the alternatives of amputation or +probable death. With us no such alternative is possible. It is either +return the joint to some semblance of its former usefulness, or destroy the +patient. + +In this case we advise the injection of the original wound, and also such +fistulous openings as may have formed, with the 1 in 1,000 sublimate +solution. Also, in order to avoid the sometimes abortive attempts of the +antiseptic pad, to maintain a condition of asepsis around the wound, we +advise the continual soaking of the whole foot in a cold antiseptic bath. +This may be either carbolic acid 1 in 20, or--what is less volatile, +perhaps more effectual, and certainly more economical--perchloride of +mercury 1 in 1,000. + +It has been our good fortune, even when we have seen the foot almost +detached from the limb by the devastating inroads of the pus, to see +the suppurative process by this means gradually overcome, a reparative +anchylosis set in, and the animal restored to good health and usefulness, +if not to soundness. + +Once the suppurative process is checked and anchylosis commences, it is +good treatment to smartly blister the whole of the region of the coronet, +the pastern, and the wound itself with a mixed blister of cantharides and +biniodide of mercury, repeated at intervals of a fortnight. This prevents +to some extent further infection of the wound, and assists also in +promoting the changes that tend to anchylosis. + +_(d)_ ANCHYLOSIS. + +The word anchylosis signifies the stiffening of a joint. When one has read +the serious changes occurring within the joint in the more serious forms +of arthritis, it is easy to understand how it comes about. In suppurative +arthritis, for instance, we have the synovial membrane destroyed, the +articular cartilages partly or wholly obliterated, and the former +boundaries of the joint entirely lost. If the animal lives, nature is +bound to make repair of a sort. The synovial membrane and the articular +cartilages utterly destroyed, as we have described, cannot again be +replaced. Nature can only build again from such materials as are left to +her. In this case the material is bone. + +It must be remembered, however, that often the bone has been so diseased +that spots of necrosis or caries within it are bound to remain unless moved +by operative interference. Such diseased portions, when dealing with the +foot, are beyond reach of the surgeon's knife, and we have no alternative +but to allow them to remain. We get, therefore, in many cases, a condition +of rarefactive ostitis occurring side by side with a slowly progressive +caries within the bone, while outside is occurring an osteoplastic +periostitis. The concurrence of these conditions leads in time to great +increase in size of the parts, together with increasing anchylosis and +deformity. + + +C. NAVICULAR DISEASE. + +_Definition_.--Chronic inflammatory changes occurring in connection with +the navicular bursa, affecting variously the bursa itself, the perforans +tendon, or the navicular bone, and characterized by changes in the form +of the hoof and persisting lameness. The disease is commonly noticed +in thoroughbreds or in horses of the lighter breeds, and is but seldom +observed in heavy cart animals. Usually it is met with in one or both +fore-feet. Although of extremely rare occurrence, it has been noticed in +the hind. + +_History_.--To English veterinarians appears to belong the credit of +discovering navicular disease. As early as 1752 we find one, Jeremiah +Bridges, in 'No Foot, No Horse,' drawing attention to 'coffin-joint +lameness,' and advocating for its treatment setoning of the frog. It +appears, too, that Moorcroft, prior to his departure for India in 1808, was +acquainted with what was then known as coffin-joint[A] lameness, having +drawn attention to it in 1804 in a letter to Sir Edward Codrington.[B] In +1819 Moorcroft made it even plainer still that he was fully acquainted with +what we now know as navicular disease. This we learn from a letter written +by him to Sewell, in which he laid claim to being the originator of +neurectomy. In this letter he says: + +[Footnote A: The coffin-joint at this time included the navicular bursa.] + +[Footnote B: Percival's 'Hippopathology,' vol. iv., p. 132.] + +'On dissecting feet affected with these lamenesses, the flexor tendon was +now and then observed to have been broken, partially or entirely, but +more commonly to have been bruised and inflamed in its course under the +navicular or shuttle bone, or at its insertion into the bone of the foot. +Sometimes, although seldom, the navicular bone itself has been found to +have been fractured; at others its surface has been deprived of its usual +coating, and studded with projecting points or ridges of new growth, or +exhibiting superficial excavations more or less extensive.'[A] + +[Footnote A: _Ibid_.] + +_Pathology and Point of Commencement of the Disease_.--The exact position +in which the diseased process starts has for a long time been a subject +of discussion, and even now it is doubtful whether the point has been +definitely settled. To mention but a few among many: We find Mr. Broad, of +Bath, strenuously insisting on the fact that the disease commences in the +interior of the navicular bone. Just as strenuously we find the editor of +the journal in which the matter is being discussed, the late Mr. Fleming, +asserting that the disease commences in the bursa.[A] Others, too, hold +that the disease commences primarily in the tendon. Wedded to this view was +the discoverer, Mr. Turner, of Croydon; while Percival commits himself to +the statement that it is either the central ridge or the postero-inferior +surface of the navicular bone, or the opposed concavity in the perforans +tendon, that shows the earliest signs of the disease. The observations made +by Dr. Brauell, the first Continental writer to fully describe the disease, +led him to the statement that neither the bone nor the bursa was the +_invariable_ starting-point of the trouble, but that usually it commenced +in inflammation of the bursa itself. + +[Footnote A: Percival's 'Hippopathology,' vol. iv., p. 132.] + +Without, therefore, committing ourselves to an expression of opinion as +to the precise starting-point of the affection, we shall describe the +pathological changes occurring in navicular disease as noted in (1) the +bursa, (2) the cartilage, (3) the tendon, and (4) the bone. + +1. _Changes in the Bursa_.--Upon the internal surface of the bursal +membrane is first noticed a slight inflammatory hyperaemia, accompanied +by more or less swelling and tumefaction, owing to its infiltration with +inflammatory exudate. The portion covering the hyaline cartilage of the +navicular bone has lost its peculiar pearl-blue shimmer, and become a dirty +yellow. + +Remembering that the bursal membrane is a synovia-secreting one, and +bearing in mind what happens in ordinary synovitis and arthritis (with +which, of course, this may be very closely compared), we shall first expect +changes in the bursal contents. It is highly probable, though difficult of +proof, that in the very early stages the chronic inflammatory stimulus has +the effect of increasing the flow of synovia. In every case, however, where +it can with any certainty be said that navicular disease exists, it is too +late to meet with this condition. The disease has then progressed until +destruction of the secreting layer of the bursal membrane has been +seriously interfered with, and in this case we find a distinct deficiency +in the quantity of synovia in the bursa. In advanced cases it is even found +that the bursa is _absolutely dry_. + +2. _Changes in the Cartilage_.--Directly that portion of the bursal +membrane covering the cartilage is the subject of inflammatory change, the +cartilage itself, by reason of its low vitality, soon suffers. + +Under a process, which we may term 'dry ulcerative,' the cartilage covering +the ridge on the lower surface of the bone commences to become eroded, and +in appearance has been likened, both by English and Continental writers, to +a piece of wood that has been worm-eaten (see Fig. 161). + +[Illustration: FIG. 161.--NAVICULAR BONE (POSTERO-INFERIOR SURFACE) SHOWING +THE 'WORM-EATEN' APPEARANCE CAUSED BY EROSION OF THE HYALINE CARTILAGE, AND +COMMENCING RAREFACTIVE ARTHRITIS.] + +'At this stage, or much earlier'--we are quoting Colonel Smith, +A.V.D.--'may be found calcareous deposits in the fibro-cartilage and the +bone. They are scattered like fine sand here and there, generally across +the inferior half of the face of the bone; they are sometimes numerous, +frequently scanty, occasionally entirely absent. The amount of calcareous +degeneration depends upon the lesions present. If much destruction of bone +exists, there will be but few calcareous deposits; whilst if there are many +calcareous deposits, there may be but slight ulceration of bone tissue, and +perhaps none at all. In fact, I have held the opinion, and see no reason to +modify it, that calcareous deposits are safeguards against caries.'[A] + +[Footnote A: _Journal of Comparative Pathology and Therapeutics_, vol. vi., +p. 195.] + +3. _Changes in the Tendon_.--The effect of these calcareous deposits on +the under surface of the bone is to produce a certain amount of roughness. +Seeing that with every movement of the foot the perforans tendon is called +upon to glide over this surface, it is clear that a secondary effect must +be that of inducing erosion and destruction of the tendon. The point at +which this usually commences is at the bottom of the depression that +accommodates the ridge on the bone. With erosion of the cartilage and of +the tendon at points exactly opposite each other, we have two surfaces come +together that are prone to readily unite, and fibrous tissue adhesions +often take place between the bone and the tendon. In some measure this +accounts for the torn and ragged appearance of the tendon. Adhesions take +place, and, under some small strain, are broken down. This may happen more +than once or twice, and with each breaking of the adhesion between the bone +and tendon, fibres from the latter are lacerated and torn from their place +(see Fig. 162). + +4. _Changes in the Bone_.--The changes occurring in the bone are +essentially those of a rarefactive ostitis. These changes are described by +many writers, and, whether originating primarily in the bone or not, it +seems certain that extensive changes may have occurred within the bone, +with but little or nothing to be noted on its outer surface. It would seem +that the first change is one of congestion of the vessels of the bone's +cancellous tissue. With the cause, whatever it may be, in constant +operation, the congestion persists until a low type of inflammation is set +up, interfering, not only with the flow of synovia in the adjoining bursa, +but with the nutrition of the bone itself. As the disease progresses, there +is softening and enlarging of the cancellated tissue towards the centre +of the bone. The cells break up, and absorption takes place. This goes on +until a large portion of the interior of the bone is in a state of dry +necrosis, with, in many cases, but slight signs of mischief on the exterior +of the bone. + +In other cases, however, the changes in the interior of the bone are +accompanied by well-marked lesions on its gliding or postero-inferior +surface, and by evidences of an osteoplastic periostitis along its edges. + +That an osteoplastic periostitis has been in existence is witnessed by the +appearance along the edges of the bone of numerous outgrowths of bone, +termed osteophytes (see Fig. 163). + +[Illustration: FIG. 162.--A FOOT WITH THE SEAT OF NAVICULAR DISEASE +EXPOSED. On the anterior surface of the perforans fibres of the tendon are +seen to be torn away from their abnormal adhesion with the navicular bone, +while others are seen to be still attached thereto. The surface of the +navicular bone itself exhibits small defects in the bony substance, which +have been brought about by a rarefactive ostitis. _a_, The perforans tendon +cut through and reflected; _b_, the sole.] + +The interosseous and postero-lateral ligaments of the articulation +often participate in the inflammatory changes, and in many cases become +completely ossified. The true articulatory surface of the bone, that +articulating with the os pedis and with the os coronae, is never affected. + +_Causes_.--In enumerating the causes of navicular disease, we shall +follow the example of Colonel Smith and classify them under certain +headings--namely, (1) _Hereditary Predisposition_; (2) _Compression_; (3) +_Concussion_; (4) _A Weak Navicular Bone_; (5) _A Defective or Irregular +Blood-supply to the Bone_; and (6) _Senile Decay_. + +[Illustration: FIG. 163.--THE NAVICULAR BONE FROM A CASE OF LONG-STANDING +NAVICULAR DISEASE. The erosion of the cartilage on its central ridge is +most marked, and the porous appearance of the bone thus uncovered points +to the existence within it of a rarefactive ostitis. Along its edges +large osteophytic outgrowths speak of the effects of an osteoplastic +periostitis.] + +1. _Hereditary Predisposition_.--That navicular disease is hereditary is +a fact that has for a long time been insisted on, and has come to be so +generally admitted that we do not intend to dwell on it here. As we have +said before, it is found in the lighter breeds of horses (and, according +to Zundel, especially in the English breeds), and is there seen to be +frequently transmitted from parent to offspring. + +2. _Compression_.--By this is meant the compression of the navicular bone +between the os pedis and the os coronae in front, and the perforans tendon +behind. + +In order to appreciate this explanation of the causation of navicular +disease at its true value, it will be well to consider briefly the +physiology of the parts in question. + +The navicular bone is what we may term a complement of the os pedis. It +exists, in fact, simply in order that the os coronae may have a sufficiently +large articulatory surface to play upon. One wonders at first that Nature +did not arrive at this by originally placing a larger bone below. Colonel +Smith explains this by suggesting that this would in all probability have +meant its fracture. In progression the hind part of the foot comes to the +ground first, and upon the hinder portion of the articulation would fall +the first effects of concussion, together with the greater part of the +body-weight. A yielding joint was in this position necessary, and that +formed by the navicular bone fills all requirements. + +In this connection one next considers the part played by the front limbs +during progression. As Zundel expresses it, they are columns of support +rather than of impulsion, and, as the body-weight is thrown forward by the +hind-limbs, it is the duty of the fore-limbs to receive it. The shock or +concussion of the body-weight thus thrown forwards is first received by +the muscles uniting the limb to the trunk, and a great part of it there +minimized by their sling-like attachment. It is further absorbed by the +shoulder-joint, and from there passed on to the almost vertical bony column +represented by the radius and ulna, the knee, and the metacarpus. On +reaching the first phalanx, a portion of the remaining force is passed on +to the front of the phalanges and loses itself in front of the hoof, while +the other portion is transmitted to the flexor tendons, finally to the +perforans, and to the posterior parts of the foot. During progression, +therefore, the navicular bone is constantly pushed downwards and backwards +by the bony column, and is just as constantly pushed forwards and upwards +by the resistance of the perforans tendon. This means, of course, that +the navicular bone is more or less constantly subject to compression, +and constant pressure, as we know full well, is a pretty sure factor +in bringing about malnutrition of the parts, with atrophy or chronic +inflammatory changes as an end result. + +Even with the limb at rest the pressure on both sides of the navicular bone +is still constant. The only circumstances under which we can conceive of +it being entirely absent, in fact, are when the tension on the tendon is +relaxed, and the body-weight altogether removed by the animal adopting the +recumbent position. + +The compression theory as to the causation of navicular disease was, we +believe, first originated by Colonel Smith. He, at any rate, has laid much +stress on it in his writings. If we accept it, and we see every reason +that we should, then we must, with the author, admit the possibility of +navicular disease arising from long standing in one position. + +3. _Concussion_.--This we are bound to admit as a cause, and in so doing +partly explain the comparative, almost total, immunity of the hind-feet +from the disease. The fore-limbs, as we have already pointed out, are +little more than props of support, and the force of the propelled +body-weight is transmitted largely down their almost vertical lines, to +end largely in concussion in the foot. With the hind-limbs matters are +different. 'These,' as Percival explains it, 'have their bones obliquely +placed, so as to constitute, one with the other, so many obtuse angles, to +the end, that by forming powerful levers, and affording every advantage for +action to the muscles attached to them, they may be fitted for the purpose +of propulsion of the body onward.' + +The effect of these several obtuse-angled joints in the limb is to absorb +the greater part of the force exerted by the body-weight before it reaches +the foot. When with this we take the facts that the fore-limbs have to +carry the head and neck, and that they have to bear this added weight, plus +a propelling force from behind, we see why it is that they should be so +subject to the disease, and the hind-limbs so exempt. + +As pointing out the part that concussion plays in its causation, we may +mention that navicular disease is a disease of the middle-aged and the +worked animal. It is interesting to note, too, that it occurs in animals +with well developed frogs--in feet in which frog-pressure with the ground +is most marked. This at first sight appears to flatly contradict what we +have said with regard to frog-pressure in other portions of this work. With +this, however, must be reckoned other predisposing causes. In this case it +is not to frog-pressure alone we must look, but to the condition of the +frog itself, and that of the neighbouring parts. It is when we have a frog +which, though well developed and apparently satisfying all demands as +to size and build, is at the same time composed of a hard, dry, and +non-yielding horn that we must look for trouble. + +The foot predisposed to navicular disease is the strong, round, short-toed +or clubby foot, open at the heels, with a sound frog jutting prominently +out between them. Here is a frog exposed to all the pressure that might +be desired for it, bounded at its sides by heels thick and strong, and +indisposed to yield, and itself liable, from its very exposure, to become, +in the warm stable, hard and dry, and incompressible' (Percival). + +Here, instead of acting, as normally it should, as a resilient body, and an +aid to the absorption of concussion, it seems rather to play the part of +a foreign body, and to bring concussion about. Seeing, then, that the +navicular bursa is in very near contact with it, it is conceivable that +this joint-like apparatus should suffer, and the pedal articulation be left +unaffected, the more so when we take into consideration the compression +theory just described. + +4. _A Weak Navicular Bone_.--When the disease commences first in the +bone--and there is no denying the fact that sometimes, although not +invariably, it does--it may be explained by attributing to the structure of +the bone an abnormal weakness in build. + +The navicular bone consists normally of compact and cancellated tissue +arranged in certain proportions, the compact tissue without, and the +cancellated within. These proportions can only be judged of by the +examinations of sections of the bone, and when it is found in any case that +the cancellated tissue bulks more largely in the formation of the bone than +normally it should, we have what we may term a weak navicular bone. In this +connection Colonel Smith says: 'Though it is far from present in every case +of the disease, still I consider it a factor of great importance.' + +5. _A Defective or Irregular Blood-supply to the Bone_.--This, Colonel +Smith considers, is brought about by excessive and irregular work, and by +the opposite condition--rest. The author points out that the bloodvessels +passing to and from the navicular bone run in the substance of the +interosseous ligaments, or in such proximity to them that it is conceivable +that under certain circumstances mechanical interference may occur to the +navicular circulation. He further points out a fact that is, of course, +well known to every veterinarian, that in periods of work the circulation +of the foot is hurried, and that in rest there is always a tendency to +congestion; and he says in conclusion: 'I cannot help thinking that +irregularities in the blood-supply in a naturally weak bone must be a +factor of some importance, especially when the kind of work the horse is +performing is a series of vigorous efforts followed by rest.' + +6. _Senile Decay_.--With approaching age the various tissues lose their +vigour, and are prone to disease. The navicular bone and surrounding +structures are not exempt. With the other and more active causes we have +described acting at the same time it is not surprising that navicular +disease is seen as a result. + +In conclusion, it is well, perhaps, to say that, no matter to which +particular theory of causation we may lean, we should make up our minds to +consider them as a whole. While one cause may be exciting, the other may +be predisposing, and the two must act together before evil results are +noticed. It may be that even more than two are concerned in bringing on the +disease, and to each the careful veterinarian will give due consideration. + +_Symptoms and Diagnosis_.--In the early stages of navicular disease the +symptoms are obscure. Pointing of the affected limb is the first evidence +the animal gives. This, however, more often than not, goes unnoticed, +and the first symptom usually observed by the owner or attendant is the +lameness. Even this is such as to at first occasion no alarm, being +intermittent and slight, and only very gradually becoming marked. In a few +cases, however, lameness will come on suddenly, and is excessive from the +commencement. It is the lameness, slow in its onset, intermittent in +its character, and gradual in its progress, however, that is ordinarily +characteristic of navicular disease. + +The animal is taken out from the stable sound, with just a vague suspicion, +perhaps, that he moved a bit stiffly. While out he is thought by his driver +or rider to be going feelingly with one foot or with both. Even this is not +marked, and the driver has some difficulty in assuring himself whether or +no he really observed it, or whether it was but imagination. + +On the return home the limb is examined, and nothing abnormal is to be +found. The leg is of its normal appearance, and neither heat nor tenderness +is to be observed in it or in the foot. On the following day the animal +again is sound, and the lameness of the previous day is put down to a +slight strain or something equally simple. The patient is then, perhaps, +rested for a day or two. When next he is worked he again moves out from the +stable sound, but again during the going gives the driver the unpleasant +impression that something is amiss; and so the case goes on. One day the +owner fears the animal is becoming seriously enough affected to warrant him +in calling in his veterinary surgeon; the next he is confidently assuring +himself that nothing is wrong. + +Perhaps the animal is now rested for a week or two, or even for a month or +two, hoping that this will put him sound. Immediately on commencing work, +however, the same symptoms as before assert themselves, and the veterinary +surgeon is called in. + +With a history such as we have given the veterinarian's suspicions are +aroused. He has the animal trotted, and may notice at this stage that there +is an inclination to go on the toes, that the lame limb or limbs are not +put forward freely, and that progression is stilty and uncertain; it +is such, in fact, as to at once suggest the possibility of corns being +present. + +In some cases there is just the suspicion of a limp with one limb, and +this only at intervals during the trot. At one moment the veterinarian +is positive that he sees the animal going lame; at another he is just as +confident he sees him coming towards him sound. + +Nothing is found in the limb--neither heat, tenderness, nor swelling. There +is nothing in the gait (either a limited movement of the radius, or a +circular sweep with the leg) to indicate shoulder or other lameness, and +the veterinary surgeon, by eliminative evidence, is bound to conclude that +the trouble is in the foot. + +The foot is then examined--pared, percussed, pinched, and in other ways +manipulated--but nothing further is forthcoming. In such a case the +veterinary surgeon is wise to declare the abortive result of his +examination, to hint darkly of his suspicions, and to suggest a second +examination at some future date. It may be that two, three, four, or even +more, such examinations are necessary before he can justly pronounce a +positive verdict. + +Later he is enabled to do this by an increase in the severity of the +symptoms, and by the changes that take place in the form of the foot. +The lameness is now more marked, and the 'pointing' in the stable more +frequent. With regard to the latter symptom, it has been seriously +discussed whether the horse with navicular disease points with the heel +elevated or with it pressed to the ground. In either case, of course, the +limb is advanced; but while some hold that the phalangeal articulations are +flexed and the heel slightly raised, in order to relieve the pressure of +the perforans tendon on the affected area, and so obtain ease, there are +others who hold that the heel is pressed firmly to the ground in order to +deaden the pain. It may be, and most probably is, that both are right; but, +in our opinion, there is no doubt whatever that pointing with the heel +elevated is by far the most common. + +The lameness is now excessive, and is especially noticeable when the animal +is put to work on a rough or on a hard ground. Even now, however, heat of +the foot or tenderness is so slight as to be out of all proportion to the +alteration in gait. + +With the case thus far advanced, evidence of pain may be obtained by +pressing with the thumb in the hollow of the heel. Evidence of pain may +also be obtained by using the farrier's pincers on the frog. These methods, +however, are never wholly satisfactory, as a horse with the soundest of +feet will sometimes flinch under these manipulations. + +Extreme and forcible flexion of the corono-pedal articulation also +sometimes gives evidence of tenderness. In this case the foot is held up, +the animal's metacarpus resting on the operator's knee, and the toe of the +hoof pushed downwards with some degree of force. + +The same movement of the joint is given by causing the animal to put full +weight upon the diseased limb, a small wedge of wood being first placed +under the toe. In this manner the pressure of the perforans tendon upon the +bursa is greatly increased, and the animal is caused to show symptoms of +distress. + +The lameness may also be increased, and diagnosis helped, by paring +the heels, so as to leave the frog prominent and take the whole of the +body-weight. The same end is also obtained by applying a bar shoe. This was +originally pointed out by Brauell, and is quoted by Zundel and by Moeller. + +The changes in the form of the hoof may now be noticed. These are largely +dependent on the fact that more or less constantly the patient saves the +heel. The horn of the walls in this region, and the horn of the frog, +is thereby put out of action and induced to atrophy. The hoof gradually +assumes a more upright shape, and the heels contract. We thus get a hoof +which is visibly narrowed from side to side, with a frog that is atrophied +and often thrushy, and with a sole that is abnormally concave, hard, and +affected with corns. + +When occurring in the hind-feet--a condition that is rare, but which has +been noticed by Loiset, and quoted by Zundel--the animal is stiff behind, +walks on his toes, and gives one the impression that he is suffering from +some affection in the region of the loins. + +One such case is reported by an English veterinary surgeon, and we quote it +here: + +'A gray gelding, and a capital hunter, the property of a gentleman in this +neighbourhood, became lame in the near fore-foot after the hunting season +of 1859. The lameness was believed to be due to navicular disease. +The operation of neurectomy was ultimately had recourse to. The horse +subsequently did his work as well as ever, and was ridden to hounds +regularly till the end of the year 1861, when he went lame of the off +fore-foot. From this date he also showed very peculiar action behind, and +was at times lame of both hind-limbs without any apparent cause. + +'In the year 1862, from the groom's indiscreet use of physic, +superpurgation was brought on which caused the animal's death. On a +post-mortem examination being made, the horse was found to have _navicular +disease of all four feet_. It is worthy of note that this horse had +always "extravagant" action behind, but was a remarkably quick and good +jumper.'[A] + +[Footnote A: F. Blakeway, M.R.C.V.S., _Veterinarian_, vol. ii., p. 21.] + +_Differential Diagnosis_.--Navicular disease may be mistaken for ordinary +contracted foot. It will be remembered, however, that in the early stages +of navicular disease contraction is absent, and that it is only when the +disease in the bursa is of long standing that contraction comes on. With +ordinary contracted foot, too, careful paring and suitable shoeing soon +sees a diminution in the degree of lameness, and a return to the normal in +shape (see Treatment of Contracted Foot, p. 125). With navicular disease, +however, such shoeing as is beneficial in the treatment of contracted foot +(notably the various methods of giving to the frog counter-pressure with +ground) soon brings on an aggravation of the lameness. + +It is, perhaps, even more likely to be confounded with contraction when we +have with the contraction a state of atrophy and thrush of the frog. With +a frog in this condition pressure will give rise to pain, and navicular +disease be erroneously judged to be present. In such a case we must rely +wholly upon either extreme flexion or extreme extension of the joint to +guide us, when, if contraction _only_ is the offending condition, no +symptom of pain will be shown. + +Navicular disease may also be confused with rheumatic affections, +with sprain of the posterior ligaments of the first interphalangeal +articulation, and with sesamoid lameness. Mistakes are sometimes made, too, +especially with a hasty observer, in confounding it with shoulder lameness. + +In rheumatism the constant changing of the seat of pain, the sometimes +elevated temperature, and the appearance of symptoms of heat, tenderness, +and swelling in the affected area should guide one to a right conclusion. + +In sprain of the posterior ligaments of the coronet and in sesamoid +lameness, nothing but a careful examination and manipulation of the parts +will ward off error, for in each of these cases there is 'pointing' and +resting of the limb, and considerable disinclination to put weight firmly +upon it. If at the same time manipulation gives distinct evidence of pain, +all doubt may be set at rest. + +Roughly speaking, sesamoid lameness is a condition of the gliding surface +of the sesamoids, and the face of the tendon playing over them, similar to +that found in navicular disease. All symptoms of pointing, the constant +maintaining of the limb in a state of flexion, and a feeling manner of +progression are again all present. It is plain from this that in all cases +where an animal with a gait at all suggestive of navicular disease is +brought for our examination, the manipulation of the limb should be +thorough. The character of the lameness is almost sure to deceive us; and +it is not until we are able to obtain local symptoms pointing to the one or +the other of the conditions we have enumerated that a decisive opinion may +be given. In sesamoid lameness the local symptoms are those of heat and +pain in the fetlock on palpation, and a swelling of the affected parts, +such swelling being at first slight, yielding, and barely distinguishable, +and afterwards larger, bony and hard, and more marked. Later still there is +distinct evidence of 'knuckling' over at the fetlock and inability to fully +flex it. + +In cases of shoulder lameness the gait alone should be sufficient to render +liability of error small, for with nearly every case there is a manifest +inability to 'get the limb forward', and this is best seen at a side view +when the animal is trotting past the observer. When trotting towards +one, there is a further and unmistakable symptom common to most shoulder +lamenesses that serves to distinguish it at once, and that is the peculiar +'sweeping' outwards with the affected limb. + +Lastly, with either of the conditions we have just mentioned, it is the +exception to get contracted foot follow on. With navicular disease it +sooner or later makes its appearance. + +_Prognosis_.--The prognosis of navicular disease (once diagnosed with +certainty) must almost of necessity be unfavourable. The facts that the +disease has made serious progress before it is really noticeable, that +the situation of the parts prohibits operative interference, and that the +disease is one of a chronic and slowly progressive type, all point to an +unfavourable termination. + +_Treatment_.--We have seen from the pathology of this disease that it may +commence either as a rarefactive ostitis, or as a synovitis and tenositis +in connection with the bursa. With the former condition in existence, or +when this and the synovitis has led to erosion of the cartilage, treatment +is probably of no avail, on account of the more chronic nature of these two +conditions. When, however, the condition is simply that of synovitis or +tenositis, a more or less acute condition, we may assume that suitable +treatment and a long rest will bring about resolution. + +The first indications in treatment are those of what we may term 'nursing' +the foot. It should have sufficient rest, should be placed so as to +minimize as far as possible compression of the parts, and should have +its posterior half treated so as to render it softer and less liable to +concussion. + +The period of rest required cannot be satisfactorily advised, and the +practitioner is wise who makes it a long one. Best should be advised, in +fact, long after symptoms of lameness have disappeared and recovery is +judged to have taken place. + +Compression of the parts may be somewhat minimized, if the animal be kept +in the stable, by allowing the floor upon which the front-feet are to stand +to be slightly sloping from behind forwards. The same effect, though not so +marked, is obtained by removing the shoes, and considerably lowering the +wall at the toe, while allowing that of the heels to remain. It may here be +remarked that it is a good practice to allow the shoes to remain on, and +this even when the animal is at grass. They should, however, be frequently +removed, and the foot trimmed as we have directed. + +With the foot thus trimmed so as to most suitably adjust the angles of +the articulations, it should next be thoroughly pared and rasped in its +posterior half, so as to render the horn of the sole and the frog and the +horn of the quarters as thin as possible. The heels, however, should not be +excessively lowered, _if at all_. We now have the foot in a soft condition, +and easily expanded. It should, if possible, be kept so; and this may be +done either by the use of poultices, by tepid baths, or by standing the +animal upon a bedding that may easily be kept constantly damp. Such +materials as tan, peat moss, or sawdust, are either of them suitable. + +All this, of course, calls for keeping the animal in the stable. It is far +better, however, more especially if a piece of marshy land is at hand, to +turn him out in that. A moderate amount of exercise is beneficial rather +than not, and the feet are thus constantly kept damp without trouble to the +attendants. + +The second indication in the treatment is that of applying a +counter-irritant as near to the diseased parts as possible. Regarding its +efficacy we must confess to being somewhat sceptical. The treatment has +been constantly practised and advised, however, and we feel bound to give +it mention here. A smart blister may, therefore, be applied to the whole of +the coronet, and need not be prevented from running into the hollow of the +heel. + +Instead of blistering the coronet (or in conjunction with that treatment), +the counter-irritant may be applied by passing a seton through the plantar +cushion or fibro-fatty frog. Setoning the frog appears to have been +introduced by Sewell. In many cases great benefit is claimed to have been +derived from it, especially by English veterinarians of Sewell's time, and +by others on the Continent. Percival, however, was not an advocate for it, +and, at the present day, it is a practice which appears to have dropped out +of use altogether. + +[Illustration: FIG. 164.--FROG SETON NEEDLE.] + +To perform this operation a seton needle of a curved pattern is needed +(see Fig. 164). This is threaded with a piece of stout tape dressed with a +cantharides, hellebore, or other blistering ointment, and then passed in at +the hollow of the heel, emerging at the point of the frog. The course the +needle should take will be understood from a reference to Fig. 165. + +The seton may be passed with the horse in the standing position. Previously +the point of the frog should be thinned, and the animal should be twitched. +After-treatment consists simply in moving the seton daily, and dressing it +occasionally with any stimulating ointment, or with turpentine. + +If, in spite of these treatments, the disease persists, then nothing +remains but neurectomy. + + +D. DISLOCATIONS. + +The firm and rigid manner in which the bones of the pedal articulation +are held together renders dislocation of this joint an exceedingly rare +occurrence, and then it is only liable to happen under the operation of +great force. In the literature to our hand we have only been successful +in discovering one reported instance, and, strange to say, in this, a +well-marked case, the cause was altogether obscure. We quote the case at +the end of this section. + +[Illustration: FIG. 165.--DIAGRAM SHOWING THE COURSE TAKEN BY THE NEEDLE +WHEN SETONING THE FROG. This is shown by the dotted curved line _a, b_. +1, The navicular bone; 2, the plantar cushion; 3, the os pedis; 4, the +perforans tendon.] + +A partial dislocation of this articulation is the condition met with in +'Buttress Foot.' In this case the fracture of the pyramidal process, and +the consequent lengthening of the tendon of the extensor pedis, allows the +os coronae to occupy upon the articulatory surface of the os pedis a more +backward position than normally it should. + +It is quite probable, too, that slight lesions of the other restraining +ligaments and tendons of the articulation may bring about a similar though +less marked condition. We may be quite sure of this--that whenever such +lesions (as, for example, sprain and partial rupture of the lateral +ligaments) do occur, and the normal position of the opposing bones is +changed, if only slightly, that great pain and excessive lameness must be +the result, and this with but little to show in the foot. Many of our cases +of obscure foot lameness might, if capable of demonstration, turn out to be +cases of sprain and partial dislocation of the pedal articulation. + +_Recorded Case_.--'The animal, a trooper of the 8th Hussars, was found on +the morning of April 17 unable to bear any weight on the limb (the +near hind). Cause not known--the heel-rope I thought at first; but on +investigation I found the heel-rope had been on the other leg. + +_Diagnosis_.--Dislocation of the left os coronae from the articulating +surface of the os pedis in a backward direction. + +'Every devisable means were unsuccessful in reducing the limb to its +natural position. The horse was thrown, and a strong rope, with four men +pulling at it, was fastened round the hoof, whilst I put my knee to the +back of the pastern, using all possible force, with one hand to the foot +and the other to the fetlock, but all to no purpose. Next day other means +were tried. First by throwing the horse and placing him on his belly, with +the fore-legs stretched out forwards, and the hind-legs backwards. This I +did so as to get the injured limb placed as nearly flat on the ground as +possible, with its anterior aspect downwards. Then a very heavy man, with +his boots off, was made to jump on the back of the pastern, where the +prominence showed most; and afterwards, when these means failed, a strong +piece of wood, well covered with leather, was placed (where the hollow of +the heel ought to have been) on the most prominent part, and hit several +times with a heavy hammer; but all efforts were futile. + +'_Prognosis_.--Unfavourable. During the latter operations I had a very +strong pressure applied to the hoof, and the horse firmly fastened in every +way, and it appeared as though no amount of force would ever reduce the +dislocation. + +'_Tautological_.--The case was destroyed on April 30, being of no further +use to the service. + +'_Post-mortem_.--The os coronae was found to have slipped out of the +articulating cavity of the os pedis, backwards and past the lateral +ligaments. These last-named structures prevented the bone being forced +forward into its proper position, being firmly locked over the lateral +prominences. The capsular ligament was considerably lacerated and inflamed, +causing slight effusion and swelling about the region of the coronet.'[A] + +[Footnote A: T. Flintoff, A.V.D., _Veterinary Journal_, vol. xix., p. 74.] + +_Treatment_.--After the forcible means of reduction related by Mr. +Flintoff, we may add that when they are successful, they should be followed +by suitable bandaging of the parts, and rest. The first is effected by +applying plaster of Paris and linen, and the second by having the animal +put in slings. + + + +INDEX + +Accidental tearing off of the entire hoof +Acute arthritis + causes of + symptoms of + treatment of +Acute laminitis + causes of + complications in + congestion in + course of + definition of + diagnosis in + exudation in + pathological anatomy of + prognosis in + suppuration in + symptoms of + treatment of +Acute periostitis simple +Acute simple coronitis + causes of + definition of + symptoms of + prognosis of + treatment of +Acute simple synovitis +Advantages of neurectomy +Amputational neuroma after neurectomy +Anatomy, pathological, of corn +Applying poultices, method of +Arteries of the foot +Arthritis, acute + causes of + symptoms of + treatment of +Arthritis, simple or serous +Arthritis, suppurative + causes of + definition of + diagnosis of + pathology of + symptoms of + treatment of +Articulation, the first interphalangeal +Articulation, the second interphalangeal + +Bar pad and a half-shoe in the treatment of contracted feet +Bar shoes in the treatment of contraction +Bayer's treatment for chronic laminitis +Bermbach's treatment for canker +Bind +Bone, caries of +Bones, fracture of the, after neurectomy +Bones, fracture of the +Bones, necrosis of +Bones, the +Brittle hoof + causes of + definition of + symptoms of + treatment of +Broad's treatment of laminitis +Broue's expansion shoe +Bruised sole, chronic +Buttress foot + +Canker + Bermbach's treatment of + causes of + definition of + differential diagnosis in + history of + Hoffmann's treatment of + Imminger's treatment of + Malcolm's treatment of + pathological anatomy of + prognosis in + Rose's treatment of + symptoms of + treatment of +Caries of bone +Caries of the os pedis in pricked foot +Cartilage, the lateral +Cartilaginous quittor +Causes of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of corn + of contracted feet + of coronary contraction of the + foot + of crooked foot + of curved hoof + of false quarter + of flat-foot + of keraphyllocele + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of ringed hoof + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of simple cutaneous quittor + of specific coronitis + of sub-horny quittor + of thrush + of weak heels +Caustic solution, Villate's +Changes in the bone in navicular disease + in the bursa in navicular disease + in the cartilage in navicular disease + in the internal structures of the foot in contraction + in the tendon in navicular disease +Charlier shoe, the +Charlier shoeing for contracted foot +Chemical properties of horn +Chronic coronitis, simple + causes of + definition of + symptoms of + treatment of +Chronic bruised sole + treatment of +Chronic laminitis + Bayer's treatment of + causes of + definition of + Gross's treatment of + Gunther's treatment of + Imminger's treatment of + Joly's treatment of + Meyer's treatment of + pathological anatomy of + surgical shoeing for + symptoms of + treatment of + treatment of, by ligaturing the digital arteries +Chronic oedema of the leg after neurectomy +Chronic synovitis +Clamp, sand-crack, Koster's + McGill's + Vachette's +Clamping sand-cracks, methods of +Classification of corns + of punctured foot according to the situation of the wound + of sand-crack + of quittor +Club-foot + causes of + definition of + symptoms of + treatment of +Cocaine injections as an aid to diagnosis in foot lamenesses +Colic, metastatic, in laminitis +Commencement, point of, in navicular disease +Common situations of the wound in punctured foot. +Complicated sand-crack, operations for +Complications in coronitis + in laminitis + in pricked foot + in sand-crack + in simple or cutaneous quittor + in sub-horny quittor +Compression as a cause of navicular disease +Concussion as a cause of navicular disease +Conformation, faulty +Congestion in laminitis +Contracted foot + causes of + changes in the internal structures of + definition of + local or coronary + prognosis of + surgical shoeing for + symptoms of + treatment of +Contraction of the foot, a bar pad and a half-shoe in the treatment of + bar shoes in the treatment of + expansion shoes in the treatment of +Corn + causes of + classification of + definition of + pathological anatomy of + prognosis in + surgical shoeing in + symptoms of + the dry + the moist + the suppurating + treatment of +Coronary contraction of the foot + causes of + definition of + symptoms of + treatment of +Coronary cushion, the +Coronary edge of the wall, expansion and contraction of the +Coronitis + acute simple + causes of + complications in + definition of + prognosis of + symptoms of + treatment of +Coronitis, simple chronic + causes of + definition of + symptoms of + treatment of +Coronitis, specific + causes of + definition of + symptoms of + treatment of +Course of acute laminitis +Crooked foot + causes of + definition of + symptoms of + treatment of +Curved hoof + causes of + definition of + treatment of +Cushion + the coronary + the plantar +Cutaneous or simple quittor + +De Fay's expansion shoe. +Defective or irregular blood-supply to the bone a cause of navicular + disease +Definition + of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of contracted foot + of corn + of coronary contraction of the foot + of crooked foot + of curved hoof + of false quarter + of flat-foot + of keraphyllocele + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of pyramidal disease + of quittor + of ringed hoof + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of specific coronitis + of spongy hoof + of sub-horny quittor + of thrush + of weak heels +Development of the hoof +Diagnosis + of acute laminitis + of canker + of foot lameness by injections of cocaine + of navicular disease + of punctured foot + of pyramidal disease + of side-bone + of sub-horny quittor +Differential diagnosis in canker + in navicular disease +Diseases arising from faulty conformation +Dislocation of the os coronae + recorded case of +Dislocations +Dry corn + +Einsiedel's expansion shoe +Examining the foot method of +Exercise, forced, in the treatment of laminitis +Expansion and contraction + of the coronary edge of the wall + of the hoof under the body-weight + of the solar edge of the wall + of the sole +Expansion shoe Broue's + De Fay's + Einsiedel's + Hartmann's + Smith's +Expansion shoes in the treatment of contraction +Extensor pedis tendon, the +Extirpation + of the lateral cartilage in quittor + of the lateral cartilage, after Moller and Frick + of the lateral cartilage, after Bayer +Exudation in laminitis + +False quarter + causes of + definition of + symptoms of + treatment of +Faulty conformation + diseases arising from +Feeding a cause of laminitis +Flat-foot + causes of + definition of + symptoms of + treatment of +Flexor pedis perforans tendon, the +Flexor pedis perforatus tendon, the +Foot, buttress +Foot, changes in the internal structures in contraction of the +Foot, contracted + causes of + definition of + prognosis of + symptoms of + treatment of +Forced exercise in laminitis +Fractures +Fractures of the bones after neurectomy + of the navicular bone + of the os coronae + of the os pedis +Frog, the +Functions of the lateral cartilages + +Gangrene of the sensitive structures in laminitis +Gathered nail +Gelatinous degeneration after neurectomy +Grooving the wall + in laminitis (Smith's operation) + in treatment of sand-crack + in treatment of side-bone (Smith's operation) +Gross's treatment of chronic laminitis +Growth of hoof, rate of +Gunther's treatment of chronic laminitis + +Hartmann's expansion shoe +Heels, weak + causes of + definition of + symptoms of + treatment of +Heredity + as a cause of navicular disease + as a cause of side-bone +Histology of horn +History + of canker + of navicular disease + of neurectomy +Hind-feet, navicular disease in the +Hind-limb with the side-line, method of securing +Hoffmann's treatment of canker +Hoof, the + accidental tearing off of + expansion and contraction of + development of + rate of growth of +Horn + chemical properties of + histology of +Hutlederkitt + +Imminger's treatment + for chronic laminitis + for canker +Immobilizing a sand-crack by grooving the wall, methods of +Infection of the limb, septic +Injections of cocaine as an aid to diagnosis in foot lameness +Interphalangeal articulation + the first + the second +Instruments + required in plantar neurectomy + in operations on the foot +Irregular blood-supply to the bone as a cause of navicular disease + +Joly's treatment of chronic laminitis + +Koster's sand-crack clamp +Keraphyllocele + causes of + definition of + pathological anatomy of + symptoms of + treatment of +Keratoma + +Lameness, cocaine injections as an aid to diagnosis in +Laminae, the sensitive +Laminitis + acute + Broad's treatment of + causes of + complications in + congestion in + course of + definition of + diagnosis in + exudation in + feeding, a cause of + forced exercise in the treatment of + gangrene of the sensitive structures in + grooving the wall in the treatment of + local applications in the treatment of + local bleeding in the treatment of + metastatic colic in + metastatic pneumonia in + neurectomy in + opening the sole in the treatment of + parturient + pathological anatomy of + periostitis and ostitis in + phlebotomy in the treatment of + prognosis in + rocker bar shoes in the treatment of + Smith's operation in + suppuration in + symptoms of + symptoms of, in the four feet + symptoms of, in the fore-feet alone + symptoms of, in the hind-feet alone + treatment of +Laminitis + chronic + Bayer's treatment of + causes of + definition of + Gross's treatment of + Gunther's treatment of + Imminger's treatment of + Joly's treatment of + Meyer's treatment of + pathological anatomy of + surgical shoeing for + symptoms of + treatment of +Laminitis, parturient +Lateral cartilage, the + extirpation of, in quittor, after Holier and Frick + extirpation of, in quittor, after Bayer + functions of + necrosed, pathological anatomy of + necrosis of + ossification of + wounds of +Leg, chronic oedema of the, after neurectomy +Length of rest required after neurectomy +Ligaments, the +Ligaturing the digital arteries, in chronic laminitis +Limb, septic infection of +Local applications in laminitis +Local bleeding in laminitis +Local or coronary contraction of the foot +Low ringbone + +Malcolm's treatment of canker +McGill's sand-crack clamp +Median neurectomy +Metal plates in the treatment of sand-crack +Metastatic colic in laminitis +Metastatic pneumonia in laminitis +Methods of applying poultices + of examining the foot + of immobilizing sand-crack by grooving the wall +Methods of restraint + of securing a hind-limb with the side-line + of securing the foot to the cannon of another limb +Meyer's treatment of chronic laminitis +Moist corn + +Nail-bound + causes of + definition of + symptoms of + treatment of +Nail-tread +Navicular bone, the + fracture of +Navicular bursa, puncture of the, in pricked foot +Navicular bursa punctured, treatment of +Navicular disease + causes of + changes in the bone in + changes in the bursa in + changes in the cartilage in + changes in the tendon in + definition of + diagnosis of + differential diagnosis of + history of + in the hind-feet + point of commencement of + prognosis of + symptoms of + treatment of +Necrosed lateral cartilage + pathological anatomy of +Necrosis of bone + of tendon and ligament in sub-horny quittor + of the lateral cartilage (cartilaginous quittor) +Necrotic plantar aponeurosis, treatment of +Nerve, reunion of, after neurectomy +Nerves, the +Neurectomy + advantages of + amputational neuroma in + fracture of the bones after + gelatinous degeneration after + history of + instruments required in + in laminitis + length of rest required after + persistent pruritus after + pricked foot after + reunion of divided nerve after + sequelae of + stumbling after + use of the horse after +Neurectomy + median + plantar +Neuroma, amputational, after neurectomy + +Oedema of the leg after neurectomy +Opening the sole in the treatment of laminitis +Operation for complicated sand-crack + for laminitis + for necrosed lateral cartilage in quittor + for necrosed plantar aponeurosis + for side-bone +Operations on the foot, instruments required in +Operations on the horn, treatment of contracted foot by +Os coronae, the + dislocation of + fracture of +Os pedis, the + caries of, in pricked foot + fracture of +Osteoplastic ostitis +Osteoplastic periostitis +Ostitis in laminitis +Ostitis, + rarefying + osteoplastic +Ossification of the lateral cartilages (side-bone) +Overreach + shoeing for + treatment of + +Parturient laminitis +Pathological anatomy of acute laminitis + of canker + of chronic laminitis + of corn + of keraphyllocele + of necrosed lateral cartilage + of pyramidal disease + of simple cutaneous quittor + of navicular disease +Pedal articulation, puncture of the +Perforans tendon, the flexor pedis +Perforates tendon, the flexor pedis +Periople, the +Periostitis and ostitis in laminitis +Periostitis, osteoplastic +Periostitis, recorded cases of +Periostitis, + simple acute + suppurative +Periostitis, treatment of +Persistent pruritus after neurectomy +Phlebotomy in laminitis +Plantar aponeurosis, + wounds of the + treatment of necrosed +Plantar cushion +Plantar neurectomy + history of + instruments required in + operation of +Pneumonia in laminitis + metastatic +Point of commencement of navicular disease +Poultices, methods of applying +Preventive treatment of cutaneous quittor +Pricked foot + after neurectomy + complications of +Prognosis + in acute simple coronitis + in canker + in contracted foot + in corn + in laminitis + in navicular disease + in punctured foot + in sand-crack + in simple cutaneous quittor +Properties of horn, chemical +Protection of sand-crack by metal plates +Pruritus after neurectomy +Pumiced foot + causes of + definition of + symptoms of + treatment of +Punctured foot + causes of + classification of + common situation of the wound in + complications in + definition of + diagnosis of + prognosis of + symptoms of + treatment of +Puncture of the navicular bursa + treatment of +Puncture of the pedal articulation +Purulent synovitis +Pyramidal disease + +Quittor + classification of + definition of +Quittor, simple or cutaneous + causes of + complications in + curative treatment of + definition of + pathological anatomy of + preventive treatment of + prognosis of + symptoms of + treatment of + sub-horny + causes of + complications in + definition of + diagnosis of + extirpation of the lateral cartilage in, after Moller and Frick + extirpation of the lateral cartilage in, after Bayer + necrosis of the lateral cartilage in (cartilaginous quittor) + necrosis _of_ tendon and ligament in (tendinous quittor) + surgical shoeing in + symptoms of + treatment of + +Rarefying ostitis +Recorded case of dislocation + of the os coronae + of navicular disease in both hind-feet + of periostitis + of pyramidal disease +Rest required after neurectomy, length of +Restraint, methods of +Reunion of the divided nerve after neurectomy +Ringbone, low +Ringed hoof + causes of + definition of + treatment of +Rocker bar shoes in laminitis +Rose's treatment of canker + +Sand-crack + causes of + clamp + Koster's + McGill's + Vachette's + clamping, methods of + classification of + complications in + definition of + operations for complicated + prognosis in + surgical shoeing for + symptoms of + treatment of + treatment of, by grooving the wall + treatment of, by wedging the fissure +Second interphalangeal articulation, the +Securing a hind-limb with the side-line, method of +Securing the foot to the cannon of another limb, method of +Seedy-toe + causes of + definition of + symptoms of + treatment of +Senile decay as a cause of navicular disease +Sensitive laminae, the +Sensitive structures, gangrene of, in laminitis +Septic infection of the limb +Sequelae of neurectomy +Serous arthritis +Shoe, bar + Charlier's + Charlier's tip + expansion + Broue's + De Fay's + Einsiedel's + Hartmann's + Smith's + for overreach + plate + rocker bar + slipper, Broue's + slipper and bar-clip, Einsiedel's + three-quarter + three-quarter bar + thinned tip + tip + with 'dropped' heel + with extended toe-piece + with extended toe-piece (Nunn's) + with heel-clip + with 'set' heel +Side-bone + causes of + definition of + diagnosis of + heredity a cause of + Smith's operation for + symptoms of + treatment of +Side-line, the +Simple acute coronitis +Simple acute periostitis +Simple coronitis + acute + chronic +Simple or cutaneous quittor + causes of + complications in + curative treatment of + definition of + pathological anatomy of + preventive treatment of + prognosis of + symptoms of + treatment of +Simple serous arthritis +Simple synovitis, acute +Smith's expansion shoe + operation for laminitis + operation for side-bone +Solar edge of the wall, expansion and contraction of the +Sole, chronic bruised +Sole, expansion and contraction of the +Sole, the +Specific coronitis + causes of + definition of + symptoms of + treatment of +Spongy hoof + definition of + symptoms of + treatment of +Stumbling after neurectomy +Sub-horny quittor + causes of + complications in + definition of + diagnosis of + necrosis of the lateral cartilage in (cartilaginous quittor) + necrosis of tendon and ligament in (tendinous quittor) + symptoms of + treatment of + surgical shoeing for +Suppurating corn +Suppuration in laminitis +Suppurative arthritis + causes of + definition of + diagnosis of + pathology of + symptoms of + treatment of +Suppurative periostitis +Suppurative synovitis +Surgical shoeing for corn + for chronic laminitis + for laminitis, acute + for sand-crack + for quittor +Symptoms + of acute simple coronitis + of brittle hoof + of canker + of chronic coronitis + of chronic laminitis + of club-foot + of contracted foot + of corn + of coronary contraction of the foot + of crooked foot + of false quarter + of flat-foot + of keraphyllocele + of laminitis + of laminitis in all four feet + of laminitis in the fore-feet alone + of laminitis in the hind-feet alone + of nail-bound + of navicular disease + of pumiced foot + of punctured foot + of pyramidal disease + of sand-crack + of seedy-toe + of side-bone + of simple chronic coronitis + of simple cutaneous quittor + of specific coronitis + of spongy hoof + of sub-horny quittor + of synovitis, chronic + of synovitis, purulent or suppurative + of synovitis, simple acute + of thrush + of weak heels +Synovitis, acute simple + causes of + treatment of + +Tearing off of the entire hoof, accidental +Tendon + the extensor pedis + the flexor pedis perforans + the flexor pedis perforatus +Tendons, the +Thrush + causes of + definition of + symptoms of + treatment of +Tight-nailing +Tip-shoes +Tissue, the velvety +Tread, See Overreach +Treatment + of acute laminitis + of acute simple coronitis + of brittle hoof + of canker + of canker + Bermbach's + Hoffmann's + Imminger's + Malcolm's + Rose's + of chronic bruised sole + of chronic coronitis + of chronic laminitis + of chronic laminitis by ligaturing the digital arteries + of club-foot + of contracted feet + of contracted feet by expansion shoes + of contracted feet by operations on the horn + of corns + of coronary contraction of the foot + of crooked foot + of curved hoof + of cutaneous quittor + of false quarter + of keraphyllocele + of nail-bound + of navicular disease + of necrotic plantar aponeurosis + of periostitis + of pumiced foot + of punctured foot + of punctured navicular bursa + of pyramidal disease + of ringed hoof + of sand-crack + of sand-crack by clamping the fissure + of sand-crack by grooving the wall + of sand-crack by wedging the fissure + of seedy-toe + of side-bone + of simple chronic coronitis + of specific coronitis + of spongy hoof + of sub-horny quittor + of synovitis + of thrush + of weak heels +Use of the horse that has undergone neurectomy +Vachette's sand-crack clamp +Veins, the +Velvety tissue, the +Villate's caustic solution + +Wall, the +Weak heels + causes of + definition of + symptoms of + treatment of +Wedging the fissure in the treatment of sand-crack +Wound in punctured foot, common situations of the +Wounds of the lateral cartilages +Wounds of the plantar aponeurosis + + + +THE END + + + + + + + + + + + + +End of the Project Gutenberg EBook of Diseases of the Horse's Foot +by Harry Caulton Reeks + +*** END OF THIS PROJECT GUTENBERG EBOOK DISEASES OF THE HORSE'S FOOT *** + 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