Lameness of the Horse Veterinary Practitioners' Series, No. 1

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Title: Lameness of the Horse

Veterinary Practitioners' Series, No. 1

Author: John Victor Lacroix

Release Date: July 27, 2005 [eBook #16370]

Language: English

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VETERINARY PRACTITIONERS' SERIES

NO. 1

LAMENESS of the HORSE

BY

J.V. Lacroix, D.V.S.

Professor of Surgery, The Kansas City Veterinary College

Author of Animal Castration

Illustrated

Chicago

AMERICAN JOURNAL OF VETERINARY MEDICINE

1916

PREFACE

All that can be known on the subject of lameness, is founded on a knowledge of anatomy and of the physiology of locomotion. Without such knowledge, no one can master the principles of the diagnosis of lameness. However, it must be assumed that the readers are informed on these subjects, as it is impossible to include this fundamental instruction in a work so brief as this one.

The technic of certain operative or corrective procedures, has been described at length only where such methods are not generally employed. Where there is no departure from the usual methods, treatment that is essentially within the domain of surgery or practice is not given in specific detail.

Realizing the need for a treatise in the English language dealing with diagnosis and treatment of lameness, the author undertook the preparation of this manuscript. That the difficulties of depicting by means of word-pictures, the symptoms evinced in baffling cases of lameness, presented themselves in due course of writing, it is needless to say.

It is hoped that this volume will serve its readers to the end that the handling of cases of lameness will become a more satisfactory and successful part of their work; that both the practitioner and his clients may profit thereby; and last but by no means least, that the horse, which has given such incalculable service to mankind and is deserving of a more concrete reward, will be benefited by the application of the principles herein outlined.

In addition to the consultation of standard works bearing on various phases of the subject of lameness, the author wishes to thankfully acknowledge helpful advice and assistance received from the publisher, Dr. D.M. Campbell; to appreciatively credit Drs. L.A. Merillat, A. Trickett and F.F. Brown for valuable suggestions given from time to time. Particular acknowledgment is made to Dr. Septimus Sisson, author, and W.B. Saunders & Co., publishers of The Anatomy of Domestic Animals, for permission to use a number of illustrations from that work.

J.V.L.

Chicago, Illinois, October, 1916.

Justice shows a triumphant face at the works of humane practitioners, who give serious thought and expend honest effort, for the alleviation of animal suffering.

TABLE OF CONTENTS

Page

Illustrations7

Introduction11

SECTION I

Etiology and Occurrence15

Affections of Bones15

Rarefying Osteitis, or Degenerative Changes16

Fractures16

Affections of Ligaments20

Luxations—Dislocations21

Arthritis22

Affections of Bursae and Thecae27

Affections of Muscles and Tendons28

Affections of Nerves30

Affections of Blood Vessels31

Affections of Lymph Vessels and Glands32

Affections of the Feet34

SECTION II

Diagnostic Principles37

Anamnesis38

Visual Examination39

Attitude of the Subject41

Examination by Palpation43

Passive Movements47

Observing the Character of the Gait48

Special Methods of Examination53

SECTION III

Lameness in the Fore Leg

Anatomo-Physiological Review of Parts of the Fore Leg55

Shoulder Lameness61

Fracture of the Scapula62

Scapulohumeral Arthritis65

Infectious Arthritis66

Injuries66

Wounds67

Luxation of the Scapulohumeral Joint67

Inflammation of the Bicipital Bursa68

Contusions of the Triceps Brachii71

Shoulder Atrophy (Sweeny)73

Paralysis of the Suprascapular Nerve75

Radial Paralysis77

Thrombosis of the Brachial Artery81

Fracture of the Humerus82

Inflammation of the Elbow84

Fracture of the Ulna86

Fracture of the Radius87

Wounds of the Anterior Brachial Region90

Inflammation and Contraction of the Carpal Flexors93

Fracture and Luxation of the Carpal Bones96

Carpitis98

Open Carpal Joint100

Thecitis and Bursitis104

Fracture of the Metacarpus106

Splints107

Open Fetlock Joint110

Phalangeal Exostosis (Ringbone)118

Open Sheath of the Flexors of the Phalanges124

Luxation of the Fetlock Joint125

Sesamoiditis127

Fracture of the Proximal Sesamoids128

Inflammation of the Posterior Ligaments of the Pastern Proximal Interphalangeal Joint129

Fracture of the First and Second Phalanges131

Tendinitis (Inflammation of the Flexor Tendons)135

Chronic Tendinitis and Contraction of the Flexor Tendons137

Contracted Tendons of Foals143

Rupture of the Flexor Tendons and Suspensory Ligament146

Thecitis and Bursitis in the Fetlock Region150

Arthritis of the Fetlock Joint152

Ossification of the Cartilages of the Third Phalanx155

Navicular Disease157

Laminitis160

Calk Wounds (Paronychia)170

Corns172

Quittor174

Nail Punctures178

SECTION IV

Lameness in the Hind Leg

Anatomo-Physiological Consideration of the Pelvic Limbs185

Hip Lameness195

Fractures of the Pelvic Bones196

Fractures of the Femur199

Luxation of the Femur201

Gluteal Tendo-Synovitis203

Paralysis of the Hind Leg204

Paralysis of the Femoral (Crural) Nerve204

Paralysis of the Obturator Nerve206

Paralysis of the Sciatic Nerve208

Iliac Thrombosis209

Fracture of the Patella212

Luxation of the Patella213

Chronic Gonitis217

Open Stifle Joint220

Fracture of the Tibia222

Rupture and Wounds of the Tendo Achillis224

Spring-Halt (String-Halt)225

Open Tarsal Joint229

Fracture of the Fibular Tarsal Bone (Calcaneum)230

Tarsal Sprains232

Curb233

Spavin (Bone Spavin)235

Distension of the Tarsal Joint Capsule (Bog Spavin)242

Distension of the Tarsal Sheath of the Deep Digital Flexor (Thoroughpin)246

Capped Hock251

Rupture and Division of the Long Digital Extensor (Extensor Pedis)253

Wounds from Interfering255

Lymphangitis257

Authorities Cited265

Index267

ILLUSTRATIONS

Page

Fig.   1—Hoof Testers53

Fig.   2—Muscles of Left Thoracic Limb, Lateral View56

Fig.   3—Muscles of Left Thoracic Limb, Medial View57

Fig.   4—Sagital Section of Digit and Distal Part of Metacarpus59

Fig.   5—Ordinary Type of Heavy Sling62

Fig.   6—A Sling Made in Two Parts63

Fig.   7—Paralysis of the Suprascapular Nerve of Left Shoulder76

Fig.   8—Radial Paralysis78

Fig.   9—Merillat's Method of Fixing Carpus in Radial Paralysis79

Fig. 10—Contraction of Carpal Flexors, Knee Sprung95

Fig. 11—Pericarpal Inflammation and Enlargement Due to Injury99

Fig. 12—Hygromatous Condition of the Right Carpus100

Fig. 13—Carpal Exostosis in Aged Horse101

Fig. 14—Exostosis of Carpus Resultant from Carpitis102

Fig. 15—Distal End of Radius, Illustrating Effects of Carpitis102

Fig. 16—Posterior View of Radius, Illustrating Effects of Splint108

Fig. 17—Phalangeal Exosteses120

Fig. 18—Rarefying Osteitis in Chronic Ringbone121

Fig. 19—Phalangeal Exostoses in Chronic Ringbone122

Fig. 20—Contraction of Superficial Digital Flexor Tendon Due to Tendinitis138

Fig. 21—Contraction of Deep Flexor Tendon Due to Tendinitis139

Fig. 22—Chronic Case of Contraction of Both Flexor Tendons of the Phalanges140

Fig. 23—Contraction of Superficial and Deep Flexor Tendons141

Fig. 24—Contraction of Superficial Digital Flexor and Slight Contraction of Deep Flexor Tendon142

Fig. 25—Fish Knees145

Fig. 26—Extreme Dorsal Flexion146

Fig. 27—A Good Style of Shoe for Bracing the Fetlock148

Fig. 28—The Roberts Brace in Operation149

Fig. 29—Distension of Theca of Extensor of the Digit151

Fig. 30—Rarefying Osteitis Wherein Articular Cartilage Was Destroyed153

Fig. 31—Ringbone and Sidebone156

Fig. 32—Position Assumed by Horse Having Unilateral Navicular Disease159

Fig. 33—The Hoof in Chronic Laminitis165

Fig. 34—Effects of Laminitis166

Fig. 35—Cochran Shoe, Inferior Surface168

Fig. 36—Cochran Shoe, Superior Surface169

Fig. 37—Hyperplasia of Eight Forefoot Due to Chronic Quittor176

Fig. 38—Chronic Quittor, Left Hind Foot177

Fig. 39—Skiagraph of Foot179

Fig. 40—Sagital Section of Eight Hock186

Fig. 41—Muscles of Right Leg; Front View187

Fig. 42—Muscles of Lower Part of Thigh, Leg and Foot189

Fig. 43—Right Stifle Joint; Lateral View190

Fig. 44—Left Stifle Joint; Medial View191

Fig. 45—Left Stifle Joint; Front View193

Fig. 46—Oblique Fracture of the Femur200

Fig. 47—Fracture of Femur After Six Months' Treatment201

Fig. 48—Aorta and Its Branches Showing Location of Thrombi210

Fig. 49—Thrombosis of the Aorta, Iliacs and Branches211

Fig. 50—Chronic Gonitis218

Fig. 51—Position Assumed in Gonitis219

Fig. 52—Spring-halt226

Fig. 53—Lateral View of Tarsus Showing Effects of Tarsitis228

Fig. 54—Right Hock Joint231

Fig. 55—Spavin235

Fig. 56—Bog Spavin243

Fig. 57—Thoroughpin247

Fig. 58—Fibrosity of Tarsus in Chronic Thoroughpin248

Fig. 59—Another View of Case Shown in Fig. 58249

Fig. 60—Capped Hock252

Fig. 61—Chronic Lymphangitis258

Fig. 62—Elephantiasis259

INTRODUCTION

Lameness is a symptom of an ailment or affection and is not to be considered in itself as an anomalous condition. It is the manifestation of a structural or functional disorder of some part of the locomotory apparatus, characterized by a limping or halting gait. Therefore, any affection causing a sensation and sign of pain which is increased by the bearing of weight upon the affected member, or by the moving of such a distressed part, results in an irregularity in locomotion, which is known as lameness or claudication. A halting gait may also be produced by the abnormal development of a member, or by the shortening of the leg occasioned by the loss of a shoe.

For descriptive purposes lameness may be classified as true and false. True lameness is such as is occasioned by structural or functional defects of some part of the apparatus of locomotion, such as would be caused by spavin, ring-bone, or tendinitis. False lameness is an impediment in the gait not caused by structural or functional disturbances, but is brought on by conditions such as may result from the too rapid driving of an unbridle-wise colt over an irregular road surface, or by urging a horse to trot at a pace exceeding the normal gait of the animal's capacity, causing it to crow-hop or to lose balance in the stride. The latter manifestation might, to the inexperienced eye, simulate true lameness of the hind legs, but in reality, is merely the result of the animal having been forced to assume an abnormal pace and a lack of balance in locomotion is the consequence.

The degree of lameness, though variable in different instances, is in most cases proportionate to the causative factor, and this fact serves as a helpful indicator in the matter of establishing a diagnosis and giving the prognosis, especially in cases of somewhat unusual character. An animal may be slightly lame and the exhibition of lameness be such as to render the cause bafflingly obscure. Cases of this nature are sometimes quite difficult to classify and in occasional instances a positive diagnosis is impossible. Subjects of this kind may not be sufficiently inconvenienced to warrant their being taken out of service, yet a lame horse, no matter how slightly affected, should not be continued in service unless it can be positively established that the degree of discomfort occasioned by the claudication is small and the work to be done by the animal, of the sort that will not aggravate the condition.

Subjects that are very lame—so lame that little weight is borne by the affected member—are, of course, unfit for service and as a rule are not difficult of diagnosis. For instance, a fracture of the second phalanx would cause much more lameness than an injury to the lateral ligament of the coronary joint wherein there had occurred only a slight sprain, and though crepitation is not recognized, the diagnostician is not justified in excluding the possibility of fracture, if the lameness seems disproportionate to the apparent first cause.

The course taken by cases of lameness is as variable as the degree of its manifestation, and no one can definitely predict the duration of any given cause of claudication.

Because of the fact that horses are not often good self-nurses at best, and that it is difficult to enforce proper care for the parts affected, one can not wisely state that resolution will promptly follow in an acute involvement, nor can he predict that the case will or will not become chronic. Experience has proved that complete or partial recovery may result, or again, that no change may occur in any given case, and that in some instances even where rational treatment is early administered, a decided aggravation of the condition may follow unaccountably.

However, because of the economic element to be reckoned with, it is of some value to be able to give a fairly accurate prognosis in the handling of cases of lameness, as in the majority of instances the treatment and manner of after-care are determined largely by the expense that any prescribed line of attention will occasion.

A case of acute bone spavin in a horse of little value is not generally treated in a manner that will incur an expense equivalent to one-half the value of the subject. The fact is always to be considered in such cases, that even where ideal conditions favor proper treatment, the outcome is uncertain. Where less than six weeks of rest can be allowed the animal, one affected with bone spavin would therefore not be treated with the expectation of obtaining good results, as six weeks' time, at least, is necessary for a successful outcome. If the cost attending the enforced idleness of an animal of this kind is considered prohibitive for the employment of proper measures to affect a cure, and if lameness is slight, the animal should be given suitable work, but in cases of articular spavin in aged subjects, they should be humanely destroyed and not subjected to prolonged misery.

A thorough knowledge of the structure and functions of the affected parts is necessary to proceed in cases of lameness; likewise, the age, conformation and temperament of the subject need to be taken into consideration; the presence or absence of complications demand the attention; the kind of care the subject will probably receive directly influences the outcome; and the character of service expected of the subject, too, needs to be carefully considered before the ultimate outcome may reasonably be foretold.

The practitioner is often confronted with the problem of how best to handle certain cases. Will they do better under conditions where absolute quiet is enforced, or is it preferable to allow exercise at will? The temperament of the animal must be considered in such cases, and if a lame horse is too active and playful when given his freedom, exercise must be restricted or prevented, as the case may require. In cases of strains of tendons, during the acute stage, immobilization of the affected parts is in order. In certain sub-acute inflammatory processes or in instances of paralytic disturbance where convalescence is in progress, moderate exercise is highly beneficial.

Consequently, each case in itself presents an individual problem to be judged and handled in the manner experience has taught to be most effective, appropriate and practical, and the veterinarian should give due consideration to the comfort and welfare of the crippled animal as well as to the interests of the owner.

SECTION I.

ETIOLOGY AND OCCURRENCE.

In discussions of pathological conditions contributing to lameness in the horse, cause is generally classified under two heads—predisposing and exciting. It becomes necessary, however, to adopt a more general and comprehensive method of classification, herein, which will enable the reader to obtain a better conception of the subject and to more clearly associate the parts so grouped descriptively.

Though predisposing factors, such as faulty conformation, are often to be reckoned with, exciting causes predominate more frequently in any given number of cases. The noble tendency of the horse to serve its master under the stress of pain, even to the point of complete exhaustion and sudden death, should win for these willing servants a deeper consideration of their welfare. Too frequently are their manifestations of discomfort allowed to pass unheeded by careless, incompetent drivers lacking in a sense of compassion. Symptoms of malaise should never be ignored in any case; the humane and economic features should be realized by any owner of animals.

In the consideration of group causes, lameness may be said to originate from affections of bones, ligaments, thecae and bursae, muscles and tendons, nerves, lymph vessels and glands, and blood vessels, and may also result from an involvement of one or several of the aforementioned tissues, caused by rheumatism. Further, affections of the feet merit separate consideration, and, finally, a miscellaneous grouping of various dissimilar ailments, which for the most part, do not directly involve the locomotory apparatus but do, by their nature, impede normal movement.

AFFECTIONS OF BONES.

The bony column serving as the framework and support of the legs, probably constitutes the most vital element having to do with weight bearing and locomotion, and therefore during the acute and painful stage of bone affections, the pain becomes more intense in the process and pressure of standing than when the member is swung or advanced.

Certain bones are so well protected by muscular structures that they are not frequently injured except as a result of violence which may produce fracture. However, there are certain bones which receive the constant shock of concussion when the animal is subjected to daily, rapid work on hard road surfaces. Splints, ringbones and spavins are the most general examples produced by these conditions.

Varying pathological developments often result from concussion, contusion or other violent shocks to the bony structures. In such cases there either follows a simple periostitis which may resolve spontaneously with no obvious outward symptom, or osteitis, which may occur with tissue changes, as in exostosis; or the case may produce any degree of reaction between these two possible extremes.

Rarefying Osteitis, or Degenerative Changes.

Certain bone affections, such as osteomalacia or osteoporosis, are in the main, responsible for distortions and morphological changes of bone, causing lameness, permanent blemish and even resulting in death of the affected animal. The climatic conditions in some localities favor these occurrences but they may also be ascribed to improper food constituents and to possible infective agencies.

Rarefying degenerative changes manifested by exostosis involving the phalanges of the young, causing ringbone, are fairly common in occurrence throughout this country. This is due, supposedly, to a lack of mineral substance in the bony structure of the affected animals, and is known as rachitis—commonly called rickets. Since the affected subjects suffer involvement of several of the extremities at the same time, the theory of rachitic origin seems well supported.

Fractures.

Fractures of bones constitute serious conditions and are always manifested by lameness. A sub-classification is essential here for the student of veterinary medicine who would comprehend the technic of reduction and subsequent treatment in such cases.

Fractures are classified by many authorities as being simple, compound, and comminuted. This method is practical because it separates dissimilar conditions. There are also grouped fractures, the pathologic anatomy of which is similar. Classification on an etiological basis would attempt to associate conditions, the morbid anatomy and gravity of which would justly preclude their being combined.

Simple Fracture is a condition where the continuity of the bone has been broken without serious destruction of the soft structures adjacent, and where no opening has been made to the surface of the flesh. Such fractures do not reduce the bone to fragments. Long bones are frequently subjected to simple fracture, while short thick bones, such as the second phalanx, may suffer multiple or comminuted fractures.

Compound Fracture designates a break of bone with the destruction of the soft tissues covering it, making an open wound to the surface of the skin. This form of fracture is serious because of the attendant danger of infection, and in treatment, necessitates special precaution being taken in the application of splints that the wound may be cared for without infection of the tissues. These fractures generally occur as a result of some forceful impact through the flesh to the bone, or where the bones are driven outward by the blow. Common examples are in fractures of the metacarpus and metatarsus of the first phalanx. This kind of injury in mature horses usually produces an irreparable condition, and viewed economically, is generally considered fatal.

Comminuted Fractures, as the term implies, are those cases wherein the bone is reduced to a number of small pieces. This kind of break may be classified as simple-comminuted fracture when the skin is unbroken, and when the bone is exposed as a result of the injury, it is known as a compound-comminuted fracture. Such fractures are caused by violent contusion or where the member is caught between two objects and crushed.

Multiple Fractures.

Fractures are called multiple when the bone is reduced to a number of pieces of large size. This condition differs from a comminuted fracture in that the multiple fracture may break the bone into several pieces without the pieces being ground or crushed, and the affected bone may still retain its normal shape.

Further classification is of value in describing fractures of bone with respect to the manner in which the bone is broken—the direction of the fissure or fissures in relation to its long axis.

A fracture is transverse when the bone is broken at a right angle from its long axis. Such breaks when simple, are the least trouble to care for because there is little likelihood that the broken ends of bone will become so displaced that they will not remain in apposition. Simple transverse fracture of the metacarpus, for instance, constitutes a favorable case for treatment if other conditions are favorable.

Oblique fractures, as may be surmised, are solutions of continuity of bone in such manner that the fissure crosses the long axis of a bone at an acute or obtuse angle. These fractures are prone to injure the soft structures adjacent, and are frequently compound, as well. Moreover, because of the fact that the apposing pieces of bone are beveled, the broken ends of bone are likely to pass one another in such a way as to shorten the distance between the extremities of the injured member. Contraction of muscles also tends to exert traction upon a bone so fractured, resulting in a lateral approximation of the diaphysis and thus preventing union because the broken surfaces are not in proper contact.

Fractures are longitudinal when the fissure is parallel with the long axis of the bone. This variety of break is not infrequent in the first phalanx; and a vertical fracture of the second phalanx is also said to be longitudinal, however, there is little difference (if any, in some subjects) between the vertical and transverse diameters of this particular bone.

Green stick fractures are essentially those resulting from falls to young animals. They are usually sub-periosteal and when the periosteum is left intact or nearly so, no crepitation is discernible. If this fracture is simple, prompt recovery may be expected. Bones of young animals, because they do not contain proportionately as much mineral substance as do bones of adults, are more resilient and less apt to become completely fractured. They are, however, subject to what is known as green stick fracture.

Impacted fractures are usually occasioned by falls. When the weight of the body is suddenly caught by a member in such manner as to forcefully drive the epiphyseal portions of bone into and against the diaphysis, multiple longitudinal fractures occur at the point of least resistance. Parts so affected undergo a fibrillary separation, increasing the transverse diameter of the bone; or if the impact has been sufficiently violent, the portion becomes an amorphous mass.

In a treatise on the subject of lameness, the bones chiefly concerned and most often affected must be especially considered. The shape and size of a bone when injured, determines in a measure, the course and probable outcome in most cases, but of first and greater importance is the function of the bone. A fracture of the fibula in the horse need not incapacitate the subject, but a tibial fracture is serious and generally proves cause for fatal termination. The body of the scapula may be completely fractured and recovery will probably result in most cases without much attention being given to the subject, yet a fracture of the neck of this same bone constitutes an injury of serious consequence. The difference in the function of different parts of this same bone, as well as its shape and mode of attachment, determine the gravity of the case; so it is in fractures of other bones with respect to the course and prognosis of the case—function is the important factor to be considered.

Next in importance is the age of the animal suffering fracture of the bone. Capacity for regeneration is naturally greater in a vigorous, young animal than in aged or even middle-aged subjects. A healthy condition of the bone and the body favor the process of repair in case of fracture, and prognosis may be favorable or unfavorable, depending upon these factors mentioned for consideration. Individuals of the same species, differing in temperament, may comport themselves in a manner that is conductive to prompt recovery, or to early destruction.