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Transcriber's Note:
The original text was inconsistent in the use of accents and
hyphenation. These variants and a small number of typographical
errors were maintained in this transcription. A complete list
of the variant spellings is found at the end of the book along
with the list of typographical errors.
The Table of Contents lists the Authorities Cited section as
preceding the Index, but it was printed following the Index.
This order has been retained in this transcription.
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
Illustrations 7
Introduction 11
SECTION I
Etiology and Occurrence 15
Affections of Bones 15
Rarefying Osteitis, or Degenerative Changes 16
Fractures 16
Affections of Ligaments 20
Luxations--Dislocations 21
Arthritis 22
Affections of Bursae and Thecae 27
Affections of Muscles and Tendons 28
Affections of Nerves 30
Affections of Blood Vessels 31
Affections of Lymph Vessels and Glands 32
Affections of the Feet 34
SECTION II
Diagnostic Principles 37
Anamnesis 38
Visual Examination 39
Attitude of the Subject 41
Examination by Palpation 43
Passive Movements 47
Observing the Character of the Gait 48
Special Methods of Examination 53
SECTION III
Lameness in the Fore Leg
Anatomo-Physiological Review of Parts of the Fore Leg 55
Shoulder Lameness 61
Fracture of the Scapula 62
Scapulohumeral Arthritis 65
Infectious Arthritis 66
Injuries 66
Wounds 67
Luxation of the Scapulohumeral Joint 67
Inflammation of the Bicipital Bursa 68
Contusions of the Triceps Brachii 71
Shoulder Atrophy (Sweeny) 73
Paralysis of the Suprascapular Nerve 75
Radial Paralysis 77
Thrombosis of the Brachial Artery 81
Fracture of the Humerus 82
Inflammation of the Elbow 84
Fracture of the Ulna 86
Fracture of the Radius 87
Wounds of the Anterior Brachial Region 90
Inflammation and Contraction of the Carpal Flexors 93
Fracture and Luxation of the Carpal Bones 96
Carpitis 98
Open Carpal Joint 100
Thecitis and Bursitis 104
Fracture of the Metacarpus 106
Splints 107
Open Fetlock Joint 110
Phalangeal Exostosis (Ringbone) 118
Open Sheath of the Flexors of the Phalanges 124
Luxation of the Fetlock Joint 125
Sesamoiditis 127
Fracture of the Proximal Sesamoids 128
Inflammation of the Posterior Ligaments of the Pastern
Proximal Interphalangeal Joint 129
Fracture of the First and Second Phalanges 131
Tendinitis (Inflammation of the Flexor Tendons) 135
Chronic Tendinitis and Contraction of the Flexor Tendons 137
Contracted Tendons of Foals 143
Rupture of the Flexor Tendons and Suspensory Ligament 146
Thecitis and Bursitis in the Fetlock Region 150
Arthritis of the Fetlock Joint 152
Ossification of the Cartilages of the Third Phalanx 155
Navicular Disease 157
Laminitis 160
Calk Wounds (Paronychia) 170
Corns 172
Quittor 174
Nail Punctures 178
SECTION IV
Lameness in the Hind Leg
Anatomo-Physiological Consideration of the Pelvic Limbs 185
Hip Lameness 195
Fractures of the Pelvic Bones 196
Fractures of the Femur 199
Luxation of the Femur 201
Gluteal Tendo-Synovitis 203
Paralysis of the Hind Leg 204
Paralysis of the Femoral (Crural) Nerve 204
Paralysis of the Obturator Nerve 206
Paralysis of the Sciatic Nerve 208
Iliac Thrombosis 209
Fracture of the Patella 212
Luxation of the Patella 213
Chronic Gonitis 217
Open Stifle Joint 220
Fracture of the Tibia 222
Rupture and Wounds of the Tendo Achillis 224
Spring-Halt (String-Halt) 225
Open Tarsal Joint 229
Fracture of the Fibular Tarsal Bone (Calcaneum) 230
Tarsal Sprains 232
Curb 233
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 Hock 251
Rupture and Division of the Long Digital Extensor (Extensor
Pedis) 253
Wounds from Interfering 255
Lymphangitis 257
Authorities Cited 265
Index 267
ILLUSTRATIONS
Page
Fig. 1--Hoof Testers 53
Fig. 2--Muscles of Left Thoracic Limb, Lateral View 56
Fig. 3--Muscles of Left Thoracic Limb, Medial View 57
Fig. 4--Sagital Section of Digit and Distal Part of
Metacarpus 59
Fig. 5--Ordinary Type of Heavy Sling 62
Fig. 6--A Sling Made in Two Parts 63
Fig. 7--Paralysis of the Suprascapular Nerve of Left
Shoulder 76
Fig. 8--Radial Paralysis 78
Fig. 9--Merillat's Method of Fixing Carpus in Radial
Paralysis 79
Fig. 10--Contraction of Carpal Flexors, "Knee Sprung" 95
Fig. 11--Pericarpal Inflammation and Enlargement Due to
Injury 99
Fig. 12--Hygromatous Condition of the Right Carpus 100
Fig. 13--Carpal Exostosis in Aged Horse 101
Fig. 14--Exostosis of Carpus Resultant from Carpitis 102
Fig. 15--Distal End of Radius, Illustrating Effects of
Carpitis 102
Fig. 16--Posterior View of Radius, Illustrating Effects of
Splint 108
Fig. 17--Phalangeal Exosteses 120
Fig. 18--Rarefying Osteitis in Chronic Ringbone 121
Fig. 19--Phalangeal Exostoses in Chronic Ringbone 122
Fig. 20--Contraction of Superficial Digital Flexor Tendon
Due to Tendinitis 138
Fig. 21--Contraction of Deep Flexor Tendon Due to
Tendinitis 139
Fig. 22--Chronic Case of Contraction of Both Flexor Tendons
of the Phalanges 140
Fig. 23--Contraction of Superficial and Deep Flexor
Tendons 141
Fig. 24--Contraction of Superficial Digital Flexor and
Slight Contraction of Deep Flexor Tendon 142
Fig. 25--"Fish Knees" 145
Fig. 26--Extreme Dorsal Flexion 146
Fig. 27--A Good Style of Shoe for Bracing the Fetlock 148
Fig. 28--The Roberts Brace in Operation 149
Fig. 29--Distension of Theca of Extensor of the Digit 151
Fig. 30--Rarefying Osteitis Wherein Articular Cartilage
Was Destroyed 153
Fig. 31--Ringbone and Sidebone 156
Fig. 32--Position Assumed by Horse Having Unilateral
Navicular Disease 159
Fig. 33--The Hoof in Chronic Laminitis 165
Fig. 34--Effects of Laminitis 166
Fig. 35--Cochran Shoe, Inferior Surface 168
Fig. 36--Cochran Shoe, Superior Surface 169
Fig. 37--Hyperplasia of Eight Forefoot Due to Chronic
Quittor 176
Fig. 38--Chronic Quittor, Left Hind Foot 177
Fig. 39--Skiagraph of Foot 179
Fig. 40--Sagital Section of Eight Hock 186
Fig. 41--Muscles of Right Leg; Front View 187
Fig. 42--Muscles of Lower Part of Thigh, Leg and Foot 189
Fig. 43--Right Stifle Joint; Lateral View 190
Fig. 44--Left Stifle Joint; Medial View 191
Fig. 45--Left Stifle Joint; Front View 193
Fig. 46--Oblique Fracture of the Femur 200
Fig. 47--Fracture of Femur After Six Months' Treatment 201
Fig. 48--Aorta and Its Branches Showing Location of
Thrombi 210
Fig. 49--Thrombosis of the Aorta, Iliacs and Branches 211
Fig. 50--Chronic Gonitis 218
Fig. 51--Position Assumed in Gonitis 219
Fig. 52--Spring-halt 226
Fig. 53--Lateral View of Tarsus Showing Effects of Tarsitis 228
Fig. 54--Right Hock Joint 231
Fig. 55--Spavin 235
Fig. 56--Bog Spavin 243
Fig. 57--Thoroughpin 247
Fig. 58--Fibrosity of Tarsus in Chronic Thoroughpin 248
Fig. 59--Another View of Case Shown in Fig. 58 249
Fig. 60--"Capped Hock" 252
Fig. 61--Chronic Lymphangitis 258
Fig. 62--Elephantiasis 259
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. This
feature cannot be overestimated in importance, as it is sometimes a
decisive element, regardless of other conditions. A horse suffering from
an otherwise remediable pelvic fracture may be so worried and tortured
by being confined in a sling that the case calls for special attention
and care because of the animal's temperament. Sometimes, the constant
presence of a kind attendant will so reassure the subject that it will
become resigned to unnatural confinement, in a day or two. This
precaution may, in itself, determine the outcome, and the wise
veterinarian will not overlook this feature or fail to deviate from the
usual rote in the handling of average cases. Recovery may be brought
about in irritable subjects by this concession to the individual
idiosyncrasies of such animals.
AFFECTIONS OF LIGAMENTS.
Ligaments which have to do with the locomotory apparatus are, for the
most part, inelastic structures which are composed of white fibrous
tissue and serve to join together the articular ends of bones; to bind
down tendons; and to act as sheathes or grooves through which tendons
pass, and as capsular membranes for retention of synovia in contact with
articular surfaces of bones.
Ligaments are injured less frequently than are bones. Because of their
flexibility they escape fracture in the manner that bones suffer. They
are, however, completely severed by being cut or ruptured, though
fibrillary fracture the result of constant or intermittent tensile
strain is of more frequent occurrence.
Simple inflammation of ligaments is of occasional occurrence but, unless
considerable injury is done this tissue, no perceptible manifestation of
injury results. No doubt many cases wherein fibrillary fracture of
ligaments (sprain) takes place some lameness is caused, but because of
the dense, comparatively nonvascular nature of these structures, little
if any manifestation, except lameness, is evident. And such cases, if
recognized are usually diagnosed by excluding the existence of other
possible causes and conditions which might also cause lameness.
Certain ligaments are subjected to strain more than are others and
therefore, when so involved, frequently cause lameness. Examples of this
kind are affections of the collateral (lateral) ligaments of the
phalanges. Because of the leverage afforded by the transverse diameter
of the foot, when an animal is made to travel over uneven road surfaces,
considerable strain is brought to bear on the collateral ligaments of
the phalanges. A sequel to this form of injury is a circumscribed
periostitis at the site of attachment of the ligaments and frequently
the formation of an exostosis--ringbone--results.
Where sudden and violent strain is placed upon a ligament and rupture
occurs, the division is usually effected by the ligament being torn from
its attachment to the bone. In such cases, a portion of periosteum and
bone is usually detached and the condition may then properly be called
one of fracture. In some cases of this kind recovery is tardy, because
of the difficulty in maintaining perfect apposition of the divided
structures, and reactionary inflammation is not of sufficient extent to
enhance prompt repair. In fact, some cases of this kind seem to progress
more favorably, when no attempt at immobilization of the affected member
is attempted.
If some freedom of movement is allowed, acute inflammation resulting in
nature's provisional swelling soon develops and repair is hastened
because of increased vascularity. But where luxation of phalanges
accompanies sprain, reposition and immobilization are necessary--that is
if cases are thought likely to benefit by any treatment.
Luxations--Dislocations.
Luxation or dislocation is a condition where the normal relation between
articular ends of bones has been deranged to the extent that partial or
complete loss of function results. When a bone is luxated (out of
joint), there has occurred a partial or complete rupture of certain
ligaments or tendons; or a bone may be luxated when an abnormal or
unusual elasticity of inhibitory ligaments or tendons obtains.
Luxations may be practically classified as _temporary_ and _fixed_. In
temporary luxations, disarticulation is but momentary and spontaneous
reposition always results; while a fixed luxation does not reduce
spontaneously but remains luxated until reposition is effected by proper
manipulation and treatment. Fixed luxation may be of such character as
to be practically irreducible because of extensive damage done to
ligaments or cartilage. Where a complete luxation of the
metacarpophalangeal joint exists, it is probable that in most cases
sufficient injury to collateral and capsular ligaments has been done to
render complete recovery improbable, if not impossible.
Temporary luxation of the patella is a common affection of the horse and
fixed luxation of this bone also occurs. As a matter of fact, in the
horse, patellar luxation is the one frequent affection of this kind.
As a rule, complete disarticulation immobilizes the affected joint and
in most instances there is noticeable an abnormal prominence in the
immediate vicinity--in patellar luxation, the whole bone. In other
instances the articular portion only, of the affected bone is
malpositioned. Usually, luxation and fracture may be differentiated in
that there is no crepitation in luxation and more or less crepitation
exists in fracture.
It is evident, when one considers the symptomatology and nature of the
affection, that fixed luxation is usually caused by undue strain or
violent and abnormal movement of a part. Joints having the greater
freedom of movement are apt to suffer luxation more frequently.
Arthritis.
The study of arthritis in the horse is limited to a consideration of
joint inflammations which, for the most part, are of traumatic origin.
Unlike the human, the horse is not subject to many forms of specific
arthritis--tubercular, gonorrheal, syphilitic, etc.
A practical manner of classification of arthritis is _traumatic_ and
_metastatic_.
_Traumatic arthritis_ may result from all sorts of accidents wherein
joints are contused. Such cases may be considered as being caused by
direct injuries. Instances of this kind, depending on the degree of
insult, manifest evidence of injury which ranges from a simple
synovitis to the most active inflammatory involvement of the entire
structure and adjacent tissues.
The reactionary inflammation which attends a case of tarsitis caused by
a horse being kicked is a good example of the result of direct injury.
Such cases, if the contusion is of sufficient violence, result in
arthritis and periarthritis. In inactive farm horses, during cold
weather, this condition becomes chronic, swelling remains for weeks
after all lameness and pain have subsided and occasionally hyperthrophy
is permanent.
Arthritis occasioned by indirect injury, such as characterizes joint
inflammation from continuous concussion, is seen in horses that are
worked at a rapid pace on city streets or other hard road surfaces. Such
affections may be acute, as in some cases of spavin, but are usually
inflammatory conditions that do not occasion serious disturbance when
these affections become chronic. If the involvement persists with
sufficient active inflammation, there may follow erosion of cartilage
and incurable lameness. If extensive necrosis of cartilage takes place,
the attendant pain will be sufficient to cause the animal to favor the
diseased part and such immobilization enhances early ankylosis--nature's
substitute for resolution in this disease.
Wounds invading the tissues adjacent to joints, when these wounds are of
considerable extent, cause inflammation of such articulations by
contiguous extension of inflammation. As long as an injury remains
practically aseptic, or if infected and the septic process does not
involve the joint proper by direct extension, no more serious
disturbance than a simple synovitis will result. If, instead, a
periarthritic inflammation is serious or destructive in character, the
type of arthritis will be grave--even though due to an indirect cause.
Where a vulnerant body penetrates all structures and invades the
interior of the joint capsule the result is that a more or less active
disturbance is incited. The introduction of a sterile instrument into a
joint cavity, under strict asepsis, where a perfect technic is executed,
does not cause perceptible manifestation of the injury, if the opening
so made is small--such as a suitable exploratory trocar makes. But a
puncture made in a similar manner and with the same instrument without
due regard to asepsis is likely to cause an infectious synovitis and
arthritis usually follows.
A larger opening than is produced by means of an exploratory trochar may
be made into a joint cavity, causing escape of synovia as it is secreted
for days and even for weeks and no serious or permanent trouble is
experienced in some cases. If the synovitis or arthritis remains
non-infected and the wound, traumatic or surgical, is not too large,
healing by granulation occurs, and the discharge of synovia ceases.
However, if synovial discharge persists too long because of tardy
closure of an open joint, there is great danger of infection gaining
entrance into the synovial cavity, or in some instances, desiccation of
endothelial cells of the articulation occurs, in areas, and the
reactionary inflammation eventually results in ankylosis.
A small puncture which introduces into the synovial cavity infectious
material of active virulence will cause an arthritis that is more
serious, much more painful and more difficult to handle than is
occasioned by a wound of moderate size, that affords ready escape of
synovia even through the virulence of the infection be the same.
Synovia is a good culture medium and the environment is ideal for
multiplication of bacteria; consequently, the grave disturbances which
may attend the introduction of pathogenic organisms into a synovial
cavity as the result of a puncture wound are not to be forgotten. The
veterinarian is in no position to estimate the virulency of organisms so
introduced; neither can he determine the exact degree of resistance
possessed by the subject in any given case. Therefore, he is uncertain
as to the best method of handling such cases where an injury has been
recently inflicted and positive evidence of the existence of an
infectious synovitis is not present. If one could determine in advance
the degree of infection and injury that is to follow small penetrant
wounds of joint capsules, it would then be possible to select certain
cases and immediately drain away all synovia and fill the cavity by
injection with suitable antiseptic solutions.
This offers a broad field for experimentation which will in time be
productive of a radical change in the manner of treating such cases.
_Metastatic arthritis_ is seen more frequently in colts or young animals
than in mature horses and we here take the liberty of classifying with
the arthritis of omphalophlebitis and strangles the so-called rheumatic
variety.
A specific polyarthritis or synovitis which attends navel infection of
foals is perhaps the most frequent form of arthritis that is to be
considered metastatic. This condition is truly a disease of young
animals and, while it is a specific arthritis, the cause is yet to be
attributed to any definite pathogenic organism with certainty. This
condition is well defined by Bollinger as quoted by Hoare,[1] when he
calls it a purulent omphalophlebitis due to local infection of the
umbilicus and umbilical vessels, by pyogenic organisms, causing a
metastatic pyemia.
This affection is grave; its course is comparatively brief; the
prognosis is usually unfavorable; and omphalophlebitis occasions a form
of lameness which at once impresses the practitioner that serious
constitutional disturbance exists. Its consideration properly belongs to
discussions on practice or obstetrics and diseases of the new born, and
it has received careful attention and is discussed at length in these
works.
A second form of metastatic arthritis is met with in strangles.
Strangles occurs in the young principally and is not a frequent cause of
synovitis or arthritis in the adult animal.
Strangles or distemper is, according to most pathologists, due to the
Streptococcus equi. Hoare[2] states that in this type of specific
arthritis the contagium is probably carried by the blood. He gives it as
his opinion that even laminitis has occurred as a result of the
streptococcus-equi. This, indeed, would point toward probable extension
by the blood as well as by way of lymph vessels.
Septic synovitis and infectious arthritis are always serious affections
even in young animals and much depends upon individual resistance and
early rational treatment in such cases, if recovery is to follow.
The same general plan of treatment is indicated in this kind of septic
synovitis as is employed in all cases of infective synovitis and septic
infection in open joints. There is to be considered, however, the fact
that the young animal is more agile, a better self-nurse, and in a
general way more apt to recover than is the adult, under similar
conditions.
_Rheumatic arthritis_, if one is justified in classifying rheumatic
inflammation of joints as a metastatic form of arthritis, is not a
common condition, though seen in mature and aged animals. Cases that may
be diagnosed with certainty are usually advanced affections wherein
dependable history is obtainable and the symptoms are well marked.
Rheumatism may be thought of, with respect to arthritic inflammation
caused thereby, as a sort of pyemia. Undoubtedly, exposure to wet and
cold weather is an active factor, but probably a predisposing one only.
Likewise a member that suffers from chronic inflammation due to
recurrent injury or to constant or repeated strain is less able to
resist the vicissitudes of climate and work.
Consequently, rheumatic arthritis is to be seen affecting horses that
are in service, more often at heavy draft work where they are exposed to
severe straining of joints; where stabling is insanitary; and where they
are obliged to lie down (if they do not remain standing) upon cold and
wet ground or upon hard unbedded floors or paving.
Where such inhumane and cruel treatment is given animals those
responsible ought to be impressed with the unfairness to the animal as
well as the economic loss occasioned by inflicting such unnecessary and
merciless treatment upon their helpless and uncomplaining subjects. The
very nature of the veterinarian's work affords him constant and frequent
opportunity to convince those who are responsible for keeping animals in
this manner, that it is inhumane and unprofitable.
Cases of this kind are not uncommon about some grading and lumbering
camps and in contract work where, often, shelter for animals is given
little thought; the result is a cruel waste of horseflesh.
Chronic articular rheumatism is occasionally observed in young animals
that have never been in service. In these cases it seems that there
exists an individual susceptibility and in some instances the condition
is recurrent. Each attack is of longer duration, and eventually death
results from continued suffering, emaciation and intoxication.
AFFECTIONS OF BURSAE AND THECAE.
Acute bursitis and thecitis is of frequent occurrence in horses because
of direct injury from contusion, punctures and other forms of
traumatism. These synovial membranes, with few exceptions, when inflamed
occasion a synovitis that may be very acute, yet there is less
manifestation of pain than in arthritis.
It is only in structures such as the bursa intertubercularis or in the
sheath of the deep digital flexor that an inflammation causes much pain
and is apt to result in permanent lameness. This is due to the peculiar
character of the function of such structures.
An acute inflammation of a small bursa may even result in the
destruction of such synovial apparatus without serious inconvenience to
the subject, either at the time of destruction or thereafter.
Obliteration of the superficial bursa over the summit of the os calcis
is not likely to cause serious inconvenience or distress to the subject
unless it be due to an infected wound. Even then, with reasonably good
care given the animal, recovery is almost certain. Complete return of
function of the member and cessation of lameness takes place within a
few weeks in the average case.
Where an infectious synovitis involves a structure such as the sheath of
the tendon of the deep digital flexor (perforans) the condition is grave
and because of the location of this theca the prognosis is not much more
favorable than in an articular synovitis.
Inflammation of bursae and thecae may be classified on a chronological
basis with propriety because the duration of such affections, in many
cases, materially modifies the result. A chronic inflammatory
involvement of a theca through which an important tendon plays may cause
adhesions to form. Or there may occur erosions of the parts with
eventual hypertrophy and loss of function, partial or complete.
However, in general practice a classification on an etiological basis
is probably more practical and we shall consider inflammation of bursae
and thecae as _infectious_ and _noninfectious_.
_Infectious_ bursitis and thecitis is usually the result of direct
introduction of septic material into the synovial structure by means of
injuries. Infection by contiguous extension occurs and also metastatic
involvement is met with occasionally.
The noninfectious inflammation of bursae and thecae usually result from
contusions or strains and generally run their course without becoming
infective in character, where vitality and resistance of the subject are
normal.
In a general way, inflammation and other affections of bursae and thecae
are considered very similar to like affections of joints.
AFFECTIONS OF MUSCLES AND TENDONS.
Muscles and tendons having to do with locomotion are more frequently
injured than are any of the other structures whose function is to propel
the body or sustain weight. This is due in part to the exposed position
of muscles and tendons. They serve as a protection to the underlying
structures and in this manner receive many blows the force and violence
of which are spent before injury extends beyond these tissues.
Muscles of the breast, shoulder and rump are most frequently the
recipient of injuries of various kinds. The abductors of the thigh are
subjected to bruising when horses are thrown astride of wagon poles or
similar objects. Thus in one way or another muscle injuries are
occasioned and cause lameness.
Traumatic affection of muscles of locomotion may be surface or
subsurface--subsurface with little injury done the skin and fascia, but
with subsurface extravasation of blood and masceration of tissue.
Puncture wounds wherein the vulnerant body is of small diameter, are
observed, and they occasion deep seated infectious inflammation of the
parts affected, with surface wounds that are often unnoticeable. Such
injuries--puncture wounds--are always serious, and because of the fact
that, there exists little evidence of injury at the time of their
infliction, treatment is usually deferred several days and often
infection has become quite extensive when the practitioner is consulted.
Where infective wounds of muscles of locomotion occur, the course and
gravity of the affection are directly influenced by the proximity of the
injury to lymph plexuses. For instance, injuries causing an infectious
inflammatory involvement of the adductors of the thigh may result in a
generalization of the infection by way of the inguinal lymph glands.
Large open wounds that extend deep into muscles, render inactive such
structures, and even where division is not complete, the pain occasioned
causes the subject to favor the part in every way possible. Contraction
of muscular fibers of such parts increases pain and because of this fact
groups of muscles are at times disabled because of injury done to one
muscle. Instances of this kind are frequently seen where shoulder
injuries, which affect but one muscle, exist; yet because of such injury
a marked swinging-leg lameness is present.
Tendons, because of their inelasticity, are subjected to injuries
peculiar to themselves. In addition to being affected as are muscles,
wounds of many kinds are found to affect tendons--contusions,
interference wounds, penetrant wounds, incised wounds and lacerations.
However, the commoner form of injury done tendons, is strain or sprain.
Because of the sudden tensile strain brought to bear upon tendons in the
shocks of concussion, as well as in propulsion of the body, there
frequently occurs a rupture of fibers and this we know as sprain.
Sprains may be considered as fibrillary fractures of soft structures and
since this form of injury is subsurface, and limited to fractional
portions of tendons, the inflammation occasioned usually remains an
aseptic one. Reaction to this form of injury is characterized by
inflammation, the course of which is erratic and variable. In chronic
inflammation of tendons, where animals are continued in service, the
usual sequel is contraction, or shortening of these structures.
The degree of contraction as well as its import varies in different
subjects and in the various tendons which may be affected. Contraction
is a slow-going process that is progressive, gradually causing a
decrease in the length of the affected structure and eventually
rendering the animal useless.
The practice of applying shoes with extended toe-calks for the purpose
of "stretching" contracted deep digital flexor tendons (flexor pedis
perforans) cannot be too strongly condemned. While the addition of an
extension such as is ordinarily employed to the toe of a shoe of this
kind, prevents for a time, frequent stumbling in such cases, the
increased tensile strain which is thus occasioned hastens further
contraction and subjects animals so shod to much unnecessary pain.
AFFECTIONS OF NERVES.
Because of their being protected by other structures, nerve trunks,
which supply muscles of locomotion, are not subjected to frequent
injuries such as contusions. However, they do become injured at times
and the result is lameness, more or less severe.
Lameness originating from nerve affection, may involve central
structures as, for example, the spinal cord, medulla oblongata or parts
of the brain. In making an examination of some lame animals it is
necessary to distinguish between cases of lameness that are of central
origin and marked by incoördination of movement, and disturbances caused
by other affections. Tetanus in its incipiency should not be confused
with laminitis involving all four feet, or with certain forms of
pleuritis, when careful examination is made, yet, in a way, to one not
trained, the clinical symptoms are similar.
Disturbances of nerve function are caused in a variety of ways. It is
not within the scope of this work to discuss central nervous
disturbances caused by ingestion of mouldy provender, or disturbances of
the brain or cord occasioned by infectious diseases, but mention of the
existence of such conditions is appropriate.
By direct injury the result of blows, certain nerves are injured and
muscles supplied by such nerves are rendered inactive. Depending upon
the nature and extent of an injury thus inflicted, so the manner in
which the affection is manifested varies. The suprascapular nerve is
rather frequently injured causing partial or complete loss of function
of the structures supplied by this nerve, and abduction of the
scapulohumeral joint naturally results.
In some cases of dystocia the obturator nerve, (or nerves, if the
involvement is bilateral), becomes injured by being caught between the
maternal pelvis and some dense part of the fetus. This results in
paralysis of the adductors of the thigh if sufficient injury is done.
It is said that nerves become over-stretched and held tense, in certain
positions in which animals are obliged to remain while cast in
confinement such as in some instances where unusual methods of restraint
are employed. When the fore feet are drawn backward in such manner that
great strain is put upon the radial nerve, it suffers more or less
injury, and this is followed by partial or complete paralysis which may
be temporary or permanent.
Degenerative changes affecting nerves, as in other tissues, occur and
more or less locomotory impediment will follow--this depending upon the
nerve or nerves affected and the nature of such involvement. Tumors may
surround nerves and eventually the nerve so exposed becomes implicated
in the destructive process. Before degenerative changes take place in
the nerve substance, in such cases, pressure may completely paralyze a
nerve when it is so situated. Melanotic tumors in the paraproctal tissue
in some cases, because of the large size of the new-growths, cause
paralysis of the sciatic nerve. The author has seen one case of brachial
paralysis occasioned by an enormous development of fibrous tissue
involving the structures about the ulna.
AFFECTIONS OF BLOOD VESSELS.
Lameness caused by disturbances of circulation may be due to structural
affection of vessels, or functional disorders of the heart, and in some
instances, a combination of these causes may be active.
Direct involvement of vessels is the commoner form of circulatory
disturbance which occasions lameness, and the most frequent cause is of
parasitic origin. Sclerostomiasis with attendant arteritis, thrombus
formation and subsequent lodgement of emboli in the iliac, femoral, or
other arteries, causes sufficient obstruction to prevent free
circulation of blood, and the characteristic lameness of thrombosis
results.
Indirect injury to vessels may occur because of contused wounds and
subsequent inflammation of tissues supplied by such vessels. If the
injury be of sufficient extent, considerable extravasation of blood will
take place and the painfully swollen parts necessarily impair
locomotion. In such instances lymph vessels participate in the
disturbance, and the condition then becomes one wherein lymphangitis is
the predominant disturbing element.
Angiomatous tumors are occasionally found affecting horses'
legs--usually the result of some injury; and because of their size or
position, they mechanically interfere with function. Furthermore, when
such tumors are located on the inner or flexor side of joints, enough
pain is occasioned that affected animals show evidence of distress,
usually by intermittent lameness.
Horses do not suffer from distension of veins as does man, that is,
there is rarely to be seen a case wherein much disturbance from this
source exists.
AFFECTIONS OF LYMPH VESSELS AND GLANDS.
Inflamed lymph vessels and glands, the result of various causes, is a
rather common source of lameness of horses. When one considers the
proportion of tissue that is composed of lymph vessels and glands, it is
then obvious that inflammation of these structures should cause a
painful affection of members, when so affected, and that marked lameness
and, in some instances, general constitutional disturbance such as
anorexia, hyperthermia and general circulatory disorder are to follow.
Lymphangitis is most frequently occasioned by the introduction of septic
material into the tissues; consequently, infectious lymphangitis is more
frequently observed than the non-infectious type.
Specific infectious forms of lymphangitis are seen in glanders and in
strangles; infectious types of this disturbance are found in many
instances where, initially, a localized or circumscribed infection has
occurred--the contagium having been introduced by way of an injury. An
example of this kind is to be seen in a wound perforating the tibial
fascia, where the injury is inflicted by means of a horse being kicked
by another animal shod with sharp shoe-calks. Cases of this kind
invariably result in a septic lymphangitis, and frequently lymphadenitis
also occurs, for the inguinal lymph glands are so situated that their
becoming contaminated is almost certain.
The trite phrase that "the tissues are bathed in lymph" should make
clear the reason for the frequent occurrence of infectious lymphangitis
and lymphadenitis. Foreign substances, bacteria and their products,
inorganic material and in fact, anything that is introduced into the
tissues, if soluble or miscible, will be taken up and conveyed by the
afferent lymph vessels and disseminated throughout the system--hence the
constitutional disturbances so frequently thus caused.
A non-infectious type of lymphangitis is frequently seen in the heavy
draft breeds of horses and in such cases one or both hind legs are
involved--it is very seldom that the thoracic limbs become so affected.
Law[3] refers to this ailment as "Acute Lymphangitis of Plethora in
Horse." When one takes into consideration that these cases so frequently
occur in heavy draft animals that are not worked regularly, that the
pelvic limbs are the ones involved, and that the disorder often runs a
short course (recovery often taking place within two or three days, with
no treatment given other than a purge, circulatory stimulants and
walking exercise) it is plausible to ascribe the condition to idiopathic
factors.
Admitting the frequency of non-infectious lymphangitis, the practitioner
must not confuse this type with similar lymphatic inflammation
occasioned by nail punctures of the foot. It is very embarrassing indeed
to make a diagnosis of lymphangitis--expecting that the disturbance will
terminate favorably and uneventually--and later to discover a sub-solar
abscess caused by a nail prick in the region of the heel.
Recurrent attacks of this disturbance cause hypertrophy of the lymph
vessels and in some cases lymphangiectasis. In old subjects used for
dissection or surgical purposes, it is very evident that in the ones
which have suffered from chronic lymphangitis there exists an excessive
amount of sub-facial connective tissue, making subcutaneous neurectomies
quite difficult in some instances.
A sequel of chronic lymphangitis is a condition known as elephantiasis.
In such cases there occurs a hyperplasia of the skin and subcutaneous
tissues, resulting in some instances, in the affected member attaining
an enormous size. Sporadic cases of this kind are to be seen
occasionally, and are apparently caused by repeated attacks of
lymphangitis. The affection is not benefited by treatment, and while a
horse's leg may become so heavy and cumbersome as to mechanically impede
its gait, as well as to fatigue the subject when made to do service even
at a slow pace, elephantiasis causes no constitutional derangement. The
hind legs, in elephantiasis, are affected and a unilateral involvement
is more often seen than a bilateral one. The legs may be enlarged from
the extremity to the body, but ordinarily the affection does not extend
higher than the hock or the mid-tibial region.
A chronic, progressive, hyperplastic-degeneration exists in some cases
and the subjects are in time rendered unserviceable because of the
burden of getting about encumbered by the affected extremity. In other
animals hyperplasia progresses for a time--until the parts become
greatly enlarged and conditions apparently attain an immutable state.
Nevertheless animals so affected may continue in service for years
without being distressed.
AFFECTIONS OF THE FEET.
Lameness is very often due to affections of the feet, and in all foot
diseases probably the most constant cause is injury inflicted in some
manner. Resultant from injury, there frequently develops complications
and the one most often seen is infection.
Because of the fact that the feet are constantly exposed to germ-laden
soil and filth, if not actually bathed in such infectious materials, it
naturally follows that septic infection of some part of the feet must be
of frequent occurrence.
Subsequent to being obliged to stand in mud and other damp or wet media,
exposure to desiccating influences such as stabling upon dry floors, or
at service on hot and dry road surfaces causes the insensitive parts of
the feet to become dry, hard and brittle. This favors "checking" of the
protecting structures and it frequently results in the formation of
large fissures which expose the underlying sensitive parts of the feet
and lameness is the inevitable outcome.
The function of the feet--bearing the weight of the animal at all times
when the subject is not recumbent, and in addition to this, the
increased strain put upon them at heavy draft work, together with the
concussion and buffeting occasioned by locomotion, make the feet
susceptible to frequent affections of various kinds.
Being almost completely encased by a somewhat inexpansible and
insensitive wall and sole, renders the foot subject to pathologic
changes peculiar to itself. The very nature of the structure of the foot
together with the function of the sensitive lamina is sufficient cause
for an affection unlike that seen involving other tissues--laminitis.
An exhaustive consideration of foot affections is a study in itself and
one that comes within the realm of pathologic shoeing; nevertheless, a
practical knowledge of diseases of the foot is indispensable in the
diagnosis of lameness wherein the foot may be at fault.
The peculiar nature of foot affections renders them difficult of
classification on any sort of basis that is helpful in the consideration
of this subject. Injuries are the most constant cause of foot lameness,
yet one must admit that there results complications because of infection
in most instances; and that in some cases the injury is slight--just
enough to permit the introduction of vulnerant organisms into the
tissues. Therefore, one might well classify affections of the feet as
infectious and non-infectious. There can be grouped in the class of
infectious affections such conditions as nail pricks, calk wounds and
canker. In the class of non-infectious affections one may consider
conditions such as laminitis, strain and fractures.
FOOTNOTES:
[Footnote 1: A System of Veterinary Medicine by E. Wallis Hoare,
F.R.C.V.S., Vol. I, page 519.]
[Footnote 2: Ibid, page 807.]
[Footnote 3: Vol. I, page 534, Veterinary Medicine, by James Law,
F.R.C.V.S.]