an easy matter to a careful observer. Such a person will readily note
the changes of movements which will have taken place in the animal he
has been accustomed to drive or ride, unless they are indeed slight and
limited to the last degree. But what is not always easy is the
detection, after discovering the fact of an existing irregularity, of
the locality of its point of origin, and whether its seat be in the near
or off leg, or in the fore or the hind part of the body. These are
questions too often wrongly answered, notwithstanding the fact that with
a little careful scrutiny the point may be easily settled. The error,
which is too often committed, of pronouncing the leg upon which the
animal travels soundly as the seat of the lameness, is the result of a
misinterpretation of the physiology of locomotion in the crippled
animal. Much depends upon the gait with which the animal moves while
under examination. The act of walking is unfavorable for accurate
observation, though, if the animal walks on three legs, the decision is
easy to reach. The action of galloping will often, by the rapidity of
the muscular movements and their quick succession, interfere with a nice
study of their rhythm, and it is only under some peculiar circumstances
that the examination can be safely conducted while the animal is moving
with that gait. It is while the animal is trotting that the
investigation is made with the best chances of an intelligent decision,
and it is while moving with that gait, therefore, that the points should
be looked for which must form the elements of the diagnosis.
[Illustration: PLATE XXIII.
SKELETON OF HORSE.]
[Illustration: PLATE XXIV.
SUPERFICIAL LAYER OF MUSCLES.]
Our first consideration should be the physiology of normal or healthy
locomotion, that thence we may the more easily reach our conclusions
touching lameness, or that which is abnormal, and by this process we
ought to succeed in obtaining a clew to the solution of the first
problem, to wit, in which leg is the seat of the lameness?
A word of definition is here necessary, in order to render that which
follows more easily intelligible. In veterinary nomenclature each two of
the legs, as referred to in pairs, is denominated a biped. Of the four
points occupied by the feet of the animal while standing at rest,
forming a square, the two fore legs are known as the anterior biped; the
two hinder, the posterior; the two on one side, the lateral: and one of
either the front or hind biped with the opposite leg of the hind or
front biped will form the diagonal biped.
Considering, as it is proper to do, that in a condition of health each
separate biped and each individual leg is required to perform an equal
and uniform function and to carry an even or equal portion of the weight
of the body, it will be readily appreciated that the result of this
distribution will be a regular, evenly balanced, and smooth displacement
of the body thus supported by the four legs, and that therefore,
according to the rapidity of the motion in different gaits, each single
leg will be required at certain successive moments to bear the weight
which had rested upon its congener while it was itself in the air, in
the act of moving; or, again, two different legs of a biped may be
called upon to bear the weight of the two legs of the opposite biped
while also in the air in the act of moving.
To simplify the matter by an illustration, the weight of an animal may
be placed at 1,000 pounds, of which each leg, in a normal and healthy
condition, supports while at rest 250 pounds. When one of the fore legs
is in action, or in the air, and carrying no weight, its 250 pounds
share of the weight will be thrown upon its congener, or partner, to
sustain. If the two legs of a biped are both in action and raised from
the ground, their congeners, still resting in inaction, will carry the
total weight of the other two, or 500 pounds. And as the succession of
movements continues, and the change from one leg to another or from one
biped to another, as may be required by the gait, proceeds, there will
result a smooth, even, and equal balancing of active movements, shifting
the weight from one leg or one biped to another, with symmetrical
precision, and we shall be presented with an interesting example of the
play of vital machanics in a healthy organization.
Much may be learned from the accurate study of the action of a single
leg. Normally, its movements will be without variation or failure. When
at rest it will easily sustain the weight assigned to it without
showing hesitancy or betraying pain, and when it is raised from the
ground in order to transfer the weight to its mate it will perform the
act in such manner that when it is again placed upon the ground to rest
it will be with a firm tread, indicative of its ability to receive again
the burden to be thrown back upon it. In planting it upon the ground or
raising it again for the forward movement while in action, and again
replanting it upon the earth, each movement will be the same for each
leg and for each biped, whether the act is that of walking or trotting,
or even of galloping. In short, the regular play of every part of the
apparatus will testify to the existence of that condition of orderly
soundness and efficient activity eloquently suggestive of the condition
of vital integrity which is simply but comprehensively expressed by the
terms health and soundness.
But let some change, though slight and obscure, occur among the elements
of the case; some invisible agency of evil intrude among the harmonizing
processes going forward; any disorder occur in the relations of
cooperating parts; anything appear to neutralize the efficiency of
vitalizing forces; any disability of a limb to accept and to throw back
upon its mate the portion of the weight which belongs to it to
sustain--present itself, whether as the effect of accident or otherwise;
in short, let anything develop which tends to defeat the purpose of
nature in organizing the locomotive apparatus and we are confronted at
once by that which may be looked upon as a cause of lameness.
Not the least of the facts which it is important to remember is that it
is not sufficient to look for the manifestation of an existing
discordance in the action of the affected limb alone, but that it is
shared by the sound one and must be searched for in that as well as the
halting member, if the hazard of an error is to be avoided. The mode of
action of the leg which is the seat of the lameness will vary greatly
from that which it exhibited when in a healthy condition, and the sound
leg will also offer important modifications in the same three
particulars before alluded to, to wit, that of resting on the ground,
that of its elevation and forward motion, and that of striking the
ground again when the full action of stepping is accomplished. Inability
in the lame leg to sustain weight will imply excessive exertion by the
sound one, and lack of facility or disposition to rest the lame member
on the ground will necessitate a longer continuance of that action on
the sound side. Changes in the act of elevating the leg, or of carrying
it forward, or in both, will present entirely opposite conditions
between the two. The lame member will be elevated rapidly, moved
carefully forward, and returned to the ground with caution and
hesitancy, and the contact with the earth will be effected as lightly as
possible, while the sound limb will rest longer on the ground, move
boldly and rapidly forward, and strike the ground promptly and forcibly.
All this is due to the fact that the sound member carries more than its
normal, healthy share of the weight of the body, a share which may be in
excess from 1 to 250 pounds, and thus bring its burden to a figure
varying from 251 to 500 pounds, all depending upon the degree of the
existing lameness, whether it is simply a slight tenderness or soreness,
or whether the trouble has reached a stage which compels the patient to
the awkwardness of traveling on three legs.
That all this is not mere theory, but rests on a foundation of fact may
be established by observing the manifestations attending a single
alteration in the balancing of the body. In health the support and
equilibrium of that mass of the body which is borne by the fore legs is
equalized and passes by regular alternations from the right to the left
side and vice versa. But if the left leg, becoming disabled, relieves
itself by leaning, as it were, on the right, the latter becomes,
consequently, practically heavier and the mass of the body will incline
or settle upon that side. Lameness of the left side, therefore, means
dropping or settling on the right and vice versa. We emphasize this
statement and insist upon it, the more from the frequency of the
instances of error which have come under our notice, in which persons
have insisted upon their view that the leg which is the seat of the
lameness is that upon which he drops and which the animal is usually
supposed to favor.
HOW TO DETECT THE SEAT OF LAMENESS.
Properly appreciating the remarks which have preceded, and fully
comprehending the modus operandi and the true pathology of lameness, but
little remains to be done in order to reach an answer to the question as
to which side of the animal is the seat of the lameness, except to
examine the patient while in action. We have already stated our reasons
for preferring the movement of trotting for this purpose. In conducting
such an examination the animal should be unblanketed, and held by a
plain halter in the hands of a man who knows how to manage his paces,
and the trial should always be made over a firm, hard road whenever it
is available. He is to be examined from various positions--from before,
from behind, and from each side. Watching him as he approaches, as he
passes by, and as he recedes, the observer should carefully study that
important action which we have spoken of as the dropping of the body
upon one extremity or the other, and this can readily be detected by
attending closely to the motions of the head and of the hip. The head
drops on the same side on which the mass of the body will fall, dropping
toward the right when the lameness is in the left fore leg, and the hip
dropping in posterior lameness, also on the sound leg, the reversal of
the conditions, of course, producing reversed effects. In other words,
when the animal in trotting exhibits signs of irregularity of action, or
lameness, and this irregularity is accompanied with dropping or nodding
the head, or depressing the hip on the right side of the body, at the
time the feet of the right side strike the ground, the horse is lame on
the left side. If the dropping and nodding are on the near side the
lameness is on the off side.
In a majority of cases, however, the answer to the first question
relating to the lameness of a horse is, after all, not a very difficult
task. There are two other problems in the case more difficult of
solution and which often require the exercise of a closer scrutiny, and
draw upon all the resources of the experienced practitioner to settle
satisfactorily. That a horse is lame in a given leg may be easily
determined, but when it becomes necessary to pronounce upon the query as
to what part, what region, what structure is affected, the easy part of
the task is over, and the more difficult and important, because more
obscure, portion of the investigation has commenced--except, of course,
in cases of which the features are too distinctly evident to the senses
to admit of error. It is true that by carefully noting the manner in
which a lame leg is performing its functions, and closely scrutinizing
the motions of the whole extremity, and especially of the various joints
which enter into its structure; by minutely examining every part of the
limb; by observing the outlines; by testing the change, if any, in
temperature and the state of the sensibility--all these investigations
may guide the surgeon to a correct localization of the seat of trouble,
but he must carefully refrain from the adoption of a hasty conclusion,
and, above all, assure himself that he has not failed to make the foot,
of all the organs of the horse the most liable to injury and lesion, the
subject of the most thorough and minute examination of all the parts
which compose the suffering extremity.
The greater liability of the foot than of any other part of the
extremities to injury from casualties, natural to its situation and use,
should always suggest the beginning of an inquiry, especially in an
obscure case of lameness at that point. Indeed the lameness may have an
apparent location elsewhere when that is the true seat of the trouble,
and the surgeon who, while examining his lame patient, discovers a
ringbone, and convincing himself that he has encountered the cause of
the disordered action suspends his investigation without subjecting the
foot to a close scrutiny, at a later day when regrets will avail
nothing, may deeply regret his neglect and inadvertence. As in human
pathological experience, however, there are instances when inscrutable
diseases will deliver their fatal messages, while leaving no mark and
making no sign by which they might be identified and classified, so it
will happen that in the humbler animals the onset and progress of
mysterious and unrecognizable ailments will at times baffle the most
skilled veterinarian, and leave our burden-bearing servants to succumb
to the inevitable, and suffer and perish in unrelieved distress.
DISEASES OF BONES.
PERIOSTITIS, OSTITIS, AND EXOSTOSIS.
From the closeness and intimacy of the connection existing between the
two principal elements of the bony structure while in health, it
frequently becomes exceedingly difficult, when a state of disease has
supervened, to discriminate accurately as to the part primarily affected
and to determine positively whether the periosteum or the body of the
bone is originally implicated. Yet a knowledge of the fact is often of
the first importance, in order to obtain a favorable result from the
treatment to be instituted. It is, however, quite evident that in a
majority of instances the bony growths which so frequently appear on the
surface of their structure, to which the general term of exostosis is
applied, have had their origin in an inflammation of the periosteum, or
enveloping membrane, and known as periostitis. However this may be, we
have as a frequent result, sometimes on the body of the bone, sometimes
at the extremities, and sometimes involving the articulation itself,
certain bony growths, or exostoses, known otherwise by the term of
splint, ringbone, and spavin, all of which, in an important sense, may
be finally referred to the periosteum as their nutrient source and
support, at least after their formation, if not for their incipient
existence.
_Cause._--It is certain that inflammation of the periosteum is
frequently referable to wounds and bruises caused by external agencies,
and it is also true that it may possibly result from the spreading
inflammation of surrounding diseased tissues, but in any case the result
is uniformly seen in the deposit of a bony growth, more or less diffuse,
sometimes of irregular outline, and at others projecting distinctly from
the surface from which it springs, as so commonly presented in the
ringbone and the spavin.
_Symptoms._--This condition of periostitis is often difficult to
determine. The signs of inflammation are so obscure, the swelling of the
parts so insignificant, any increase of heat so imperceptible, and the
soreness so slight, that even the most acute observer may fail to find
the point of its existence, and it is often long after the discovery of
the disease itself that its location is positively revealed by the
visible presence of the exostosis. Yet the first question had been
resolved, in discovering the fact of the lameness, while the second and
third remained unanswered, and the identification of the affected limb
and the point of origin of the trouble remained unknown until their
palpable revelation to the senses.
_Treatment._--When, by careful scrutiny, the ailment has been located, a
resort to treatment must be had at once, in order to prevent, if
possible, any further deposit of the calcareous structure and increase
of the exostotic growth. With this view the application of water, either
warm or cold, rendered astringent by the addition of alum or sugar of
lead, will be beneficial. The tendency to the formation of the bony
growth, and the increase of its development after its actual formation,
may often be checked by the application of a severe blister of Spanish
fly. The failure of these means and the establishment of the diseased
process in the form of chronic periostitis cause various changes in the
bone covered by the disordered membrane, and the result may be
softening, degeneration, or necrosis, but more usually it is followed by
the formation of the bony growths referred to, on the cannon bone, the
coronet, the hock, etc.
SPLINTS.
We first turn our attention to the splint, as certain bony enlargements
that are developed on the cannon bone, between the knee or the hock and
the fetlock joint, are called. (See Plate XXV.) They are found on the
inside of the leg, from the knee, near which they are frequently found,
downward to about the lower third of the principal cannon bone. They are
of various dimensions, and are readily perceptible both to the eye and
to the touch. They vary considerably in size, ranging from that of a
large nut downward to very small proportions. In searching for them they
may be readily detected by the hand if they have attained sufficient
development in their usual situation, but must be distinguished from a
small, bony enlargement that may be felt at the lower third of the
cannon bone, which is neither a splint nor a pathological formation of
any kind, but merely the buttonlike enlargement at the lower extremity
of the small metacarpal or splint bone.
We have said that splints are to be found on the inside of the leg. This
is true as a general statement, but it is not invariably so, for they
occasionally appear on the outside. It is also true that they appear
most commonly on the fore legs, but this is not exclusively the case,
because they may at times be found on both the inside and outside of the
hind leg. Usually a splint forms only a true exostosis, or a single bony
growth, with a somewhat diffuse base, but neither is this invariably the
case. In some instances they assume more important dimensions, and pass
from the inside to the outside of the bone, on its posterior face,
between that and the suspensory ligament. This form is termed the pegged
splint, and constitutes a serious and permanent deformity, in
consequence of its interference with the play of the fibrous cord which
passes behind it, becoming thus a source of continual irritation and
consequently of permanent lameness.
_Symptoms._--A splint may thus frequently become a cause of lameness
though not necessarily in every instance, but it is a lameness
possessing features peculiar to itself. It is not always continuous, but
at times assumes an intermittent character, and is more marked when the
animal is warm than when cool. If the lameness is near the knee joint,
it is very liable to become aggravated when the animal is put to work,
and the gait acquires then a peculiar character, arising from the manner
in which the limb is carried outward from the knees downward, which is
done by a kind of abduction of the lower part of the leg. Other
symptoms, however, than the lameness and the presence of the splint,
which is its cause, may be looked for in the same connection as those
which have been mentioned as pertaining to certain evidences of
periostitis, in the increase of the temperature of the part, with
swelling and probably pain on pressure. This last symptom is of no
little importance, since its presence or absence has in many cases
formed the determining point in deciding a question of difficult
diagnosis.
_Cause._--A splint being one of the results of periostitis, and the
latter one of the effects of external hurts, it naturally follows that
the parts which are most exposed to blows and collisions will be those
on which the splint will most commonly be found, and it may not be
improper, therefore, to refer to hurts from without as among the common
causes of the lesion. But other causes may also be productive of the
evil, and among these may be mentioned the over-straining of an immature
organism by the imposition of excessive labor upon a young animal at a
too early period of his life. The bones which enter into the formation
of the cannon are three in number, one large and two smaller, which,
during the youth of the animal, are more or less articulated, with a
limited amount of mobility, but which become in maturity firmly joined
by a rigid union and ossification of their interarticular surface. If
the immature animal is compelled, then, to perform exacting tasks beyond
his strength, the inevitable result will follow in the muscular
straining, and perhaps tearing asunder of the fibers which unite the
bones at their points of juncture, and it is difficult to understand how
inflammation or periostitis can fail to develop as the natural
consequence of such local irritation. If the result were deliberately
and intelligently designed, it could hardly be more effectually
accomplished.
The splint is an object of the commonest occurrence--so common, indeed,
that in large cities a horse which can not exhibit one or more specimens
upon some portion of his extremities is one of the rarest of spectacles.
Though it is in some instances a cause of lameness, and its discovery
and cure are sometimes beyond the ability of the shrewdest and most
experienced veterinarians, yet as a source of vital danger to the
general equine organization, or even of functional disturbance, or of
practical inconvenience, aside from the rare exceptional cases which
exist as mere samples of possibility, it can not be considered to belong
to the category of serious lesions. The worst stigma that attaches to it
is that in general estimation it is ranked among eyesores and continues
indefinitely to be that and nothing different. The inflammation in which
they originated, acute at first, either subsides or assumes the chronic
form, and the bony growth becomes a permanence--more or less
established, it is true, but doing no positive harm and not hindering
the animal from continuing his daily routine of labor. All this,
however, requires a proviso against the occurrence of a subsequent acute
attack, when, as with other exostoses, a fresh access of acute symptoms
may be followed by a new pathological activity, which shall again
develop, as a natural result, a reappearance of the lameness.
_Treatment._--It is, of course, the consideration of the comparative
harmlessness of splints that suggests and justifies the policy of
noninterference, except as they become a positive cause of lameness. And
a more positive argument for such noninterference consists in the fact
that any active and irritating treatment may so excite the parts as to
bring about a renewed pathological activity, which may result in a
reduplication of the phenomena, with a second edition, if not a second
and enlarged volume, of the whole story. For our part, our faith is firm
in the impolicy of interference, and this faith is founded on an
experience of many years, during which our practice has been that of
abstention.
Of course, there will be exceptional conditions which will at times
indicate a different course. These will become evident when the
occasions present themselves, and extraordinary forms and effects of
inflammation and growth in the tumors offer special indications. But our
conviction remains unshaken that surgical treatment of the operative
kind is usually useless, if not dangerous. We have little faith in the
method of extirpation except under very special conditions, among which
that of diminutive size has been named; this seems in itself to
constitute a sufficient negative argument. Even in such a case a resort
to the knife or the gouge could scarcely find a justification, since no
operative procedure is ever without a degree of hazard, to say nothing
of the considerations which are always forcibly negative in any question
of the infliction of pain and the unnecessary use of the knife.
[Illustration: PLATE XXV.
SPLINT.]
[Illustration: PLATE XXVI.
SOUND FOOT.
RINGBONE.]
[Illustration: PLATE XXVII.
VARIOUS TYPES OF SPAVIN.]
[Illustration: PLATE XXVIII.
BONE SPAVIN. HOCKS, WITH SKIN REMOVED.]
[Illustration: PLATE XXIX.
BONE SPAVIN.]