Lameness of the Horse | Page 6

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