ate, to be intimately united lower down, and
terminating at the lower end by a division into four tendinous bands. It
is a powerful muscle of the hinder shank bone, and also acts as a
strong means of support for the stifle joint; that is, of the
articulation of the thigh and shank bone, in front and outside of which
it passes. Its situation and its use cause it to be liable to severe
stretching and straining, and a rupture of some of its fibers is
sometimes the consequence.

_Cause._--This injury may be the result of a violent effort of the
animal in leaping over a high obstacle; in missing his foothold and
suddenly slipping backward while powerfully grasping the ground with the
feet in striving to start a heavily loaded vehicle; in making a violent
effort to prevent a probable fall; or in attempting to lift the feet
from miry ground.

_Symptoms._--The accident is immediately followed by disability which
will vary according to the true seat of the injury and the period of its
duration. This rupture will not prevent the horse from standing
perfectly and firmly on his feet when kept at rest, and while no
muscular efforts are required from him there is no appearance of any
lesion or unsoundness. An attempt to move him backward, however, will
cause him to throw all his weight upon his hind-quarters, and he will
refuse to raise his foot from the ground. If compelled to do so, or
required to move forward, the hock being no longer capable of flexion,
the muscle which effects that movement being the injured one, the
opposite muscles, the extensors, acting freely, the entire lower part of
the leg, from the hock down, will be suddenly, with a jerk, extended on
the tibia or shank bone, and simultaneously with this the tendo
Achillis, the cord of the hock, the tendons of the extensors of the hock
will be put in a wrinkled and relaxed condition. The leg is behind the
animal and the toe rests on the ground. Examination of the fore part of
the shank from the stifle down to the hock may reveal soreness, and
possibly some swelling and heat at the seat of the lesion.

_Treatment._--Our experience with injuries of this form convinces us
that, generally speaking, they are amenable to treatment. Provided a
sufficient time has been allowed for union to take place, very few
instances in which radical recovery has not been effected have come to
our knowledge. The more flexed the leg can be kept, the quicker will it
heal.

In these cases,