eat pain and uneasiness; the hock was unduly flexed;
the calcaneum was displaced forward; and marked crepitation was present.
A portion of the body of the calcaneum was protruding through the
perforated skin. The animal was destroyed and the bone was found broken
in three pieces.

[Illustration: Fig. 54--Right hock joint. Viewed from the front and
slightly laterally after removal of joint capsule and long collateral
ligaments. T.t., Tibial tarsal bone (distal tuberosity). T.c., central
tarsal bone. T.3. Ridge of third tarsal bone. T.f. Fibular tarsal bone
(distal end). T.4. Fourth tarsal bone. Mt. III, Mt. IV. Metatarsal
bones. Arrow points to vascular canal. (From Sisson's "Anatomy of the
Domestic Animals.")]

Since the support for the tendo Achillis is removed in such fracture and
no leverage on the metatarsus obtains, it naturally follows that any
attempt to sustain weight must result in extreme flexion of the hock and
descent of this part in a manner similar to cases of rupture or division
of the Achilles' tendon. The two conditions should not be confused,
however, as the parts may be definitely outlined by palpation and the
slack condition of the tendon and displaced summit of the calcaneum,
which characterize fracture of the fibular tarsal bone, are easily
recognized.

Treatment.--Prognosis is unfavorable in the majority of cases, but
should attempts at treatment be undertaken in young and quiet mares
which might prove valuable for breeding purposes in case of imperfect
recovery, they should be put in slings and the member is to be
immobilized as in tibial fracture. Authorities are agreed that prognosis
is entirely unfavorable in mature animals, when the case is viewed from
an economic standpoint.

Tarsal Sprains.

Etiology and Occurrence.--The hock joint is often subjected to great
strain because of the structural nature of this part and its relation to
the hip as well as the manner in which the tarsus functionates during
locomotion. That ligamentous injuries owing to sprain frequently occur
and attendant periarticular inflammations with subsequent hypertrophic
changes follow, is a logical inference. Fibrillary fracture of the
collateral ligaments may take place in falls or when animals make
violent efforts to maintain their footing on slippery streets. In
expressing opinions concerning the frequency with which the hock is
found to be the seat of trouble in lameness of the pelvic members,
different write