This is an accident of exceptionally rare occurrence, and mostly concerns the calcaneum (os calcis) or bone forming the point of the hock. Occupying a prominent position, and standing exposed to external violence, it is remarkable that it so seldom suffers fracture.

Kicks, blows, and violent struggling when cast are the most common causes. In foals the point of the hock is sometimes torn off when rearing and walking backwards on the hind-legs.

The Symptoms

The symptoms resulting from this mishap are very striking and characteristic.

There is a complete inability to support weight on the broken limb. When an attempt is made to do so the hock joint sinks towards the ground, and the point of the hock is drawn upwards by the pull of the tendo achillis, the foot is advanced, and the quarter on the injured side inclined downward. In progression the limb as a whole is raised as far as possible, and then trailed forwards with the advancing body.

Treatment

Treatment in these cases offers but little prospect of success. The tendo achillis, acting upon the broken fragment, displaces it upward beyond readjustment, and where it is practicable to bring the broken parts together it is usually found impossible to maintain them in their natural position.

Fractures below the hock may be such as have been described as taking place below the knee, and will require to be healed on the same lines.