Bilateral subluxation of the pastern joint in the forelimbs of a foal.

A three-month-old foal was presented with subluxation of the proximal interphalangeal joint in both forelimbs. The condition, which was considered to represent an unusual manifestation of breakdown of the suspensory apparatus, appeared to have developed as a consequence of extreme overexertion, 10 days previously. This had resulted in rupture of the palmar supporting structures of the joint; namely, the superficial distal sesamoidean ligament, the insertion of the superficial digital flexor tendon and the palmar joint capsule. Severe laxity of the flexor tendons had been present in the neonatal period, and it is postulated that this might have contributed to the development of the condition by weakening the suspensory apparatus, and placing increased strain on the suspensory ligament and its associated structures.