Rupture of the short head tendon of the biceps brachii.

Subcutaneous rupture of the short head tendon of the biceps brachii is a very rare lesion, with only five cases previously reported. The case of a 67-year-old farmer whose tendon ruptured following a mild muscle effort is presented. The degenerative changes revealed by histological examination of the injured tendon were so severe as to lead to the conclusion that its tensile strength must have fallen considerably prior to rupture. The most characteristic clinical signs of this rupture are a sizeable bulge in the middle third of the injured arm, and a hollow in the site normally occupied by the short head of the biceps. Suture of the ruptured tendon to that of the coracobrachialis led to full functional recovery.