Loss of the fibrocartilaginous lining of the intertubercular sulcus associated with rupture of the tendon of the long head of biceps brachii.

Fibrocartilage lines the intertubercular sulcus of the humerus and protects both the bone and the tendon of the long head of biceps brachii where the tendon passes through the sulcus. It provides a smooth, resilient, lubricated gliding surface on the bone. The fibrocartilage is highly metachromatic and organised into distinct superficial and deep zones. In the superficial zone, the cells are small and the fibres run parallel to the articular surface. In the deep zone, the cells are large and rounded and the coarse bundles of fibres are interwoven. In 6 of the 26 dissecting room cadavers examined the tendons were completely ruptured. In these, the fibrocartilage was replaced by loose connective tissue that resembled the synovium of the tendon sheath. The results suggest that bone fibrocartilage exhibits dynamic behaviour in response to changes in its environment, in the same manner as tendon fibrocartilage.