Overview
The shoulder joint is considered a 'ball and socket' joint. However, in bony terms the 'socket' (the glenoid fossa of the scapula) is quite small, covering at most only a third of the 'ball' (the head of the humerus). The socket is somewhat deepened by a circumferential rim of fibrocartilage which is called the glenoidal labrum. Previously there was some argument as to the structure (it is fibrocartilaginous as opposed to the hyaline cartilage found in the remainder of the glenoid fossa) and function (it was considered a redundant evolutionary remnant, but is now considered integral to shoulder stability). Most authorities agree that the tendon of the long head of the biceps brachii muscle proximally becomes fibrocartilaginous prior to attaching to the superior aspect of the glenoid. Similarly the long head of the triceps brachii inserts inferiorly. Together these cartilaginous extensions of the tendon are termed the 'glenoid labrum'. A SLAP tear or lesion occurs when there is damage to the superior or uppermost area of the labrum. SLAP lesions have come into public awareness with their increasing frequency in overhead and particularly throwing athletes. The increased frequency relates to the relatively recent description of labral injuries in throwing athletes and the initial definitions of the 4 SLAP sub-types all happening since the 1990s. The identification and treatment of these injuries continues to evolve, however it is safe to say that a baseball pitcher suffering a 'dead arm' caused by a SLAP lesion today is far more likely to recover such that he can return to the game at its highest level than was the case previously.
Read more about this topic: SLAP Tear