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 (whilst it has previously been considered a redundant evolutionary remnant, it is now considered an integral structure in the shoulder's stability). Currently 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, and in a similar arrangement the long head of the triceps brachii inserts inferiorly. Together these cartilaginous extensions of the tendon are termed the 'glenoid labrum'. A<unk>  (Superior Labrum from Anterior to Posterior) tear or lesion occurs when there is damage to the superior or uppermost area of the labrum.<unk>  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<unk>  sub-types all happening in the last 20 years or so. The identification and treatment of these injuries continues to evolve today, however it is safe to say that a baseball pitcher suffering a 'dead arm' caused by a<unk>  lesion today is far more likely to recover such that he can return to the game at its highest level than was the case 20 or 30 years ago.
At least ten types of this injury are recognized with varying degrees of damage, seven of which are listed here
SLAP tear
Nursemaid's elbow
Triquetral fracture
Burst fracture
Rolando's fracture
Acromioclavicular separation
Tear of meniscus
Avulsion fracture