SLAP TEAR SHOULDER JOINT

he 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.^[1] 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 ^[2] and the initial definitions of the 4 SLAP sub-types^[3] 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.

Sub-types

At least ten types of this injury are recognized with varying degrees of damage,^[4] seven of which are listed here

1. Degenerative fraying of the superior portion of the labrum, with the labrum remaining firmly attached to the glenoid rim
2. Separation of the superior portion of the glenoid labrum and tendon of the biceps brachii muscle from the glenoid rim
3. Bucket-handle tears of the superior portion of the labrum without involvement of the biceps brachii (long head) attachment
4. Bucket-handle tears of the superior portion of the labrum extending into the biceps tendon
5. Anteroinferior Bankart lesion that extends upward to include a separation of the biceps tendon
6. Unstable radial of flap tears associated with separation of the biceps anchor
7. Anterior extension of the SLAP lesion beneath the middle glenohumeral ligament