Symptomatic shoulder instability due to lesions of the glenoid labrum.

Lesions of the glenoid labrum can be associated with and cause shoulder instability and symptomatology by (1) allowing the shoulder to dislocate recurrently (anatomical instability); (2) allowing the shoulder to subluxate (anatomical instability); and (3) allowing the shoulder to click, catch, and lock secondary to partially attached fragments becoming interposed between the articular surfaces (functional instability). The latter two clinical entities are usually associated with "lesser" labral damage and diagnosis can be difficult. Six illustrative cases are presented and salient diagnostic and therapeutic points are discussed. The glenohumeral axillary arthrotomogram is presented as a sensitive diagnostic test for detecting labral lesions.