The shoulder (unlike the hip or elbow) is an inherently unstable joint; it has been likened to a golf ball sitting on a tee. To enhance structural stability, the glenoid (anatomically, a very shallow socket) is deepened by the labrum, which is a rubbery, fibrocartilaginous material attached around the lip of the glenoid. This structure can tear during athletics, especially during throwing sports, or as a result of blunt trauma when falling and landing on an outstretched upper extremity.
Physical therapy is the initial treatment. If symptoms do not subside with physical therapy, and the diagnosis has been confirmed by MRI, surgical debridement or repair is the treatment of choice. Surgery is usually done arthroscopically.