The shoulder joint is the body’s most mobile joint but this luxury of mobility can come with consequences of injury. The shoulder complex is a ball and socket joint and is comprised of 4 main muscles, several bones and several soft tissue structures. The scapula (shoulder blade), clavicle (collar bone), and humerus (upper arm bone) make up the bony components. The upper end of your arm bone (humerus) rests within the scapular socket (glenoid). The resting area of the glenoid is rather shallow and unstable. However, your labrum increases the stability by deepening the area by 50%. Your labrum is anatomically divided into several compartments including the top or superior (SLAP), anterior (bankart) and posterior (reverse bankart).