The labrum is the cup-shaped rim of cartilage that lines and reinforces the shoulder joint. The shoulder is a ball and socket joint, and the labrum is where the ligaments that support the joint attach. It also supports the rotator cuff tendons and muscles, and is a vital part of shoulder stability.

When the labrum is torn, the shoulder can become dislocated. Two of the most common labral injuries are SLAP (Superior Labrum from Anterior to Posterior) tears and Bankart tears.

SLAP tears occur where the biceps tendon connects to the shoulder. Baseball and volleyball players are prone to this type of injury, because of the quick movements of the arm over the head.

Bankart tears generally happen in younger patients, accompanying shoulder dislocation.