The labrum is a ring of soft rubber-like cartilage located around the shoulder socket. The labrum deepens the socket and is thus important in maintaining joint stability. It also acts as a shock absorber cushioning loads. The biceps tendon attaches to the top of the labrum. Ligaments attach to the front and back of the labrum.

The labrum is at risk of tearing especially in overhead sports of a repetitive nature, such as tennis and cricket. Patients with instability or excessive mobility are at special risk of sustaining a labral tear. One specific type of labral tear is called a slap lesion. This is a tear from in front of to behind the point of attachment of the biceps tendon. This type of tear usually happens following a violent pull on the arm or a violent fall onto the outstretched arm. Once the labrum has torn, a flap of tissue can flip in and out of the joint. This can cause pain, locking and clicking particularly with certain positions or movements.

Some labral tears may heal on their own with simple treatments. However, in persistent cases surgery may be required. Surgery is usually performed arthroscopically. If the labral tear is small it may be removed with a shaver. If it is large, and particularly, if the tear is associated with a pull-off of the biceps tendon then the labrum should be reattached to the bone with stitches. Labral tears involving the biceps tendon are called SLAP lesions, which stands for Superior Labrum Anterior to Posterior. Occasionally the biceps tendon attachment is so badly damaged that the tendon is shortened and attached to the bone in the upper arm (Biceps tenodesis).