The labrum is the cup-shaped rim of cartilage that lines and reinforces a ball-and-socket joint. In the shoulder, this joint is composed of the glenoid – the shallow shoulder socket – and the head (or ball) of the upper arm bone known as the humerus. The labrum is the attachment site for the ligaments and supports the ball and socket joint along with the rotator cuff tendons and muscles. It contributes to shoulder stability. A torn glenoid labrum can lead to partial or complete shoulder dislocation.
The two most common types of labral injuries are SLAP (superior labrum from anterior to posterior) tears and Bankart tears (also known as Bankart lesions). SLAP tears occur at the front of the upper arm where the biceps tendon connects to the shoulder. Bankart tears, on the other hand, typically occur with shoulder dislocation in younger patients; the head of the humerus either shifts toward the front of the body, leading to “anterior instability,” or the back of the body, called “posterior instability.”
Both types of torn laburm are usually accompanied by aching pain and difficulty performing normal shoulder movements. With Bankart tears in particular, patients may feel apprehension that the shoulder may slip out of place or dislocate in certain positions. Patients with SLAP tears may experience pain at the front of the shoulder near the biceps tendon.
Unfortunately, shoulder labral tears are hard to prevent, especially in athletes, because the force of the overhead motion contributes to the injury. Although athletes are most prone to labral tears, people who experience a traumatic event – such as falling down a flight of stairs – are also at risk, particularly older adults whose cartilage becomes more brittle with age.