The glenoid labrum provides extra support for the shoulder joint, helping to keep it in place. A labral tear occurs when part of this ring is disrupted, frayed, or torn. Tears may lead to shoulder pain, an unstable shoulder joint, and, in severe cases, dislocation of the shoulder. Likewise, a shoulder dislocation can result in labral tears.
When you think of the shoulder joint, picture a golf ball (the head of the upper-arm bone, or humerus) resting on a golf tee (the glenoid fossa, a shallow cavity or socket located on the shoulder blade, or scapula). The labrum provides a rim for the socket (golf tee) so that the humerus (golf ball) does not easily fall off. If the labrum is torn, it is harder for the humerus to stay in the socket. The end result is that the shoulder joint becomes unstable and prone to injury.
Because the biceps tendon attaches to the shoulder blade through the labrum, labral tears can occur when you put extra strain on the biceps muscle, such as when you throw a ball. Tears also can result from pinching or compressing the shoulder joint when the arm is raised overhead. There are 2 types of tears:
- Traumatic labral tears usually happen because of a single incident, such as a shoulder dislocation or an injury from heavy lifting. People who use their arms raised over their heads—such as weight lifters, gymnasts, and construction workers—are more likely to have traumatic labral tears. Activities the force is at a distance from the shoulder, such as striking a hammer or swinging a racquet, also can create shoulder joint problems.
- Nontraumatic labral tears most often occur because of muscle weakness or shoulder joint instability. When the muscles that stabilize the shoulder joint are weak, more stress is put on the labrum, leading to a tear. People with nontraumatic tears tend to have more “looseness” or greater mobility throughout all their joints, which might be a factor in the