Labral Tears | eorthopod.com
What is the labrum?
The shoulder is made up of three bones: the scapula (shoulder blade), the humerus (upper arm bone), and the clavicle (collarbone).
A part of the scapula, called the glenoid, makes up the socket of the shoulder. The glenoid is very shallow and flat. The labrum is a rim of soft tissue that makes the socket more like a cup. The labrum turns the flat surface of the glenoid into a deeper socket that molds to fit the head of the humerus.
The rotator cuff connects the humerus to the scapula. The rotator cuff is formed by the tendons of four muscles: the supraspinatus, infraspinatus, teres minor, and subscapularis.
Tendons attach muscles to bones. Muscles move the bones by pulling on the tendons. The rotator cuff helps raise and rotate the arm. As the arm is raised, the rotator cuff also keeps the humerus tightly in the glenoid of the scapula.
The soft labral tissue can be caught between the glenoid and the humerus. When this happens, the labrum may start to tear. If the tear gets worse, it may become a flap of tissue that can move in and out of the joint, getting caught between the head of the humerus and the glenoid. The flap can cause pain and catching when you move your shoulder. Several tendons and ligaments attach to the labrum that help maintain the stability of the shoulder. So when the labrum tears, the shoulder often becomes much less stable.
Causes
What causes labral tears?Labral tears are often caused by a direct injury to the shoulder, such as falling on an outstretched hand. The labrum can also become torn from the wear and tear of activity, a condition called overuse. An injured labrum can lead to shoulder instability. The extra motion of the humerus within the socket causes additional damage to the labrum. An extremely unstable shoulder may slip or dislocate. This can also cause the labrum to tear.
Related Document: A Patient's Guide to Shoulder Instability
The biceps tendon attaches to the front part of the labrum. The biceps is the large muscle on the front of your upper arm. Sports can cause injuries to the labrum when the biceps tendon pulls sharply against the front of the labrum. Baseball pitchers are prone to labral tears because the action of throwing causes the biceps tendon to pull strongly against the top part of the labrum. Weightlifters can have similar problems when pressing weights overhead. Golfers may tear their labrum if their club strikes the ground during the golf swing.
Related Document: A Patient's Guide to Biceps Tendonitis
