What Is the Anterior Labrum?

The human shoulder is a ball and socket joint compromised of the humerus, or upper arm bone, and a part of the shoulder blade known as the glenoid. This joint is held together not only by the shapes of the bones themselves, but also by ligaments and cartilage. One section of this cartilage, the labrum, rings the glenoid to deepen the socket and make the ball of the humerus fit more securely. The anterior labrum is the part of this structure located toward the front of the body.

The cartilage of the anterior labrum differs from articular, or connective, cartilage in several ways. Articular cartilage is found between the bones that comprise a joint, while labrum cartilage is only found around the socket portion of a ball and socket joint. The function of articular cartilage is also different, as this tissue serves to allow a full range of motion in the joint by cushioning the bones. The erosion of this cartilage can lead to osteoarthritis. The anterior labrum is not prone to osteoarthritis and is comprised of much tougher, more rigid tissue than articular cartilage is.

Despite its stronger construction, the labrum is not immune to injury. Tears may occur in any part of the cartilage, either from a single traumatic injury such as an automobile accident, or over time from repetitive motion such as pitching a baseball. These tears are referred to by their location, with those in the front being anterior labrum tears and those in back known as posterior labrum tears. The injury may be further classified as inferior or superior, with the former being closer to the elbow and the latter closer to the top of the shoulder.

If a patient presents with symptoms of an anterior labrum tear, such as pain that may worsen when holding the arm above the head or popping noises as the arm is rotated, the doctor will typically order a magnetic resonance imaging (MRI) scan. This test will give the doctor a clear picture of the extent of the injury. Treatment options vary based upon the severity of the tear.

In cases of a very mild tear or fraying injury, pain medications and a period of resting the joint may be prescribed. This rest period may be followed by physical therapy to strengthen the nearby muscles and restore the range of motion. More severe anterior labrum tears, as well as minor ones that do not respond to the less aggressive treatment, generally require surgical repair. This procedure is often done arthoscopically; that is, with a camera and instruments inserted through a small incision in the skin. Recovery, during which the patient should take part in physical therapy, may last three to four months.