Medical Definition of Labrum
Labrum: In medicine, a ring of fibrocartilage (fibrous cartilage) around the edge of the articular (joint) surface of a bone. The term labrum is used in anatomy to designate a lip, edge, or brim. Plural: labra.
The glenoid labrum is a ring of fibrocartilage that runs around the cavity of the scapula (wingbone) in which the head of the humerus (the bone in the upper arm) fits. The labrum deepens this cavity (the glenoid cavity) and effectively increases the surface of the shoulder joint.
Injuries to the glenoid labrum can occur from chronic trauma due to repetitive shoulder motion or from acute trauma. For example, from a fall on an outstretched arm, a direct blow to the shoulder, a sudden pull from trying to lift a heavy object, or a violent motion like pitching a baseball.
Signs and symptoms of a glenoid labrum injury include pain accompanying overhead arm motion, occasional pain in the shoulder at night or during daily activities, decreased range of motion and loss of strength in the shoulder.
Treatment may include anti-inflammatory medication and rest. Exercises to strengthen the rotator cuff muscles may then be recommended. If these measures are not effective, arthroscopic surgery may be done.
The acetabular labrum is a ring of fibrocartilage that runs around the acetabulum (cup) of the hip joint and increases its depth. The causes of injury to the acetabular labrum, the signs and symptoms, and treatment are like those for a glenoid labrum injury.
Labrum was borrowed from the Latin for lip. Labrum also gave rise to a number of other words including labia, labial; labrose, and, circuitously, lip.
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