- In medicine, a ring of fibrocartilage (fibrous cartilage) around the edge of the articular (joint) surface of a bone. The Latin "labrum" means "lip." The term is used 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.
* * *1. A lip. 2. A lip-shaped structure. 3. A fibrocartilaginous lip around the margin of the concave portion of some joints. SYN: articular l., articular lip, l. articulare. [L.]- acetabular l. [TA] a fibrocartilaginous rim attached to the margin of the acetabulum of the hip bone. SYN: l. acetabulare [TA], acetabular lip, circumferential cartilage (1), cotyloid ligament, ligamentum cotyloideum.- l. acetabulare [TA] SYN: acetabular l..- glenoid l. of scapula [TA] a ring of fibrocartilage attached to the margin of the glenoid cavity of the scapula to increase its depth. SYN: l. glenoidale scapulae [TA], articular margin, circumferential cartilage (2), glenoid ligament (1), glenoidal lip, ligamentum glenoidale.
* * *la·brum 'lā-brəm n1) an upper or anterior mouthpart of an arthropod consisting of a single median piece in front of or above the mandibles
* * *n. (pl. labra)a lip or liplike structure; occurring, for example, around the margins of the articulating socket (acetabulum) of the hip bone.
* * *la·brum (laґbrəm) pl. laґbra [L. lip] 1. anatomic nomenclature for an edge, brim, or liplike part or structure. 2. the shelflike projection of the head of arthropods that anteriorly covers the mandible and forms the roof of the mouth.
Medical dictionary. 2011.