Labrum:In the field of medicine, the labrum refers to a ring of fibrous cartilage that encircles the edge of a bone's joint surface. It is commonly used to describe a lip, edge, or brim in anatomical terms. The plural form is labra. The glenoid labrum is a fibrocartilaginous ring that surrounds the cavity of the scapula, where the head of the humerus (upper arm bone) fits. This structure deepens the glenoid cavity and effectively enlarges the surface area of the joint. Glenoid labrum injuries can result from chronic overuse due to repetitive shoulder movements or sudden trauma, such as falling on an outstretched arm, receiving a direct shoulder hit, experiencing a sudden pull while lifting heavy objects, or performing a vigorous motion like pitching a baseball.Symptoms of a glenoid labrum injury include pain during overhead arm movements, occasional nighttime shoulder pain or discomfort during daily activities, reduced range of motion, and weakened shoulder strength. Treatment options may involve anti-inflammatory medications and rest, followed by exercises aimed at strengthening the shoulder muscles. If these methods prove ineffective, arthroscopic surgery might be necessary.The acetabular labrum is a fibrocartilaginous ring that encircles the hip joint's acetabulum (socket) and increases its depth. The causes, symptoms, and treatments for acetabular labrum injuries are similar to those of glenoid labrum injuries.The term "labrum" originates from the Latin word for lip, and has given rise to related terms such as labial, labrose, and, indirectly, lip.