Origin and distribution of cranial nerves (CN) VI, IV, and III, which innervate extraocular eye muscles. The focus of the upper part of this figure includes the abducens nerve (CN VI) and the general somatic efferent component of the oculomotor nerve (CN III), which are essential for horizontal gaze. The lower part of this figure depicts the muscles of the eye and their relationship with CN III, IV, and VI.
The labrum is a cartilage ring that surrounds the shoulder socket (called the glenoid) and makes it deeper. In the above picture, it is numbered "5" - the thin blue ring around the glenoid. Since the socket is deepened by the labrum, the ball of the arm bone (called the head of the humerus) has a better fit into it. Labrum or labral tears are usually associated with trauma, instability of the shoulder, or repetitive throwing as with a baseball player.