long thoracic nerve injury, damage to the nerve (C5-7) that innervates the serratus muscle, which anchors the apex of the scapula to the posterior of the rib cage. Symptoms include an abnormally prominent scapula and difficulty in flexing the outstretched arm above the shoulder level, protracting the shoulder, or performing scapula abduction and adduction. See also winged scapula.
