Accessory coracobrachialis muscle as a cause of anterior impingement syndrome of the rotator cuff in an athlete.

Subcoracoid impingement is a rare but well-know cause of anterior shoulder pain in throwing and overhead athletics. Bulging of the walls or the contents of the coracohumeral space may hamper the smooth gliding of soft tissue between the coracoid process and glenohumeral joint, especially in forward elevation and internal rotation of the arm. Following is a case report of subcoracoid impingement caused by an accessory coracobrachialis muscle in an alpinist treated by resection of the muscular supernumerary slip.