Nontraumatic shoulder pain in the overhand athlete is a diagnostic challenge. The causes of chronic shoulder pain are numerous, but it is often difficult to identify and to diagnose the exact problem. Research indicates that shoulder impingement is the most common cause of shoulder pain in overhand athletes. The term “shoulder impingement” was first introduced by Neer42 in 1972 and describes mechanical compression of the rotator cuff and subacromial bursa against the anterior undersurface of the acromion and coracoacromial ligament, especially during elevation of the arm.