Shoulder impingement syndrome, a common disorder directly related to the unique anatomy, mobility, and biomechanics of the shoulder girdle complex, is a condition that results from repetitive microtrauma to the structures within the subacromial space, primarily the supraspinatus, the long head of the biceps, and the subacromial bursa. Several factors contribute to shoulder impingement syndrome, including rotator cuff weakness, capsular tightness, poor scapulohumeral rhythm, and muscle imbalance of the scapular upward rotation force couple. This article briefly reviews the biomechanics of the shoulder girdle complex and the pathology of shoulder impingement syndrome. The author introduces an adjunctive assessment procedure that assists the clinician in isolating the primary tissue and the structures involved with shoulder impingement syndrome. Conservative treatment management can then be directed to the involved contractile and/or noncontractile tissue involved with shoulder impingement syndrome.