Figure 2. Motion patterns in massive rotator cuff ruptures, based on the fluoroscopic study of Burkhart. "Stable" pattern in patients with a normal range of motion of the shoulder. "Unstable" pattern characterized by anterior and superior translation of the humeral head, without active shoulder elevation. Capture pattern, where although the rotator cuff is unable to adequately keep the humeral head centered in the glenoid cavity, the deltoid muscle is strong enough to allow active elevation of the shoulder, displacing the center of rotation of the humeral head towards the lower surface of the acromion. Original drawings.