The head of the humerus then moves anteriorly causing impingement on the long head of the biceps. This occurs as a result of humeral abduction activity without appropriate scapular rotation. The scapula is in a position of downward rotation b. The scapula is elevated on the chest wall. It is pulled up under the acromial process.
Clients attempt to move their arm with whatever muscles are available.
The first to return include the levator scapulae which promotes downward rotation of the scapula. As clients attempt to move their arms over their heads, the deltoid acts usually without rotator cuff innervation. This pulls the head of the humerus up into the superohumeral space causing impingement and pain. If superior subluxation is allowed to continue, the coracohumeral ligament may be torn leading to structural instability of the gleno-humeral joint. When low tone exists in the lower extremity, clients are largely under the influences of gravity.