The disabled throwing shoulder: spectrum of pathology Part III: The SICK scapula, scapular dyskinesis, the kinetic chain, and rehabilitation.

We use the acronym SICK to refer to the findings one sees in this syndrome (Scapular malposition, Inferior medial border prominence, Coracoid pain and malposition, and dysKinesis of scapular movement). This recently recognized overuse muscular fatigue syndrome is yet another cause of shoulder pain in the throwing athlete who presents with dead arm complaints.1 The hallmark feature of this syndrome is asymmetric malposition of the scapula in the dominant throwing shoulder, which usually appears on examination as if one shoulder is lower than the other. This statically observable position is suggestive of underlying muscle activation alterations that produce altered kinematics of the scapula upon dynamic use. The altered kinematics fall into 3 clinically recognizable patterns of scapular dyskinesis, 2 of which are most commonly associated with labral pathology: type I, inferior medial scapular border prominence, and type II, medial scapular border prominence. The type III pattern, which is associated with impingement and rotator cuff lesions rather than labral lesions, displays prominence of the superomedial border of the scapula. In the SICK scapula syndrome, scapular asymmetry is measured statically, but actively produces scapular dyskinesis as the shoulder goes through the throwing cycle. The malpositioned dyskinetic scapula, in turn, dynamically produces altered kinematics of the glenohumeral and acromioclavicular joints and the muscles that insert on the scapula. Because of these complex interrelationships, scapular dyskinesis, including the SICK scapula syndrome, can cause a spectrum of clinical complaints originating from any or all of these anatomic locations. A thrower with this syndrome presents with an apparent “dropped” scapula in his dominant symptomatic shoulder compared with the contralateral shoulder’s scapular position. In actuality, the scapula initially protracts, rotating about a horizontal axis, with the upper scapula rotating anteroinferiorly. However, the clinical appearance, with the arms relaxed in adduction at the side, is that the involved scapula is lower than the scapula on the uninvolved side (Figs 1 and 2). Viewing from behind, the inferior medial scapular border appears very prominent, with the superior medial border and acromion less prominent. When viewed from the front, this tilting (protraction) of the scapula makes the shoulder appear to be lower than the opposite side. The pectoralis minor tightens as the coracoid tilts inferiorly and shifts laterally away from the midline, and its insertion at the coracoid becomes very tender. Symptomatic patients with an isolated SICK scapula may complain of anterior shoulder pain, posterosuperior scapular pain, superior shoulder pain, proximal lateral arm pain, or any combination of the above. In addition, posterosuperior scapular pain may radiate into the ipsilateral paraspinous cervical region or the patient may complain of radicular/thoracic outlet type symptoms into the affected arm, forearm, and hand or any combination of the above. The onset of symptoms with the SICK scapula syndrome is almost always insidious. By far, the most common presenting complaint is anterior shoulder pain in the region of the coracoid, which can easily be confused with anterior Address correspondence and reprint requests to Stephen S. Burkhart, M.D., 540 Madison Oak Dr, Suite 620, San Antonio, TX 78258, U.S.A. © 2003 by the Arthroscopy Association of North America 0749-8063/03/1906-3489-3$30.00/0 doi:10.1016/S0749-8063(03)00389-X