Periscapular Muscles

Abstract

The scapula is shown to have several roles in shoulder function (Kibler and Sciascia, Br J Sports Med 44(5):300–305, 2010; Kibler et al., J Am Acad Orthop Surg 20(6):364–372, 2012). Control of static position and control of the motions and translations allow the scapula to fulfill its roles. In normal functional tasks, the scapula upwardly rotates, posteriorly tilts, and externally rotates to clear the acromion from the moving arm in forward elevation or abduction (Lukasiewicz et al., J Orthop Sports Phys Ther 29(10):574–586, 1999; McClure et al., J Shoulder Elbow Surg 10:269–277, 2001; Ludewig and Cook, Phys Ther 80(3):276–291, 2000). Also, the scapula must synchronously internally/externally rotate and posteriorly tilt to maintain the glenoid as a congruent socket for the moving arm and maximize concavity/compression as well as ball and socket kinematics (Kibler and McMullen, J Am Acad Orthop Surg 11:142–151, 2003). Finally, the scapula must be stabilized dynamically in a position of relative retraction during arm use to maximize activation of all the muscles that originate on the scapula (Kebaetse et al., Archiv Phys Med Rehabil 80:945–950, 1999; Smith et al., Archiv Phys Med Rehabil 83:367–370, 2002). Because of the minimal bony stabilization of the scapula, dynamic muscle function is the major method by which the scapula is stabilized and purposefully moved to accomplish its roles. Muscle activation is coordinated in task-specific force couple patterns to allow stabilization of position and control of dynamic coupled motion. A review of the bony and muscular anatomy is provided to assist clinicians in understanding the scapular roles and normal scapular function .