ScapulohumeralRhythmusBewegung

Scapulohumeral rhythm is the coordinated movement of the scapula and the glenohumeral joint that accompanies arm elevation. It describes how the shoulder blade and the upper arm work together to raise the arm and maintain shoulder mechanics during flexion and abduction. Proper rhythm depends on neuromuscular coordination and the integrated action of the thorax, scapula, and humerus.

During arm elevation, about two-thirds of the motion occurs at the glenohumeral joint and about one-third via scapulothoracic motion, totaling roughly 180 degrees of elevation (about 120 degrees from the shoulder joint and about 60 degrees of scapular upward rotation). The commonly described ratio of glenohumeral to scapulothoracic contribution is 2:1, though individual variation and pathology can alter the pattern. The scapula undergoes upward rotation, posterior tilt, and external rotation as the arm rises, with the trapezius and serratus anterior providing key control of scapular positioning.

Muscular control involves the serratus anterior and the upper, middle, and lower trapezius, along with contributions from the levator scapulae and rhomboids. Dysfunction of scapulohumeral rhythm, or scapulohumeral dyskinesis, can be associated with shoulder impingement, rotator cuff tendinopathy, and other shoulder disorders. Conversely, restoring balanced rhythm through targeted strengthening and neuromuscular training can improve function and reduce pain.

Clinically, assessment includes observing scapular motion during arm elevation, looking for abnormal winging or dyskinesis, and correlating findings with symptoms. Rehabilitation emphasizes coordinated activation of the periscapular muscles, posture optimization, and control of humeral head depression to maintain smooth rhythm throughout the range.