Next semester, you will extend your knowledge of manual muscle testing to the upper limb. To assess the direction of glenohumeral rotation during abduction or flexion, palpate the epicondyles at the humerus' distal end. Review and diagram two important muscular synergies that produce scapular upward rotation as the shoulder elevates. Serratus anterior and upper trapezius, during the initial phase of shoulder elevation, when the scapula rotates upward around an AP axis that projects through the sternoclavicular joint to the base of the scapular spine . We have focused most of our discussion thus far on the muscles involved in shoulder elevation.
People also employ the shoulder girdle in activities that require shoulder depression.
Bearing weight through the handles of a walker to achieve a non-weightbearing gait pattern is one example. Both of these examples involve closed chain movements wherein thorax moves while the scapula and humerus are the relatively stable segments. Focus on the scapulothoracic joint, and analyze scapular depression during either of these activities. Remember that the movements are closed chain movements, and that the scapula is relatively stable. Understand that the moving segment is the thorax, then determine gravity's effect on it.