Scapulohumeral Rhythm

The shoulder complex moves as one unit, and this is important to achieve full ROM in the upper extremity. In scapulohumeral rhythm, the scapulothoracic joint moves in tandem with the glenohumeral joint in order to achieve a position of the shoulder that is functional for every day life and ADLs. This relationship is also important because of what anatomical structures lie in the shoulder complex. The subacromial space is the structure at most risk for problems, if there are complications with scapulohumeral rhythm. Impingement in the subacromial space can cause pain to the structures in the space. This relationship is also significant to allow for abduction of the shoulder. The deltoid and supraspinatus  are able to get a balance between muscle length and tension in order to abduct. Decrease in function in either the glenohumeral or scapulothoracic joint, can cause detriment to the shoulder complex's ability to function as a cohesive unit. The ability for the scapula to move also cuts down on friction in the shoulder complex. The ability for these two joints to move cohesively also cuts down on shear forces in the shoulder.