Scapulohumeral Rhythm

 Scapulohumeral rhythm is used to access muscle function and shoulder joint motion. Scapulohumeral rhythm allows the glenoid fossa to maintain a good position for certain movements of the humerus. Abduction of the shoulder is a movement of the glenohumeral joint and the scapulothoracic articulation (scapulohumeral rhythm). Due to the changing position of the glenoid fossa, scapulohumeral rhythm allows for a better length-tension relationship in the muscles at the glenohumeral joint to produce shoulder motion. In a clinical setting, it is important to know how these two things work together when someone complains of shoulder pain. For example, if the scapula will not rotate upward the way it should, the humerus may compress the underside of the acromion process during abduction. The client may try to overcompensate. They may also over compensate when they have "frozen shoulder" which is why it is important to understand scapulohumeral rhythm and how it affects the shoulder.