Scapulohumeral Rhythm

The Scapulohumeral Rhythm is the articulation between the glenoid fossa of the scapula and the humeral head of the humerus moving. It is where the the body has the greatest amount of ROM. In order to achieve full ROM, the humeral head must laterally rotate. The motion with Scapulohumeral Rhythm is distributed between both joints, glenohumeral and scapulothoracic) and therefore the movement has to be synchronous. If there is damage to either joints, the therapist will be able to identify this. With the joints congruence, it allows for a decrease in shear forces. The Scapulohumeral Rhythm also produces a good length-tension relationship. I can affect your ROM measurements of the shoulder due to the ratio that is put in place between the joints. For every 3° of shoulder movement, there is 2° at the glenohumeral joint and 1° at the scapulothoracic joint. If this rhythm is impaired at either of the joints, this ratio could be thrown off.