Scapulohumeral Rhythm

Scapulohumeral rhythm is important and relevant clinically because it shows the joint congruency or the ratio of movement between the scapula and humerus. If there is any dysfunction in the shoulder complex, it can affect the range of motion, function, and there can be pain or impingement. With every 3° of shoulder movement, there is 2° at the glenohumeral joint and 1° at the scapulothoracic joint. Furthermore if the client is properly coordinated (full 180° ROM), there should be 120° of glenohumeral abduction and 60° of upward rotation of the scapula. Knowing this ratio can help with seeing if range of motion has been affected, so if there are any problems with any movements with the scapula or humerus, the ROM of measurements will be different.This scapulohumeral rhythm also needs to have a good length-tension relationship to be able to carry out optimal function. Without optimal function, the ROM will be compromised especially with the osteokinematics and arthrokinematics of the shoulder complex. In detail, if the shoulder cannot elevate, the primary movements, (upward rotation, posterior tilt, and lateral rotation) cannot be carried out with full ROM.