Scapulohumeral Rhythm

          Scapulohumeral rhythm is the relationship of movement between the scapula and the humerus. There are two joints that contribute to the movement which includes the scapulothoracic joint and the glenohumeral joint. When there is movement in this region it is important that the movement is synchronous between the two joints because if it is not, it can lead to shoulder impingement and injury. If there is impingement in this area it can seriously lead to occupational performance deficits. For every one degree of movement at the scapulothoracic joint there is 2 degrees of movement at the glenohumeral joint. It is important that the movement here is congruent in nature to reduce the amount of shear force from the humeral head in the scapula socket. For a person to get full ROM the humeral head must rotate laterally. This is also important because if the humerus does not rotate laterally it can cause injury from the shear forces. Additionally, this movement allows clients to perform ADLs such as reaching to get things on shelves, reaching to scratch your head, reaching to wash your hair, and many other movements. The ratio of movement is also important when considering the movement ratio because this can help with deciphering which joint is lacking in movement. Testing ROM in the shoulder is critical when trying to determine the movement deficiency in our clients.