Scapulohumeral Rhythm

The scapulohumeral rhythm is relevant clinically for several reasons. The first reason being that it is what assists in the synchronized movement of the humerus and scapula. The scapulohumeral rhythm is also clinically significant because it allows for the glenohumeral muscles involved to be in the optimal length-tension relationship, which helps to prevent active insufficiency of these muscles. Another reason it is important to know and understand this concept for clinical purposes is that it's what assists in maintaining the subacromial space - if this space is not maintained in your client, they may have an impingement, which can be painful and lead to other problems, too. Additionally, the scapulohumeral rhythm's joint congruency works to decrease the shear forces of those joints. Without scapulohumeral rhythm, the ability to move the arm efficiently would be significantly lower, which is another reason it's so important! It helps aligns the humeral head and glenoid fossa in their proper anatomical positions to allow for the joint's full range of motion. Therefore, it can also affect range of motion measurement of the shoulder; if the scapula and/or humerus is not moving properly, it is likely that the range of motion of the joint will be lower than the average range of motion for that joint (180°). As a therapist, you should be able to consider all of these things when measuring the range of motion of the shoulder to help deduce what may be the cause of a lower than average measurement.