Biomechanics Reflection #3

Scapulohumeral rhythm is an important clinical concept that describes the movement at the glenohumeral joint between the scapula and the humerus. The scapula has three primary movements upward rotation, posterior tilt, and lateral rotation. Scapulohumeral rhythm is described as a ratio of 2:1 (humerus:scapula), which means that in general for every three degrees the shoulder moves the humerus will move 2 degrees while the scapula moves only moves one. The concept is important for clinicians because it allows client to have full range of motion at the glenohumeral joint, helps to prevent active insufficiency of glenohumeral muscles, as well as permits a good tension-length relationship, and maintains the subacromial space. Maintaining the subacromial space is important for the ROM of the glenohumeral joint. Without the synchronization of movements between the humerus and scapula Shoulder Impingement Syndrome can develop, which is inflammation of the tendons passing through the subacromial space due to friction caused by irregular rubbing during movements. This syndrome can cause pain and limit a client's ROM.