Biomechanics of the shoulder

The glenohumeral (GH) joint is a complex and unstable articulation. The interaction between various structures of the shoulder caused by mechanical stimuli and motion provides multiple degrees of shoulder motion. The static stability of the shoulder is supported by the articulation of the humeral head and the glenoid with additional GH ligaments, capsule, and labrum. The rotator cuff muscles surrounding the shoulder joint provide dynamic stability. The combination of these factors forms the biomechanical system that can respond in accordance with the arm movement. Different pathological processes and injuries may result in similar clinical manifestations. It is crucial to know the etiology of these different pathological factors from the viewpoint of the shoulder joint biomechanics to provide the most effective and curable treatments for patients suffering from shoulder diseases and disorders.