Anatomy and Kinematics of the Shoulder Joint

Barnechea Rey A.R. · Orthopaedic Biomechanics in Sports Medicine (2021) · DOI: 10.1007/978-3-030-81549-3_10

Resumen

The shoulder is comprised by the glenohumeral, acromioclavicular, and sternoclavicular joints, the scapulothoracic interface and the subacromial space. It is the most mobile joint in the body; this is due to its unique anatomy and biomechanical behavior. The scapula is the base of the shoulder and has several muscle insertions; the superior shoulder suspensory complex, formed by parts of the scapula and clavicle, connects the upper limb to the trunk through the sternoclavicular joint and the scapulothoracic muscles. The glenohumeral joint is the main joint of the shoulder and is stabilized primarily by soft tissues: the static stabilizers, which include the labrum with its unique shape and attachments, the glenohumeral capsule and ligaments; and the dynamic stabilizers, mainly the rotator cuff and external glenohumeral muscles and tendons. To achieve motion, scapular stability through the range of motion is achieved by dynamic co-contraction of scapular muscles; in turn, this stability provides a platform for optimal glenohumeral motion and thus adequate positioning of the upper limb in space. The apparent incongruity of the humeral head and glenoid surface is what allows a wide, coordinated and stable range of motion; also, coordinated scapular, clavicular, and humeral motion helps achieve these extreme ranges observed in normal shoulders. © ISAKOS 2021.