The shoulder is a highly complex, very mobile region of the body containing several anatomically distinct joints. However, the joints are functionally inseparable; movements of the shoulder-girdle extend the range of motions of the glenohumeral joint allowing, for example, circumduction. All the shoulder muscles help to steady the shoulder when the humerus (arm) is moved and to adjust the angle of the glenoid cavity, allowing a great range of motion. The main shoulder muscles are the levator scapulae, pectoralis minor, rhomboids serratus anterior, subclavius, and trapezius. In addition, the rotator cuff muscles are essential for keeping the head of the humerus within the glenoid cavity.
Subjects: Sports and Exercise Medicine.