Anatomy, Shoulder and Upper Limb, Shoulder Muscles

Excerpt

The shoulder joint, also known as the glenohumeral joint, is a ball and socket joint with the most extensive range of motion in the human body. The shoulder muscles have a wide range of functions, including abduction, adduction, flexion, extension, internal and external rotation. The central bony structure of the shoulder is the scapula, where all of the muscles interact. At the lateral aspect of the scapula is the articular surface of the glenohumeral joint, the glenoid cavity. The glenoid cavity is peripherally surrounded and reinforced by the glenoid labrum, shoulder joint capsule, supporting ligaments, and the myotendinous attachments of the rotator cuff muscles. The muscles of the shoulder play a critical role in providing stability to the shoulder joint. The primary muscle group that supports the shoulder joint is the rotator cuff muscles. The four rotator cuff muscles include the supraspinatus, infraspinatus, teres minor, and subscapularis. Other muscles that form the shoulder girdle include the pectoralis major, pectoralis minor, the deltoids, trapezius, and the serratus anterior.