Anatomy, Shoulder and Upper Limb, Shoulder Muscles.
The shoulder joint (glenohumeral joint) is a ball and socket joint with the most extensive range of motion in the human body. The muscles of the shoulder dynamically function in performing a wide range of motion, specifically the rotator cuff muscles which function to move the shoulder and arm as well as provide structural integrity to the shoulder joint. The different movements of the shoulder are: abduction, adduction, flexion, extension, internal rotation, and external rotation. The central bony structure of the shoulder is the scapula. All the muscles of the shoulder joint interact with the scapula. 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:: Supraspinatus. Infraspinatus. Teres minor. Subscapularis.