These ligaments are the main source of stability for the shoulder, and help to keep the shoulder from dislocating. There are also ligaments that attach the clavicle to the acromion, and two ligaments that connect the clavicle to the scapula by attaching to the coracoid process. The tendons and muscles are the next layer out from the joint. The first layer of muscles that move the shoulder are the rotator cuff muscles . This group of muscles lies just outside the shoulder joint itself and helps to rotate the shoulder in the many directions that we require to function in day to day activities.
Tendons are soft tissue structures that attach muscles to bone.
The rotator cuff tendons are a group of tendons that connect the deepest layer of muscles to the humerus. The rotator cuff muscles and tendons control our ability to raise the arm from the side. The rotator cuff mechanism also helps with the stability of the shoulder joint by holding the humeral head in the socket formed by the glenoid. The outer layer is formed by the large deltoid muscle . This is probably the largest, strongest muscle of the shoulder.