The Shoulder

Normal Shoulder Anatomy

Scapula  The scapula is a large bone, which is commonly referred to as the shoulder blade. The scapula includes the structures of the glenoid and the acromion. 

Humerus  The humerus is the upper arm bone. The head of the humerus articulates with the glenoid and is covered with hyaline cartilage.

Glenoid   The glenoid is a small concave bone which articulates with the head of the humerus. Like all joint surfaces, it is covered with hyaline cartilage. The glenoid and the humerus form a ball and socket type of joint that permits a great range of motion.

Labrum   The labrum is a thin tissue that covers the rim of the glenoid. The labrum acts as a gasket which helps to stabilize and properly position the humerus upon the glenoid.

Acromion  The acromion is the portion of the scapula that extends over the top of the shoulder joint.

Clavicle   Commonly referred to as the collar bone, the clavicle extends from the rib cage to the acromion.

Cartilage  The joint surfaces of the glenoid and the humeral head are covered with hyaline cartilage. It is present wherever bones meet and articulate. It serves to cushion the forces upon the joint's surface as well as reduce friction and decrease wear. 

Rotator Cuff  The rotator cuff consists of several muscles and their tendons. These tendons insert into the humeral head and are responsible for raising the arm away from the body. Please see the Common Shoulder Problems page for a more complete description.