Shoulder Anatomy

The shoulder provides more flexibilty than any other part of the body. The two main bones of the shoulder are the humerus and the scapula (shoulder blade).

The top portion of the scapula, the acromion, attaches to the clavicle, or collar bone. The end of the scapula, called the glenoid, holds the ball-like head of the humerus in place and acts as a flexible ball-and-socket joint.

Four short muscles originate on the scapula and pass around the shoulder where their tendons fuse together to form the rotator cuff.