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Shoulder Joint Replacement

Understanding How Shoulders Work

Shoulder Anatomy and Function
The shoulder is the most moveable joint in the body. It is made up of three bones: the collar bone (clavicle), the shoulder blade (scapula), and the upper arm bone (humerus), as well as two important joints that allow for movement. The glenohumeral joint, also known as the shoulder joint, is a ball-and-socket that connects the humerus to the shoulder blade. This joint allows free movement of the arm so that it can rotate in a circular fashion.

The rotator cuff is made up of four muscles and their tendons, which act to hold the upper arm (humerus) to the socket of the shoulder (glenoid fossa). The rotator cuff also provides mobility and strength to the shoulder joint.

A smooth substance called articular cartilage covers the surface of the bones where they touch each other within a joint. This articular cartilage acts as a cushion between the bones.