The human shoulder consists of three bones:

  1. The upper arm bone (humerus).
  2. The shoulder blade (scapula).
  3. The collarbone (clavicle).

The shoulder is a ball-and-socket joint in which the ball of your upper arm bone fits into a shallow socket in your shoulder blade. The socket is called the glenoid.

The bone surfaces are covered with articular cartilage, a white tissue that protects the bones where they come together to form joints and enables them to move together easily. There is also a smooth, thin tissue called synovial membrane lining the inside of your shoulder joint. It excretes a small amount of fluid that lubricates your shoulder joint and eliminates friction between the bones.

Muscles and tendons surround the shoulder joint providing support and stability.

The bone and tissue structure of the shoulder allows it to rotate at a greater range of motion than any other joint in the human body.

For more information or to make an appointment, call 877-442-SJRI (7574).