What is shoulder arthritis?

Shoulder arthritis is damage to the cartilage inside the shoulder joint. The shoulder has two joints. Shoulder arthritis commonly refers to the bigger ball-and-socket joint named the glenohumeral joint after the bones it connects (glenoid and humerus). The cartilage covers both the ball (the humeral head) and the socket (the glenoid).

When the cartilage in the shoulder begins to break down on the surface and eventually in the deeper layers, it’s called shoulder arthritis. The second joint in the shoulder, the acromioclavicular or AC joint, can also develop arthritis known as AC joint arthritis.