Arthritis is inflammation of one or more of your joints. In a diseased shoulder, inflammation causes pain and stiffness.

Although there is no cure for arthritis of the shoulder, there are many treatment options available. Using these, most people with arthritis are able to manage pain and stay active.

Your shoulder is made up of three bones: your upper arm bone (humerus), your shoulder blade (scapula), and your collarbone (clavicle).

The head of your upper arm bone fits into a rounded socket in your shoulder blade. This socket is called the glenoid. A combination of muscles and tendons keeps your arm bone centered in your shoulder socket. These tissues are called the rotator cuff.

There are two joints in the shoulder, and both may be affected by arthritis. One joint is located where the clavicle meets the tip of the shoulder blade (acromion). This is called the acromioclavicular (AC) joint.

Where the head of the humerus fits into the scapula is called the glenohumeral joint. To provide you with effective treatment, your physician will need to determine which joint is affected and what type of arthritis you have.

Arthritis also known as “wear-and-tear” arthritis, osteoarthritis is a condition that destroys the smooth outer covering (articular cartilage) of bone. As the cartilage wears away, it becomes frayed and rough, and the protective space between the bones decreases. During movement, the bones of the joint rub against each other, causing pain.

Osteoarthritis usually affects people over 50 years of age and is more common in the acromioclavicular joint than in the glenohumeral shoulder joint.