After discussing your symptoms and medical history, your doctor will examine your shoulder. During the physical examination, your doctor will look for muscle weakness, tenderness to touch, signs of previous injuries, and other indicators. Your doctor may also use an X-ray to help determine the type of arthritis. An X-ray of an arthritic shoulder shows a narrowing of the joint space, changes in the bone, and the formation of bone spurs (osteophytes). Your doctor may inject a local anesthetic into the joint to confirm the diagnosis. If the anesthetic temporarily relieves the pain, the diagnosis is supported.