Rheumatoid arthritis of the left hand.
Rhematoid arthritis. Computer artwork of the bones of the hands of patients with severe rheumatoid arthritis. Arthritis is joint inflammation (red areas). Rheumatoid arthritis is where the immune system attacks the body's own tissues, causing progressive joint and cartilage destruction. As the cartilage is worn away, new bone grows as part of the repair process. This causes stiffness and deformity of the fingers and wrists. Treatment is with anti-inflammatory drugs and physiotherapy.