Basically, the body is trying to defend itself against the process of wear and tear on the joints by building up more bone in the weak area. Pain is experienced when the new bone formations rub against each other and when they put pressure on nerves. Rheumatoid arthritis not only affects the joints, but can have a great impact on other parts of the body like the heart, blood vessels, eyes and muscles. Inflammation plays a major role in rheumatoid arthritis. Inflammation is protective response of the body to an injury or an irritation.
Inflammation often involves redness, heat, swelling, and pain of the affected area.
With rheumatoid arthritis, the immune system, which normally defends the body, turns against certain body parts. The joints are most commonly targeted. The inflammatory process starts in the synovium, the thin membrane that lines the joint. This area becomes very thick and eventually invades cartilage and even the bone. This can lead to joint damage.