Rheumatoid arthritis is another form of arthritis. The body’s own immune system attacks a joint’s synovial membrane, which secretes fluid and lines the joint. The synovium becomes inflamed, produces excess fluid, and the cartilage becomes rough and pitted.
Update Date 2/2/2012
Updated by: Ariel D. Teitel, MD, MBA, Clinical Associate Professor of Medicine, NYU Langone Medical Center. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.