Rheumatoid arthritis is a systemic autoimmune disease which initially attacks the synovium, a connective tissue membrane that lines the capsule around joints and secretes a lubricating fluid.
Reviewed last on: 5/3/2009
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.