Rheumatoid arthritis (RA) is a form of arthritis which has inflammation in the lining of the joints (synovium) and at times in internal organs. This inflammation separates Rheumatoid arthritis from the most common form of arthritis, osteoarthritis. Rheumatoid arthritis can affect any joint with synovium, especially in the hands, feet, knees, shoulders, & hips. The course of Rheumatoid arthritis is variable and unpredictable with damage occurring to joint cartilage, tendons, ligaments, and bone.