What does RA stand for in medical terms?

The most common condition that is described by RA is rheumatoid arthritis. However, it can also refer to right atrium, which is the right upper chamber of the heart. Rheumatoid arthritis is an autoimmune disease that causes inflammation of the joints. It is a different disease than osteoarthritis, which is a degenerative joint disorder caused by the breakdown of cartilage. Cartilage is the connective tissue that cushions joints.