rheumatoid arthritis ra that usually affects knees. the auto immune disease.

immune acute therapy deformity knee membrane rheumatism synovial osteoporosis swelling arthritis healthcare capsule medicine science medical inflammation human body cartilage autoimmune pain rheumatoid healthy anatomy joint disease bone secretion physical fluid age care muscle organ diagram skeleton chronic osteoarthritis enhanced skeletal injury normal rough pitted painful vector fla source file available inflammatory type affects knees