Abstract
Category C is the capsula articularis, intra articular. It includes the changes of joint paces and calcifications. In this category, joint space narrowing (JSN) and ankylosis are important in rheumatoid arthritis (RA). Also, joint effusion and synovitis are detectable by US and MRI.
Keywords: Ankylosis, Joint effusion, Joint Space Narrowing (JSN), Rheumatoid arthritis, Synovitis.