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.
