rheumatoid arthritis!!! articular erosions on the PIP and MCP joints, starting laterally to the articular surface (these erosions are different from gout or psoriatic arthritis ones), with osteopenia restricted to the epiphysis of the bones involved in the arthritic process (different from osteoporosis, that is more diffuse) . ulnar deviation of the MCP (pathognomonic). Erosion on the ulnar styloid (usually the first radiological finding in this disease). DIP joints not interested by the inflammatory process (useful for distinguishing RA from osteoarthritis). Carpal sclerosis on the left and a developing carpal ankylosis on the right (carpal ankylosis in D.D. with Adult Still's disease).
