In rheumatoid ahritis the characteristic joint involvement is:

The hallmark feature of rheumatoid ahritis (RA) is persistent symmetric polyahritis (synovitis) that affects the hands and feet, although any joint lined by a synol membrane may be involved. In general, the small joints of the hands and feet are affected in a relatively symmetric distribution. In decreasing frequency, the metacarpophalangeal (MCP), wrist, proximal interphalangeal (PIP), knee, metatarsophalangeal (MTP), shoulder, ankle, cervical are involved.