<prompt> In rheumatoid ahritis the characteristic joint involvement is:SpineKneeMetacarpophalangeal jointHip joint  <response>: 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. 