Arthritis

This paper reports on the radiologic hallmarks of rheumatoid arthritis. They are periarticular soft-tissue swelling, symmetric joint-space narrowing, marginal cortical erosions, osteoporosis, and subchondral cysts. Rheumatoid arthritis is a systemic disease of unknown cause. The radiographic changes in the soft tissues, cartilage, and bone are secondary to abnormalities that occur in the synovial membranes of joints, bursae, and tendon sheaths. Perivascular inflammation of the synovium (synovitis) leads to synovial hypertrophy, joint effusion, and edema of adjacent soft tissues. These changes combine to result in fusiform periparticular swelling and increased soft-tissue density, which are early and important radiographic findings in rheumatoid arthritis. The pattern or distribution of involvement is of diagnostic significance. The foot not only is a common site of involvement but also is involved early in the disease process; it may be the initial site affected