Which joint deformity is characteristic of rheumatoid arthritis?

The characteristic joint deformity associated with rheumatoid arthritis is the Swan neck deformity. This condition occurs when there is a hyperextension of the proximal interphalangeal (PIP) joint and flexion of the distal interphalangeal (DIP) joint, leading to a "swan-neck" appearance of the fingers. This deformity arises due to the underlying inflammatory and destructive processes that rheumatoid arthritis induces in the joints and surrounding tissues.

In contrast, Bouchard's nodes and Heberden's nodes are deformities associated with osteoarthritis rather than rheumatoid arthritis. Bouchard's nodes develop on the proximal interphalangeal joints, while Heberden's nodes appear on the distal interphalangeal joints. Therefore, identifying Swan neck deformity as characteristic of rheumatoid arthritis highlights the distinct pathophysiology and clinical manifestations of inflammatory arthritis compared to degenerative joint diseases.