In rheumatoid arthritis, which can be seen at MCP joints?

• A. Radial drift
• B. Ulnar drift
• C. Median drift
• D. Dorsal drift

Answer: (B)

In rheumatoid arthritis, the MCP joints commonly show ulnar drift. This happens because chronic synovitis and pannus formation around the MCP joints weaken the periarticular structures, especially the ligaments on the radial side and the volar plates, allowing the joints to sublux toward the ulnar (little finger) side. As the extensor mechanism and intrinsic muscles pull, the fingers drift toward the ulna, giving a characteristic ulnar deviation at the MCP joints. Other direction drifts aren’t typically seen with RA at these joints, so the ulnar drift best fits the clinical pattern.