Bouchard's nodes are hard, bony outgrowths or gelatinous cysts on the proximal interphalangeal joints (the middle joints of fingers or toes.) They are a sign of either osteoarthritis or Rheumatoid arthritis. Seen commonly in osteoarthritis, they are caused by formation of calcific spurs of the articular (joint) cartilage. Not often seen in Rheumatoid arthritis, they are caused by antibody deposition to the synovium.
Bouchard's nodes are comparable in presentation to Heberden's nodes, similar osteoarthritic growths on the distal interphalangeal joints, but are significantly less common.
Bouchard's nodes are named after French pathologist Charles Bouchard (1837-1915).