Ulnar deviation

An angular deformity in which the fingers or wrist are displaced toward the ulna at the metacarpophalangeal or radiocarpal joints, typically due to chronic synovitis. Often seen in rheumatoid arthritis, osteoarthritis, systemic lupus erythematosus, psoriatic arthritis, congenital conditions (brachial plexus palsy, diastrophic dysplasia), and severe trauma.