Ulnar deviation

Ulnar deviation, also known as ulnar drift, is a hand

deformity A deformity, dysmorphism, or dysmorphic feature is a major abnormality of an organism that makes a part of the body appear or function differently than how it is supposed to. Causes Deformity can be caused by a variety of factors: *Arthritis an ...

in which the swelling of the metacarpophalangeal joints (the big knuckles at the base of the fingers) causes the fingers to become displaced, tending towards the little finger. Its name comes from the displacement toward the

ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...

(as opposed to radial deviation, in which fingers are displaced toward the

radius In classical geometry, a radius (plural, : radii) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', ...

). Ulnar deviation is likely to be a characteristic of

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are inv ...

, more than of

osteoarthritis Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the ...

. Consideration should also be given to pigmented villonodular synovitis, in the setting of ulnar deviation and metacarpophalangeal synovitis. Ulnar deviation is also a physiological movement of the wrist, where the hand including the fingers move towards the ulna. Ulnar deviation is a disorder in which flexion by ulnar nerve innervated muscles is intact while flexion on the median nerve side is not. Hand {{Symptom-stub