| Swan neck deformity | |
|---|---|
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| Swan neck deformity in a 65-year-old rheumatoid arthritis patient. | |
| Specialty | Orthopedic |
Swan neck deformity is a deformed position of thefinger, in which the joint closest to the fingertip is permanently bent toward the palm while the nearest joint to the palm is bent away from it (DIPflexion withPIPhyperextension). It is commonly caused by injury,hypermobility or inflammatory conditions likerheumatoid arthritis or sometimes familial (congenital, likeEhlers–Danlos syndrome[1]).
Swan neckdeformity has many of possible causes arising from the DIP,PIP, or even theMCP joints. In all cases, there is a stretching of thevolar plate at the PIP joint to allowhyperextension, plus some damage to the attachment of the extensor tendon to the base of the distal phalanx that produces a hyperflexedmallet finger. Duck billdeformity is a similar condition affecting the thumb (which cannot have true swan neck deformity because it does not have enough joints).[citation needed]
Diagnosis of swan neck deformity is mainly clinical. MRI of the hand may suggest volar plate attenuation of PIP and extensor tendon damage for DIP[citation needed] Genetic screening tests such as forCMT disease may also be indicated.
Splinting for fingers. Passive stretching and clearing thedeformity.[citation needed]