Swan neck deformity

Infobox_Disease
Name = Swan neck deformity


Caption = Human hand bones (Joints visible but not labeled.)
DiseasesDB =
ICD10 = ICD10|M|20|0|m|20
ICD9 = ICD9|736.22
ICDO =
OMIM =
MedlinePlus =
eMedicineSubj = Orthoped
eMedicineTopic = 562
MeshID =

Swan neck deformity is a deformed position of the finger, in which the joint farthest from the knuckle is permanently bent toward the palm while the nearest joint is bent away from it (DIP hyperflexion with PIP hyperextension). It is commonly caused by injury or inflammatory conditions like rheumatoid arthritis.

Pathophysiology

Swan neck deformity has many possible causes arising from the DIP, PIP, or even the MCP joints. In all cases, there is a stretching of the volar plate at the PIP joint to allow hyperextension, plus some damage to the attachment of the extensor tendon to the base of the distal phalanx that produces a hyperflexed mallet finger. Duck bill deformity is a similar condition affecting the thumb (which cannot have true swan neck deformity because it does not have enough joints).

External links

* [http://www.wheelessonline.com/ortho/swan_neck_deformity Swan neck deformity] at Wheeless' Textbook of Orthopedics, a technical review of the condition