This article may have too many red links. You can help Wikipedia by writing articles to help lower the number of red links.(April 2026)
Left hand with sixth finger. This is an example of polydactyly.
Polydactyly is a birth defect which may affect the hands, feet, or both. It causes one or more extra fingers or toes. It can affect people, and other mammals such as dogs, and cats.
It is also called hyperdactyly. It is the opposite of oligodactyly.
Diagnosis/Classification
Ulnar polydactyly
The classification of ulnar polydactyly exists of either two or three types. In type A, there is another finger at the metacarpophalangeal joint. In type B, there may be a nubbin to an extra finger part.
Radial polydactyly
The Wassel classification is the most popular classification of radial polydactyly. It is widely used by many scientists.
Wikimedia Commons has media related to Polydactyly.
Swanson AB (1976). "A classification for congenital limb malformations". J Hand Surg Am. 1 (1): 8–22. doi:10.1016/s0363-5023(76)80021-4. PMID 1021591.Watt AJ, Chung KC (2009). "Duplication". Hand Clin. 25 (2): 215–227. doi:10.1016/j.hcl.2009.01.001. PMID 19380061.
Biesecker LG (2002). "Polydactyly: how many disorders and how many genes". Am J Med Genet. 12 (3): 279–83. doi:10.1002/ajmg.10779. PMID 12357471.
Hirota, Yuka; Ueda, Koichi; Umeda, Chizuru; Yoshida, Eriko (2022-11-03). "New Notations for Better Morphological Distinction of Postaxial Polydactyly of the Foot". Plastic and Reconstructive Surgery Global Open. 10 (11): e4504. doi:10.1097/GOX.0000000000004504. ISSN 2169-7574. PMC 9633084. PMID 36348750.
Eaton, Charles. "Polydactyly (Extra Fingers)". Retrieved 9 February 2010.