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Polydactyly

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Left foot with postaxial polydactyly of 5th ray
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Left foot with postaxial polydactyly of 5th ray

Right foot with postaxial polydactyly of 5th ray
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Right foot with postaxial polydactyly of 5th ray

Left hand with mid-ray duplication
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Left hand with mid-ray duplication

Right hand with mid-ray duplication
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Right hand with mid-ray duplication

Polydactyly, or polydactylism, also known as hyperdactyly, is the anatomical variant consisting of more than the usual number of digits on the hands and/or feet. It is a congenital abnormality, usually genetically inherited as an autosomal dominant trait.

Photograph of the left hand of a 27 year old man. The supernumerary thumb had normal sensation; with no joints, it could not move independently.
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Photograph of the left hand of a 27 year old man. The supernumerary thumb had normal sensation; with no joints, it could not move independently.

Polydactyls have six or more digits on their hands or feet. The extra digits vary from small pieces of soft tissue to apparently complete digits. In Western societies, they are usually surgically removed during early life, but not always.

The condition is reported in about 1 child in every 500, although the frequency varies greatly from population to population. It is higher in some groups (an example is the Amish in the United States) due to the founder effect.

Range of motor skills in these extra digits is hard to chart given the rarity of the condition, but cases have varied. In some cases, the extra digit has no joints in the bone and thus is completely immobile, in other cases the extra digit has limited dexterity, and some cases have been reported in which an extra finger was fully functional, and indistinguishable from the rest of the fingers. [[Citing sources citation needed]]

Historically and in the contemporary world, polydactylyism has been associated with witchcraft, psychic power, the extraterrestrial, divine connection, and sporting prowess.

Nowadays, reactions to polydactylyism is mixed. Although the condition is usually not life-threatening or even particularly debilitating, most people in Western societies have the extra digits removed surgically. However, there are other people who enjoy the physical distinction.

Extra fingers in fiction

Types of polydactyly

There are several types of polydactyly, of varying frequency. Here are some of them:

See also

External links

 


From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.

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