The accessory nail of the fifth toe, also known as petaloid toenail, is a physical trait of the small toe, where a minuscule "sixth toenail" is present in the outer corner of the nail situated on the smallest toe.
Trait
The trait can be observed on either one or both feet, where there is a separation of the toenail situated on the smallest toe. The separated part of the nail forms a smaller "sixth toenail" on the corner of the larger, or "main" section of the toenail, on the outermost side of the foot, which protrudes outwards from the corner of the larger nail. The additional "nail" can be cut with a
nail clipper
A nail clipper (also called nail clippers, a nail trimmer, a nail cutter or nipper type) is a hand tool used to trim fingernails, toenails and hangnails.
Design
Nail clippers are usually made of stainless steel but can also be made of plastic a ...
, just like any other nail.
Genome-wide scans indicate that it is a heritable trait. However, instead of following a
Mendelian pattern of inheritance, it is likely to be a complex trait affected by multiple genes with minor genetic effects.
Removal
Many people do not request or seek out removal, as the accessory nail typically does not cause symptoms.
Surgical or chemical matricectomy, or complete removal or destruction of the nail matrix, has been used for successful removal of the accessory toenail.
Legend
While it was thought to be a prevalent feature amongst
Han Chinese
The Han Chinese () or Han people (), are an East Asian ethnic group native to China. They constitute the world's largest ethnic group, making up about 18% of the global population and consisting of various subgroups speaking distinctiv ...
,
it is observed in people from all ethnicities and races.
Chinese mythology has it that during the time of the
Yellow Emperor
The Yellow Emperor, also known as the Yellow Thearch or by his Chinese name Huangdi (), is a deity ('' shen'') in Chinese religion, one of the legendary Chinese sovereigns and culture heroes included among the mytho-historical Three Soverei ...
, there were two types of people living in China: those who were the descendants of the Yellow Emperor, and those who were nomadic
Qiang people
The Qiang people ( Qiangic: ''Rrmea''; ) are an ethnic group in China. They form one of the 56 ethnic groups officially recognised by the People's Republic of China, with a population of approximately 310,000 in 2000. They live mainly in a ...
. The
Henan
Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...
people, led by Yin Wang, attacked the Qiang and abducted a Qiang woman, who later tried to escape. Yin Wang stabbed her in the abdomen as she tried to escape, so she gave birth to two children with a scar on the small toe of the foot. The children were taken back by Yin Wang for adoption, and their descendants were born with double nails on their small toes.
See also
*
Dominance (genetics)
*
Mongolian spot
A Mongolian spot, also known as slate grey nevus or congenital dermal melanocytosis, is a benign, flat, congenital birthmark with wavy borders and an irregular shape. In 1883, it was described and named after Mongolians by Erwin Bälz, a German a ...
*
Epicanthal fold
An epicanthic fold or epicanthus is a skin fold of the upper eyelid that covers the inner corner (medial canthus) of the eye. However, variation occurs in the nature of this feature and the possession of "partial epicanthic folds" or "slight ...
*
Congenital malformations of the dermatoglyphs
Congenital malformations of the dermatoglyphs are a cutaneous condition divided into four main categories based on the appearance of the dermal ridges of which they are composed: (1) ridge aplasia
Aplasia (; from Greek ''a'', "not", "no" + ''pla ...
*
List of cutaneous conditions
References
{{reflist
Cutaneous congenital anomalies
Human anatomy
Toes