Epicanthic fold

From Wikipedia, the free encyclopedia
Jump to: navigation, search
"Mongoloid fold" redirects here. For other uses, see Mongoloid (disambiguation).
Epicanthic fold
Epicanthicfold-highlighted.JPG
The epicanthic fold is the skin fold of the upper eyelid covering the inner angle of the eye.[1]
Latin plica palpebronasalis
Anatomical terminology

Epicanthic fold (/ɛpɪˌkænθɪkˈfld/),[1] epicanthal fold, epicanthus, or simply eye fold[2] are names for a skin fold of the upper eyelid, covering the inner corner (medial canthus) of the eye. Other names for this trait include plica palpebronasalis[3] and palpebronasal fold.[4] One of the primary facial features often closely associated with the epicanthic folds is the nasal bridge; all else equal, a lower-based nose bridge is more likely to cause epicanthic folds, and a higher-based nose bridge is less likely to do so.[5] There are various factors influencing whether someone has epicanthic folds, including geographical ancestry, age, and certain medical conditions.

Factors[edit]

Geographic distribution[edit]

Epicanthic fold depicted in a painting.

Epicanthic folds can, and most commonly do,[citation needed] appear in East Asians, Southeast Asians, Central Asians, Indigenous Americans, the San people, Berbers and "occasionally in Europeans (e.g., Scandinavians and Poles)".[6][7][8]

Anthropologist Carleton S. Coon said that the "median fold" appears in "Finnic" and "Slavic" populations while the "true inner or mongoloid fold" appears in populations of the "east" and the "far north".[9]

Age[edit]

Many fetuses lose their epicanthic folds after 3 to 6 months of gestation.[10][non-primary source needed]

Medical conditions[edit]

Epicanthic fold is sometimes found as a congenital abnormality.[1] Medical conditions that cause the nasal bridge not to mature and project are associated with epicanthic folds. About 60% of individuals with Down syndrome have prominent epicanthic folds.[11][12] In 1862, John Langdon Down classified what is now called Down syndrome. He used the term mongoloid for the condition. This was derived from then-prevailing ethnic theory[13] and from his perception that children with Down syndrome shared physical facial similarities (epicanthic folds) with those of Blumenbach's Mongolian race. While the term "mongoloid" (also "mongol" or "mongoloid idiot") continued to be used until the early 1970s, it is now considered pejorative and inaccurate and is no longer in common use.[14]

In Zellweger syndrome, epicanthic folds are prominent.[15] Other examples are fetal alcohol syndrome, phenylketonuria, and Turner syndrome.[16]

Evolutionary origin[edit]

It is hypothesized that epicanthic folds are caused by climatic factors and it may have originated more than once during human evolution. The genetic basis of epicanthic folds is not well understood.[17]

The fat above the eyes insulates the eyes, conserving body heat.[18][19]

See also[edit]

References[edit]

  1. ^ a b c "epicanthic". Oxford Dictionaries. Oxford University Press. Retrieved 11 October 2012. 
  2. ^ "Eye fold". Merriam-Webster Dictionary. Retrieved 14 December 2012. 
  3. ^ "AllRefer Health - Epicanthal Folds (Plica Palpebronasalis)". AllRefer.com. Retrieved 2009-10-01. 
  4. ^ "Palpebronasal Fold - Medical Dictionary Search". Stedman's Medical Dictionary. 2006. Retrieved 2009-10-01. .
  5. ^ Montagu, A. (1989) Growing Young N.Y.: McGraw Hill pp. 40
  6. ^ Montagu, A. (1989). Growing Young. Bergin & Garvey: CT.
  7. ^ "Epicanthus". Retrieved 25 April 2014. 
  8. ^ "epicanthic fold (anatomy)". Encyclopaedia Britannica. Retrieved 25 April 2014. 
  9. ^ Coon, Carleton S. The Races of Europe. Distribution of Bodily Characters.
  10. ^ Park, J.I. Modified Z-Epicanthoplasty in the Asian Eyelid. ARCH FACIAL PLAST SURG/VOL 2, JAN-MAR 2000.
  11. ^ Hammer, edited by Stephen J. McPhee, Gary D. (2010). "Pathophysiology of Selected Genetic Diseases". Pathophysiology of disease : an introduction to clinical medicine (6th ed. ed.). New York: McGraw-Hill Medical. pp. Chapter 2. ISBN 978-0-07-162167-0. 
  12. ^ Pham, V. (2010). COMMON OTOLARYNGOLOGICAL CONGENITAL ABNORMALITIES. UTMB, Dept. of Otolaryngology. [1]
  13. ^ Conor, WO (1999). "John Langdon Down: The Man and the Message". Down Syndrome Research and Practice 6 (1): 19–24. doi:10.3104/perspectives.94. 
  14. ^ Howard-Jones, Norman (1979). "On the diagnostic term "Down's disease"". Medical History 23 (1): 102–04. doi:10.1017/s0025727300051048. PMC 1082401. PMID 153994. 
  15. ^ Kalyanasundaram, S. (2010). Peroxisomal Disorder-Unusual Presentation as Failure to Thrive in Early Infancy. In Indian Journal of Pediatrics. 77:1151–1152
  16. ^ MedlinePlus Medical Encyclopedia
  17. ^ Hotep, Amon (September 4, 2000). "Race, Genetics and History". Retrieved 17 October 2012. 
  18. ^ Wilson. Climate and the Human body. 2003. September 14, 2006.
  19. ^ Hotep, Amon. Race, Genetics History. 2000. September 14, 2006