Chin - wikipedia Chin This article is about the part of the face. For other uses, see Chin ( disambiguation ). Chin Chin or mental region labeled in purple Details Artery Inferior alveolar artery Nerve Mental nerve Identifiers Latin Mentum MeSH A01. 456.505. 259 Dorlands / Elsevier 12232781 TA A01. 1.00. 011 FMA 46495 Anatomical terminology ( edit on Wikidata ) The chin or the mental region is the area of the face below the lower lip and including the mandibular prominence. It is formed by the lower front of the mandible. Contents 1 Evolution 2 Cleft chin 3 Double chin 4 See also 5 References Evolution In human evolution, the chin is a cladistic apomorphy, partially defining anatomically modern humans as distinct from archaic forms. Non-human anthropoid apes have a simian shelf for example. Elephants are the only other animals considered to display such a feature, although this leads to debate over the use of the term. The chin emerged during the Middle and Late Pleistocene, but its origin and biomechanical significance are the subjects of controversy. Prominent hypotheses include buttressing the jaw against stresses resulting from speech or chewing as well as simple sexual selection through mate choice. With the advent of more advanced computational facilities, finite element analyses have been used to support hypotheses involving mechanical stress. On the other hand, increased availability of data regarding sexual dimorphism in chins has also lent support to the sexual selection hypothesis as sexual dimorphism is more difficult to explain under other regimes. It is possible that multiple causal factors have played a role in the chin 's evolution. Cleft chin Example of a cleft chin ( William McKinley ) Human jaw front view The terms cleft chin, chin cleft, dimple chin, or chin dimple, refer to a dimple on the chin. It is a Y - shaped fissure on the chin with an underlying bony peculiarity. Specifically, the chin fissure follows the fissure in the lower jaw bone that resulted from the incomplete fusion of the left and right halves of the jaw bone, or muscle, during the embryonal and fetal development. For other individuals, it can develop over time, often because one half of the jaw is longer than the other, leading to facial asymmetry. This is an inherited trait in humans, where the recessive gene causes the cleft chin, while the dominant genotype presents without a cleft. However, it is also a classic example for variable penetrance with environmental factors or a modifier gene possibly affecting the phenotypical expression of the actual genotype. Cleft chins are common among people originating from Europe and the Middle East. In Persian literature, the chin dimple is considered a factor of beauty, and is metaphorically referred to as `` the chin pit '' or `` the chin well '' : a well in which the poor lover is fallen and trapped. Double chin Drawing circa 1900 depicting Joseph Urban as having a double chin. A double chin is a layer of subcutaneous fat around the neck that sags down and creates a wrinkle, making the owner appear to have a second chin. This fat pad is sometimes surgically removed and the muscles under the jaw shortened to remove the double chin. See also Chin augmentation ( genioplasty ) Masseter Mastication Otofacial syndrome Ptosis ( chin ) References Jump up ^ `` Full Definition of chin ''. Merriam - Webster Dictionary. Retrieved 2015 - 09 - 22. Jump up ^ O'Loughlin, Michael McKinley, Valerie Dean ( 2006 ). Human anatomy. Boston : McGraw - Hill Higher Education. pp. 400 -- 01. ISBN 0 - 07 - 249585 - 5. Jump up ^ Enlow, Donald H. ( 1982 ). Handbook of facial growth. Philadelphia : Saunders. p. 283. ISBN 0 - 7216 - 3386 - 2. In the human mandible, a prominent chin marks this region, a distinctive feature that characterizes the face of modern man ( and also, for reasons yet to be studied, the elephant ). Jump up ^ Schwartz, Jeffrey H. ( 2000 ). `` The human chin revisited : what is it and who has it ? ''. Journal of Human Evolution. 38 ( 3 ) : 402. doi : 10.1006 / jhev. 1999.0339. PMID 10683306. When humans and elephants can both be described as having chins, it is probably time to reconsider the applicability of the term. ^ Jump up to : Ichim, Ionut ; Jules Kieser ; Michael Swain ( 2007 ). `` Tongue contractions during speech may have led to the development of the bony geometry of the chin following the evolution of human language : A mechanobiological hypothesis for the development of the human chin ''. Medical Hypotheses. 69 ( 1 ) : 20 -- 24. doi : 10.1016 / j. mehy. 2006.11. 048. PMID 17280797. Jump up ^ Daegling, David J. ( 1993 ). `` Functional morphology of the human chin ''. Evolutionary Anthropology : Issues, News, and Reviews. 1 ( 5 ) : 170 -- 77. doi : 10.1002 / evan. 1360010506. ^ Jump up to : Thayer, Zaneta M. ; Seth D. Dobson ( 2010 ). `` Sexual dimorphism in chin shape : Implications for adaptive hypotheses ''. American Journal of Physical Anthropology. 143 ( 3 ) : 417 -- 25. doi : 10.1002 / ajpa. 21330. PMID 20949612. Jump up ^ Gröning, Flora ; Jia Liu ; Michael J. Fagan ; Paul O'Higgins ( 2011 ). `` Why do humans have chins ? Testing the mechanical significance of modern human symphyseal morphology with finite element analysis ''. American Journal of Physical Anthropology. 144 ( 4 ) : 593 -- 606. doi : 10.1002 / ajpa. 21447. PMID 21404235. Jump up ^ Wayman, Erin. `` Why Do Humans Have Chins ? ''. Smithsonian magazine -- Hominid Hunting. Smithsonian Institution. Retrieved 2012 - 12 - 22. ^ Jump up to : Mammalian Phenotype Browser : Cleft chin Jump up ^ Sharks of the world, Vol. 2, p. 143 ; by Leonard J.V. Compagno, Food and Agriculture Organization of the United Nations, 2001. Jump up ^ Rob Roy, p. 229 ( in 1872 edition, pub. Osgood ) ; by Sir Walter Scott, 1817. Jump up ^ ( 1 ) Jump up ^ Online Mendelian Inheritance in Man ( OMIM ) 119000 Jump up ^ Starr, Barry. `` Ask a Geneticist ''. Understanding Genetics. TheTech. Archived from the original on 2007 - 05 - 13. Retrieved 2007 - 07 - 01. Jump up ^ Günther, H. `` Anomalien und Anomaliekomplexe in der Gegend des ersten Schlundbogens ''. Zeitschrift für menschliche Vererbungs - und Konstitutionslehre. 23 : 43 -- 52. ; Lebow, M.R. ; Sawin, P.B. `` Inheritance of human facial features : a pedigree study involving length of face, prominent ears and chin cleft ''. Journal of Heredity. 32 : 127 -- 32. doi : 10.1093 / oxfordjournals. jhered. a105016. Jump up ^ چاه زنخدان the chin well Archived 2014 - 08 - 08 at the Wayback Machine. Jump up ^ Larkin, Dimitrije E. Panfilov ; translated by Grahame ( 2005 ). Cosmetic surgery today. Stuttgart : Thieme Medical Publishers. p. 64. ISBN 1 - 58890 - 334 - 6. Wikimedia Commons has media related to Chins. Human regional anatomy Head Ear Face Cheek Chin Eye Mouth Nose Forehead Jaw Occiput Scalp Temple Neck Adam 's apple Throat Trunk Abdomen Waist Midriff Navel Back Thorax Breast Pelvis Sex organs Limbs Arm Shoulder Axilla Brachium Elbow Forearm Wrist Hand Finger Thumb Index Middle Ring Little Leg Buttocks Hip Thigh Knee Calf Foot Ankle Heel Sole Toe Other Écorché General anatomy : systems and organs, regional anatomy, planes and lines, superficial axial anatomy, superficial anatomy of limbs Retrieved from `` https://en.wikipedia.org/w/index.php?title=Chin&oldid=815809872 '' Categories : Facial features Hidden categories : Webarchive template wayback links Medicine infobox template using Dorlands parameter All articles lacking reliable references Articles lacking reliable references from November 2017 Talk Contents About Wikipedia Aragonés ܐܪܡܝܐ Avañe'ẽ Авар Aymar aru Bahasa Banjar Беларуская Bosanski Brezhoneg Català Čeština Dansk Deutsch ދިވެހިބަސް Eesti Emiliàn e rumagnòl Español Esperanto Euskara فارسی Français Frysk Galego 贛 語 客家 語 / Hak - kâ - ngî हिन्दी Ido Bahasa Indonesia Iñupiak IsiXhosa Íslenska Italiano עברית Basa Jawa Kapampangan ქართული Kiswahili Kreyòl ayisyen Лакку Latina Latviešu Lingála Lumbaart മലയാളം मराठी მარგალური Bahasa Melayu Mìng - dĕ̤ng - ngṳ̄ Nederlands 日本 語 Norsk Norsk nynorsk Occitan ਪੰਜਾਬੀ پنجابی پښتو Polski Português Ripoarisch Runa Simi Русский संस्कृतम् Scots Sicilianu Simple English کوردی Suomi Svenska Tagalog తెలుగు ไทย Українська اردو ئۇيغۇرچە / Uyghurche Tiếng Việt Walon Winaray ייִדיש 粵語 中文 Edit links This page was last edited on 17 December 2017, at 08 : 25. 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Question: where does the dimple in the chin come from
Answer: inherited trait in humans, where the recessive gene causes the cleft chin