# Incisor > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Incisor > Markdown URL: https://mediated.wiki/source/Incisor.md > Source: https://en.wikipedia.org/wiki/Incisor > Source revision: 1297501839 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Front teeth of most mammals Incisor Permanent teeth of the right half of the lower dental arch, seen from above. The permanent teeth of a human, viewed from the right. Details Identifiers Latin dens incisivus MeSH D007180 TA98 A05.1.03.004 TA2 906 FMA 12823 Anatomical terminology [edit on Wikidata] **Incisors** (from Latin *incidere*, "to cut") are the front [teeth](/source/Teeth) present in most [mammals](/source/Mammal). They are located in the [premaxilla](/source/Premaxilla) above and on the [mandible](/source/Mandible) below. Humans have a total of eight (two on each side, top and bottom). [Opossums](/source/Opossum) have 18, whereas [armadillos](/source/Armadillo), [anteaters](/source/Anteater) and other animals in the superorder [Xenarthra](/source/Xenarthra) have none.[1] ## Structure Adult [humans](/source/Human) normally have eight incisors, two of each type. The types of incisors are: - [maxillary central incisor](/source/Maxillary_central_incisor) (upper jaw, closest to the center of the lips) - [maxillary lateral incisor](/source/Maxillary_lateral_incisor) (upper jaw, beside the maxillary central incisor) - [mandibular central incisor](/source/Mandibular_central_incisor) (lower jaw, closest to the center of the lips) - [mandibular lateral incisor](/source/Mandibular_lateral_incisor) (lower jaw, beside the mandibular central incisor) Children with a full set of [deciduous teeth](/source/Deciduous_teeth) (primary teeth) also have eight incisors, named the same way as in [permanent teeth](/source/Permanent_teeth). Young children may have from zero to eight incisors depending on the stage of their [tooth eruption](/source/Tooth_eruption) and [tooth development](/source/Human_tooth_development). Typically, the mandibular central incisors erupt first, followed by the maxillary central incisors, the mandibular lateral incisors and finally the maxillary laterals. The rest of the primary dentition erupts after the incisors.[2] Apart from the [first molars](/source/First_molar), the incisors are also the first permanent teeth to erupt, following the same order as the primary teeth, among themselves. ### Other animals Among other animals, the number varies from species to species. [Opossums](/source/Opossum) have 18, whereas [armadillos](/source/Armadillo) have none. Cats, dogs, foxes, pigs, and horses have twelve. [Rodents](/source/Rodent) have four. Rabbits and hares ([lagomorphs](/source/Lagomorph)) were once considered rodents, but are distinguished by having six—one small pair, called "peg teeth", is located directly behind the most anterior pair. Incisors are used to bite off tough foods, such as red meat. [Cattle](/source/Cattle) (cows, bulls, etc.) have none on top but a total of six on the bottom. ## Function In [cats](/source/Cat), the incisors are small; biting off meat is done with the [canines](/source/Canine_tooth) and the [carnassials](/source/Carnassial). In [elephants](/source/Elephant), the upper incisors are modified into curved [tusks](/source/Tusk) (unlike with [narwhals](/source/Narwhal), where it is a canine that develops into a straight and twisted tusk).[3] The incisors of [rodents](/source/Rodent) grow throughout life and are worn by gnawing. In humans, the incisors serve to cut off pieces of food, as well as in the grip of other food items. ## Additional images - Arrangement of incisors in an adult human. - Mouth (oral cavity) - Left maxilla. Outer surface. - Base of skull. Inferior surface. ## See also - [Canine tooth](/source/Canine_tooth) - [Molar](/source/Molar_(tooth)) - [Premolar](/source/Premolar) - [Shovel-shaped incisors](/source/Shovel-shaped_incisors) ## References 1. **[^](#cite_ref-1)** ["Archives"](https://www.dentalcare.com/en-us/archives). *dentalcare.com*. [Archived](https://web.archive.org/web/20180429001759/https://www.dentalcare.com/en-us/archives) from the original on 29 April 2018. Retrieved 29 April 2018. 1. **[^](#cite_ref-2)** Scheid, RC. (2012). *Woelfel's dental anatomy* (8 ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. 1. **[^](#cite_ref-3)** Nweeia, Martin; Eichmiller, Frederick C.; Hauschka, Peter V.; Tyler, Ethan; Mead, James G.; Potter, Charles W.; Angnatsiak, David P.; Richard, Pierre R.; et al. (30 March 2012). "Vestigial Tooth Anatomy and Tusk Nomenclature for Monodon Monoceros". *The Anatomical Record*. **295** (6): 1006–1016. [doi](/source/Doi_(identifier)):[10.1002/ar.22449](https://doi.org/10.1002%2Far.22449). [PMID](/source/PMID_(identifier)) [22467529](https://pubmed.ncbi.nlm.nih.gov/22467529). ## External links - Media related to [Incisors](https://commons.wikimedia.org/wiki/Category:Incisors) at Wikimedia Commons v t e Dental anatomy Nomenclature Glossary of dentistry FDI World Dental Federation notation Universal Numbering System (a.k.a. the "American system") Teeth Permanent incisor canine premolar molar Deciduous Maxillary teeth Incisor Central incisor Lateral incisor Canine Premolar First premolar Second premolar Molar First molar Second molar Third molar Mandibular teeth Incisor Central incisor Lateral incisor Canine Premolar First premolar Second premolar Molar First molar Second molar Third molar Parts Crown Cusp Cusp of Carabelli Zuckerkandl's tubercle Pulp Root canal Apical foramen Cementoenamel junction Enamel Dental-enamel junction Dentin Dental papilla Mamelon Dental alveolus Authority control databases International GND Other Terminologia Anatomica Yale LUX --- Adapted from the Wikipedia article [Incisor](https://en.wikipedia.org/wiki/Incisor) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Incisor?action=history)). 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