View source for Incus

{{Short description|Bone of the middle ear}}
{{Italic title}}
{{About|ossicle||Incus Records|and|Cumulonimbus incus}}
{{Infobox bone
| Name         = Incus
| Latin         = incus
| Image         = Gray917.png
| Caption       = Left incus. A. From within. B. From the front.
| Image2        = Gray915.png
| Caption2      = [[Auditory tube]], laid open by a cut in its long axis.
| Precursor     = First [[branchial arch]]<ref>{{EmbryologyUNC|hednk|023}}</ref>
| PartOf = [[Middle ear]]
| Articulations = [[Incudomalleolar joint|Incudomalleolar]] and [[incudostapedial joint]]
| Pronunciation = {{IPAc-en|'|I|N|k|@|s}}
}}
{{Ear series|expanded=Middle}}

The '''''incus''''' ({{plural form}}: '''incudes''') or '''anvil''' in the [[ear]] is one of three small [[bone]]s ([[ossicles]]) in the [[middle ear]]. The incus receives vibrations from the [[malleus]], to which it is connected laterally, and transmits these to the [[stapes]] medially. The incus is named for its resemblance to an [[anvil]] ({{langx|la|incus}}).

==Structure==
{{See also|Ossicles}}
The incus is the second of three [[ossicles]], very small bones in the [[middle ear]] which act to transmit sound. It is shaped like an [[anvil]], and has a long and short crus extending from the body, which articulates with the [[malleus]].<ref name=GRAYS2005>{{cite book |last=Drake|first=Richard L.|title=Gray's anatomy for students|year=2005|publisher=Elsevier/Churchill Livingstone |location=Philadelphia|isbn=978-0-8089-2306-0|author2=Vogl, Wayne |author3=Tibbitts, Adam W.M. Mitchell  |author4=illustrations by Richard |author5= Richardson, Paul }}</ref>{{rp|862}} The short crus attaches to the [[posterior ligament of the incus]]. The long crus articulates with the [[stapes]] at the lenticular process.

The [[superior ligament of the incus]] attaches at the body of the incus to the roof of the [[tympanic cavity]].

The incus is [[Homology (biology)|homologous]] to the [[quadrate bone]] found in other tetrapods.<ref>{{Cite journal |last1=Luo |first1=Zhexi |last2=Crompton |first2=Alfred W. |date=1994-09-07 |title=Transformation of the quadrate (incus) through the transition from non-mammalian cynodonts to mammals |url=http://www.tandfonline.com/doi/abs/10.1080/02724634.1994.10011564 |journal=Journal of Vertebrate Paleontology |language=en |volume=14 |issue=3 |pages=341–374 |doi=10.1080/02724634.1994.10011564 |bibcode=1994JVPal..14..341L |issn=0272-4634|url-access=subscription }}</ref>

==Function==
{{Main|Hearing}}
Vibrations in the [[middle ear]] are received via the [[tympanic membrane]]. The malleus, resting on the membrane, conveys vibrations to the incus. This in turn conveys vibrations to the [[stapes]].<ref name=GRAYS2005 />

==History==
"Incus" means "anvil" in Latin. Several sources  attribute the discovery of the incus to the anatomist and philosopher [[Alessandro Achillini]].<ref>Alidosi, GNP. ''I dottori Bolognesi di teologia, filosofia, medicina e d'arti liberali dall'anno 1000 per tutto marzo del 1623'', Tebaldini, N., Bologna, 1623. http://gallica.bnf.fr/ark:/12148/bpt6k51029z/f35.image#</ref><ref>Lind, L. R. ''Studies in pre-Vesalian anatomy. Biography, translations, documents'', American Philosophical Society, Philadelphia, 1975. p.40</ref> The first brief written description of the ''incus'' was by [[Berengario da Carpi]] in his ''Commentaria super anatomia Mundini'' (1521).<ref>Jacopo Berengario da Carpi,''Commentaria super anatomia Mundini'', Bologna, 1521. https://archive.org/details/ita-bnc-mag-00001056-001</ref> [[Andreas Vesalius]], in his ''[[De humani corporis fabrica]]'',<ref>Andreas Vesalius, ''De humani corporis fabrica''. Johannes Oporinus, Basle, 1543.</ref> was the first to compare the second element of the ossicles to an anvil, thereby giving it the name ''incus''.<ref>O'Malley, C.D. ''Andreas Vesalius of Brussels, 1514-1564.'' Berkeley: University of California Press, 1964. p. 121</ref> The final part of the long limb was once described as a "fourth ossicle" by [[Pieter Paaw]] in 1615.<ref>{{cite journal|last=Graboyes|first=Evan M.|author2=Chole, Richard A. |author3=Hullar, Timothy E. |title=The Ossicle of Paaw|journal=Otology & Neurotology|date=September 2011|volume=32|issue=7|pages=1185–1188|doi=10.1097/MAO.0b013e31822a28df|pmc=3158805|pmid=21844785}}</ref>

==Additional images==
<gallery>
File:Illu auditory ossicles-en.svg|Ossicles
File:Occipital bone dissection.jpg|Tympanic cavity. Facial canal. Internal carotid artery.
File:Slide1ghe.JPG|Auditory ossicles. Tympanic cavity. Deep dissection.
File:Slide2ghe2.JPG|Aditory ossicles. Incus and malleus. Deep dissection.
</gallery>

==References==
{{Reflist}}

==External links==
* [https://web.archive.org/web/20070926225617/http://www.anatomywiz.com/?Incus1 The Anatomy Wiz] ''Incus''

{{Auditory system}}
{{HumanBones}}
{{Tetrapod osteology}}
{{Authority control}}

[[Category:Bones of the head and neck]]
[[Category:Auditory system]]
[[Category:Ear]]
[[Category:Ossicles]]
[[Category:Otorhinolaryngology]]
[[Category:Otology]]
[[Category:Middle ear]]