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{{EmbryologyUNC|hednk|023}}
| PartOf = Middle ear
| Articulations = 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 bones (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.{{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 }}{{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 homologous to the quadrate bone found in other tetrapods.{{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 }}
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.
History
"Incus" means "anvil" in Latin. Several sources attribute the discovery of the incus to the anatomist and philosopher Alessandro Achillini.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#Lind, L. R. Studies in pre-Vesalian anatomy. Biography, translations, documents, American Philosophical Society, Philadelphia, 1975. p.40 The first brief written description of the incus was by Berengario da Carpi in his Commentaria super anatomia Mundini (1521).Jacopo Berengario da Carpi,Commentaria super anatomia Mundini, Bologna, 1521. https://archive.org/details/ita-bnc-mag-00001056-001 Andreas Vesalius, in his De humani corporis fabrica,Andreas Vesalius, De humani corporis fabrica. Johannes Oporinus, Basle, 1543. was the first to compare the second element of the ossicles to an anvil, thereby giving it the name incus.O'Malley, C.D. Andreas Vesalius of Brussels, 1514-1564. Berkeley: University of California Press, 1964. p. 121 The final part of the long limb was once described as a "fourth ossicle" by Pieter Paaw in 1615.{{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}}
Additional images
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.
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}}