View source for Hyoid bone

{{Anatomy-terms}}
{{Short description|Bone situated in the neck between the chin and the thyroid-cartilage}}
{{Infobox bone
| Name          = Hyoid 
| Latin         = os hyoideum
| Image         = 712 Hyoid Bone.jpg
| Width         =
| Caption       = The '''hyoid bone''', present at the front of the neck, has a body and two sets of horns
| Origins       =
| Insertions    =
| Articulations =
| Precursor     = Second and third [[pharyngeal arch]]<ref>{{EmbryologyUNC|hednk|023}}</ref>
}}
The '''hyoid bone''' ('''lingual bone''' or '''tongue-bone''') ({{IPAc-en|ˈ|h|aɪ|ɔɪ|d}}<ref>''[[Oxford English Dictionary]]'' 2nd edition, 1989.</ref><ref>[http://www.merriam-webster.com/dictionary/hyoid Entry "hyoid"] {{webarchive|url=https://web.archive.org/web/20111229140551/http://www.merriam-webster.com/dictionary/hyoid |date=2011-12-29 }} in ''[http://www.merriam-webster.com/ Merriam-Webster Online Dictionary] {{webarchive|url=https://web.archive.org/web/20170922151722/https://www.merriam-webster.com/ |date=2017-09-22 }}''.</ref>) is a [[horseshoe-shaped]] [[bone]] situated in the anterior midline of the [[neck]] between the [[chin]] and the [[thyroid cartilage]].  At rest, it lies between the base of the [[Human mandible|mandible]] and the third [[Cervical vertebrae|cervical vertebra]].

Unlike other bones, the hyoid is only distantly [[Joint|articulated]] to other bones by muscles or ligaments. It is the only bone in the human body that is not connected to any other bones. The hyoid is anchored by muscles from the anterior, posterior and inferior directions, and aids in tongue movement and swallowing. The hyoid bone provides attachment to the muscles of the [[Human mouth#Mouth cavity|floor of the mouth]] and the tongue above, the [[larynx]] below, and the [[epiglottis]] and [[pharynx]] behind.{{Citation needed|date=April 2022}}

Its name is derived {{Etymology|el|hyoeides|shaped like the letter [[upsilon]] (υ)}}.<ref>Dorland illustrated medical dictionary</ref><ref>American heritage dictionary for English language</ref>

==Structure==
{{multiple image
| align = Right
| image1 = Hyoid bone - animation.gif
| width1 = 180
| image2 = Hyoid bone - close-up - animation.gif
| width2 = 180
| footer = ''Left'': Position of hyoid bone (shown in red). ''Right'': Shape of hyoid bone.
}}

[[File:Hyoid_bone_hariadhi.svg|Hyoid bone|thumb]]
The hyoid bone is classed as an [[irregular bone]] and consists of a central part called the body, and two pairs of horns, the greater and lesser horns.

=== Body ===

The body of the hyoid bone is the central part of the hyoid bone.{{clarify|date=February 2022}}
*At the front, the body is convex and directed forward and upward.
* It is crossed in its upper half by a well-marked transverse ridge with a slight downward convexity, and in many cases a vertical median ridge divides it into two lateral halves. 
* The portion of the vertical ridge above the transverse line is present in a majority of specimens, but the lower portion is evident only in rare cases.{{Clarify|reason=Not able to understand the sentence.|date=September 2023}}
* The anterior surface gives insertion to the [[geniohyoid muscle]] in the greater part of its extent both above and below the transverse ridge; a portion of the origin of the [[hyoglossus muscle|hyoglossus]] notches the lateral margin of the geniohyoid attachment. 
* Below the transverse ridge the [[mylohyoid muscle|mylohyoid]], [[sternohyoid muscle|sternohyoid]], and [[omohyoid muscle|omohyoid]] are inserted.
* At the back, the bone is smooth, concave, directed backward and downward, and separated from the [[epiglottis]] by the [[hyothyroid membrane]] and a quantity of [[loose areolar tissue]]; a [[Bursa (anatomy)|bursa]] intervenes between it and the hyothyroid membrane.
* Above, the body is rounded, and gives attachment to the hyothyroid membrane and some [[aponeurosis|aponeurotic]] fibers of the [[genioglossus muscle|genioglossus]].
* Below, the body affords insertion medially to the sternohyoid and laterally to the omohyoid and occasionally a portion of the [[thyrohyoid muscle|thyrohyoid]]. It also gives attachment to the Levator glandulae thyreoideae, when this muscle is present.

===Horns===
[[File:Gray186.png|thumbnail|The lesser and greater horns of the hyoid]]
The greater and lesser horns ({{langx|la|cornua}}) are two sections of bone that project from each side of the hyoid.

==== Greater horns ====
The greater horns project backward from the outer borders of the body; they are flattened from above downward and taper to their end, which is a bony [[Tubercle (anatomy)|tubercle]] connecting to the [[lateral thyrohyoid ligament]]. The upper surface of the greater horns are rough and close to its lateral border, and facilitates muscular attachment. The largest of muscles that attach to the upper surface of the greater horns are the [[hyoglossus]] and the [[middle pharyngeal constrictor]], which extend along the whole length of the horns; the [[digastric muscle]] and [[stylohyoid muscle]] have small insertions in front of these near the junction of the body with the horns. To the medial border, the [[thyrohyoid membrane]] is attached, while the anterior half of the lateral border gives insertion to the [[thyrohyoid muscle]].{{Citation needed|date=January 2014}}

==== Lesser horns ====
The lesser horns are two small, conical eminences, attached by their bases to the angles of junction between the body and greater horns of the hyoid bone. They are connected to the body of the bone by fibrous tissue, and occasionally to the greater horns by distinct diarthrodial [[joint]]s, which usually persist throughout life, but occasionally become [[ankylosis|ankylosed]]. The lesser horns are situated in the line of the transverse ridge on the body and appear to be continuations of it. The apex of each horn gives attachment to the [[stylohyoid ligament]]; the [[chondroglossus]] rises from the medial side of the base.{{Citation needed|date=January 2014}}

===Development===
The [[second arch|second pharyngeal arch]], also called the hyoid arch, gives rise to the lesser cornu of the hyoid and the upper part of the body of the hyoid. The cartilage of the third pharyngeal arch forms the greater cornu of the hyoid and the lower portion of the body of the hyoid.

The hyoid is [[ossification|ossified]] from six centers: two for the body, and one for each cornu.  Ossification commences in the greater cornua toward the end of [[prenatal development|fetal development]], in the hyoid body shortly afterward, and in the lesser cornua during the first or second year after birth.  Until middle age, the connection between the body and greater cornu is [[connective tissue|fibrous]].

In early life, the outer borders of the body are connected to the greater horns by synchondroses; after middle life, usually by bony union.

===Blood supply===
Blood is supplied to the hyoid bone via the [[lingual artery]], which runs down from the [[human tongue|tongue]] to the greater horns of the bone. The suprahyoid branch of the lingual artery runs along the upper border of the hyoid bone and supplies blood to the attached muscles.

==Function==
[[File:Larynx external en.svg|thumb|The hyoid bone sits above the [[thyroid cartilage]].]]
The hyoid bone is present in many [[mammal]]s. It allows a wider range of tongue, pharyngeal and laryngeal movements by bracing these structures alongside each other in order to produce variation.<ref>{{cite journal |title=Descent of the larynx in chimpanzee infants |doi=10.1073/pnas.1231107100 |volume=100 |year=2003 |journal=Proceedings of the National Academy of Sciences |pages=6930–6933 | last1 = Nishimura | first1 = T.|issue=12 |pmc=165807 |pmid=12775758 |bibcode=2003PNAS..100.6930N |doi-access=free }} Descent of the larynx in chimpanzee infants</ref> Its descent in living creatures is not unique to ''[[Homo sapiens]]'',<ref>{{cite journal| last1 = Nishimura | first1 = T. | display-authors = etal  | year = 2006 | title = Descent of the hyoid in chimpanzees: evolution of face flattening and speech | journal = Journal of Human Evolution | volume = 51 | issue = 3 | pages = 244–254 | doi=10.1016/j.jhevol.2006.03.005 | pmid = 16730049| bibcode = 2006JHumE..51..244N }}</ref> and does not allow the production of a wide range of sounds: with a lower larynx, men do not produce a wider range of sounds than women and two-year-old babies. Moreover, the larynx position of Neanderthals was not a handicap to producing speech sounds.<ref>{{cite journal | last1 = Boë | first1 = L.J. | display-authors = etal  | year = 2002 | title = The potential of Neandertal vowel space was as large as that of modern humans | journal = Journal of Phonetics | volume = 30 | issue = 3 | pages = 465–484 | doi=10.1006/jpho.2002.0170}}</ref>   The discovery of a modern-looking hyoid bone of a [[Neanderthal]] man in the [[Kebara Cave]] in [[Israel]] led its discoverers to argue that the Neanderthals had a descended [[larynx]], and thus human-like [[speech]] capabilities.<ref>Arsenburg, B. et al., A reappraisal of the anatomical basis for speech in middle Paleolithic hominids, in: American Journal of Physiological Anthropology 83 (1990), pp. 137–146.</ref>  However, other researchers have claimed that the morphology of the hyoid is not indicative of the larynx's position. Recent research has indicated that the hyoid bone may have significant involvement in the ability to swallow. It has been hypothesized that the mammalian hyoid bone evolved in conjunction with the development of [[lactation]], thus allowing babies to suckle milk.<ref>Fitch, Tecumseh W., The evolution of speech: a comparative review, in: Trends in Cognitive Sciences, Vol. 4, No. 7, July 2000 ({{cite web |url=http://www3.isrl.uiuc.edu/~junwang4/langev/localcopy/pdf/fitch00speech.pdf |title=Archived copy |access-date=2007-09-09 |url-status=dead |archive-url=https://web.archive.org/web/20070809073918/http://www3.isrl.uiuc.edu/~junwang4/langev/localcopy/pdf/fitch00speech.pdf |archive-date=2007-08-09}})</ref> It is necessary to take into consideration the skull base, the mandible and the cervical vertebrae and a cranial reference plane.<ref>{{cite journal | last1 = Granat | display-authors = etal | year = 2006 | title = Hyoid bone and larynx in Homo. Estimated position by biometrics | journal = Biom. Hum. Et Anthropolol | volume = 24 | issue = 3–4| pages = 243–255 }}</ref><ref>{{cite journal | last1 = Boë | first1 = L.J. | display-authors = etal | year = 2006 | title = Variation and prediction of the hyoid bone position for modern Man and Neanderthal | journal = Biom. Hum. Et Anthropolol | volume = 24 | issue = 3–4| pages = 257–271 }}</ref>

===Muscle attachments===
A large number of muscles attach to the hyoid:<ref>{{cite journal|last2=Martino|first2=R.|year=2013|title=The normal swallow: muscular and neurophysiological control|journal=Otolaryngol Clin N Am|volume=46|issue=6|pages=937–956|doi=10.1016/j.otc.2013.09.006|last1=Shaw|first1=S. M.|pmid=24262952}}</ref>

*Superior
**[[Middle pharyngeal constrictor muscle]]
**[[Hyoglossus|Hyoglossus muscle]]
**[[Genioglossus]]
**[[Intrinsic muscles of the tongue]]
**[[Suprahyoid muscles]]
***[[Digastric muscle]]
***[[Stylohyoid muscle]]
***[[Geniohyoid muscle]]
***[[Mylohyoid muscle]]
*Inferior
**[[Thyrohyoid muscle]]
**[[Omohyoid muscle]]
**[[Sternohyoid muscle]]
**[[Sternothyroid muscle]]

<gallery>
File:Gray380.png|[[Muscle]]s of the [[pharynx]] and [[cheek]]
File:Gray385.png|Muscles of the [[neck]].  Lateral view.
</gallery>

==Clinical significance==
The hyoid bone is important to a number of physiological functions, including breathing, swallowing and speech. It is also thought to play a key role in keeping the upper airway open during sleep,<ref>{{cite journal|last1=Amatoury|first1=J|last2=Kairaitis|first2=K|last3=Wheatley|first3=JR|last4=Bilston|first4=LE|last5=Amis|first5=TC|title=Peripharyngeal tissue deformation and stress distributions in response to caudal tracheal displacement: pivotal influence of the hyoid bone?|journal=Journal of Applied Physiology|date=1 April 2014|volume=116|issue=7|pages=746–56|pmid=24557799|doi=10.1152/japplphysiol.01245.2013}}</ref><ref>{{cite journal|last1=Amatoury|first1=J|last2=Kairaitis|first2=K|last3=Wheatley|first3=JR|last4=Bilston|first4=LE|last5=Amis|first5=TC|title=Peripharyngeal tissue deformation, stress distributions, and hyoid bone movement in response to mandibular advancement.|journal=Journal of Applied Physiology|date=1 February 2015|volume=118|issue=3|pages=282–91|pmid=25505028|doi=10.1152/japplphysiol.00668.2014}}</ref> and as such, the development and treatment of [[obstructive sleep apnea]] (OSA; characterized by repetitive collapse of the upper airway during sleep). A mechanistic involvement of the hyoid bone in OSA is supported by numerous studies demonstrating that a more inferiorly positioned hyoid bone is strongly associated with the presence and severity of the disorder.<ref>{{cite journal|last1=Sforza|first1=E|last2=Bacon|first2=W|last3=Weiss|first3=T|last4=Thibault|first4=A|last5=Petiau|first5=C|last6=Krieger|first6=J|title=Upper airway collapsibility and cephalometric variables in patients with obstructive sleep apnea.|journal=American Journal of Respiratory and Critical Care Medicine|date=February 2000|volume=161|issue=2 Pt 1|pages=347–52|pmid=10673170|doi=10.1164/ajrccm.161.2.9810091}}</ref><ref>{{cite journal|last1=Genta|first1=PR|last2=Schorr|first2=F|last3=Eckert|first3=DJ|last4=Gebrim|first4=E|last5=Kayamori|first5=F|last6=Moriya|first6=HT|last7=Malhotra|first7=A|last8=Lorenzi-Filho|first8=G|title=Upper airway collapsibility is associated with obesity and hyoid position.|journal=Sleep|date=1 October 2014|volume=37|issue=10|pages=1673–8|pmid=25197805|doi=10.5665/sleep.4078|pmc=4173923}}</ref> Movement of the hyoid bone is also thought to be important in modifying upper airway properties, which was recently demonstrated in computer model simulations.<ref>{{cite journal| last1=Amatoury |first1=J |last2=Cheng |first2=S |last3=Kairaitis |first3=K |last4=Wheatley |first4=JR |last5=Amis |first5=TC |last6= Bilston |first6=LE| title=Development and validation of a computational finite element model of the rabbit upper airway: simulations of mandibular advancement and tracheal displacement. | journal=J Appl Physiol | year= 2016 | volume= 120 | issue= 7 | pages= 743–57 | pmid=26769952 | doi=10.1152/japplphysiol.00820.2015 | url=http://handle.unsw.edu.au/1959.4/unsworks_42699|doi-access=free |hdl=1959.4/unsworks_42699 |hdl-access=free }}</ref> A [[surgery|surgical procedure]] that aims to potentially increase and improve the airway is called [[hyoid suspension]].

Due to its position, the hyoid bone is not easily susceptible to fracture. In a suspected case of murder of an adult, a fractured hyoid strongly indicates [[strangulation]]. However, in children and adolescents, where the hyoid bone is still flexible as ossification is yet to be completed, strangulation is less likely to fracture the hyoid. 

==Other animals==
The hyoid bone is derived from the lower half of the second [[Branchial arch|gill arch]] in [[fish]], which separates the first gill slit from the [[Spiracle (vertebrates)|spiracle]], and is often called the ''[[hyoid arch]]''. In many vertebrates, it also incorporates elements of other gill arches, and has a correspondingly greater number of cornua. [[Amphibian]]s and non-avian [[reptile]]s may have many cornua, while mammals (including humans) have two pairs, and [[bird]]s only one. In birds, and some reptiles, the body of the hyoid is greatly extended forward, creating a solid bony support for the [[tongue]].<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|page= 214|isbn= 0-03-910284-X}}</ref>  The howler monkey ''[[Alouatta]]'' has a [[pneumatized bones|pneumatized]] hyoid bone, one of the few cases of postcranial pneumatization of bones outside [[Saurischia]].

In [[woodpeckers]], the hyoid bone is elongated, with the horns wrapping around the back of the skull. This is part of the system that keeps the brain cushioned and undamaged by the pecking action.

In [[mammals]], the hyoid often determines whether one can [[Roar (vocalization)|roar]]. If the hyoid is incompletely [[ossification|ossified]] (for example: [[lion|lions]]), it allows the animal to roar, but not purr. If the hyoid is completely ossified (for example: [[cheetah|cheetahs]]), it does not allow the animal to roar, but instead will allow the animal to purr and meow, as seen in [[cat|house cats]] (lions, cheetahs and house cats all belong to the family [[Felidae]]).<ref>SeaWorld https://seaworld.org/animals/all-about/cheetah/communication/</ref>
{{Gallery
|File:Eublepharis maculatus hyoid.jpg|The hyoid bone of a [[gecko]] with attached [[tracheal rings]]
|File:Vogelzungenbeine, Naturhistorisches Museum Wien.jpg|Hyoid bones of various birds in the [[Natural History Museum, Vienna]]
}}

In veterinary anatomy, the term [[hyoid apparatus]] is the collective term used to refer to the [[bone]]s of the [[tongue]]—a pair of [[Stylohyoid muscle|stylohyoidea]], a pair of [[Thyrohyoid muscle|thyrohyoidea]], and unpaired basihyoideum<ref>Shoshani J., Marchant G.H. (2001.) Hyoid apparatus: a little-known complex of bones and its "contribution" to proboscidean evolution, ''The World of Elephants - International Congress, Rome'', pp. 668–675.</ref>—and associated, upper-[[throat|gular]] connective tissues.<ref>{{Cite web|url=http://animals.about.com/od/h/g/hyoidapparatus.htm|title=Hyoid Apparatus - Definition of Hyoid Apparatus|last=Klappenbach|first=Laura|publisher=[[The New York Times Company]]|access-date=2017-03-20|url-status=dead|archive-url=https://web.archive.org/web/20120120213743/http://animals.about.com/od/h/g/hyoidapparatus.htm|archive-date=2012-01-20}}</ref> In humans, the single hyoid bone is an equivalent of the hyoid apparatus.<ref>{{Cite web|url=http://www.mondofacto.com/facts/dictionary?hyoid+apparatus|title=hyoid apparatus - Definition|publisher=mondofacto.com|url-status=live|archive-url=https://web.archive.org/web/20111108034148/http://mondofacto.com/facts/dictionary?hyoid+apparatus|archive-date=2011-11-08}}</ref>

==See also==
* [[Hyoid bone fracture]]
* [[Adam's apple]]

==References==
{{Gray's}}
{{Reflist|30em}}

==External links==
{{Commons category|Hyoid bones}}
* {{NormanAnatomy|Lesson11}} ({{NormanAnatomyFig|larynxskel1}})

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[[Category:Bones of the head and neck]]
[[Category:Irregular bones]]
[[Category:Otorhinolaryngology]]
[[Category:Human head and neck]]