View source for Tongue

{{short description|Muscular organ in the mouth of most vertebrates}}
{{Other uses}}
{{Infobox anatomy
| Name = Tongue
| Latin = lingua
| Image = زبان tongue.jpg
| Caption = The human tongue
| Precursor = [[Pharyngeal arches]], [[lateral lingual swelling]], [[tuberculum impar]]<ref>{{EmbryologyUNC|hednk|024}}</ref>
| Artery = [[lingual artery|Lingual]], [[Tonsillar branch of the facial artery|tonsillar branch]], [[ascending pharyngeal artery|ascending pharyngeal]]
| Vein = [[lingual veins|Lingual]]
| Nerve = '''Sensory'''<br />Anterior two-thirds: [[lingual nerve|Lingual]] (sensation) and [[chorda tympani]] (taste)<br />Posterior one-third: [[Glossopharyngeal nerve|Glossopharyngeal]] (IX)<br />'''Motor'''<br />[[Hypoglossal nerve|Hypoglossal]] (XII), except [[palatoglossus muscle]] supplied by the [[pharyngeal plexus]] via [[vagus nerve|vagus]] (X)
| Lymph = [[Deep cervical lymph nodes|Deep cervical]], [[Submandibular lymph nodes|submandibular]], [[Submental lymph nodes|submental]]
| System = [[Alimentary tract]], [[gustatory system]]
}}
The '''tongue''' is a [[Muscle|muscular]] [[organ (anatomy)|organ]] in the [[mouth]] of a typical [[tetrapod]]. It manipulates food for chewing and swallowing as part of the [[digestive system|digestive process]], and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by [[taste buds]] housed in numerous [[lingual papilla]]e. It is sensitive and kept moist by [[saliva]] and is richly supplied with [[nerve]]s and [[blood vessel]]s. The tongue also serves as a natural means of cleaning the teeth.<ref>{{cite book |last1=Maton |first1=Anthea |last2=Hopkins |first2=Jean |last3=McLaughlin |first3=Charles William |last4=Johnson |first4=Susan |last5=Warner |first5=Maryanna Quon |last6=LaHart |first6=David |last7=Wright |first7=Jill D. |title=Human Biology and Health |publisher=Prentice Hall |year=1993 |location=Englewood Cliffs, New Jersey, US |isbn=0-13-981176-1 |url-access=registration |url=https://archive.org/details/humanbiologyheal00scho }}</ref> A major function of the tongue is to enable speech in humans and [[animal communication|vocalization]] in other animals.

The human tongue is divided into two parts, an [[oral cavity|oral]] part at the front and a [[pharynx|pharyngeal]] part at the back. The left and right sides are also separated along most of its length by a vertical section of [[connective tissue|fibrous tissue]] (the [[lingual septum]]) that results in a groove, the median sulcus, on the tongue's surface.

There are two groups of glossal muscles. The four intrinsic muscles alter the shape of the tongue and are not attached to bone. The four paired extrinsic muscles change the position of the tongue and are anchored to bone.

==Etymology==
The word '''tongue''' derives from the [[Old English]] ''tunge'', which comes from [[Proto-Germanic]] *''tungōn''.<ref name="OED">{{cite web | url = https://www.etymonline.com/index.php?term=tongue | title = Tongue | work = Online Etymology Dictionary | access-date = 17 September 2017}}</ref> It has [[cognates]] in other [[Germanic languages]]—for example ''tonge'' in [[West Frisian language|West Frisian]], ''tong'' in [[Dutch language|Dutch]] and [[Afrikaans]], ''Zunge'' in [[German language|German]], ''tunge'' in [[Danish language|Danish]] and [[Norwegian language|Norwegian]], and ''tunga'' in [[Icelandic language|Icelandic]], [[Faroese language|Faroese]] and [[Swedish language|Swedish]]. The ''ue'' ending of the word seems to be a fourteenth-century attempt to show "proper pronunciation", but it is "neither etymological nor phonetic".<ref name="OED"/> Some used the spelling ''tunge'' and ''tonge'' as late as the sixteenth century.

==In humans==
===Structure===
[[File:Facies inferior linguae.JPG|right|thumb|175px|The underside of a human tongue, showing its rich blood supply.]]
The tongue is a [[muscular hydrostat]] that forms part of the floor of the [[Human mouth|oral cavity]]. The left and right sides of the tongue are separated by a vertical section of fibrous tissue known as the [[lingual septum]]. This division is along the length of the tongue save for the very back of the pharyngeal part and is visible as a groove called the median sulcus. The human tongue is divided into [[Anatomical terms of location#Anterior and posterior|anterior and posterior]] parts by the terminal sulcus, which is a "V"-shaped groove. The apex of the terminal sulcus is marked by a blind foramen, the foramen cecum, which is a remnant of the median [[thyroid diverticulum]] in early [[embryogenesis|embryonic development]]. The anterior ''oral'' part is the visible part situated at the front and makes up roughly two-thirds the length of the tongue. The posterior ''pharyngeal'' part is the part closest to the [[throat]], roughly one-third of its length. These parts differ in terms of their [[embryogenesis|embryological development]] and [[innervation|nerve supply]].

The anterior tongue is, at its apex, thin and narrow. It is directed forward against the lingual surfaces of the lower [[incisor]] teeth. The posterior part is, at its root, directed backward, and connected with the [[hyoid bone]] by the [[hyoglossi]] and [[genioglossi]] muscles and the [[hyoglossal membrane]], with the [[epiglottis]] by three [[glossoepiglottic folds]] of mucous membrane, with the [[soft palate]] by the [[glossopalatine arches]], and with the [[pharynx]] by the [[superior pharyngeal constrictor muscle]] and the [[mucous membrane]]. It also forms the anterior wall of the [[oropharynx]].

The average length of the human tongue from the [[oropharynx]] to the tip is 10&nbsp;cm.<ref>{{cite book |year=1997 |last=Kerrod |first=Robin |title=MacMillan's Encyclopedia of Science |publisher=Macmillan Publishing Company, Inc. |volume=6 |isbn=0-02-864558-8}}</ref> The average weight of the human tongue from adult males is 99g and for adult females 79g.<ref>{{cite journal |last1=Nashi |first1=Nadia |title=Lingual fat at autopsy |journal=Laryngoscope |date=Aug 2007 |volume=117 |issue=8 |pages=1467–1473 |doi=10.1097/MLG.0b013e318068b566 |pmid=17592392 }}</ref>

In [[phonetics]] and [[phonology]], a distinction is made between the '''tip''' of the tongue and the '''blade''' (the portion just behind the tip).  Sounds made with the tongue tip are said to be [[apical consonant|apical]], while those made with the tongue blade are said to be [[laminal consonant|laminal]].

Tongue posture is the resting position of the tongue in the mouth. Evidence demonstrates that the tongue plays a role in mouth and face development.<ref>{{Cite journal |last=Moyers |first=ROBERT E. |date=1964-07-01 |title=Tongue Problems and Malocclusion |url=https://www.sciencedirect.com/science/article/pii/S0011853222019899 |journal=Dental Clinics of North America |language=en |volume=8 |issue=2 |pages=529–539 |doi=10.1016/S0011-8532(22)01989-9 |issn=0011-8532 |s2cid=248762393 |url-access=subscription}}</ref><ref>{{Cite journal |last=Klineberg |first=I. |date=1988-03-01 |title=Occlusion as the cause of undiagnosed pain |url=https://europepmc.org/article/med/3290113 |journal=International Dental Journal |volume=38 |issue=1 |pages=19–27 |issn=1875-595X |pmid=3290113}}</ref>

====Upper surface====
[[File:Foramen caecum.png|thumb|right|200px|Foramen cecum and terminal sulcus labelled above]]
[[File:Tongue.svg|thumb|200px|Features of the tongue surface]]
The upper surface of the tongue, the dorsal surface, is called the dorsum, and is divided by a groove into symmetrical halves by the ''median sulcus''. The ''foramen cecum'' marks the end of this division (at about 2.5&nbsp;cm from the root of the tongue) and the beginning of the ''terminal sulcus''. The foramen cecum is also the point of attachment of the [[thyroglossal duct]] and is formed during the descent of the [[thyroid diverticulum]] in [[human embryogenesis|embryonic development]].

The terminal sulcus is a shallow groove that runs forward as a shallow groove in a ''V'' shape from the foramen cecum, forwards and outwards to the margins (borders) of the tongue. The terminal sulcus divides the tongue into a posterior [[pharynx|pharyngeal]] part and an anterior [[Human mouth|oral]] part. The pharyngeal part is supplied by the [[glossopharyngeal nerve]] and the oral part is supplied by the [[lingual nerve]] (a branch of the mandibular branch (V3) of the [[trigeminal nerve]]) for somatosensory perception and by the [[chorda tympani]] (a branch of the [[facial nerve]]) for [[taste|taste perception]].

Both parts of the tongue develop from different [[pharyngeal arch]]es.

====Undersurface====
On the undersurface, the ventral surface, of the tongue is a fold of mucous membrane called the [[frenulum of tongue|frenulum]] that tethers the tongue at the midline to the floor of the mouth. On either side of the frenulum are small prominences called [[Submandibular gland#Structure|sublingual caruncle]]s that the major salivary [[submandibular gland]]s drain into.

====Muscles====
The eight muscles of the human tongue are classified as either ''intrinsic'' or ''extrinsic''. The four intrinsic muscles act to change the shape of the tongue, and are not attached to any bone. The four extrinsic muscles act to change the position of the tongue, and are anchored to bone.

=====Extrinsic=====
[[File:Hyoglossus.png|thumb|right|220px|Lateral view of the tongue, with extrinsic muscles highlighted]]
The four extrinsic muscles originate from bone and extend to the tongue. They are the [[genioglossus]], the [[hyoglossus]] (often including the [[chondroglossus]]) the [[styloglossus]], and the [[palatoglossus]]. Their main functions are altering the tongue's position allowing for protrusion, retraction, and side-to-side movement.<ref name="GRAYS2005">{{cite book|title=Gray's anatomy for students|date=2005|publisher=Elsevier|isbn=978-0-8089-2306-0|location=Philadelphia, Pennsylvania |pages=989–995|first1=Richard L. | last1 = Drake | first2 = Wayne | last2 = Vogl | first3 = Adam W. M. | last3 = Mitchell}}</ref>

The genioglossus arises from the [[mandible]] and protrudes the tongue. It is also known as the tongue's "safety muscle" since it is the only muscle that propels the tongue forward.

The hyoglossus, arises from the [[hyoid bone]] and retracts and depresses the tongue. The chondroglossus is often included with this muscle.

The styloglossus arises from the [[Temporal styloid process|styloid process]] of the [[temporal bone]] and draws the sides of the tongue up to create a trough for swallowing.

The palatoglossus arises from the [[palatine aponeurosis]], and depresses the [[soft palate]], moves the ''palatoglossal fold'' towards the midline, and elevates the back of the tongue during swallowing.

=====Intrinsic=====
[[File:Gray1020.png|thumb|right|240px|Coronal section of tongue, showing intrinsic muscles]]
Four paired intrinsic muscles of the tongue originate and insert within the tongue, running along its length. They are the [[superior longitudinal muscle of tongue|superior longitudinal muscle]], the [[inferior longitudinal muscle]], the [[vertical muscle of tongue|vertical muscle]], and the [[transverse muscle of tongue|transverse muscle]]. These muscles alter the shape of the tongue by lengthening and shortening it, curling and uncurling its apex and edges as in [[tongue rolling]], and flattening and rounding its surface. This provides shape and helps facilitate speech, swallowing, and eating.<ref name=GRAYS2005 />

The superior longitudinal muscle runs along the upper surface of the tongue under the mucous membrane, and functions to shorten and curl the tongue upward. It originates near the [[epiglottis]], at the [[hyoid bone]], from the median fibrous septum.

The inferior longitudinal muscle lines the sides of the tongue, and is joined to the styloglossus muscle. It functions to shorten and curl the tongue downward.

The vertical muscle is located in the middle of the tongue, and joins the superior and inferior longitudinal muscles. It functions to flatten the tongue.

The transverse muscle divides the tongue at the middle, and is attached to the [[mucous membrane]]s that run along the sides. It functions to lengthen and narrow the tongue.

====Blood supply====
[[File:Gray559.png|thumb|Blood supply of the tongue]]
The tongue receives its [[blood]] supply primarily from the [[lingual artery]], a branch of the [[external carotid artery]]. The [[lingual veins]] drain into the [[internal jugular vein]]. The floor of the mouth also receives its blood supply from the lingual artery.<ref name=GRAYS2005 /> There is also a secondary blood supply to the root of tongue from the [[tonsillar branch of the facial artery]] and the [[ascending pharyngeal artery]].

An area in the neck sometimes called the [[Pirogov triangle]] is formed by the intermediate tendon of the [[digastric muscle]], the posterior border of the [[mylohyoid muscle]], and the [[hypoglossal]] nerve.<ref>{{cite web | url = https://www.whonamedit.com/synd.cfm/3186.html | title = Pirogov's triangle | work =  Whonamedit? - A dictionary of medical eponyms | publisher = Ole Daniel Enersen }}</ref><ref>{{cite journal |title=Topographic anatomy of lingual arterial anastomoses; Pirogov-Belclard's triangle |last1=Jamrozik |first1=T. |last2=Wender |first2=W. |journal=Folia Morphologica |volume=3 |issue=1 |pages=51–62 |date=January 1952 |pmid=13010300}}</ref> The lingual artery is a good place to stop severe [[hemorrhage]] from the tongue.

====Nerve supply====
Innervation of the tongue consists of motor fibers, [[special visceral afferent|special sensory]] fibers for taste, and [[general visceral afferent|general sensory]] fibers for sensation.<ref name=GRAYS2005 />
* Motor supply for all intrinsic and extrinsic muscles of the tongue is supplied by [[efferent nerve fiber|efferent motor nerve fibers]] from the [[hypoglossal nerve]] (CN XII), with the exception of the [[palatoglossus]], which is innervated by the [[vagus nerve]] (CN X).<ref name=GRAYS2005 />

Innervation of taste and sensation is different for the anterior and posterior part of the tongue because they are derived from different embryological structures ([[pharyngeal arch]] 1 and pharyngeal arches 3 and 4, respectively).<ref>{{Cite book | edition = Sixth | publisher = LWW | isbn = 978-1451190380 | last = Dudek | first = Dr Ronald W. | title = Board Review Series: Embryology | date = 2014}}</ref>
* Anterior two-thirds of tongue (anterior to the [[Lingual papilla#Circumvallate papillae|vallate papillae]]):
** Taste: chorda tympani branch of the [[facial nerve]] (CN VII) via [[special visceral afferent]] fibers
** Sensation: lingual branch of the mandibular (V3) division of the [[trigeminal nerve]] (CN V) via [[general visceral afferent]] fibers
* Posterior one third of tongue:
** Taste and sensation: [[glossopharyngeal nerve]] (CN IX) via a mixture of special and general visceral afferent fibers
* Base of tongue
** Taste and sensation: internal branch of the [[superior laryngeal nerve]] (itself a branch of the [[vagus nerve]], CN X)

==== Lymphatic drainage ====
The tip of tongue drains to the submental nodes. The left and right halves of the anterior two-thirds of the tongue drains to [[submandibular lymph nodes]], while the posterior one-third of the tongue drains to the jugulo-omohyoid nodes.

====Microanatomy====
[[File:Human tongue (251 09) Section.jpg|thumb|right|Section through the human tongue; stained [[Hematoxylin and eosin stain|H&E]]]]
The upper surface of the tongue is covered in [[oral mucosa#Classification|masticatory mucosa]], a type of [[oral mucosa]], which is of [[oral mucosa#Types|keratinized stratified squamous epithelium]]. Embedded in this are numerous [[lingual papilla|papillae]], some of which house the [[taste bud]]s and their [[taste receptor]]s.<ref>{{cite web|title=taste bud anatomy|url=http://www.britannica.com/science/taste-bud|website=Encyclopædia Britannica | first1 = Elizabeth | last1 = Bernays | first2 = Reginald | last2 = Chapman }}</ref> The lingual papillae consist of [[filiform papillae|filiform]], [[fungiform papillae|fungiform]], [[vallate papillae|vallate]] and [[foliate papillae]],<ref name=GRAYS2005 /> and only the filiform papillae are not associated with any taste buds.

The tongue can divide itself in dorsal and ventral surface. The dorsal surface is a stratified squamous keratinized epithelium, which is characterized by numerous mucosal projections called papillae.<ref>{{cite book|last1=Fiore|first1=Mariano|last2=Eroschenko|first2=Victor|title=Di Fiore's atlas of histology with functional correlations|date=2000|publisher=Lippincott Williams & Wilkins|pages=238|url=http://www.almustafauniversity.com/wp-content/uploads/2016/04/difiores-atlas-of-histology-with-functional-correlations-11th-ed.pdf |url-status=dead |archive-url=https://web.archive.org/web/20170621161523/http://www.almustafauniversity.com/wp-content/uploads/2016/04/difiores-atlas-of-histology-with-functional-correlations-11th-ed.pdf |archive-date=21 June 2017}}</ref> The lingual papillae covers the dorsal side of the tongue towards the front of the terminal groove. The ventral surface is stratified squamous non-keratinized epithelium which is smooth.<ref>{{cite book|last1=Hib|first1=José|title=Histología de Di Fiore: texto y atlas|url=https://archive.org/details/histologiadedifi00hibj|url-access=limited|date=2001|publisher=El Ateneo|location=Buenos Aires|isbn=950-02-0386-3|page=[https://archive.org/details/histologiadedifi00hibj/page/n196 189]}}</ref>

===Development===
[[File:Gray979.png|thumb|Floor of pharynx at about 26 days showing lateral swellings at first pharyngeal arch (mandibular arch).]]
The tongue begins to develop in the fourth week of [[human embryonic development|embryonic development]] from a median swelling – the [[median tongue bud]] (tuberculum impar) of the [[first pharyngeal arch]].<ref name=Larsen />

In the fifth week a pair of ''lateral lingual swellings'', one on the right side and one on the left, form on the first pharyngeal arch. These lingual swellings quickly expand and cover the median tongue bud. They form the anterior part of the tongue that makes up two-thirds of the length of the tongue, and continue to develop through [[prenatal development]]. The line of their fusion is marked by the [[Tongue#Upper surface of the tongue|median sulcus]].<ref name=Larsen/>

In the fourth week, a swelling appears from the second [[pharyngeal arch]], in the midline, called the [[copula linguae|copula]]. During the fifth and sixth weeks, the copula is overgrown by a swelling from the third and fourth arches (mainly from the third arch) called the [[hypopharyngeal eminence]], and this develops into the posterior part of the tongue (the other third and the posterior most part of the tongue is developed from the fourth pharyngeal arch). The hypopharyngeal eminence develops mainly by the growth of [[endoderm]] from the third pharyngeal arch. The boundary between the two parts of the tongue, the anterior from the first arch and the posterior from the third arch is marked by the terminal sulcus.<ref name="Larsen">{{cite book|last1=Larsen|first1=William J.|title=Human embryology|url=https://archive.org/details/humanembryology0003lars|url-access=registration|date=2001|publisher=Churchill Livingstone|location=Philadelphia, Pennsylvania|isbn=0-443-06583-7|pages=[https://archive.org/details/humanembryology0003lars/page/372 372]–374|edition=Third}}</ref> The terminal sulcus is shaped like a ''V'' with the tip of the V situated posteriorly. At the tip of the terminal sulcus is the [[Tongue#Upper surface of the tongue|foramen cecum]], which is the point of attachment of the [[thyroglossal duct]] where the embryonic [[thyroid]] begins to descend.<ref name=GRAYS2005 />

===Function===
{{multiple image
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| image1    = Tongue_and_taste_buds.jpg
| width1    = 250
| alt1      = Human tongue and taste buds
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| alt2      = Taste receptors in papillae
| footer    = Taste receptors are present on the human tongue in papillae
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====Taste====
{{main|Taste|Taste receptor|Supertaster}}
Chemicals that stimulate [[taste receptor]] cells are known as [[Gustatory cortex#Tastant concentration-dependent neuronal activity|tastants]]. Once a tastant is dissolved in [[saliva]], it can make contact with the [[plasma membrane]] of the gustatory hairs, which are the sites of taste [[transduction (physiology)|transduction]].<ref>{{cite book | last1 = Tortora | first1 = Gerard J. | first2 = Bryan H. | last2 = Derrickson | title = Principles of Anatomy and Physiology | edition = 12th | chapter = 17 | page = 602 | publisher = Wiley | year = 2008 | isbn = 978-0470084717}}</ref>

The tongue is equipped with many [[taste buds]] on its [[Anatomical terms of location|dorsal]] surface, and each taste bud is equipped with taste receptor cells that can sense particular classes of tastes. Distinct types of taste receptor cells respectively detect substances that are sweet, bitter, salty, sour, spicy, or taste of [[umami]].<ref>{{cite book | last1 = Silverhorn | first1 = Dee Unglaub | title = Human Physiology: An integrated approach | edition = 5th | chapter = 10 | page = 352 | publisher = Benjamin Cummings | year = 2009 | isbn = 978-0321559807}}</ref> Umami receptor cells are the least understood and accordingly are the type most intensively under research.<ref>{{cite book | last1 = Schacter | first1 = Daniel L. | first2 = Daniel Todd | last2 = Gilbert | first3 = Daniel M. | last3 = Wegner | chapter = Sensation and Perception | title = Psychology | url = https://archive.org/details/psychology0000scha_e2x8 | url-access = limited | edition = 2nd | location = New York | publisher = Worth | year = 2009 | page = [https://archive.org/details/psychology0000scha_e2x8/page/166 166]| isbn = 9780716752158 }}</ref> There is a [[common misconception]] that different sections of the tongue are exclusively responsible for different [[basic taste]]s. Although widely taught in schools in the form of the [[tongue map]], this is incorrect; all taste sensations come from all regions of the tongue, although certain parts are more sensitive to certain tastes.<ref name=times>{{cite news|date=November 10, 2008 |title=The Claim: The tongue is mapped into four areas of taste |first=Anahad |last=O'Connor |newspaper=[[The New York Times]] |url=https://www.nytimes.com/2008/11/11/health/11real.html?_r=1 |access-date=June 24, 2011}}</ref>

====Mastication====
The tongue is an important accessory organ in the digestive system. The tongue is used for crushing food against the hard palate, during mastication and manipulation of food for softening prior to swallowing. The [[epithelium]] on the tongue's upper, or dorsal surface is [[keratin]]ised. Consequently, the tongue can grind against the hard palate without being itself damaged or irritated.<ref>{{cite book | last1 = Atkinson | first1 = Martin E. | quote = the tongue is also responsible for the shaping of the bolus as food passes from the mouth to the rest of the alimentary canal | title = Anatomy for Dental Students | edition = 4th | publisher = Oxford University Press | year = 2013 | isbn = 978-0199234462}}</ref>

====Speech====

The tongue is one of the primary articulators in the production of [[speech]], and this is facilitated by both the extrinsic muscles that move the tongue and the intrinsic muscles that change its shape. Specifically, different [[vowel]]s are [[articulatory phonetics|articulated]] by changing the tongue's height and retraction to alter the [[acoustic resonance|resonant]] properties of the [[vocal tract]]. These resonant properties amplify specific [[harmonic|harmonic frequencies]] ([[formant]]s) that are different for each vowel, while attenuating other harmonics. For example, [a] is produced with the tongue [[open central unrounded vowel|lowered and centered]] and [i] is produced with the tongue [[close front unrounded vowel|raised and fronted]]. [[Consonant]]s are articulated by constricting airflow through the vocal tract, and many consonants feature a constriction between the tongue and some other part of the vocal tract. For example, [[alveolar consonant]]s like [s] and [n] are articulated with the tongue against the [[alveolar ridge]], while [[velar consonants]] like [k] and [g] are articulated with the tongue dorsum against the soft palate (velum). Tongue shape is also relevant to speech articulation, for example in [[retroflex consonants]], where the tip of the tongue is curved backward.

====Intimacy====
The tongue plays a role in [[physical intimacy]] and [[human sexuality|sexuality]]. The tongue is part of the [[erogenous zone]] of the mouth and can be used in intimate contact, as in the [[French kiss]] and in [[oral sex]].

===Clinical significance===
====Disease====
{{Main|Tongue disease}}

A [[congenital disorder]] of the tongue is that of [[ankyloglossia]] also known as ''tongue-tie''. The tongue is ''tied'' to the floor of the mouth by a very short and thickened [[Frenulum of tongue|frenulum]] and this affects speech, eating, and swallowing.

The tongue is prone to several [[pathology|pathologies]] including [[glossitis]] and other [[inflammation]]s such as [[geographic tongue]], and [[median rhomboid glossitis]]; [[burning mouth syndrome]], [[oral hairy leukoplakia]], [[oral candidiasis]] (thrush), [[black hairy tongue]], bifid tongue (due to failure in fusion of two lingual swellings of first pharyngeal arch) and [[fissured tongue]].

There are several types of [[oral cancer]] that mainly affect the tongue. Mostly these are [[squamous cell carcinoma]]s.<ref>{{cite web | url = https://www.oralcancerfoundation.org/facts/index.htm | title = Oral Cancer Facts | publisher = The Oral Cancer Foundation | date = 28 August 2017 | access-date = 17 September 2017 | archive-date = 22 June 2013 | archive-url = https://web.archive.org/web/20130622051333/http://oralcancerfoundation.org/facts/index.htm | url-status = dead }}</ref><ref name="SCC">{{cite journal |last1=Lam |first1=L. |last2=Logan |first2=R. M. |last3=Luke |first3=C. |title=Epidemiological analysis of tongue cancer in South Australia for the 24-year period, 1977-2001 |journal=Australian Dental Journal |volume=51 |issue=1 |pages=16–22 |date=March 2006 |pmid=16669472 |doi=10.1111/j.1834-7819.2006.tb00395.x|hdl=2440/22632 |url=https://digital.library.adelaide.edu.au/dspace/bitstream/2440/22632/1/adj_V51n1_2006_LamEpi.pdf |hdl-access=free }}</ref>

Food debris, [[desquamation|desquamated]] [[epithelium|epithelial cells]] and [[bacteria]] often form a visible tongue coating.<ref name=Newman2012>{{cite book|first1= Michael G. | last1 = Newman | first2 = Henry | last2 = Takei | first3 = Perry R. | last3 = Klokkevold | first4 = Fermin A. | last4 = Carranza |title=Carranza's Clinical Periodontology |url= https://archive.org/details/carranzasclinica00newm_586 |url-access= limited |year=2012 |publisher=Elsevier/Saunders |location=St. Louis, Missouri |isbn=978-1-4377-0416-7 |pages=[https://archive.org/details/carranzasclinica00newm_586/page/n131 84]–96 |edition=11th}}</ref> This coating has been identified as a major factor contributing to [[bad breath]] (halitosis),<ref name=Newman2012 /> which can be managed by using a [[tongue cleaner]].

====Medication delivery====
The [[sublingual]] region underneath the front of the tongue is an ideal location for the [[route of administration|administration]] of certain medications into the body. The [[oral mucosa]] is very thin underneath the tongue, and is underlain by a plexus of veins. The sublingual route takes advantage of the highly [[Blood vessel|vascular]] quality of the oral cavity, and allows for the speedy application of medication into the cardiovascular system, bypassing the gastrointestinal tract. This is the only convenient and efficacious [[route of administration]] (apart from [[Intravenous therapy]]) of [[Glyceryl trinitrate (pharmacology)|nitroglycerin]] to a patient suffering chest pain from [[angina pectoris]].

==Other animals==
[[File:Giraffe's tongue.jpg|thumb|left|Giraffe's tongue]]
[[File:Macroglossum stellatarum anatomy - MHNT.jpg|thumb|140px|Extended proboscis of a long tongued ''[[Macroglossum]]'' [[moth]]]]
The muscles of the tongue evolved in [[amphibians]] from [[occipital bone|occipital]] [[somite]]s. Most amphibians show a proper tongue after their [[metamorphosis]].<ref>{{Cite journal|last=Iwasaki|first=Shin-ichi|date=July 2002|title=Evolution of the structure and function of the vertebrate tongue|journal=Journal of Anatomy|volume=201|issue=1|pages=1–13|doi=10.1046/j.1469-7580.2002.00073.x|issn=0021-8782|pmc=1570891|pmid=12171472}}</ref> As a consequence, most [[tetrapod]] animals—amphibians, reptiles, birds, and mammals—have tongues (the [[frog]] family of [[Pipidae|pipids]] lack tongue). In mammals such as [[dog]]s and [[cat]]s, the tongue is often used to clean the fur and body by [[licking]]. The tongues of these species have a very rough texture, which allows them to remove oils and parasites. Some dogs have a tendency to consistently lick a part of their foreleg, which can result in a [[cutaneous condition|skin condition]] known as a [[lick granuloma]]. A dog's tongue also acts as a heat regulator. As a dog increases its exercise the tongue will increase in size due to greater blood flow. The tongue hangs out of the dog's mouth and the moisture on the tongue will work to cool the bloodflow.<ref>{{cite web | url = http://www.doctordog.com/drdognewsletter/tongue.html | title = A Dog's Tongue | work = DrDog.com | publisher = Dr. Dog Animal Health Care Division of BioChemics | date = 2014 | access-date = 2007-03-09 | archive-date = 2010-09-20 | archive-url = https://web.archive.org/web/20100920005834/http://doctordog.com/drdognewsletter/tongue.html | url-status = dead }}</ref><ref>{{cite journal |title=Lingual blood flow and its hypothalamic control in the dog during panting |journal=[[Pflügers Archiv: European Journal of Physiology]] |date=January 1976 |issn=0031-6768 |doi=10.1007/BF00583652 |pmid=1034283 |pages=25–31 |volume=367 |issue=1 |last1=Krönert |first1=H. |last2=Pleschka |first2=K. |s2cid=23295086 }}</ref>

Some animals have tongues that are specially adapted for catching prey. For example, [[chameleon]]s, [[frog]]s, [[pangolin]]s and [[anteater]]s have [[prehensility|prehensile]] tongues.

Other animals may have organs that are [[analogy (biology)|analogous]] to tongues, such as a [[butterfly]]'s [[proboscis]] or a [[radula]] on a [[mollusca|mollusc]], but these are not [[Homology (biology)|homologous]] with the tongues found in vertebrates and often have little resemblance in function. For example, butterflies do not lick with their proboscides; they suck through them, and the proboscis is not a single organ, but two jaws held together to form a tube.<ref name= "isbn0-412-61390-5">{{cite book |last1=Richards |first1=O. W. |last2=Davies |first2=R. G. |title=Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development, Volume 2: Classification and Biology |publisher=Springer |location=Berlin |year=1977 |isbn=0-412-61390-5}}</ref> Many species of fish have small folds at the base of their mouths that might informally be called tongues, but they lack a muscular structure like the true tongues found in most [[tetrapod]]s.<ref name=VB>{{cite book |last1=Romer |first1=Alfred Sherwood |last2=Parsons |first2=Thomas S. |year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, Philadelphia |pages=298–299 |isbn= 0-03-910284-X}}</ref><ref>{{cite book |last=Kingsley |first=John Sterling |year=1912 |title=Comparative anatomy of vertebrates |url=https://archive.org/details/cu31924002902389 |publisher=P. Blackiston's Son & Co. |pages=[https://archive.org/details/cu31924002902389/page/n232 217]–220 |isbn= 1-112-23645-7}}</ref>

==Society and culture==
===Figures of speech===
The tongue can serve as a [[metonymy|metonym]] for ''language''. For example, the [[New Testament]] of the Bible, in the Book of [[Acts of the Apostles]], [[Jesus]]' disciples on the Day of [[Pentecost]] received a type of [[spiritual gift]]: "there appeared unto them cloven tongues like as of fire, and it sat upon each of them. And they were all filled with the [[Holy Ghost]], and began to speak with other tongues&nbsp;....", which amazed the crowd of [[Jew]]ish people in [[Jerusalem]], who were from various parts of the [[Roman Empire]] but could now understand what was being preached. The phrase ''[[mother tongue]]'' is used as a child's first language.  Many languages<ref>[[Afrikaans language|Afrikaans]] ''tong''; [[Danish language|Danish]] ''tunge''; [[Albanian language|Albanian]] ''gjuha''; [[Armenian language|Armenian]] ''lezu'' (լեզու); [[Greek language|Greek]] ''glóssa'' (γλώσσα); [[Irish language|Irish]] ''teanga''; [[Manx language|Manx]] ''çhengey''; [[Latin]] and [[Italian language|Italian]] ''lingua''; [[Catalan language|Catalan]] ''llengua''; [[French language|French]] ''langue''; [[Portuguese language|Portuguese]] ''língua''; [[Spanish language|Spanish]] ''lengua''; [[Romanian language|Romanian]] ''limba''; [[Bulgarian language|Bulgarian]] ''ezik'' (език); [[Polish language|Polish]] ''język''; [[Russian language|Russian]] ''yazyk'' (язык); [[Czech language|Czech]] and [[Slovak language|Slovak]] ''jazyk''; [[Slovene language|Slovene]] and [[Serbo-Croatian]] ''jezik'' (језик); [[Kurdish language|Kurdish]] ''ziman'' (زمان); [[Persian language|Persian]] and [[Urdu]] ''zabān'' (زبان); [[Arabic]] ''lisān'' (لسان); [[Aramaic language|Aramaic]] ''liššānā'' (ܠܫܢܐ/לשנא); [[Hebrew language|Hebrew]] ''lāšon'' (לָשׁוֹן); [[Maltese language|Maltese]] ''ilsien''; [[Estonian language|Estonian]] ''keel''; [[Finnish language|Finnish]] ''kieli''; [[Hungarian language|Hungarian]] ''nyelv''; [[Azerbaijani language|Azerbaijani]] and [[Turkish language|Turkish]] ''dil''; [[Kazakh language|Kazakh]] and [[Khakas language|Khakas]] ''til'' (тіл)</ref> have the same word for "tongue" and "[[language]]", as did the [[English language]] before the [[Middle Ages]].

A common temporary failure in word [[Recollection|retrieval]] from [[memory]] is referred to as the [[Tip of the tongue|''tip-of-the-tongue'']] [[phenomenon]]. The expression ''[[Tongue-in-cheek|tongue in cheek]]'' refers to a statement that is not to be taken entirely seriously – something said or done with subtle ironic or sarcastic humour. A ''[[tongue twister]]'' is a phrase very difficult to pronounce. Aside from being a [[Ankyloglossia|medical condition]], "tongue-tied" means being unable to say what you want due to confusion or restriction. The phrase "cat got your tongue" refers to when a person is speechless. To "bite one's tongue" is a phrase which describes holding back an opinion to avoid causing offence. A "slip of the tongue" refers to an unintentional utterance, such as a [[Freudian slip]]. The "gift of tongues" refers to when one is uncommonly gifted to be able to speak in a foreign language, often as a type of [[spiritual gift]]. [[Speaking in tongues]] is a common phrase used to describe ''glossolalia'', which is to make smooth, language-resembling sounds that is no true spoken language itself. A deceptive person is said to have a [[forked tongue]], and a smooth-talking person is said to have a {{Linktext|silver tongue}}.

===Gestures===
Sticking one's tongue out at someone is considered a childish gesture of [[rudeness]] or defiance in many countries; the act may also have sexual connotations, depending on the way in which it is done. However, in [[Tibet]] it is considered a greeting.<ref>{{cite news |last1= Dresser |first1=Norine |title=On Sticking Out Your Tongue |url= https://www.latimes.com/archives/la-xpm-1997-nov-08-me-51420-story.html |access-date= 18 July 2022 |work=Los Angeles Times |date=8 November 1997}}</ref> In 2009, a farmer from [[Fabriano]], Italy, was convicted and fined by [[Court of Cassation (Italy)|Italy's highest court]] for sticking his tongue out at a neighbor with whom he had been arguing - proof of the affront had been captured with a cell-phone camera.<ref name="UPI">{{cite news | url = https://www.upi.com/Odd_News/2009/12/19/Sticking-out-your-tongue-ruled-illegal/UPI-71761261272837/ | title = Sticking out your tongue ruled illegal | date = 19 December 2009 | location = Rome, Italy | author = United Press International | access-date = 17 September 2017}}</ref>

===Body art===
[[Tongue piercing]] and [[tongue splitting|splitting]] have become more common in western countries in recent decades.{{when|date=April 2024}} One study found that one-fifth of young adults in Israel had at least one type of oral piercing, most commonly the tongue.<ref name="DTLEVIN">{{cite journal |last1= Liran |first1= Levin |last2= Yehuda |first2= Zadik |last3= Tal |first3= Becker |title= Oral and dental complications of intra-oral piercing |journal= Dent Traumatol |volume=21 |issue=6 |pages=341–3 |date=December 2005 |pmid=16262620 |doi= 10.1111/j.1600-9657.2005.00395.x }}</ref>

=== Representational art ===
Protruding tongues appear in the art of several [[Polynesian culture]]s.<ref>
{{cite book
 |editor-last1         = Teilhet-Fisk
 |editor-first1        = Jehanne
 |orig-date            = 1973
 |title                = Dimensions of Polynesia: Fine Arts Gallery of San Diego, October 7-November 25, 1973
 |date = 1973
 |url                  = https://books.google.com/books?id=BLEzAQAAIAAJ
 |publisher            = Fine Arts Gallery of San Diego
 |page                 = 115
 |access-date          = 15 April 2024
 |quote                = The mouth forms of Polynesia are expressive and contain a great deal of variation, from the snarling lips of Hawaiian sculpture to the tight-lipped, pursed mouths of the Easter Island statues. [...] The presence or absence of a tongue is helpful in considering the meaning of the mouth forms. The mouth forms showing protrusion of the tongue occur in the Marginal Islands (New Zealand, Hawaii, and the Marquesas), Central Polynesia (Tahiti and the Cook Islands) and the Australs.
}}
</ref>

===As food===
{{See also|Beef tongue}}
{{more citations needed section|date=October 2022}}
The tongues of some animals are consumed and sometimes prized as delicacies. Hot-tongue sandwiches frequently appear on menus in [[kashrut|kosher]] [[delicatessen]]s in America. [[Taco|Taco de lengua]] (''lengua'' being Spanish for tongue) is a taco filled with [[beef tongue]], and is especially popular in Mexican cuisine. As part of Colombian gastronomy, Tongue in Sauce (Lengua en Salsa) is a dish prepared by frying the tongue and adding tomato sauce, onions and salt.  Tongue can also be prepared as [[birria]]. Pig and beef tongue are consumed in Chinese cuisine. [[Duck]] tongues are sometimes employed in [[Sichuan cuisine|Sichuan]] dishes, while [[Lamb (food)|lamb]]'s tongue is occasionally employed in Continental and contemporary American cooking. Fried [[cod]] "tongue" is a relatively common part of fish meals in [[Norway]] and in [[Newfoundland and Labrador|Newfoundland]]. In [[Argentina]] and [[Uruguay]] cow tongue is cooked and served in vinegar (''lengua a la vinagreta'').  In the Czech Republic and in Poland, a pork tongue is considered a delicacy, and there are many ways of preparing it. In Eastern Slavic countries, pork and beef tongues are commonly consumed, boiled and garnished with horseradish or jellied; beef tongues fetch a significantly higher price and are considered more of a delicacy.  In Alaska, cow tongues are among the more common. Both cow and moose tongues are popular toppings on open-top-sandwiches in Norway, the latter usually amongst hunters.

Tongues of seals and whales have been eaten, sometimes in large quantities, by sealers and whalers, and in various times and places have been sold for food on shore.<ref>{{cite book | first = Charles Boardman | last = Hawes | title = Whaling | url = https://archive.org/details/whaling00hawe | publisher = Doubleday | year = 1924}}</ref>{{page needed|date=October 2022}}

==Gallery==
<gallery>
File:Tongue.agr.jpg|Human tongue
File:Spots on the tongue.jpg|Spots on the tongue
File:Okapitongue.jpg|An [[okapi]] cleaning its [[snout|muzzle]] with its tongue
File:Gähnende, liegende graue Katze.jpg|A yawning [[cat]]'s tongue is [[comb]]-like
</gallery>

==See also==
{{Anatomy-terms}}
* [[Electronic tongue]]
* [[Tongue map]]
* [[Vocal tract]]

== Further reading ==
* {{cite journal |last1=Pennisi |first1=Elizabeth |title=How the tongue shaped life on Earth |journal=Science |date=May 26, 2023 |volume=380 |issue=6647 |pages=786–791 |doi=10.1126/science.adi8563 |url=https://www.science.org/content/article/how-tongue-shaped-life-on-earth |access-date=25 June 2023 |publisher=American Association for the Advancement of Science |pmid=37228192 |language=en|url-access=subscription |doi-access=free }}

==References==
{{Gray's}}
{{Reflist}}

==External links==
{{Commons category|Tongues}}
{{wikiquote}}
{{Wiktionary}}
* [https://web.archive.org/web/20070406071244/http://www.umanitoba.ca/faculties/arts/linguistics/russell/138/sec1/anatomy.htm University of Manitoba, Anatomy of the Vocal Tract]

{{Human regional anatomy}}
{{Mouth anatomy}}
{{Gustatory system}}
{{Taste}}

{{Authority control}}

{{Portal bar|Anatomy}}

[[Category:Tongue| ]]
[[Category:Sensory organs]]
[[Category:Gustatory system]]
[[Category:Digestive system]]
[[Category:Human mouth anatomy]]
[[Category:Speech organs]]