Editing Tubercle

{{Short description|Rounded outgrowth found on external or internal organs of plants or animals}}
{{For|the lip feature|Cupid's bow}}
[[Image:Mammillaria marksiana.jpg|right|250px|thumb|This view of the cactus ''[[Mammillaria marksiana]]'' shows its pattern of prominent tubercles, with the spines emanating from each tubercle's tip.]]

In [[anatomy]], a '''tubercle''' (literally 'small tuber', Latin for 'lump') is any round [[Nodule (medicine)|nodule]], small [[wikt:eminence|eminence]], or [[wart]]y outgrowth found on external or internal [[Organ (anatomy)|organ]]s of a plant or an animal.

==In plants==
A '''tubercle''' is generally a wart-like projection, but it has slightly different meaning depending on which family of plants or animals it is used to refer to.

In the case of certain [[orchid]]s and [[cactus|cacti]], it denotes a round nodule, small [[wikt:eminence|eminence]], or [[wart]]y outgrowth found on the [[Labellum (botany)|lip]]. They are also known as podaria (singular  ''podarium''). When referring to some members of the [[Fabaceae|pea family]], it is used to refer to the wart-like excrescences that are found on the roots.

==In fungi==
In [[mycology]], a tubercle is used to refer to a mass of [[hypha]]e from which a [[mushroom]] is made.

==In animals==
[[File:Phyllidia.jpg|thumb|right|Nudibranch ''[[Phyllidia varicosa]]'', clearly showing the yellow tubercles on the dorsum]]

When it is used in relation to certain dorid [[nudibranch]]s such as ''[[Peltodoris nobilis]]'',  it means the nodules on the dorsum of the animal. The tubercles in nudibranchs can present themselves in different ways: each tubercle in a single, rounded, conical or angular form; in a compound form of  two or more levels; tubercles in amalgamated clusters; or as tubercles forming, or joined by a ridge.{{citation needed|date=November 2024}}

Tubercles found on the leading edge of [[humpback whale]]s' flippers were demonstrated to improve fluid flow over the flipper's surface, exhibiting the [[tubercle effect]] of fluid dynamics.<ref>{{cite journal | doi=10.1063/1.1688341 | title=Leading-edge tubercles delay stall on humpback whale ( ''Megaptera novaeangliae'' ) flippers | date=2004 | last1=Miklosovic | first1=D. S. | last2=Murray | first2=M. M. | last3=Howle | first3=L. E. | last4=Fish | first4=F. E. | journal=Physics of Fluids | volume=16 | issue=5 | pages=L39–L42 | bibcode=2004PhFl...16L..39M }}</ref>

[[File:Edmontosaurusskin.jpg|thumb|right|Skin impression from the abdomen of the [[hadrosaurid|duck-billed]] [[dinosaur]] ''[[Edmontosaurus|Edmontosaurus annectens]]'', showing tubercular scales]]

In [[dinosaur]]s, a tubercle is a general term for the scales seen in skin impressions.  In [[hadrosaurid|duck-billed dinosaurs]], for example, three main types of tubercles are defined: small tubercles with no definite arrangement (ground tubercles); larger, [[polygon]]al tubercles (pavement tubercles) up to {{cvt|1|cm|in}} in diameter, which are grouped into clusters separated by ground tubercles; and [[limpet]]-shaped conical scutes.<ref name=LW42>{{cite book |last=Lull |first=Richard Swann |author-link=Richard Swann Lull |author2=Wright, Nelda E.  |title=Hadrosaurian Dinosaurs of North America |year=1942 |publisher=[[Geological Society of America]] |series=Geological Society of America Special Paper |volume=40 |pages=111–112 }}</ref>

In fish, [[nuptial tubercles]] are formed on males for breeding. [[Nuptial pads]] on frogs also comprise [[keratin]]ised tubercles.{{citation needed|date=November 2024}}

==In humans==
Within the human body, there are numerous sites where tubercles develop.  On bones, they are usually eminences used for [[muscle]] connections. Larger tubercles are also known as ''tuberosities''.

===Mouth===
Tubercles are usually found behind the last [[molar (tooth)|molar]] in the upper jaw, covered by the [[Gingiva|gum]]. Surgery can be done to make tubercles less prominent.<ref>[http://www.colgate.com/app/Colgate/US/OC/Information/OralHealthBasics/CheckupsDentProc/DenturesAndDentalImplants/TuberosityReduction.cvsp "What is Tuberosity Reduction?", Colgate World of Care]</ref>

===Bones===
{{Main|Tubercle (human skeleton)}}
In the [[human skeleton]], a ''tubercle'' or ''tuberosity'' is a protrusion that serves as an attachment for [[skeletal muscle]]s. The muscles attach by [[tendon]]s, where the [[enthesis]] is the connective tissue between the tendon and [[bone]].<ref>{{cite web|url=http://www.medcyclopaedia.com/library/topics/volume_iii_1/e/enthesis.aspx|archive-url=https://archive.today/20120205102809/http://www.medcyclopaedia.com/library/topics/volume_iii_1/e/enthesis.aspx|url-status=dead|archive-date=2012-02-05|title=enthesis|publisher=[[General Electric|GE]]|work=Medcyclopaedia}}</ref> For example, the [[tibial tuberosity]] creates an attachment point for the [[knee|ligamentum patellae]], or patellar ligament.

===Lungs===
{{Main|Tuberculosis}}
Tubercles are nodules that contain [[caseous necrosis]], which form in the lungs as a result of an infection with ''[[Mycobacterium tuberculosis]]'' in the patients with [[tuberculosis]].  [[Granuloma]]s form in the infected tissue and undergo [[necrosis]] in the centre.  Tubercles are also known as tuberculous nodules, or [[tuberculoma]]s. The affected parts develop lesions in the form of small nodules called tubercles, from which the disease gets its name.

===Ears===
Around the sixth week of gestation, six swellings of tissue, called the ''hillocks of His'',{{efn|Named after [[Wilhelm His Sr.]] who first described them in 1855.<ref>Davis, Jack (1997). ''Otoplasty''. Springer, p. 24. {{ISBN|978-1-4612-7484-1}}</ref>}} arise around the area that will form the [[ear]] canal.<ref name="Anthwal">{{cite journal |last1=Anthwal |first1=Neal |last2=Thompson |first2=Hannah |title=The development of the mammalian outer and middle ear |journal=Journal of Anatomy |date=February 2016 |volume=228 |issue=2 |pages=217–232 |doi=10.1111/joa.12344|pmid=26227955 |pmc=4718165 }}</ref> These eventually coalesce to form the outer ear. [[Darwin's tubercle]] is a minor malformation of the junction of the fourth and fifth hillocks of His. It is found in a substantial minority of people and takes the form of a cartilaginous node or bump on the rim of their outer ear, which is thought to be the vestige of a joint that allowed the top part of the ancestral ear to swivel or flop down over the opening to the ear.<ref>{{cite news |title=Five things humans no longer need |author=Laura Spinney |url=https://www.newscientist.com/article/dn13927-five-things-humans-no-longer-need.html |newspaper=NewScientist.com news service |date=19 May 2008 <!--DASHBot-->| archive-url=https://web.archive.org/web/20080724005343/http://www.newscientist.com/article/dn13927-five-things-humans-no-longer-need.html | archive-date=24 July 2008 | url-status= live}}</ref>

===Genitals===
The [[genital tubercle]] is a small bump that eventually develops into a [[Human penis|penis]] or a [[clitoris]] on a human [[fetus]].

===Brain===
The [[septotubercular tract]] can be found in the human, as well as in the sheep brain. It is found nearby the [[septohypothalamic tract]]. Its function to the brain is ambiguous at this point.{{citation needed|date=November 2013}}

Also, the [[tuberculum sellae]] is found at the base of the skull, which holds the [[Pituitary gland|hypophysis]].

==See also==
* [[Areolar glands]], sebaceous glands surrounding the nipple

==Notes==
{{notelist}}

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

== External links ==
* [http://www.cactus-art.biz/note-book/Dictionary/Dictionary_T/dictionary_tubercle.htm Tubercle at Cactus-Art.biz]

{{Authority control}}

[[Category:Human anatomy]]
[[Category:Animal anatomy]]
[[Category:Plant morphology]]