View source for Perineum

{{Short description|Region of the body between the genitals and anus}}
{{Distinguish|Peritoneum}}
{{Use dmy dates|date=April 2017}}
{{Infobox anatomy
| Name        = Perineum
| Latin       = perineum, perinaeum
| Greek      = περίνεος, περίναιον
| Image       = File:The male and female perineum.jpg
| Caption     = The human male perineum (left) and human female perineum (right)
| Image2      = File:1116 Muscle of the Perineum.jpg
| Caption2    = The muscles of the male (left) and female (right) perineum
| Precursor   =
| System      = [[Human musculoskeletal system|Musculoskeletal system]]
| Artery      = [[Perineal artery]], [[dorsal artery of the penis]] and [[deep artery of the penis]]
| Vein        =
| Nerve       = [[Perineal nerve]], [[posterior scrotal nerves]], [[dorsal nerve of the penis]] or [[dorsal nerve of the clitoris]]
| Lymph       = Primarily [[superficial inguinal lymph nodes]]
| pronunciation = {{IPAc-en|ˌ|p|ɛr|ᵻ|ˈ|n|iː|ə|m}};<ref>''[[OED]]'' 2nd edition, 1989 as {{IPA|/pɛrɪˈniːəm/}} and {{IPA|/pɛrɪˈniːəl/}}.</ref>
}}
The '''perineum''' ({{plural form}}: '''perineums''' or '''perinea''') in [[placentalia|placental]] [[mammal]]s is the space between the [[anus]] and the [[genitals]]. The human perineum is between the anus and [[scrotum]] in the male or between the anus and [[vulva]] in the female.<ref>{{cite web|title=Perineum definition and meaning {{!}} Collins English Dictionary|url=https://www.collinsdictionary.com/dictionary/english/perineum|website=www.collinsdictionary.com|language=en}}</ref> The perineum is the region of the body between the [[pubic symphysis]] (pubic arch) and the [[coccyx]] (tail bone), including the perineal body and surrounding structures. The [[perineal raphe]] is visible and pronounced to varying degrees.
==Etymology==
[[File:Dendera Relief 13.JPG|thumb|The Egyptian word for the space between anus and genitals is ''wpt mtny.'' [[File:Wpt mnty.svg|alt=asdf|frameless|upright=0.15| ]]<ref name="Internet Archive 2023 e918">{{cite web | title=Dictionary Of Middle Egyptian By Paul Dickson ( 2006) ( Gardiner List) : elgamelyan : Free Download, Borrow, and Streaming : Internet Archive | website=Internet Archive | date=2023-03-25 | url=https://archive.org/details/dictionaryofmiddleegyptianbypauldickson2006gardinerlist | access-date=2024-05-07}}</ref> ]]
The word entered English from late Latin via [[Greek language|Greek]] περίναιος ~ περίνεος ''perinaios, perineos'', itself from περίνεος, περίνεοι 'male genitals' and earlier περίς ''perís'' 'penis' through influence from πηρίς ''pērís'' 'scrotum'. The term was originally understood as a purely male body-part with the perineal raphe seen as a continuation of the [[scrotal septum]] since [[Virilization|masculinization]] causes the development of a large [[anogenital distance]] in men, in comparison to the corresponding lack of distance in women.<ref name = "simkin">{{cite journal | author= Simkin Oliver | title= Περίς, πηρίς and περίναιος | journal= Revista de Lingüística y Filología Clásica | date= 2016 | volume= LXXXIV | issue= 2 | pages= 353–362 | url= | doi= 10.3989/emerita.2016.18.1532 | pmid= | pmc= | doi-access= free }}</ref> As a result of [[Folk etymology|folk etymologies]] (such as ἰνάω ináō, "to carry off by evacuations"), it is contemporaneously extended to both sexes.
==Structure==
The perineum is generally defined as the [[surface anatomy|surface region]] between the [[pubic symphysis]] and the [[coccyx]]. The perineum is below the [[pelvic diaphragm]] and between the legs. It is a diamond-shaped area that includes the [[human anus|anus]] and, in females, the [[vagina]].<ref>[[Henry Gray|Gray, Henry]]. ''Anatomy of the Human Body''. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000.</ref> Its definition varies: it can refer to only the superficial structures in this region, or it can be used to include both superficial and deep structures. The perineum corresponds to the [[outlet of the pelvis]].
A [[Anatomical line|line]] drawn across the surface connecting the [[tuberosity of the ischium|ischial tuberosities]] divides the space into two triangles:
* The anterior [[urogenital triangle]] contains the [[Human penis|penis]] and [[scrotum]] (males) or [[vulva]] (females)
* The posterior [[anal triangle]] contains the [[Human anus|anus]]
The formal anatomical boundaries of the perineum may be said to be:<ref>{{NormanAnatomyFig|perineumboundaries}}</ref>
* in front: the [[pubic arch]] and the [[Inferior pubic ligament|arcuate ligament]] of the [[pubis (bone)|pubis]]
* behind: the tip of the [[coccyx]]
* on either side: the [[inferior pubic ramus|inferior rami of the pubis]] and [[ischial tuberosity]], and the [[sacrotuberous ligament]]
* superiorly: [[pelvic floor]]<ref>Daftary, Shirish; Chakravarti, Sudip (2011). Manual of Obstetrics, 3rd Edition. Elsevier. pp. 1-16. {{ISBN|9788131225561}}.</ref>
* inferiorly: skin and fascia
===Body===
The '''perineal body''' (or '''central tendon of perineum''') is a pyramidal fibromuscular mass in the middle line of the perineum at the junction between the [[urogenital triangle]] and the [[anal triangle]]. In males, it is found between the [[bulb of penis|bulb of the penis]] and the [[Human anus|anus]]; in females, it is found between the [[vagina]] and anus, and about {{Cvt|1.25|cm}} in front of the latter.
The perineal body is essential for the integrity of the [[pelvic floor]], particularly in females. Its rupture during vaginal birth leads to widening of the gap between the anterior free borders of [[levator ani]] muscle of both sides, thus predisposing the child-bearer to prolapse of the [[uterine prolapse|uterus]], [[rectocele|rectum]], or even the [[cystocele|urinary bladder]]. [[Perineal tear]]s and [[episiotomy]] often occur in [[childbirth]] with first-time deliveries, but the risk of these injuries can be reduced by preparing the perineum, often through massage.<ref>{{cite journal |last1=Shipman |first1=M. K. |last2=Boniface |first2=D. R. |last3=Tefft |first3=M. E. |last4=McCloghry |first4=F. |title=Antenatal perineal massage and subsequent perineal outcomes: a randomised controlled trial |journal=British Journal of Obstetrics and Gynaecology |volume=104 |issue=7 |pages=787–91 |date=July 1997 |pmid=9236642 |doi=10.1111/j.1471-0528.1997.tb12021.x|s2cid=33507861 |doi-access= }}</ref>
At this point, the following muscles converge and are attached:
# [[External anal sphincter]]
# [[Bulbospongiosus muscle]]
# [[Superficial transverse perineal muscle]]
# Anterior fibers of the [[levator ani]]
# Fibers from [[external sphincter muscle of male urethra|male]] or [[external sphincter muscle of female urethra|female external urinary sphincter]]
# [[Deep transverse perineal muscle]]
===Fascia===
The terminology of the perineal [[fascia]] can be confusing, and there is some controversy over the nomenclature. This stems from the fact that there are two parts to the fascia, the superficial and deep parts, and each of these can be subdivided into superficial and deep parts.
The layers and contents are as follows, from superficial to deep:
{{ordered list
| [[Human skin|skin]]
| superficial perineal fascia: [[Subcutaneous tissue]] divided into two layers: (a) A superficial fatty layer, and (b) [[Colles' fascia]], a deeper, membranous layer
| deep perineal fascia and muscles:
{{wikitable| class="wikitable"
| [[Superficial perineal pouch]] || Contains superficial perineal muscles: [[Transversus perinei superficialis muscle|transversus perinei superficialis]], [[Bulbospongiosus muscle|bulbospongiosus]], [[Ischiocavernosus muscle|ischiocavernosus]]
|-
| Inferior fascia of [[urogenital diaphragm]], or [[perineal membrane]] || A membranous layer of the [[deep fascia]]
|-
| [[Deep perineal pouch]] || Contains the deep perineal muscles: [[transversus perinei profundus muscle|transversus perinei profundus]], [[Sphincter urethrae membranaceae muscle|sphincter urethrae membranaceae]]
|-
| [[Superior fascia of the urogenital diaphragm]] || Considered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region
}}
| fascia and muscles of [[pelvic floor]] ([[levator ani]], [[coccygeus]])}}
===Areas===
The region of the perineum can be considered a distinct area from pelvic cavity, with the two regions separated by the [[pelvic diaphragm]]. The perianal area (''[[wikt:peri-#Prefix|peri-]]'' and ''[[anus|anal]]'') is a subset of the perineum. The following areas are thus classified as parts of the perineal region:
* perineal pouches: superficial and deep (see above for details)
* [[ischioanal fossa]]&nbsp;– a fat-filled space at the lateral sides of [[anal canal]], bounded laterally by the obturator internus muscle, and medially by the pelvic diaphragm and anal canal; its base is the skin
** [[anal canal]]
** [[pudendal canal]]&nbsp;– contains [[internal pudendal artery]] and the [[pudendal nerve]]
==Clinical significance==
The [[anogenital distance]] is a measure of the distance between the midpoint of the anus and the underside of the scrotum or the vagina. Studies show that the human perineum is twice as long in males as in females.<ref>{{cite journal | last1 = McEwen| first1 = Gerald N.| last2 = Renner| first2 = Gerald| title = Validity of anogenital distance as a marker of in utero phthalate exposure | journal = Environmental Health Perspectives| volume = 114| issue = 1| pages = A19–20 | doi = 10.1289/ehp.114-a19b | pmid = 16393642 | pmc=1332693 | date=January 2006}}</ref> Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to determine male [[feminization (biology)|feminisation]] and thereby predict neonatal and adult [[reproductive disorder]]s.<ref>Michelle Welsh, et al.: [http://www.jci.org/articles/view/34241 "Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism"]. ''Journal of Clinical Investigation'', 13 March 2008.</ref>
Extensive deformation of the pelvic floor occurs during a vaginal delivery. Approximately 85% of women have some [[perineal tear]] during a vaginal delivery and in about 69% suturing is required.<ref>Sleep J, Grant A, Garcia J, Elbourne D, Spencer J, Chalmers I. West Berkshire perineal management trial. Br Med J (Clin Res Ed). 1984; 289(6445): 587-90.</ref><ref>McCandlish R, Bowler U, van Asten H, Berridge G, Winter C, Sames L, Garcia J, Renfrew M, Elbourne D. A randomised controlled trial of care of the perineum during second stage of normal labour. Br J Obstet Gynaecol. 1998; 105(12): 1262-72.</ref><ref>Grant A, Sleep J. Repair of perineal trauma. In: Enkin M, Keirse MJNC, Chalmers I, Eds. A Guide to Effective Care in Pregnancy and Childbirth. Oxford: Oxford University Press, 1989: 240-43.</ref> Obstetric perineal trauma contributes to postpartum morbidity and frustration of women after delivery. In many women the childbirth trauma is manifested in advanced age when the compensatory mechanisms of the pelvic floor become weakened making the problem more serious among the aged population.<ref>Barrett G, Pendry E, Peacock J, et al. Women's sexuality after childbirth: a pilot study. Archives of Sexual Behavior 1999; 28(2): 179-91.</ref><ref>Tinelli A, Malvasi A, Rahimi S, et al. Age-related pelvic floor modifications and prolapse risk factors in postmenopausal women. Menopause 2010; 17(1): 204-12.</ref>
There are claims that sometimes the perineum is excessively repaired after childbirth, using a so-called "[[The husband stitch|husband stitch]]" and that this can increase vaginal tightness or result in pain during intercourse.<ref name="Vinopal">{{cite web|last1=Vinopal|first1=Lauren|title=Are Husbands and Doctors Conspiring to Sew New Moms Up Too Tight?|url=https://www.fatherly.com/health-science/why-parents-fear-husband-stitch/|website=Fatherly|access-date=15 October 2017|date=17 August 2017}}</ref>
The perineum is an [[erogenous zone]].<ref name="winkelmann">{{cite journal |author=Winkelmann RK |date=1959 |title=The erogenous zones: their nerve supply and significance |url=http://www.cirp.org/library/anatomy/winkelmann/ |journal=Mayo Clin Proc |volume=34 |issue=2 |pages=39–47 |doi= |pmc= |pmid=13645790}}</ref> This area is also known as the '''taint''' or '''gooch''' in American slang.
==Society and culture==
Perineum sunning is a [[wellness (alternative medicine)|wellness]] practice that involves exposing the perineum (area between the genitals and anus) to sunlight. Adherents claim various unproven health benefits such as improved libido, circulation, sleep, and longevity.<ref name="conv">{{cite news |author=Beth Daley |title=There's no magic way to boost your energy. But 'perineum sunning' isn't the answer |date=23 December 2020 |newspaper=The Conversation |url=https://theconversation.com/theres-no-magic-way-to-boost-your-energy-but-perineum-sunning-isnt-the-answer-150835}}</ref> There is no scientific evidence that this behavior promotes any of the alleged benefits.<ref name=conv /> The practice of exposing a sensitive area of skin to sunlight also increases the risk of skin cancers<ref>{{cite magazine |author=EJ Dickson |title=Sorry, Anus Tanning Is Not Really a Thing |url=https://www.rollingstone.com/culture/culture-features/anus-tanning-wait-what-really-919442/ |magazine=Rolling Stone |date=27 November 2019}}</ref> such as [[melanoma]], [[squamous cell carcinoma]], and [[basal-cell carcinoma]].<ref>{{cite magazine |author-first1=Marci|author-last1=Robin|author-first2=Taylore|author-last2=Glynn|title=Dermatologists Are Warning People Not to Try Perineum Sunning |url=https://allure.com/story/viral-perineum-sunning-post-dermatologists-warning |magazine=Allure |date=7 December 2019}}</ref> Doctors recommend safer alternative options such as relaxation, meditation, and mindfulness, which can also achieve the same desired benefits.<ref>{{cite web |author=Leah Groth |title=So, Perineum Sunning is a Thing Now—Here's Why Doctors Definitely Don't Want You to Try It |url=https://www.health.com/mind-body/perineum-butt-sunning-wellness-trend | website=Health.com |date=21 February 2020}}</ref>
== Gallery ==
<gallery>
File:Gray1119.png|[[Development of the reproductive system#External genitalia|Stages in the development of the external sexual organs in the male and female]]
</gallery>
==See also==
* [[Deep perineal pouch]]
* [[Erogenous zone]]
* [[Intimate part]]
* [[Mula Bandha]]
* [[Pelvic floor]]
* [[Perineal raphe]]
* [[Perineal tear classification]]
* ''[[101 Vagina]]''
* ''[[Femalia]]''
== References ==
{{Reflist|30em}}
==External links==
{{Commons category|Human anogenital area}}
{{NIE Poster|Perinæum}}{{Muscles of perineum}}
{{Authority control}}
[[Category:Perineum| ]]
[[Category:Pelvis]]
[[Category:Human surface anatomy]]