Perineum

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Perineum
Gray408.png
The muscles of the female perineum
Gray406.png
The muscles of the male perineum
Details
LatinPerineum, perinaeum
SystemMusculoskeletal system
Perineal artery, dorsal artery of the penis and deep artery of the penis
Perineal nerve, posterior scrotal nerves, dorsal nerve of the penis or dorsal nerve of clitoris
Primarily superficial inguinal lymph nodes
Identifiers
Gray'sp.424
TAA09.5.00.001
FMAFMA:9579
Anatomical terminology
 
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Not to be confused with peritoneum.
Perineum
Gray408.png
The muscles of the female perineum
Gray406.png
The muscles of the male perineum
Details
LatinPerineum, perinaeum
SystemMusculoskeletal system
Perineal artery, dorsal artery of the penis and deep artery of the penis
Perineal nerve, posterior scrotal nerves, dorsal nerve of the penis or dorsal nerve of clitoris
Primarily superficial inguinal lymph nodes
Identifiers
Gray'sp.424
TAA09.5.00.001
FMAFMA:9579
Anatomical terminology

In human anatomy, the perineum (/pɛrəˈnəm/;[1] Late Latin, from Greek περίνεος - perineos[2]) is a region of the body including the perineal /pɛrəˈnəl/ body and surrounding structures. There is some variability in how the boundaries are defined.[3] According to some definitions, in females it is located between the vagina and anus and in males between the scrotum and anus.

Terminology[edit]

It is generally defined as the surface region in both males and females between the pubic symphysis and the coccyx. The perineum is the region of the body inferior to the pelvic diaphragm and between the legs. It is a diamond-shaped area on the inferior surface of the trunk that includes the anus and, in females, the vagina.[4] 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 term lower rabbus is used colloquially in the UK to describe this structure.[citation needed] The perineum corresponds to the outlet of the pelvis.

It is an erogenous zone for both males and females.[citation needed] Perineal tears 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.[5]

There are a number of American slang terms commonly used for this area of the human body, such as gooch, grundle, and taint.[6]

The anogenital distance is a measure of the distance between the anus and the base of the penis or vagina. Studies show that the human perineum is twice as long in males as in females.[7] Measuring the anogenital distance in neonatal humans has been suggested as a noninvasive method to determine male feminisation and thereby predict neonatal and adult reproductive disorders.[8]

Boundaries[edit]

Its deep boundaries are as follows:[9]

Triangles[edit]

A line drawn transversely across in front of the ischial tuberosities divides the space into two triangles:

NameLocationContents
Urogenital trianglethe anterior trianglein females, contains the vagina
Anal trianglethe posterior trianglecontains the anus

Perineal fascia[edit]

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:

Superficial perineal pouchContains superficial perineal muscles: transversus perinei superficialis, bulbospongiosus, ischiocavernosus
Inferior fascia of urogenital diaphragm, or perineal membraneA membranous layer of the deep fascia.
Deep perineal pouchContains the deep perineal muscles: transversus perinei profundus, sphincter urethrae membranaceae
Superior fascia of the urogenital diaphragmConsidered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region.

Areas of the perineum[edit]

The region of the perineum can be considered a distinct area from pelvic cavity, with the two regions separated by the pelvic diaphragm. The following areas are thus classified as parts of the perineal region:

Additional images[edit]

See also[edit]

References[edit]

  1. ^ OED 2nd edition, 1989 as /pɛrɪˈniːəm/ and /pɛrɪˈniːəl/.
  2. ^ περίνεος, Henry George Liddell, Robert Scott, A Greek-English Lexicon, on Perseus
  3. ^ Федеративе Коммиттее он Анатомикал Терминологий (1998). Terminologia anatomica: international anatomical terminology. Thieme. pp. 268–. ISBN 978-3-13-114361-7. Retrieved 25 August 2010. 
  4. ^ Gray, Henry. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918; Bartleby.com, 2000.
  5. ^ Shipman, M. K., Boniface, D. R., Tefft, M. E., McCloghry, F. (July 1997). "Antenatal perineal massage and subsequent perineal outcomes: a randomised controlled trial". British Journal of Obstetrics and Gynaecology 104 (7): 787–91. doi:10.1111/j.1471-0528.1997.tb12021.x. PMID 9236642. 
  6. ^ Spears, Richard A. (2007). "Dictionary of American Slang and Colloquial Expressions" (Fourth ed.). McGraw-Hill{{inconsistent citations}} 
  7. ^ "Validity of anogenital distance as a marker of in utero phthalate exposure". doi:10.1289/ehp.114-a19b PMID 16393642
  8. ^ Michelle Welsh, et al.: "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.
  9. ^ perineumboundaries
  10. ^ Daftary, Shirish; Chakravarti, Sudip (2011). Manual of Obstetrics, 3rd Edition. Elsevier. pp. 1-16. ISBN 9788131225561.

External links[edit]