Perineum
Overview
In human anatomy
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...

, the perineum (Late Latin, from Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 περίνεος - perineos) is a region of the body including the perineal body and surrounding structures. There is some variability in how the boundaries are defined, but the term generally includes the genitals and anus.
It is generally defined as the surface region in both males and females between the pubic symphysis
Pubic symphysis
The pubic symphysis or symphysis pubis is the midline cartilaginous joint uniting the superior rami of the left and right pubic bones. It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis...

 and the coccyx
Coccyx
The coccyx , commonly referred to as the tailbone, is the final segment of the vertebral column. Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between...

. The perineum is the region of the body inferior to the pelvic diaphragm and between the legs.
Encyclopedia
In human anatomy
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...

, the perineum (Late Latin, from Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 περίνεος - perineos) is a region of the body including the perineal body and surrounding structures. There is some variability in how the boundaries are defined, but the term generally includes the genitals and anus.

Terminology

It is generally defined as the surface region in both males and females between the pubic symphysis
Pubic symphysis
The pubic symphysis or symphysis pubis is the midline cartilaginous joint uniting the superior rami of the left and right pubic bones. It is located anterior to the urinary bladder and superior to the external genitalia; for females it is above the vulva and for males it is above the penis...

 and the coccyx
Coccyx
The coccyx , commonly referred to as the tailbone, is the final segment of the vertebral column. Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between...

. 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 which includes the anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...

 and, in females, the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

. 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. It is an erogenous zone for both males and females. Perineal tears and episiotomy
Episiotomy
An episiotomy , also known as perineotomy, is a surgically planned incision on the perineum and the posterior vaginal wall during second stage of labor. The incision, which can be midline or at an angle from the posterior end of the vulva, is performed under local anaesthetic , and is sutured...

 often occur in childbirth with first time deliveries, but the risk of these injuries can be reduced by preparing the perineum, e.g. through massage.

The perineum corresponds to the outlet of the pelvis.

A wide variety of slang terms are commonly used for this area of the human body, most commonly "chode," "gooch," or "taint," or even "the spot where God sewed us up" but they generally refer to a smaller, less inclusive area -- just the surface skin region between the anus and the scrotum or vaginal opening.

The anogenital distance is a measure of the distance between the anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...

 and the base of the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

 or vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

. Studies show that the human perineum is twice as long in males as in females. 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.

Boundaries

Its deep boundaries are as follows:
  • in front: the pubic arch
    Pubic arch
    The eminences of the lower circumference of the true pelvis are separated by three notches: one in front, the pubic arch, formed by the convergence of the inferior rami of the ischium and pubis on either side. The angle at which they converge is known as the subpubic angle.-External links:* *...

     and the arcuate ligament
    Arcuate ligament
    The term arcuate ligament refers to an arc-shaped ligament. Specifically, it can refer to a variety of ligaments in the human body:* Arcuate ligaments of the diaphragm** Median arcuate ligament** Medial arcuate ligament** Lateral arcuate ligament...

     of the pubis
    Pubis (bone)
    In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....

  • behind: the tip of the coccyx
    Coccyx
    The coccyx , commonly referred to as the tailbone, is the final segment of the vertebral column. Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between...

  • on either side: the inferior rami of the pubis
    Inferior pubic ramus
    The inferior pubic ramus is a part of the pelvis and is thin and flat. It passes laterally and downward from the medial end of the superior ramus; it becomes narrower as it descends and joins with the inferior ramus of the ischium below the obturator foramen....

     and ischial tuberosity, and the sacrotuberous ligament
    Sacrotuberous ligament
    The sacrotuberous ligament is situated at the lower and back part of the pelvis. It is flat, and triangular in form; narrower in the middle than at the ends....


Triangles

A line drawn transversely across in front of the ischial tuberosities
Tuberosity of the ischium
-External links: - "The Female Perineum: Bones" - "Major Joints of the Lower Extremity: Hip bone "...

 divides the space into two triangles:
Name Location Contents
>-
| Urogenital triangle
Urogenital triangle
The urogenital triangle is the anterior part of the perineum. In females, it contains the vagina and associated parts of the external genitalia.-Structure:...

 
the anterior triangle vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...


>-
| Anal triangle
Anal triangle
The anal triangle is the posterior part of the perineum. It contains the anal canal.-Structure:The anal triangle can be defined either by its vertices or its sides.* Vertices** one vertex at the coccyx bone...

 
the posterior triangle contains the anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...


Perineal fascia

The terminology of the perineal fascia
Fascia
A fascia is a layer of fibrous tissue that permeates the human body. A fascia is a connective tissue that surrounds muscles, groups of muscles, blood vessels, and nerves, binding those structures together in much the same manner as plastic wrap can be used to hold the contents of sandwiches...

 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:
  • 1) Foreskin
    Foreskin
    In male human anatomy, the foreskin is a generally retractable double-layered fold of skin and mucous membrane that covers the glans penis and protects the urinary meatus when the penis is not erect...


  • 2) superficial perineal fascia: Subcutaneous tissue divided into two layers: (a) A superficial fatty layer, and (b) Colles' fascia, a deeper, membranous layer.

  • 3) deep perineal fascia and muscles:

superficial perineal pouch
Superficial perineal pouch
The superficial perineal pouch is a compartment of the perineum.-Structure:The superficial perineal pouch is a fully enclosed compartment:* its inferior border is the perineal fascia...

 
transversus perinei superficialis
Transversus perinei superficialis muscle
-External links: - "The Female Perineum: Muscles of the Superficial Perineal Pouch"...

, bulbospongiosus
Bulbospongiosus muscle
Bulbospongiosus is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis...

, ischiocavernosus
Ischiocavernosus muscle
The ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women.-Function:It helps flex the anus, and stabilize the erect penis or tense the vagina during orgasm...


>-
| inferior fascia of urogenital diaphragm
Urogenital diaphragm
Older texts have asserted the existence of an urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm and superior fascia of the...

, or perineal membrane
Perineal membrane
The perineal membrane is an anatomical term for a fibrous membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane....

 
deep fascia
Deep fascia
Deep fascia is a layer of fascia which can surround individual muscles, and divide groups of muscles into compartments....

.
>-
| deep perineal pouch
Deep perineal pouch
The deep perineal pouch is a human anatomical term that refers to the space enclosed in part by the perineum, and located superior to the perineal membrane.-Structure:...

 
transversus perinei profundus
Transversus perinei profundus muscle
-External links: - "Muscles of the female urogenital diaphragm and structures located inferior to it."...

, sphincter urethrae membranaceae
Sphincter urethrae membranaceae muscle
The external sphincter muscle of urethra surrounds the whole length of the membranous portion of the urethra, and is enclosed in the fasciæ of the urogenital diaphragm....


>-
| superior fascia of the urogenital diaphragm
Superior fascia of the urogenital diaphragm
The superior fascia of the urogenital diaphragm is continuous with the obturator fascia and stretches across the pubic arch.If the obturator fascia be traced medially after leaving the Obturator internus muscle, it will be found attached by some of its deeper or anterior fibers to the inner margin...

 
Considered hypothetical by some modern anatomists, but still commonly used to logically divide the contents of the region.

  • 4) fascia and muscles of pelvic floor
    Pelvic floor
    The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the...

     (levator ani
    Levator ani
    The levator ani is a broad, thin muscle, situated on the side of the pelvis.It is attached to the inner surface of the side of the lesser pelvis, and unites with its fellow of the opposite side to form the greater part of the floor of the pelvic cavity....

    , coccygeus)

Areas of the perineum

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:
  • perineal pouches: superficial and deep (see above for details)
  • Ischioanal fossa – a fat filled space at the lateral sides of anal canal. It is bounded laterally by obturator internus muscle, medially by pelvic diaphragm and anal canal. Its base is the skin.
    • Anal canal
      Anal canal
      The anal canal is the terminal part of the large intestine.It is situated between the rectum and anus, below the level of the pelvic diaphragm. It lies in the anal triangle of perineum in between the right and left ischioanal fossa....

    • Pudendal canal
      Pudendal canal
      The pudendal canal is an anatomical structure in the pelvis through which the internal pudendal artery, internal pudendal veins, and the pudendal nerve pass.-Structure:...

       – contains internal pudendal artery
      Internal pudendal artery
      The internal pudendal artery is an artery that branches off the internal iliac artery, providing blood to the external genitalia.The internal pudendal artery is the terminal branch of the anterior trunk of the internal iliac artery...

       and the pudendal nerve
      Pudendal nerve
      The pudendal nerve is a sensory and somatic nerve in the pelvic region which is a large branch of the sacral plexus that innervates the external genitalia of both sexes, as well as sphincters for the bladder and the rectum...

      .

Popular Culture

The perineum has made several high-profile, albeit uncredited, guest appearances on MTV's Jackass
Jackass (TV series)
jackass is an American reality series, originally shown on MTV from 2000 to 2002, featuring people performing various dangerous, crude, ridiculous, self-injuring stunts and pranks...

, normally using the stagename gooch or taint.

See also

  • Deep perineal pouch
    Deep perineal pouch
    The deep perineal pouch is a human anatomical term that refers to the space enclosed in part by the perineum, and located superior to the perineal membrane.-Structure:...

  • Erogenous zone
    Erogenous zone
    An erogenous zone is an area of the human body that has heightened sensitivity, the stimulation of which may result in the production of erotic sensations or sexual excitement.People have erogenous zones all over their bodies, but which areas are more sensitive than others vary...

  • Intimate part
    Intimate part
    An intimate, personal, or private part is a place on the human body which is customarily kept covered by clothing in public venues and conventional settings, as a matter of decency, decorum, and respectfulness...

  • Mula Bandha
    Mula Bandha
    Mūla Bandha is a Sanskrit compound term: Mūla denotes "root", "base", "beginning", "foundation", "origin or cause", "basis", "source"; Bandha denotes "bondage", "fetter", "posture", "joining together", "catching hold of"....

  • Pelvic floor
    Pelvic floor
    The pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the levatores ani and coccygei, with which may be included the...

  • Perineal tear classification
    Perineal tear classification
    Perineal tear classification is a system used to quantify the severity of trauma to the perineum during vaginal childbirth. Delivery may lead to overstretching of the vagina, causing tears in the perineal tissue between the vagina and rectum...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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