Perineum of a female.jpg
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The perineum in humans is the space between the
anus The anus (Latin, 'ring' or 'circle') 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, the residual semi-solid waste that remains after food digestion, which, d ...
and scrotum in the male, or between the anus and the vulva in the female. 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. There is some variability in how the boundaries are defined. The perineal raphe is visible and pronounced to varying degrees. The perineum is an erogenous zone. The word perineum entered English from late Latin via 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 The septum of the scrotum is a vertical layer of fibrous tissue that divides the two compartments of the scrotum. It consists of flexible connective tissue. Its structure extends to the skin surface of the scrotum as the scrotal raphe. It is an ...
since
masculinization Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens. Virilization is most commonly used in three medical and biology ...
causes the development of a large anogenital distance in men, in comparison to the corresponding lack of distance in women. As a result of 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 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
anus The anus (Latin, 'ring' or 'circle') 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, the residual semi-solid waste that remains after food digestion, which, d ...
and, in females, the vagina. 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
line Line most often refers to: * Line (geometry), object with zero thickness and curvature that stretches to infinity * Telephone line, a single-user circuit on a telephone communication system Line, lines, The Line, or LINE may also refer to: Arts ...
drawn across the surface connecting the
ischial tuberosities The ischial tuberosity (or tuberosity of the ischium, tuber ischiadicum), also known colloquially as the sit bones or sitz bones, or as a pair the sitting bones, is a large swelling posteriorly on the superior ramus of the ischium. It marks t ...
divides the space into two triangles: * The anterior urogenital triangle, contains the penis (males) or vagina (females) * The posterior
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 two ischial tuberosities ...
containing the
anus The anus (Latin, 'ring' or 'circle') 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, the residual semi-solid waste that remains after food digestion, which, d ...
The formal anatomical boundaries of the perineum may be said to be: * in front: the pubic arch and the arcuate ligament of the pubis * behind: the tip of the coccyx * on either side: the inferior rami of the pubis and ischial tuberosity, and the
sacrotuberous ligament The sacrotuberous ligament (great or posterior sacrosciatic 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. Structure It runs from the sacrum (the lower ...
* superiorly: pelvic floor * inferiorly: skin and fascia


Perineal 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 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 two ischial tuberosities ...
. In males, it is found between the bulb of the penis and the
anus The anus (Latin, 'ring' or 'circle') 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, the residual semi-solid waste that remains after food digestion, which, d ...
; in females, it is found between the vagina and anus, and about 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 woman to prolapse of the uterus,
rectum The rectum is the final straight portion of the large intestine in humans and some other mammals, and the Gastrointestinal tract, gut in others. The adult human rectum is about long, and begins at the rectosigmoid junction (the end of the s ...
, or even the urinary bladder.
Perineal tear A perineal tear is a laceration of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum. It is the most com ...
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. 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 male or female external urinary sphincter # Deep transverse perineal muscle


Fascia

The terminology of the perineal
fascia A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organs. ...
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: # skin # superficial perineal fascia:
Subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macr ...
divided into two layers: (a) A superficial fatty layer, and (b) Colles' fascia, a deeper, membranous layer # deep perineal fascia and muscles: :4. fascia and muscles of pelvic floor ( levator ani,
coccygeus The coccygeus muscle or ischiococcygeus is a muscle of the pelvic floor, located posterior to levator ani and anterior to the sacrospinous ligament. Structure The coccygeus muscle is posterior to levator ani and anterior to the sacrospinous li ...
)


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 pelvic floor or pelvic diaphragm is composed of muscle fibers of the levator ani, the coccygeus muscle, and associated connective tissue which span the area underneath the pelvis. The pelvic diaphragm is a muscular partition formed by the leva ...
. The perianal area ('' peri-'' and '' 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 – 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 The pudendal canal (also called Alcock's canal) is an anatomical structure in the pelvis through which the internal pudendal artery, internal pudendal veins, and the pudendal nerve pass. Structure The pudendal canal is formed by the fascia of the ...
 – contains internal pudendal artery and the pudendal nerve


Clinical significance

Extensive deformation of the pelvic floor occur during a vaginal delivery. Approximately 85% of women have some
perineal tear A perineal tear is a laceration of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum. It is the most com ...
during a vaginal delivery and in about 69% suturing is required. 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. The anogenital distance is a measure of the distance between the midpoint of the
anus The anus (Latin, 'ring' or 'circle') 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, the residual semi-solid waste that remains after food digestion, which, d ...
and the underside of the scrotum or the vagina. 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. There are claims that sometimes the perineum is excessively repaired after childbirth, using a so-called "
husband stitch The husband stitch or husband's stitch, also known as the daddy stitch, husband's knot and vaginal tuck, is a surgical procedure in which one or more additional sutures than necessary are used to repair a woman's perineum after it has been torn ...
" and that this can increase vaginal tightness or result in pain during intercourse.


Society and culture

Perineum sunning is a 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. There is no scientific evidence that this behavior promotes any of the alleged benefits. The practice of exposing a sensitive area of skin to sunlight also increases the risk of skin cancers such as
melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
,
squamous cell carcinoma Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...
, and basal-cell carcinoma. Doctors recommend safer alternative options such as relaxation, meditation, and mindfulness, which can also achieve the same desired benefits.


Gallery

File:Male_perineum.jpg, Annotated male perineum: 1. Perineum. 2. Raphe perinealis. 3. Anus. 4. Testicles, Scrotum. 5. Raphe scrotalis. Image:Gray1119.png, Stages in the development of the external sexual organs in the male and female


See also

*
Deep perineal pouch The deep perineal pouch (also deep perineal space) is the anatomic space enclosed in part by the perineum, and located superior to the perineal membrane. Structure The deep perineal pouch is bordered inferiorly by the perineal membrane, also kno ...
* Erogenous zone *
Intimate part An intimate part, personal part 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 fashion and cultural norms. In several cultures, revealing these p ...
*
Mula Bandha A bandha ( sa, बंध) is a kriyā in Hatha Yoga, being a kind of internal mudra described as a "body lock," to lock the vital energy into the body. ''Bandha'' literally means bond, fetter, or "catching hold of".Iyengar, 1976: pp.435–437 Mah ...
* Pelvic floor * Perineal raphe *
Perineal tear classification A perineal tear is a laceration of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum. It is the most com ...
* ''
101 Vagina ''101 Vagina'' is a black-and-white coffee table photo-book by Philip Werner, with a foreword by Toni Childs. It was self-published in March 2013 in Melbourne, Australia. The book contains 101 close-up nude photos shot in a non- provocative way, ...
'' * ''
Femalia ''Femalia'' is a book of 32 full-color photographs of human vulvas, edited by Joani Blank and first published by Down There Press in 1993. A reprint edition was published by Last Gasp in 2011. The photographs were taken by Tee Corinne, Michael Per ...
''


References


External links


Perineum at The Anatomy Lesson
by Wesley Norman (Georgetown University) {{Authority control Pelvis Human surface anatomy