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Vulva

Vulva
Gray's subject #270 1264
Artery Internal pudendal artery
Vein Internal pudendal veins
Nerve Pudendal nerve
Lymph Superficial inguinal lymph nodes
Precursor Genital tubercle, Urogenital folds
MeSH Vulva

The external genital organs of the female are collectively known as the vulva (plural vulvae or vulvas).[1] In common speech, the term vagina is often used to refer to the vulva or female genitals generally, although, strictly speaking, the vagina is a specific internal structure, whereas the vulva is the exterior genitalia.[2]

The vulva has many major and minor anatomical structures. Its development is done in several phases: fetal and pubertal periods are the most important. True door of the human matrix, it protects its opening by a "double door": the labia majora and the labia minora as well as a vulval vestibule, and a normal microbial flora that flows from the inside out. However, a regular hygiene permits a good vulvovaginal health. The vulva is more susceptible to infections than a penis.

All these external body structures also have a sexual function associated with pleasure - they are richly innerved and participate in the sexual intercourse when they get properly stimulated. Since the origin of the human society, the vulva — the "lost paradise" of men and women — has been the subject of various art performances depicting the power this organ has "to give life" (i.e., often confused and associated with the vagina in pre-historic periods and antiquity and less and less, as human science progressed), and the sexual pleasure it provides to the human kind.

This article deals with the human vulva, although the structures are similar for other mammals.

Linguistics

Etymology

The word "vulva" was taken from Middle Latin volva or vulva "womb, female genitals", probably from Latin volvere "to roll". Similar to Sanskrit ulva "womb".[3]

An alternate term, also from Latin, is genitalia feminina externa[4]

Slang

As with nearly any aspect of the human body that is involved in sexual or excretory functions, there are many slang words for the vulva.[5]

Structures

Labelled picture of a human vulva.
Labelled picture of a human vulva.

In human beings, major structures of the vulva are[6]:

The soft mound at the front of the vulva is formed by fatty tissue covering the pubic bone, and is called is the mons pubis. The term mons pubis is Latin for "pubic mound", and is gender non-specific. In human females, the mons pubis is often referred to as the mons veneris, Latin for "mound of Venus" or "mound of love". The mons pubis separates into two folds of skin called the labia majora, literally "major (or large) lips". The cleft between the labia majora is called the pudendal cleft, or cleft of Venus, and it contains and protects the other, more delicate structures of the vulva. The labia majora meet again at a flat area between the pudendal cleft and the anus called the perineum. The colour of the outside skin of the labia majora is usually close to the overall skin colour of the individual, although there is considerable variation. The inside skin and mucus membrane are often pink or brownish. After the onset of puberty, the mons pubis and the labia majora become covered by pubic hair. This hair sometimes extends to the inner thighs and perineum.

The labia minora are two soft folds of skin within the labia majora. While labia minora translates as "minor (or small) lips", often the "minora" are of considerable size, and protrude outside the "majora". Much of the variation between vulvas lies in the significant variation in the size, shape, and color of the labia minora.

The clitoris is located at the front of the vulva, where the labia minora meet. The visible portion of the clitoris is the clitoral glans. Typically, the clitoral glans is roughly the size and shape of a pea, although it can be significantly larger or smaller. The clitoral glans is highly sensitive, containing as many nerve endings as the analogous organ in males, the glans penis. The point where the labia minora attach to the clitoris is called the frenulum clitoridis. A prepuce, the clitoral hood, normally covers and protects the clitoris, however in women with particularly large clitorises or small prepuces, the clitoris may be partially or wholly exposed at all times. Often the clitoral hood is only partially hidden inside of the pudendal cleft.

The area between the labia minora is called the vulval vestibule, and it contains the vaginal and urethral openings. The urethral opening (meatus) is located below the clitoris and just in front of the vagina. This is where urine passes from the bladder to the outside of the body.

The opening of the vagina is located at the bottom of the vulval vestibule, towards the perineum. The term introitus is more technically correct than "opening", since the vagina is collapsed, with the opening closed, unless something is inserted into it. The introitus is sometimes partly covered by a membrane called the hymen. The hymen will rupture during the first episode of vigorous sex, and the blood produced by this rupture is often used as a sign of virginity. However, the hymen may also rupture spontaneously during exercise, or be stretched by normal activities such as the use of tampons, or be so minor as to not be noticeable. In some rare cases, the hymen may completely cover the vaginal opening, requiring surgical separation. Slightly below and to the left and right of the vaginal opening are two Bartholin glands which produce a waxy, pheromone-containing substance, the purpose of which is not fully known.

The appearance of the vulva and the size of the various parts varies a great deal from one female to another, and it is common for the left and right sides to differ in appearance.

Sexual homology

Main article: Sexual homology

Most male and female sex organs originate from the same tissues in the development of a foetus. The vulva is no different. The anatomy of the vulva is related to the anatomy of the male genitalia by a shared developmental biology. Organs that have a common developmental ancestry in this way are said to be homologous.

The clitoral glans is homologous to the glans penis in males, and the clitoral body and the clitoral crura are homologous to the corpora cavernosa of the penis. The labia majora, labia minora and clitoral hood are homologous to the scrotum, shaft skin of the penis, and the foreskin, respectively. The vestibular bulbs beneath the skin of the labia minora are homologous to the corpus spongiosum, the tissue of the penis surrounding the urethra. The Bartholin's glands are homologous to Cowper's glands in males.

Development

Fetus

During the first eight weeks of life, both male and female fetuses have the same rudimentary reproductive and sexual organs, and maternal hormones control their development. Male and female organs begin to become distinct when the foetus is able to begin producing its own hormones, although visible determination of the sex is difficult until after the twelfth week.

During the sixth week, the genital tubercle develops in front of the cloacal membrane. The tubercle contains a groove termed the urethral groove. The urogenital sinus (forerunner of the bladder) opens into this groove. On either side of the grove are the urogenital folds. Beside the tubercle are a pair of ridges called the labioscrotal swellings.

Beginning in the third month of development, the genital tubercle becomes the clitoris. The urogenital folds become the labia minora, and the labioscrotal swellings become the labia majora.

Childhood

At birth, the neonate's vulva (and breasts) may be swollen or enlarged as a result of having been exposed, via the placenta, to her mother's increased levels of hormones. The clitoris is proportionally larger than it is likely to be later in life. Within a short period of time as these hormones wear off, the vulva will shrink in size.

From one year of age until the onset of puberty, the vulva does not undergo any change in appearance, other than growing in proportion with the rest of the body.

Puberty

The onset of puberty produces a number of changes. The structures of the vulva become proportionately larger and may become more pronounced. Coloration may change and pubic hair develops, first on the labia majora, and later spreading to the mons pubis, and sometimes the inner thighs and perineum.

In preadolescent girls, the vulva appears to be positioned further forward than in adults, showing a larger percentage of the labia majora and pudendal cleft when standing. During puberty the mons pubis enlarges, pushing the forward portion of the labia majora away from the pubic bone, and parallel to the ground (when standing). Variations in body fat levels affect the extent to which this occurs.

Childbirth

During childbirth, the vagina and vulva must stretch to accommodate the baby's head (approximately 9.5 cm or 3.7 in). This can result in tears in the vaginal opening, labia, and clitoris. An episiotomy (surgical pre-emptive cutting of the perineum) is sometimes performed to limit tearing, but its appropriateness as a routine procedure is under debate.

Some of the changes that occur during pregnancy may be permanent.

Post-menopause

During menopause, hormone levels decrease, and along with them tissues sensitive to these hormones also decrease. The mons pubis, labia, and clitoris may reduce in size, although not usually to pre-puberty proportions.

Sexual arousal

Sexual arousal results in a number of physical changes in the vulva. Arousal may be broken up into four somewhat arbitrary phases: Excitement, Plateau, Orgasm, and Resolution.

Excitement

Vaginal lubrication begins first. This is caused as a result of the vasocongestion of the vaginal walls. Increased blood pooling there causes moisture to seep from the walls. These droplets collect together and flow out of the vagina, moistening the vulva. The labia majora flatten and spread apart, and the clitoris and labia minora increase in size.

Unlike in men, where sexual excitement produces large and readily apparent changes, namely an erection, women are not necessarily aware that vaginal lubrication and blood engorgement of their vulva has occurred.

Plateau

Increased vasocongestion in the vagina causes it to swell, decreasing the size of the vaginal opening by about 30%. The clitoris becomes increasingly erect, and the glans moves towards the pubic bone, becoming concealed by the hood. The labia minora increase considerably in thickness, approximately 2–3 times, causing them to spread apart, displaying the vaginal opening. The labia minora change considerably in color, (in Caucasians) going from pink to red in women who have not borne a child, or red to wine in those that have.

A woman is not fully ready for vaginal intercourse until the plateau stage.

Orgasm

Immediately prior to orgasm, the clitoris becomes exceptionally engorged, causing the glans to appear to retract into the clitoral hood. This is thought to protect the sensitive glans during orgasm. However, there is some doubt that this is the case, since the same engorgement prior to orgasm occurs in the male homologous structure, the penis, the function of which is thought to be to extend the penis as close to the cervix as possible prior to ejaculation.

Rhythmic muscle contractions occur in the outer third of the vagina, as well as the uterus and anus. They occur initially at a rate of about one every 0.8 seconds, becoming less intense and more randomly spaced as the orgasm continues. An orgasm may have as few as one or as many as 15 or more contractions, depending on intensity. Orgasm may be accompanied by female ejaculation, causing liquid from either the Skene's gland or bladder to be expelled through the urethra.

Immediately after orgasm the clitoris may be so sensitive that any stimulation is uncomfortable.

Resolution

The pooled blood begins to dissipate, although at a much slower rate if orgasm has not occurred. The vagina and vaginal opening return to their normal relaxed state, and the rest of the vulva returns to its normal size, position and color.

Fluids and odour

There are a number of different secretions associated with the vulva, including urine, sweat, menses, skin oils (sebum), Bartholin's and Skene's gland secretions, and vaginal wall secretions. These secretions contain a mix of chemicals, including pyridine, squalene, urea, acetic acid, lactic acid, complex alcohols, glycols, ketones, and aldehydes. A secretion associated with ovulation is known as "spinnbarkeit".

Smegma

Smegma is a white substance formed from a combination of dead cells, skin oils, moisture and naturally occurring bacteria, that forms in mammalian genitalia. In females it collects around the clitoris and labial folds.

Aliphatic acids

Approximately one third of women produce aliphatic acids. These acids are a pungent class of chemicals which other primate species produce as sexual-olfactory signals. While there is some debate, researchers often refer to them as human pheromones. These acids are produced by natural bacteria resident on the skin. The acid content varies with the menstrual cycle, rising from one day after menstruation, and peaking mid-cycle, just before ovulation.

Disorders affecting the vulva

Blemishes and cysts

Infections

Inflammatory diseases

Pain syndromes

Vulvar cancer

Symptoms of vulvar cancer include itching, a lump or sore on the vulva which doesn't heal and/or goes larger, and sometimes discomfort/pain/swelling in the vulval area. Treatments include vulvectomy – removal of all or part of the vulva.

Ulcers

Developmental disorders

Other

Altering the female genitalia

Vulva with horizontal clitoral hood piercing
Vulva with horizontal clitoral hood piercing

The most prevalent form of genital alteration in some countries is female genital cutting: removal of any part of the female genitalia for cultural, religious or other non-medical reasons. When performed on female minors these procedures can be highly controversial, as reflected in their previous name, mutilation.

In some cases, people elect to have their genitals pierced, tattooed or otherwise altered for aesthetic or other reasons. Female genital enhancement surgery includes laser resurfacing of the labia to remove wrinkles, clitoral repositioning for those not achieving optimum stimulation, labiaplasty (reducing the size of the labia) and vaginal tightening.

Cultural attitudes

In some cultures, including modern Western culture, some women have shaved or otherwise depilated part or all of the vulva. This is a fairly recent phenomenon in the United States, but has been prevalent, usually in the form of waxing, in many eastern European and Middle Eastern cultures for centuries, usually for the belief that it is more hygienic. High-cut swimsuits compelled their wearers to shave the sides of their pubic triangles. Shaving may also include all or nearly all of the hair. Some styles retain a "racing stripe" (on either side of the labia) or "landing strip" (directly above and in line with the vulva). See the article on pubic hair.

Since the early days of Islam, Muslim women and men have followed a tradition to "pluck the armpit hairs and shave the pubic hairs". This is a preferred practice rather than an obligation, and could be carried out by shaving, waxing, trimming, or any other method. This is a regular practice that is considered in some more devout Muslim cultures as a form of worship, not a shameful practice, while in other less devout regions it is a practice for the purpose of good hygiene. (See Islamic jurisprudence.) The reasons behind removing this hair could also be applied to the hair on the scrotum and around the anus, because the purpose is to be completely clean and pure and keep away from anything that may cause dirt and impurities.[7]

Depictions of vulva

Main article: Depictions of nudity

Many cultures have commonly viewed the vulva as something shameful that should be hidden; for example, the term pudendum, which denotes the external genitalia, literally means "shameful thing". However, some cultures have celebrated and even worshipped the vulva; some Hindu sects revere it under the name yoni, and texts seem to indicate a similar attitude in some ancient Middle Eastern religions. As an aspect of Goddess worship such reverence may be part of modern Neopagan beliefs, and may be indicated in paleolithic artworks. Other cultures consider some or all parts of the vulva to be "unclean" and may go as far as to advocate the so-called "female circumcision", which in fact exists in several levels of severity.

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Many sculptors and painters have chosen not to display vulvas in their works, even when depicting nude women. The pubic region was often covered with a piece of cloth, figleaf or a hand. When it was displayed or posed, it usually lacked pubic hair (see glabrousness) as well as the physical depiction of the vulva, irrespective of whether the vulva would actually be visible in that pose. In modern times Japanese anime artists often depict female characters without vulvas (even in hentai pornography) to comply with censorship laws.

As throughout history the actual or artistic display of vulvas was uncommon, aesthetic standards for the depiction of the vulva in the West developed after visual pornography became more widespread. Currently, color desaturation is often used to purge photographic images of pornographic associations.

See also

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Slang

Health and function

Art

References

External links

 

The content of this section is licensed under the GNU Free Documentation License (local copy). It uses material from the Wikipedia article "Vulva" modified December 22, 2007 with previous authors listed in its history.