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Vagina

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Vagina
Diagram of the female human reproductive tract and ovaries
Vulva with pubic hair removed and labia separated to show the opening of the vagina
1: Clitoral hood
2: Clitoris
3: Labia minora
4: Urethral opening
5: Vaginal opening
6: Perineum
7: Anus
Details
Precursorurogenital sinus and paramesonephric ducts
Arterysuperior part to uterine artery, middle and inferior parts to vaginal artery
Veinuterovaginal venous plexus, vaginal vein
NerveSympathetic: lumbar splanchnic plexus
Parasympathetic: pelvic splanchnic plexus
Lymphupper part to internal iliac lymph nodes, lower part to superficial inguinal lymph nodes
Identifiers
LatinVagina
MeSHD014621
TA98A09.1.04.001
TA23523
FMA19949
Anatomical terminology

In mammals, the vagina is a muscular and tubular part of the female genital tract, which, in humans, extends from the vulva to the cervix. The outer vaginal opening may be partly covered by a membrane called the hymen. At the deep end, the cervix (neck of the uterus) bulges into the vagina. The vagina allows for sexual intercourse and childbirth, and channels menstrual flow, which occurs periodically as part of the menstrual cycle.

The vagina has been studied in humans more than it has been in other animals. Its location and structure varies among species, and may vary in size within the same species. Female mammals usually have two external openings, the urethral opening for the urinary tract and the vaginal opening for the genital tract. This is different from male mammals, who usually have a single opening, the external urethral opening for both urination and reproduction. The vaginal opening is much larger than the nearby urethral opening, and both are protected by the labia in humans. In amphibians, birds, reptiles and monotremes, the cloaca is the single external opening for the gastrointestinal tract and the urinary and reproductive tracts.

To accommodate smoother penetration of the vagina during sexual intercourse or other sexual activity, vaginal moisture increases during sexual arousal in human females and also in other female mammals. This increase in moisture is vaginal lubrication, which reduces friction. The texture of the vaginal walls creates friction for the penis during sexual intercourse and stimulates it toward ejaculation, enabling fertilization. Along with pleasure and bonding, women's sexual behavior with others (which can include heterosexual or lesbian sexual activity) can result in sexually transmitted infections (STIs), the risk of which can be reduced by recommended safe sex practices. Other disorders may also affect the human vagina.

The vagina and vulva have evoked strong reactions in societies throughout history, including negative perceptions and language, cultural taboos, and their use as symbols for female sexuality, spirituality, or regeneration of life. In common speech, the word vagina is often used to refer to the vulva or to the female genitals in general. By its dictionary and anatomical definitions, however, vagina refers exclusively to the specific internal structure, and understanding the distinction can improve knowledge of the female genitalia and aid in health care communication.

Etymology and definition

The term vagina is from Latin vāgīnae, literally "sheath" or "scabbard"; the Latinate plural of vagina is vaginae.[1] The vagina may also be referred to as "the birth canal" in the context of pregnancy and childbirth.[2][3] Although by its dictionary and anatomical definitions, the term vagina refers exclusively to the specific internal structure, it is colloquially used to refer to the vulva or to both the vagina and vulva.[4][5]

Using the term vagina to mean "vulva" can pose medical or legal confusion; for example, a person's interpretation of its location might not match another person's interpretation of the location.[4][6] Medically, the vagina is the muscular canal between the hymen (or remnants of the hymen) and the cervix, while, legally, it begins at the vulva (between the labia).[4] Scholars such as Craig A. Hill[7] argue that incorrect use of the term vagina is likely because not as much thought goes into the anatomy of the female genitalia. This has contributed to an absence of correct vocabulary for the external female genitals, even among health professionals, which can pose sexual and psychological harm with regard to female development. Because of this, researchers endorse correct terminology for the vulva.[6][7][8]

Structure

Overview

Pelvic anatomy including organs of the female reproductive system

The human vagina is an elastic muscular canal that extends from the vulva to the cervix.[9][10] It is pink in color, and it connects the outer vulva to the cervix of the uterus. The part of the vagina surrounding the cervix is called the fornix.[11] The opening of the vagina lies near the middle of the perineum, between the opening of the urethra and the anus. The vaginal canal then travels upwards and backwards, between the urethra at the front, and the rectum at the back. Near the upper vagina, the cervix protrudes into the vagina on its front surface at approximately a 90 degree angle.[12] The vaginal and urethral openings are protected by the labia.[13]

In its unexcited state, the vagina is a collapsed tube, with the anterior and posterior walls placed together. The lateral walls, especially their middle area, are relatively more rigid. Because of this, the collapsed vagina has a H-shaped cross section.[10][14] Behind, the inner vagina is separated from the rectum by the recto-uterine pouch, the middle vagina by loose connective tissue, and the lower vagina by the perineal body.[11] Where the vaginal lumen surrounds the cervix of the uterus, it is divided into four continuous regions or vaginal fornices; these are the anterior, posterior, right lateral, and left lateral fornices.[9][10] The posterior fornix is deeper than the anterior fornix.[10]

Supporting the vagina are its upper third, middle third and lower third muscles and ligaments. The upper third are the levator ani muscles (transcervical, pubocervical) and the sacrocervical ligaments; these areas are also described as the cardinal ligaments laterally and uterosacral ligaments posterolaterally. The middle third of the vagina concerns the urogenital diaphragm (also described as the paracolpos and pelvic diaphragm). The lower third is the perineal body; it may be described as containing the perineal body, pelvic diaphragm and urogenital diaphragm.[9][15]

Vaginal opening and hymen

The vaginal opening is at the outer end of the vulva, posterior to the opening of the urethra, at the posterior end of the vestibule. The opening is closed by the labia minora in female virgins and in females who have never given birth (nulliparae), but may be exposed in females who have given birth (parous females).[10][16]

The hymen is a membrane of tissue that surrounds or partially covers the vaginal opening.[10] The effects of vaginal intercourse and childbirth on the hymen are variable. If the hymen is sufficiently elastic, it may return to nearly its original condition. In other cases, there may be remnants (carunculae myrtiformes), or it may appear completely absent after repeated penetration.[17] Additionally, the hymen may be lacerated by disease, injury, medical examination, masturbation or physical exercise. For these reasons, it is not possible to definitively determine whether or not a girl or woman is a virgin by examining her hymen.[17][18]

Variations and size

The length of the vagina varies between women of child-bearing age. Because of the presence of the cervix in the front wall of the vagina, there is a difference in length between the front (anterior) wall, approximately 7.5 cm (2.5 to 3 in) long, and the back (posterior) wall, approximately 9 cm (3.5 in) long.[10][19] During sexual arousal, the vagina expands in both length and width. If a woman stands upright, the vaginal lumen, from the vulva upward, forms an angle of approximately 45 degrees where it meets the uterus and about 60 degrees to the horizontal.[10][15] Because of the involutions of the rugae, the total surface area of the vagina is 360cm2 (one square foot).[16] The vaginal opening and hymen also vary in size; in children, although a common appearance of the hymen is crescent-shaped, many shapes are possible.[10][20]

Development

An illustration showing a cut-away portion of the vagina and upper female genital tract (only one ovary and fallopian tube shown). Circular folds (also called rugae) of vaginal mucosa can be seen

The vaginal plate is the precursor to the vagina.[21] During development, the vaginal plate begins to grow where the solid ends of the paramesonephric ducts (Müllerian ducts) enter the back wall of the urogenital sinus. As the plate grows, it separates the sinus into the urethra and the vagina and extends the vagina by pushing the cervix deeper. Originally full of cells, as the central cells of the plate break down, the lumen of the vagina is formed.[21] This usually occurs by the twenty to twenty-fourth week of development. If the lumen does not form, or is incomplete, membranes across or around the tract called septae can form, which may cause obstruction of the outflow tract later in life.[21]

During sexual differentiation of females, without testosterone, the urogenital sinus persists as the vestibule of the vagina. The two urogenital folds (elongated spindle-shaped structures that contribute to the formation of the urethral groove on the belly aspect of the genital tubercle) form the labia minora, and the labioscrotal swellings enlarge to form the labia majora.[22][23]

Sources differ on which portion of the vagina is formed from the Müllerian ducts and which from the urogenital sinus by the growth of the sinovaginal bulb.[21][24] Dewhurst's Textbook of Obstetrics and Gynaecology states, "Some believe that the upper four-fifths of the vagina is formed by the Müllerian duct and the lower fifth by the urogenital sinus, while others believe that sinus upgrowth extends to the cervix displacing the Müllerian component completely and the vagina is thus derived wholly from the endoderm of the urogenital sinus." It adds, "It seems certain that some of the vagina is derived from the urogenital sinus, but it has not been determined whether or not the Müllerian component is involved."[21]

Microanatomy

Medium-power magnification micrograph of a H&E stained slide showing a portion of a vaginal wall. Stratified squamous epithelium and underling connective tissue can be seen. The deeper muscular layers are not shown. The black line points to a fold in the mucosa.
Vaginal mucosa normal vs. menopause

The wall of the vagina from the lumen outwards consists firstly of a mucosa of non-keratinized stratified squamous epithelium with an underlying lamina propria of connective tissue. Secondly, there is a layer of smooth muscle with bundles of circular fibers internal to longitudinal fibers. Lastly is an outer layer of connective tissue called the adventitia. Some texts list four layers by counting the two sublayers of the mucosa (epithelium and lamina propria) separately.[25][26]

The lamina propria is rich in blood vessels and lymphatic channels. The muscular layer is composed of smooth muscle fibers, with an outer layer of longitudinal muscle, an inner layer of circular muscle, and oblique muscle fibers between. The outer layer, the adventitia, is a thin dense layer of connective tissue, and it blends with loose connective tissue containing blood vessels, lymphatic vessels and nerve fibers that is present between the pelvic organs.[12][26][19] The vaginal mucosa is absent of glands. It forms folds or rugae, which are more prominent in the outer third of the vagina; they appear as transverse ridges and their function is to provide the vagina with increased surface area for extension and stretching.[9][10]

Folds of mucosa (or vaginal rugae) are shown in the front third of a vagina
A normal cervix of an adult as seen through the vagina (per vaginam or PV) using a bivalved vaginal speculum. The blades of the speculum are above and below and stretched vaginal walls are seen on the left and right.

The epithelial covering of the cervix is contiguous with the epithelial lining of the vagina.[10] The vaginal epithelium is divided into layers of cells, including the basal cells, the parabasal cells, the superficial squamous flat cells, and the intermediate cells.[27] The basal layer of the epithelium is the most mitotically active and reproduces new cells.[28] The superficial cells exfoliate continuously and basal cells replace them.[10][29][30] Estrogen induces the intermediate and superficial cells to fill with glycogen.[30][31] Cells from the lower basal layer transition from active metabolic activity to death (apoptosis). In these mid-layers of the epithelia, the cells begin to lose their mitochondria and other cell organelles.[28][32] The cells retain an usually high level of glycogen compared to other epithelial tissue in the body.[28]

The permeability of the epithelium allows for an effective response from the immune system since antibodies and other immune components can easily reach the surface.[16] The vaginal epithelium differs from the similar tissue of the skin. The epidermis of the skin is relatively resistant to water because it contains high levels of lipids. The vaginal epithelium contains lower levels of lipids. This allows the passage of water and water-soluble substances through the tissue.[16]

Under the influence of maternal estrogen, newborn females have a thick stratified squamous epithelium for two to four weeks after birth. After that, the epithelium remains thin with only a few layers of cells without glycogen.[30] The epithelium also has few rugae and is red in color before puberty.[4] When puberty begins, the epithelium thickens and glycogen containing cells are formed again, under the influence of the girl's rising estrogen levels.[30] Finally, the epithelium thins out during menopause onward and eventually ceases to contain glycogen, because of the lack of estrogen.[10][29][33]

Keratinzation happens when the epithelium is exposed to the dry external atmosphere.[10] In abnormal circumstances, such as in pelvic organ prolapse, the mucosa may be exposed to air, becoming dry and keratinized.[34]

Blood and nerve supply

Blood is mainly supplied to the vagina via the vaginal artery, which emerges from a branch of the internal iliac artery or the uterine artery.[9][35] With anastomosis, the vaginal arteries are joined along the side of the vagina with the cervical branch of the uterine artery; this forms the azygos artery,[35] which lies on the midline of the anterior and posterior vagina.[11] Other arteries which supply the vagina include the middle rectal artery and the internal pudendal artery,[10] all branches of the internal iliac artery.[11] Three groups of lymphatic vessels accompany these arteries; the upper group accompanies the vaginal branches of the uterine artery; a middle group accompanies the vaginal arteries; and the lower group, draining lymph from the area outside the hymen, drain to the inguinal lymph nodes.[11][36] Ninety-five of the lymphatic channels of the vagina are in the first 3 mm from the surface of the vagina.[37]

Two main veins drain blood from the vagina, one on the left and one on the right. These form a network of smaller veins (an anastomosis) on the sides of the vagina, connecting with similar networks of the uterine, vesical and rectal networks. These ultimately drain into the internal iliac veins.[11]

The nerve supply of the upper vagina is provided by the sympathetic and parasympathetic areas of the pelvic plexus. The lower vagina is supplied by the pudendal nerve supplying the lower area.[10][11]

Function

Secretions

The vagina provides a path for menstrual blood and tissue to leave the body. In industrial societies, tampons, menstrual cups and sanitary napkins may be used to absorb or capture these fluids. Vaginal secretions are primarily from the uterus, cervix, and vaginal epithelium in addition to minuscule vaginal lubrication from the Bartholin's glands upon sexual arousal. It takes little vaginal secretion to make the vagina moist; secretions may increase during sexual arousal, the middle of menstruation, a little prior to menstruation, or during pregnancy.[10]

The Bartholin's glands, located near the vaginal opening, were originally considered the primary source for vaginal lubrication, but further examination showed that they provide only a few drops of mucus.[38] The significant majority of vaginal lubrication is now believed to be provided by plasma seepage from the vaginal walls, which is called vaginal transudation. Vaginal transudation, which initially forms as sweat-like droplets, is caused by vascular engorgement of the vagina (vasocongestion), resulting in the pressure inside the capillaries increasing the transudation of plasma through the vaginal epithelium.[38][39][40]

Before and during ovulation, the mucus glands within the cervix secrete different variations of mucus, which provides an alkaline, fertile environment in the vaginal canal that is favorable to the survival of sperm.[41] As women age, especially following menopause, vaginal lubrication naturally decreases.[42]

Sexual activity

Nerve endings in the vagina can provide pleasurable sensations when the vagina is stimulated during sexual activity. Women may derive pleasure from one part of the vagina, or from a feeling of closeness and fullness during vaginal penetration.[43] The vagina is not rich in nerve endings, and this often contributes to a woman's inability to receive sufficient sexual stimulation, including orgasm, solely from penetration of the vagina.[43][44][45] While the literature cites the existence of a greater concentration of nerve endings near the entrance of the vagina (at the outer one-third or lower third), making it more sensitive to touch than the inner (or upper) two-thirds of the vagina,[44][45][46] some scientific examinations of vaginal wall innervation indicate no single area with a greater density of nerve endings.[47][48] Other research indicates that only some women have a greater density of nerve endings in the anterior vaginal wall.[47][49] By having a higher concentration of nerve endings in the outer part rather than along the whole length,[50] childbirth pain is significantly more tolerable.[45][51][52]

Vaginal pleasure can come from a variety of different sexual activities. In addition to penile penetration, pleasure may be by masturbation, fingering, oral sex (cunnilingus), or specific sex positions (such as the missionary position or the spoons sex position).[53] Heterosexual couples may engage in cunnilingus or fingering as forms of foreplay to incite sexual arousal, with penile-vaginal penetration as the primary sexual activity, or they may engage in them in addition to penile-vaginal penetration; in other cases, heterosexual couples use the latter acts as a way to preserve virginity or as a type of birth control.[54][55] By contrast, lesbians and other women who have sex with women commonly engage in cunnilingus or fingering as main forms of sexual activity.[56][57] Some women and couples use sex toys, such as a vibrator or dildo, for vaginal pleasure.[58] Other women may adopt Kegel exercises,[59] with the aim of tightening the vagina to increase sexual pleasure.[60] The Kama Sutra, an ancient Hindu text written by Vātsyāyana, which includes a number of sexual positions, may also be used to increase sexual pleasure,[60] with special emphasis on female sexual satisfaction.[61]

The clitoris additionally plays a part in vaginal stimulation, as it is a sex organ of multiplanar structure containing an abundance of nerve endings, with a broad attachment to the pubic arch and extensive supporting tissue to the mons pubis and labia; it is centrally attached to the urethra, and research indicates that it forms a tissue cluster with the vagina. This tissue is perhaps more extensive in some women than in others, which may contribute to orgasms experienced vaginally.[44][62][63]

During sexual arousal, and particularly the stimulation of the clitoris, the walls of the vagina lubricate. This begins after ten to thirty seconds of sexual arousal, and increases in amount the longer the woman is aroused.[64] It reduces friction or injury that can be caused by insertion of the penis into the vagina or other penetration of the vagina during sexual activity. The vagina lengthens during the arousal, and can continue to lengthen in response to pressure; as the woman becomes fully aroused, the vagina expands in length and width, while the cervix retracts.[64][65] With the upper two-thirds of the vagina expanding and lengthening, the uterus rises into the greater pelvis, and the cervix is elevated above the vaginal floor, resulting in tenting of the mid-vaginal plane.[64] This is known as the tenting or ballooning effect.[66] As the elastic walls of the vagina stretch or contract, with support from the pelvic muscles, to wrap around the inserted penis (or other object),[46] this stimulates the penis and helps to cause a man to experience orgasm and ejaculation, which in turn enables fertilization.[67]

An area in the vagina that may be an erogenous zone is the G-spot (also known as the Gräfenberg spot); it is typically defined as being located at the anterior wall of the vagina, a couple or few inches in from the entrance, and some women experience intense pleasure, and sometimes an orgasm, if this area is stimulated during sexual activity.[47][49] A G-spot orgasm may be responsible for female ejaculation, leading some doctors and researchers to believe that G-spot pleasure comes from the Skene's glands, a female homologue of the prostate, rather than any particular spot on the vaginal wall; other researchers consider the connection between the Skene's glands and the G-spot area to be weak.[47][48][49] The G-spot's existence, and existence as a distinct structure, is still under dispute, as its reported location can vary from woman to woman, appears to be nonexistent in some women, and it is hypothesized to be an extension of the clitoris and therefore the reason for orgasms experienced vaginally.[47][51][63]

Childbirth

The fetus, moving through the vagina, must pass through the lesser pelvis.

The vagina provides a channel to deliver a newborn to its independent life outside the body of the mother. When childbirth (or labor) nears, several symptoms may occur, including vaginal discharge, and the rupture of membranes and resulting gush of amniotic fluid through the vagina (also known as water breaking).[68] When the water breaks, there can be an irregular or small stream of fluid from the vagina, or a gush of fluid.[69][70]

When the body prepares for childbirth, the cervix softens, thins, moves forward to face the front, and may begin to open. This allows the fetus to settle or "drop" into the pelvis.[68] When the fetus settles into the pelvis, this may result in pain in the sciatic nerves, increased vaginal discharge, and increased urinary frequency. While these symptoms are likelier to happen after labor has already begun for women who have given birth before, they may happen approximately ten to fourteen days before labor in women experiencing the effects of nearing labor for the first time.[68]

The fetus begins to lose the support of the cervix when uterine contractions begin. With cervical dilation reaching a diameter of more than 10 cm (4 in) to accommodate the head of the fetus, the head moves from the uterus to the vagina.[68] The elasticity of the vagina allows it to stretch to many times its normal diameter in order to deliver the child.[19]

Injections for pain control during childbirth is often administered through the vaginal wall and near the pudendal nerve. This nerve carries sensations to the lower part of the vagina and vulva. This is only used late in labor, usually right before the baby's head comes out. With a pudendal block, there is some relief from the pain and the laboring woman remains awake, alert, and able to push the baby out. The baby is not affected by this medicine and it has very few disadvantages.[71]

Vaginal births are more common, but there are sometimes complications and a woman might undergo a caesarean section (commonly known as a C-section) instead of a vaginal delivery. The vaginal mucosa has an abnormal accumulation of fluid (edematous) and is thin, with few rugae, a little after birth. The mucosa thickens and rugae return in approximately three weeks once the ovaries regain usual function and estrogen flow is restored. The vaginal opening gapes and is relaxed, until it returns to its approximate pre-pregnant state by six to eight weeks in the period beginning immediately after the birth (the postpartum period); however, it will maintain a larger shape than it previously had.[72]

Vaginal microbiota

The vagina is a complex ecosystem that undergoes long-term changes throughout the life of a woman, from birth to menopause. The vaginal microbiota resides in and on the outermost layer of the vaginal epithelium.[16] This microbiome consists of species and genera which typically do not cause symptoms or infections in women with normal immunity. The vaginal microbiome is dominated by Lactobacillus species.[73] These species metabolize glycogen, breaking it down into sugar. Lactobacilli metabolize the sugar into glucose and lactic acid. Under the influence of hormones, such as estrogen, progesterone and follicle-stimulating hormone (FSH), the vaginal ecosystem undergoes cyclic or periodic changes.[74] When the normal Lactobacillus-based microbiota changes to a microbiome populated by bacteria characteristic of Bacterial Vaginosis the risk of adverse pregnancy outcome is greater.[75]

Clinical significance

General

An ultrasound showing the urinary bladder (1), uterus (2), and vagina (3)

The vagina is self-cleansing and therefore usually does not need special hygiene.[76] Clinicians generally discourage the practice of douching for maintaining vulvovaginal health.[76] Since a healthy vagina is colonized by a mutually symbiotic flora of microorganisms that protect its host from disease-causing microbes, any attempt to upset this balance may cause many undesirable outcomes, including abnormal discharge and yeast infection.[76]

The multiple layers of the vagina provide protection from pathogens, such as Chlamydia trachomatis and Neisseria gonorrhoeae.[16] The vaginal lymph nodes can trap cancerous cells that originate from the vagina so that they can be assessed for the presence of disease. Selective assessment (rather total and more invasive removal) of vaginal lymph nodes reduces the risk of complications that can accompany more radical surgeries. These selective nodes act as sentinel lymph nodes.[37] Instead of surgery, the lymph nodes of concern are sometimes treated with radiation therapy administered to the patient's pelvic or inguinal lymph nodes, or both.[77]

The vagina and cervix are examined during gynecological examinations of the pelvis, often using a speculum, which holds the vagina open for visual inspection or taking samples (see pap smear).[78] This and other medical procedures involving the vagina, including digital internal examinations and administration of medicine,[78][79] are referred to as being per vaginam, the Latin for "via the vagina",[80] often abbreviated to "p.v.".[79] Examination of the vagina may also be done during a cavity search.[81]

A disposable plastic bi-valved vaginal speculum used in gynecological examination

The healthy vagina of a woman of child-bearing age is acidic, with a pH normally ranging between 3.8 and 4.5.; this is due to the degradation of glycogen to lactic acid by enzymes secreted by the Döderlein's bacillus, which is a normal commensal of the vagina.[74] The acidity delays or slows the growth of many strains of pathogenic microbes.[74] An increased pH of the vagina (with a commonly used cut-off of pH 4.5 or higher) can be caused by bacterial overgrowth, as occurs in bacterial vaginosis and trichomoniasis, or rupture of membranes in pregnancy.[74][82] There are different types of bacterial vaginosis.[74]

Intravaginal administration is a route of administration where the medication is applied to vaginal wall. Pharmacologically, it has the potential advantage to result in effects primarily in the vagina or nearby structures (such as the vaginal portion of cervix) with limited systemic adverse effects compared to other routes of administration.[83][84]

Injuries to the vagina can occur during sexual assault. These can be tears, bruises, inflammation and abrasions. Sexual assault with objects can damage the vagina and X-ray examination may reveal the presence of foreign objects[4]

Effects of aging and childbirth

Average vaginal pH varies significantly during a woman's lifespan, from 7.0 in premenarchal girls, to 3.8-4.4 in women of reproductive age to 6.5-7.0 during menopause without hormone therapy and 4.5-5.0 with hormone replacement therapy (HRT).[85] Estrogen, glycogen and lactobacilli are important factors in this variation.[74]

After menopause, the body produces less estrogen, which causes the vaginal walls to thin out significantly.[10][29][86] The effects of menopause can lead to vaginal dryness (due to a decrease in vaginal lubrication), which causes vaginal discomfort on its own or discomfort or pain during sexual intercourse.[87] This can be alleviated with hormone replacement therapy,[88] estrogen-containing vaginal creams,[5] or non-prescription, non-hormonal products,[87] but there are risks and adverse effects associated with hormone replacement therapy.[89]

Some women have an increase in sexual desire following menopause.[87] Masters and Johnson's research indicates that menopausal women who continue to engage in sexual activity regularly experience vaginal lubrication similar to levels in women who have not entered menopause, and can enjoy sexual intercourse fully.[87]

Vaginal changes that happen with aging and childbirth include mucosal redundancy, rounding of the posterior aspect of the vagina with shortening of the distance from the distal end of the anal canal to the vaginal opening, diastasis or disruption of the pubococcygeus muscles caused by poor repair of an episiotomy, and blebs that may protrude beyond the area of the vaginal opening.[90] Other vaginal changes related to aging and childbirth are urinary incontinence, rectocele, cystocele, and stress.[90] Similar vaginal and labial changes may be due to significant weight gain and subsequent loss.[90]

During the third stage of labor, while the infant is being born, the vagina undergoes significant changes. A gush of blood from the vagina may be seen right before the baby is born. Lacerations to the vagina that can occur during birth vary in depth, severity and the amount of adjacent tissue involvement.[91][4] The laceration can be so extensive as to involve the rectum and anus. This event can be especially distressing to a new mother.[91][92] When this occurs, fecal incontinence develops and stool can leave through the vagina.[91] Lacerations can occur unrelated to childbirth.[4]

Sometimes the attending physician performs an episiotomy. This is a surgical incision that widens the opening of the vagina to reduce the tissue resistance. It is performed right before the baby is born.[16][93] The incision is a cut to the skin, underlying connective tissues and muscles between the vagina and anus.[94] The two types of episiotomies performed are the medial incision and the medio-lateral incision. The median incision is a perpendicular cut between the vagina and the anus and is the most common.[16][95] The medio-lateral incision is made between the vagina at an angle and is not as likely to tear through to the anus. The medio-lateral cut takes more time to heal than the median cut.[16] Lacerations and episiotomies can be painful after delivery. Some surgical techniques result in less pain than others. Close to 85% of spontaneous vaginal births develop some form of tearing. Out of these, 60-70% require suturing. Women often report pain during sexual intercourse up to three months after laceration repair or an episiotomy.[96][97] Lacerations from labor do not always happen, and not having an episiotomy is found to have better results than episiotomy.[16]

Infections, safe sex, and disorders

There are many infections, diseases and disorders that can affect the vagina, including candidal vulvovaginitis, vaginitis, vaginismus, sexually transmitted infections (STIs) or cancer. Vaginitis is an inflammation of the vagina, and is attributed to several vaginal diseases, while vaginismus is an involuntary tightening of the vagina muscles caused by a conditioned reflex, or disease, during vaginal penetration.[98] HIV/AIDS, human papillomavirus (HPV), genital herpes and trichomoniasis are some of the STIs that may affect the vagina, and health sources recommend safe sex (or barrier method) practices to prevent the transmission of these and other STIs.[99][100]

Safe sex commonly involves the use of condoms (also known as male condoms), but female condoms, which give women more control during the safe sex practice, may also be used; both condoms keep semen from coming in contact with the vagina, which can help prevent unwanted pregnancy.[101][102] There is, however, little research on whether female condoms are as effective as male condoms at preventing STIs,[102] and they are slightly less effective than male condoms at preventing pregnancy, which may be due to the female condom not fitting as tightly as the male condom or because it can slip into the vagina and spill semen.[103]

Cervical cancer may be prevented by pap smear screening and HPV vaccines, but HPV vaccines only identify HPV types 16 and 18, the cause of 70% of cervical cancers.[104][105] Vaginal cancer and vulvar cancer are very rare, and are primarily matters for elderly women.[106][107] Because vaginal cancer often occurs at the same time or develops consequently in relation to cervical cancer, it may be that their causes are the same.[106][108] Some symptoms of cervical and vaginal cancer are dyspareunia, and abnormal vaginal bleeding or vaginal discharge, especially after sexual intercourse or menopause.[109][110] However, most cervical cancers are asymptomatic (present no symptoms).[109] Vaginal intracavity brachytherapy (VBT) is used to treat endometrial, vaginal and cervical cancer. An applicator is inserted into the vagina to allow the administration of radiation as close to the site of cancer as possible.[93][111] Survival rates increase with VBT when compared to external beam radiation therapy.[93] By using the vagina to place the emitter as close to the cancerous growth as possible, the systemic effects of radiation therapy are less and cure rates for vaginal cancer are higher.[112]

There can be a vaginal obstruction, such as one caused by agenesis, an imperforate hymen or, less commonly, a transverse vaginal septum; these cases require differentiation because surgery for them significantly varies.[113] When there is a lump obstructing the vaginal opening, it is likely a Bartholin's cyst.[114]

Vaginal prolapse is characterized by a portion of the vaginal canal protruding (prolapsing) from the opening of the vagina. It may result in the case of weakened pelvic muscles, which is a common result of childbirth; in the case of this prolapse, the rectum, uterus, or bladder pushes on the vagina, and severe cases result in the vagina protruding out of the body. Kegel exercises have been used to strengthen the pelvic floor, and may help prevent or remedy vaginal prolapse.[59]

Modification

The vagina, including the vaginal opening, may be altered as a result of genital modification during vaginectomy, vaginoplasty or labiaplasty.[90][115] Those who undergo vaginoplasty are usually older and have given birth to one or more children.[90] A thorough examination of the vagina before a vaginoplasty is standard, as well as being referred to a urogynecologist for possible vaginal disorders.[90] With regard to labiaplasty, reduction of the labia minora is quick without hindrance, and any complications are rare and can be corrected. The complications are minor enough that those with them may still be satisfied with the procedure.[90] Any scarring from the procedure is minimal, and long-term chronic problems have not been identified.[90]

Vaginectomy is surgery to remove all or part of the vagina, and is usually used as a treatment for vaginal cancer.[115] The vulva or vagina may be altered in the case of gynecologic cancers (such as cervical cancer, vaginal cancer or vulvar cancer). Removal of some or all of the reproductive organs and genitalia can result in damage to the nerves and leave behind scarring or adhesions.[116] Sexual function may also be impaired as a result, as in the case of some cervical cancer surgeries, which impact vaginal lubrication, elasticity, pain, and sexual arousal. This mostly resolves after one year of recovery, but remedying vaginal dryness and decreased sexual satisfaction may take longer.[116]

Female genital mutilation (FGM), another aspect of female genital modification, may additionally be known as female circumcision or female genital cutting (FGC).[117][118] FGM has no known health benefits. The most severe form of FGM is infibulation, in which there is removal of all or part of the inner and outer labia (labia minora and labia majora) and the closure of the vagina; this is called Type III FGM, and it involves a small hole being left for the passage of urine and menstrual blood, with the vagina being opened up for sexual intercourse and childbirth.[118]

Society and culture

Perceptions, symbolism and vulgarity

Various perceptions of the vagina have existed throughout history, including the belief it is the center of sexual desire, a metaphor for life via birth, inferior to the penis, unappealing to sight or smell, or vulgar.[119][120][121] These views can largely be attributed to sex differences, and how they are interpreted. David Buss, an evolutionary psychologist, stated that because a penis is significantly larger than a clitoris and it is readily visible while the vagina is not, and males urinate through the penis, boys are taught from childhood to touch their penises while girls are often taught that they should not touch their vulva or vagina, which implies that there is harm in doing so. Buss attributed this to the reason why many women are not as familiar with their genitalia as men are familiar with their own, and that researchers assume these sex differences explain why boys learn to masturbate before girls, and masturbate more often than girls.[122]

The word vagina is commonly avoided in conversation,[123] and many people are confused about the vagina's anatomy, including that it is not used for urination.[124][125][126] This is exacerbated by phrases such as "boys have a penis, girls have a vagina", which causes children to think that girls have one orifice in the pelvic area.[125] Author Hilda Hutcherson stated, "Because many [women] have been conditioned since childhood through verbal and nonverbal cues to think of [their] genitals as ugly, smelly and unclean, [they] aren't able to fully enjoy intimate encounters" because of fear that their partner will dislike the sight, smell, or taste of their genitals. She argued that women, unlike men, did not have locker room experiences in school where they compared each other's genitals, which is one reason so many women wonder if their genitals are normal.[120] Scholar Catherine Blackledge stated that having a vagina meant she would typically be treated less well than her vagina-less counterparts and subject to inequalities (such as job inequality), which she categorized as being treated like a second-class citizen.[123]

The vagina represents a powerful symbol as the yoni in Hinduism. Pictured is a stone yoni found in Cát Tiên sanctuary, Lam Dong, Vietnam.

Negative views of the vagina are simultaneously contrasted by views that it is a powerful symbol of female sexuality, spirituality, or life. Author Denise Linn stated that the vagina "is a powerful symbol of womanliness, openness, acceptance, and receptivity. It is the inner valley spirit."[127] Sigmund Freud placed significant value on the vagina,[128] postulating the concept of vaginal orgasm, that it is separate from clitoral orgasm, and that, upon reaching puberty, the proper response of mature women is a change-over to vaginal orgasms (meaning orgasms without any clitoral stimulation). This theory made many women feel inadequate, as the majority of women cannot achieve orgasm via vaginal intercourse alone.[129][130][131] Regarding religion, the vagina represents a powerful symbol as the yoni in Hinduism, and this may indicate the value that Hindu society has given female sexuality and the vagina's ability to birth life.[132]

While, in ancient times, the vagina was often considered equivalent (homologous) to the penis, with anatomists Galen (129 AD – 200 AD) and Vesalius (1514–1564) regarding the organs as structurally the same except for the vagina being inverted, anatomical studies over latter centuries showed the clitoris to be the penile equivalent.[62][133] Another perception of the vagina was that the release of vaginal fluids would cure or remedy a number of ailments; various methods were used over the centuries to release "female seed" (via vaginal lubrication or female ejaculation) as a treatment for suffocation ex semine retento (suffocation of the womb), green sickness, and possibly for female hysteria. Reported methods for treatment included a midwife rubbing the walls of the vagina or insertion of the penis or penis-shaped objects into the vagina. Symptoms of the female hysteria diagnosis  – a concept that is no longer recognized by medical authorities as a medical disorder  – included faintness, nervousness, insomnia, fluid retention, heaviness in abdomen, muscle spasm, shortness of breath, irritability, loss of appetite for food or sex, and a propensity for causing trouble.[134] It may be that women who were considered suffering from female hysteria condition would sometimes undergo "pelvic massage"  – stimulation of the genitals by the doctor until the woman experienced "hysterical paroxysm" (i.e., orgasm). In this case, paroxysm was regarded as a medical treatment, and not a sexual release.[134]

The vagina and vulva have additionally been termed many vulgar names, three of which are cunt, twat, and pussy. Cunt is also used as a derogatory epithet referring to people of either sex. This usage is relatively recent, dating from the late nineteenth century.[135] Reflecting different national usages, cunt is described as "an unpleasant or stupid person" in the Compact Oxford English Dictionary,[136] whereas Merriam-Webster has a usage of the term as "usually disparaging and obscene: woman,"[137] noting that it is used in the U.S. as "an offensive way to refer to a woman."[138] Random House defines it as "a despicable, contemptible or foolish man."[135] Some feminists of the 1970s sought to eliminate disparaging terms such as cunt.[139] Twat is widely used as a derogatory epithet, especially in British English, referring to a person considered obnoxious or stupid.[140][141] Pussy can indicate "cowardice or weakness", and "the human vulva or vagina" or by extension "sexual intercourse with a woman".[142] In contemporary English, use of the word pussy to refer to women is considered derogatory or demeaning, treating people as sexual objects.[143]

In contemporary literature and art

Gustave Courbet's 1866 painting "The Origin of the World".

The vagina loquens, or "talking vagina", is a significant tradition in literature and art, dating back to the ancient folklore motifs of the "talking cunt".[144][145] These tales usually involve vaginas talking due to the effect of magic or charms, and often admitting to their unchastity.[144] Another folk tale regarding the vagina is "vagina dentata" (Latin for "toothed vagina"). In these folk tales, a woman's vagina is said to contain teeth, with the associated implication that sexual intercourse might result in injury, emasculation, or castration for the man involved. These stories were frequently told as cautionary tales warning of the dangers of unknown women and to discourage rape.[146]

In 1966, the French artist Niki de Saint Phalle collaborated with Dadaist artist Jean Tinguely and Per Olof Ultvedt on a large sculpture installation entitled "hon-en katedral" (also spelled "Hon-en-Katedrall", which means "she-a cathedral") for Moderna Museet, in Stockholm, Sweden. The outer form is a giant, reclining sculpture of a woman with her legs spread. Museum patrons can go inside her body by entering a door-sized vaginal opening.[147] Sainte Phalle stated that the sculpture represented a fertility goddess who was able to receive visitors into her body and then "give birth" to them again.[148]

From 1974 to 1979, Judy Chicago, a feminist artist, created the vagina-themed installation artwork "The Dinner Party". It consists of 39 elaborate place settings arranged along a triangular table for 39 mythical and historical famous women. Virginia Woolf, Susan B. Anthony, Sojourner Truth, Eleanor of Aquitaine, and Theodora of Byzantium are among those honored. Each plate, except the one corresponding to Sojourner Truth (a Black woman), depicts a brightly-colored, elaborately styled vagina-esque form. After it was produced, despite resistance from the art world, it toured to 16 venues in six countries to a viewing audience of 15 million.[149]

The Vagina Monologues, a 1996 episodic play by Eve Ensler, has contributed to making female sexuality a topic of public discourse. It is made up of a varying number of monologues read by a number of women. Initially, Ensler performed every monologue herself, with subsequent performances featuring three actresses; latter versions feature a different actress for every role. Each of the monologues deals with an aspect of the feminine experience, touching on matters such as sexual activity, love, rape, menstruation, female genital mutilation, masturbation, birth, orgasm, the various common names for the vagina, or simply as a physical aspect of the body. A recurring theme throughout the pieces is the vagina as a tool of female empowerment, and the ultimate embodiment of individuality.[150][151]

In 2012, an image of an 1866 Gustave Courbet painting of the female genitals, entitled "The Origin of the World", being posted on Facebook led to a legal dispute. After a French teacher posted an image of the painting, Facebook considered the image to be pornographic and suspended his account for violating its terms of use.[152] G. Roger Denson of Huff Post called the painting "a frank image of a vagina."[153] Mark Stern of Slate, who called the painting a stunning, brilliant "....cornerstone of the French Realistic movement", stated that the teacher sued the website for allegedly violating his freedom of speech.[152] In October 2013, artist Peter Reynosa created a "... red and white acrylic painting [that] depicts [pop singer] Madonna painted in the shape of a defiant yonic symbol that looks like a vagina or vulva."[154]

Cosmetic or traditional reasons for vaginal modification

Cosmetic reasons for modification of the female genitalia may be due to FGM, voluntary cosmetic operations, or surgery for intersex conditions.[155] There are two main categories of women seeking cosmetic genital surgery: those with congenital conditions (such as an intersex condition), and those with no underlying condition who experience physical discomfort or wish to alter the appearance of their genitals because they believe they do not fall within a normal range.[155]

Significant controversy surrounds FGM,[117][118] with the World Health Organization (WHO) being one of many health organizations that have campaigned against the procedures on behalf of human rights, stating that it is "a violation of the human rights of girls and women" and "reflects deep-rooted inequality between the sexes".[118] FGM has existed at one point or another in almost all human civilizations,[156] most commonly to exert control over the sexual behavior, including masturbation, of girls and women.[118][156] It is carried out in several countries, especially in Africa, and to a lesser extent in other parts of the Middle East and Southeast Asia, on girls from a few days old to mid-adolescent, often to reduce sexual desire in an effort to preserve vaginal virginity.[117][118][156] Comfort Momoh stated it may be that FGM was "practiced in ancient Egypt as a sign of distinction among the aristocracy"; there are reports that traces of infibulation are on Egyptian mummies.[156]

Custom and tradition are the most frequently cited reasons for FGM, with some cultures believing that not performing it has the possibility of disrupting the cohesiveness of their social and political systems, such as FGM also being a part of a girl's initiation into adulthood.[118][156] Often, a girl is not considered an adult in a FGM-practicing society unless she has undergone FGM.[118]

Other animals

The vagina is a feature of animals in which the female is internally fertilized, rather than by traumatic insemination used by invertebrates. The shape of the vagina varies among different animals. In placental mammals and marsupials, the vagina leads from the uterus to the exterior of the female body. Female marsupials have two lateral vaginas, which lead to separate uteri, but both open externally through the same orifice.[157] The female spotted hyena does not have an external vagina. Instead, the vagina exits through the clitoris, allowing the females to urinate, copulate and give birth through the clitoris.[158] The female vagina of the coyote contracts during copulation, forming a copulatory tie.[159]

In the case of other animals, birds, monotremes, and some reptiles have a part of the oviduct that leads from the shell gland to the cloaca.[160][161] Chickens have a vaginal aperture that opens from the vertical apex of the cloaca. The vagina extends upward from the aperture and becomes the egg gland.[161] In some jawless fish, there is neither oviduct nor vagina and instead the egg travels directly through the body cavity (and is fertilised externally as in most fish and amphibians). In insects and other invertebrates, the vagina can be a part of the oviduct (see insect reproductive system).[162] Females of some waterfowl species have developed vaginal structures called dead end sacs and clockwise coils to protect themselves from sexual coercion.[163]

In 2014, the scientific journal Current Biology reported that four species of Brazilian insects in the genus Neotrogla were found to have sex-reversed genitalia. The male insects of those species have vagina-like openings, while the females have penis-like organs.[164][165][166]

See also

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