Hymen

# Overview
The hymen (also called maidenhead) is a fold of mucous membrane which surrounds or partially covers the external vaginal opening. Its name comes from the ancient greek for "hymenaeus," which means "vaginal-flap." It was also the name for the Greek god of marriage, later also the Greek god of membranes; "Hymenaios." A slang term is "cherry", as in "popping one's cherry" (losing one's virginity). It forms part of the vulva, or external genitalia. The most common formation of the hymen is crescentic or crescent-shaped, although several other formations are possible. After a woman gives birth she may be left with remnants of the hymen called carunculae myrtiformes or the hymen may be completely absent.
The hymen has no known anatomical function. In societies which value chastity, the greatest significance of the hymen is a traditional belief that an intact hymen indicates a state of intact virginity. However, it is not possible to confirm that a woman or post-pubescent girl is not a virgin by examining the hymen. A physician routinely checks the appearance of the hymen of baby girls at birth, and again during all future pelvic examinations. In cases of suspected rape or sexual abuse, a detailed examination of the hymen may be carried out; however, the condition of the hymen alone is often inconclusive or open to misinterpretation, especially if the patient has reached puberty.

# Types
There are several different formations of the hymen, some more common than others. In about 1 in 2000 females, the hymen fails to develop any opening at all: this is called an imperforate hymen and if it does not spontaneously resolve itself before puberty a physician will need to make a hole in the hymen to allow menstrual fluids to escape. A hymenotomy may also be required if the hymen is particularly thick or inelastic as it may interfere with sexual intercourse.
The shape of the hymen is easiest to observe in girls past infancy but before they reach puberty: at this time their hymen is thin and less likely to be redundant, that is to protrude or fold over on itself.
When describing the shape of a hymen, a clock face is used. The 12 o'clock position is below the urethra, and 6 o'clock is towards the anus, which is based on the patient lying on her back.

## Most common forms of the hymen
- crescent-shaped, crescentic, or posterior rim: no hymenal tissue at the 12 o'clock position; narrow band of tissue starts at 1 or 2 o'clock going clockwise, is at its widest around 6 o'clock, and tapers off at 10 or 11 o'clock
- annular, or circumferential: the hymen forms a ring around the vaginal opening; especially common in newborns
- redundant; sometimes sleeve-like: folds in on itself, which sometimes causes it to protrude; most common in infancy and at/following puberty due to estrogen levels; can be combined with other type such as "annular and redundant"

## Less common forms
- Fimbriated or denticular: an irregular edge to the hymenal orifice; more likely at an age when estrogen is present
- Septate: the hymen has one or more bands extending across the opening
- Cribriform, or microperforate: the hymen stretches completely across the vaginal opening, but is perforated with several holes
- Labial, or vertical: hymen has an opening from the 12 to the 6 o'clock positions and can look similar to a third set of vulvar lips
- Imperforate: hymen completely covers vaginal orifice; will require minor surgery if it has not corrected itself by puberty to allow menstrual fluids to escape
Imperforated hymen must be differentiated from other diseases that cause latency in secondary sexual characteristics development (amenorrhea), such as constitutional delay of puberty, hypopituitarism, delayed puberty, and chromosomal abnormalities. Chromosomal abnormalities are Turner's syndrome, and Noonan's syndrome.
- Imperforated hymen must be differentiated from other diseases that cause latency in secondary sexual characteristics development (amenorrhea), such as constitutional delay of puberty, hypopituitarism, delayed puberty, and chromosomal abnormalities. Chromosomal abnormalities are Turner's syndrome, and Noonan's syndrome.
The hymen is torn or stretched by penetrative sex, and more so when a woman gives birth vaginally.
- parous introitus refers to the vaginal opening which has had a baby pass through it and consequently has nothing left of its hymen but a fleshy irregular outline decorating its perimeter; these tags are called carunculae mytriformes

# Development of the hymen
During the early stages of fetal development there is no opening into the vagina at all. The thin layer of tissue that covers the vagina at this time usually divides to a certain extent prior to birth, forming the hymen. That layer was the Mullerian eminence before, and thus, the hymen is a remnant of that structure.
In newborn babies, who are still under the influence of the mother's hormones, the hymen is thick, pale pink, and redundant (folds in on itself and may protrude). For the first two to four years of life, the infant produces hormones which continue this effect.
By the time a girl reaches school-age, this hormonal influence has stopped and the hymen becomes thin, smooth, delicate and almost translucent. It is also very sensitive to touch; a physician who needed to swab the area would avoid the hymen and swab the outer vulval vestibule instead.
From puberty onwards the appearance of the hymen is affected once more by estrogen. It thickens and becomes pale pink, the opening is often fibriated or erratically shaped, and redundant: the hymen often appears rolled or sleeve-like.
There is a surgical procedure that can repair the hymen so that it is intact. The procedure, known as hymenoplasty, has become a popular procedure for some females.

# What might damage the hymen?
The hymen may be damaged by playing sports, using tampons, pelvic examinations or even straddle injuries.
Once a girl reaches puberty, the hymen tends to become quite elastic. It is not possible to determine whether a woman uses tampons or not by examining her hymen.  Sexual intercourse is one of the most common ways to damage the hymen, although in one survey only 43% of women reported bleeding the first time they had sex; which means that in the other 57% of women the hymen likely stretched enough that it didn't tear.
It is rare to damage the hymen through accidental injury, such as falling on the top tube of a bicycle. Although such an accident may cause bleeding, this is usually due to damage to surrounding tissues such as the labia. It is unlikely that an accident would damage the hymen without injuring any other part of the vulva. Therefore, damage to the hymen alone, described as an accident, would be seen as a strong indicator of sexual assault.

# Debunking myths
- The condition of the hymen is not a reliable indicator of whether a woman past puberty has actually engaged in sexual intercourse.
- There is no such thing as "congenital absence of the hymen", i.e. it is a myth that girls are born without a hymen. However, a hymen can vary in size, and, as described above, be very hard to find, even if the person never had sex before.
- The hymen is not inside the vagina. It is part of the external genitalia.
As early as the late sixteenth century, Ambroise Pare and Andreas Laurentius asserted to have never seen the hymen and that it was "a primitive myth, unworthy of a civilized nation like France."  In the sixteenth and seventeenth centuries, medical researchers have used the presence of the hymen, or lack thereof, as founding evidence of physical diseases such as "womb-fury". If not cured, womb-fury would, according to these early doctors, result in death. The cure, naturally enough, was marriage, since a woman could then go about having sexual intercourse on a "normal" schedule that would stop womb-fury from killing her.

# Revisionist perspectives
In late 2005, Monica Christiansson, former maternity ward nurse and Carola Eriksson, a PhD student at Umea University announced that according to studies of medical literature and practical experience, the hymen should be considered a social and cultural myth, based on deeply rooted stereotypes of womens' roles in sexual relations with men. Christiansson and Eriksson support their claims by pointing out that there are no accurate medical descriptions of what a hymen actually consists of. Statistics presented by the two state that fewer than 30% of women who have gone through puberty and have consensual intercourse bleed the first time. Christiansson has expressed an opinion that the use of the term "hymen" should be discontinued and that it should be considered an integral part of the vaginal opening.
It is argued that since the hymen has been culturally constructed to be the sign of virginity, its existence plays into a political discourse that circulates around the body.  By examining women's bodies for the existence of the hymen, researchers have used it to determine whether or not women are "virtuous." Sherry B. Ortner, professor at the University of Chicago, explains how "the hymen itself emerges physiologically with the development of sexual purity codes" as an element of patriarchy. In some cultures it was customary to examine a woman for her hymen before her marriage to see if she was truly fit to be married.  If she was found with a broken hymen, or to have no hymen at all, often the male would not be obligated to marry her.  Additionally, the hymen has been used to consistently create the image of women as physically bound to their sexuality, insofar as there's a specific membrane that needs "breaking" in order to have sex and enter into full womanhood, being sexually dependent on their men.