|Latin hymen vaginae|
Similar Labiaplasty, Vaginoplasty, G spot
The hymen is a membrane that surrounds or partially covers the external vaginal opening. It forms part of the vulva, or external genitalia, and is similar in structure to the vagina. The hymen does not seem to have a specific physiological function or purpose. In children, although a common appearance of the hymen is crescent-shaped, many shapes are possible. Normal variations of the hymen range from thin and stretchy to thick and somewhat rigid; or it may also be completely absent.
The hymen often, though not always, rips or tears the first time a female engages in penetrative intercourse, which may cause some temporary bleeding and slight discomfort. The hymen can also stretch or tear as a result of various other behaviors; for example, it may be lacerated by disease, injury, medical examination, masturbation or physical exercise. For these reasons, the state of the hymen is not a conclusive indicator of virginity, though it continues to be considered so in certain cultures. Although the hymen does not regenerate itself after it is torn, it may be surgically restored in a procedure called hymenorrhaphy.
Development and histology
The genital tract develops during embryogenesis, from the third week of gestation to the second trimester, and the hymen is formed following the vagina. At week seven, the urorectal septum forms and separates the rectum from the urogenital sinus. At week nine, the Müllerian ducts move downwards to reach the urogenital sinus, forming the uterovaginal canal and inserting into the urogenital sinus. At week twelve, the Müllerian ducts fuse to create a primitive uterovaginal canal called unaleria. At month five, the vaginal canalization is complete and the fetal hymen is formed from the proliferation of the sinovaginal bulbs (where Müllerian ducts meet the urogenital sinus), and normally becomes perforate before or shortly after birth.
The hymen has no nerve innervation. In newborn babies, 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 that continue this effect. Their hymenal opening tends to be annular (circumferential).
Past neonatal stage, the diameter of the hymenal opening (measured within the hymenal ring) widens by approximately 1 mm for each year of age. During puberty, the hymenal opening can also be enlarged by tampon or menstrual cup use, pelvic examinations with a speculum, regular physical activity or sexual intercourse. Once a girl reaches puberty, the hymen tends to become very elastic.
The hymen can stretch or tear as a result of various behaviors, such as the insertion of multiple fingers or items into the vagina, and activities such as gymnastics (doing 'the splits'), or horseback riding. Remnants of the hymen are called carunculae myrtiformes.
A glass or plastic rod of 6 mm diameter having a globe on one end with varying diameter from 10 to 25 mm, called Glaister Keen rod, is used for close examination of the hymen or the degree of its rupture. In forensic medicine, it is recommended by health authorities that a physician who must swab near this area of a prepubescent girl avoid the hymen and swab the outer vulval vestibule instead. In cases of suspected rape or child sexual abuse, a detailed examination of the hymen may be performed, but the condition of the hymen alone is often inconclusive.
Normal variations of the hymen range from thin and stretchy to thick and somewhat rigid; or it may also be completely absent. The only variation that may require medical intervention is the imperforate hymen, which either completely prevents the passage of menstrual fluid or slows it significantly. In either case, surgical intervention may be needed to allow menstrual fluid to pass or intercourse to take place at all.
Prepubescent girls' hymenal openings come in many shapes, depending on hormonal and activity level, the most common being crescentic (posterior rim): no tissue at the 12 o'clock position; crescent-shaped band of tissue from 1–2 to 10–11 o'clock, at its widest around 6 o'clock. From puberty onwards, depending on estrogen and activity levels, the hymenal tissue may be thicker, and the opening is often fimbriated or erratically shaped. In younger children, a torn hymen will typically heal very quickly. In adolescents, the hymenal opening can naturally extend and variation in shape and appearance increases.
Variations of the female reproductive tract can result from agenesis or hypoplasia, canalization defects, lateral fusion and failure of resorption, resulting in various complications.
The hymen is often attributed important cultural significance in certain communities because of its association with a woman's virginity. In those cultures, an intact hymen is highly valued at marriage in the belief that this is a proof of virginity. Some women undergo hymenorrhaphy to restore their hymen for this reason.
In the 16th and 17th centuries, medical researchers saw the presence or absence of the hymen as founding evidence of physical diseases such as "womb-fury", i.e., (female) hysteria. If not cured, womb-fury would, according to these early doctors, result in death.
Due to similar reproductive system development, many mammals have hymens, including chimpanzees, elephants, manatees, whales, horses and llamas.