Hymen

Hymen
External genital organs of female. The labia minora have been drawn apart.
Details
Identifiers
Latin	hymen vaginae
MeSH	A05.360.319.779.479
TA	A09.1.04.008
FMA	20005
Anatomical terminology []

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.

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.