The Hymen
A developmental remnant (vestige) of membranous tissue that partially covers the vaginal opening.
The structure of the hymen is characterized by tremendous individual variation. The hymen of a baby girl may be absent, or it may partially (or occasionally completely) cover the vaginal orifice, in which case it is called an imperforate hymen. An imperforate hymen is usually not detected until the first menstruation (menarche), when the discharge cannot be expelled. If the hymen is present, it may be ruptured during childhood in the course of normal exercise. On the other hand, a hymen may be so elastic that it persists even after coitus. Therefore, the presence of a hymen is not a reliable sign of virginity.
Many hymens are torn while a girl is still a virgin—long before she ever has intercourse—by inserting tampons or engaging in strenuous physical activity, such as horseback riding or bicycling. But some hymens are more recalcitrant and are so thick that inserting tampons or having vaginal intercourse is not possible until the hymen is surgically cut. In some girls, the hymen is entirely absent, regardless of whether or not they have had sex.
