In mammals, the vagina is the elastic, muscular part of the
female genital tract. In humans, it extends from the vulva to the cervix. The outer vaginal opening is normally 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 birth. It also channels menstrual
flow (menses), which occurs in humans and closely related primates as part of the monthly menstrual cycle.