The thin membrane around the vaginal opening. The hymen has a central perforation which is usually stretched or torn by the use of tampons or during sexual intercourse for the 1st time. Imperforate hymen is a rare condition in which the hymen has no perforation; at the onset of menstruation, menstrual blood collects in the vagina, causing lower abdominal pain. The condition is easily corrected by a minor operation.


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