The hymen is usually located at the outer vaginal opening and is part of a perforated membrane that covers the vaginal opening, above the urethral opening and below the anus. This orifice is mostly round or crescent-shaped and is usually small enough to pass only a fingertip. In a few women, the hymenopore is extremely small and sieve-shaped, or has a mid-diaphragm and is umbrella-shaped, while the latter is more easily mistaken for a ruptured hymen. Normally the hymen ruptures after the first sexual intercourse and is accompanied by pain and a small amount of bleeding during the rupture. If the bleeding increases, the rupture is large and requires emergency treatment at the hospital, which does not rule out the possibility of surgical stitching. However, there are some women whose hymens rupture before they have sex for the first time. The causes of rupture include strenuous sports, such as high jumping and long jumping, and rupture caused by trauma, such as straddling injuries. In addition, there are very few women who have tougher hymens that do not rupture during intercourse, or even have hymenal atresia that prevents the smooth discharge of menstruation and causes paroxysmal abdominal pain, and such women are advised to visit a hospital and undergo surgical incision under the guidance of a doctor.