The hymen is located at the beginning of the external vaginal opening and is a ring-shaped membrane that covers the vaginal opening. The hymen is covered on both sides by squamous epithelium and its exact shape, size and thickness varies from person to person, being more often ring-shaped, semilunar or sieve-shaped and about 2 cm thick, but gradually becoming larger and thinner as a woman ages. Usually, the hymen develops and forms during fetal life, thus most women have a hymen, but a few lack one. It is a connective tissue membrane that contains capillaries and no nerve tissue, which acts as a natural barrier to prevent dirt from entering the vagina. In addition, there is an opening in the middle of the membrane that serves as a channel for menstruation and leucorrhea to be discharged. If there is no small hole in the membrane, the monthly menstrual blood is blocked by it and cannot be expelled from the body, which is medically called hymenal atresia. If not detected in time, the menstrual blood accumulates in the vagina and can expand upward to the uterine cavity and fallopian tubes through the distal opening of the fallopian tubes and flow into the abdominal cavity, causing fallopian tube breakage, intestinal adhesions, and abdominal infections.