part of part of contributes to morphology of orifice vagina reproductive structure vagina orifice opening of vagina vaginal orifice introitus of vagina introitus Wikipedia:Vaginal_orifice ostium vaginae The median slit located inferior and posterior to the external urethral orifice in the female; the exit for menstrual flow and birth and the entrance for the penis during sexual intercourse; the size and appearance of the vaginal orifice varies inversely with that of the hymen (G. membrane), a thin fold of mucous membrane that surrounds the vaginal orifice. vaginal introitus vagina opening orifice of vagina FMA:19984 UBERON:0012317