Vagina. The vagina is a cavity with an opening to the outside. This cavity leads to the opening of the uterus (cervix). The vagina is about 10 cm deep. The vagina. Jump to Internal organs - The internal sex organs are the uterus, Fallopian tubes, and ovaries. The external sex organs are also known as the genitals and these are the organs of the vulva including the labia, clitoris, and vaginal opening. The vagina is connected to the uterus at the cervix.Physiology · Development · Clinical significance.