Schematic diagram of the formation of the uterus and vagina

Left panel: At nine weeks, the uterine septum has disappeared.
Middle panel: At 13 weeks, the sinovaginal bulbs have begun to grow out of the pelvic part of the urogenital sinus and form a solid plate.
Right panel: In the newborn, the upper third of the vagina and the fornices are formed by vacuolization of the paramesonephric tissue, and the lower-thirds of the vagina is formed by vacuolization of the sinovaginal bulbs.