Note the disappearance the uterine septum

250Part 1ISystems-Based Embryology

Vagina

Shortly after the solid tip of the paramesonephric ducts reaches the urogenital sinus (Figs. 16.29A and 16.30A), two solid evaginations grow out from the pelvic part of the sinus (Figs. 16.29B and 16.30B). These evaginations, the sinovagi-nal bulbs, proliferate and form a solid vaginal plate. Proliferation continues at the cranial end of the plate, increasing the distance between the uterus and the urogenital sinus. By the fi fth month, the vaginal outgrowth is entirely cana-lized. The wing-like expansions of the vagina around the end of the uterus, the vaginal forni-ces, are of paramesonephric origin (Fig. 16.30C).

Uterus

Uterine

tube