vaginal fornix vaginal fornix the fornices of the vagina (sing. fornix of the vagina or fornix vaginae) are the superior portions of the vagina, extending into the recesses created by the vaginal portion of cervix. the word fornix is latin for 'arch'. vaginal fornixsagittal section of the lower part of a female trunk, right segment. sm. int. small intestine.detailsidentifierslatinfornix vaginaeta98a09.1.04.002ta23524fma19985anatomical terminology structure there are four named fornices (two primary) according to their anatomical position: the posterior fornix is the larger recess, behind the cervix. it is close to the recto-uterine pouch. there are three smaller recesses in front and at the sides: the anterior fornix is close to the vesico-uterine pouch. the two lateral fornices. sexual during sexual intercourse in the missionary position, the tip of the penis reaches the anterior fornix, while in the rear-entry position it reaches the posterior fornix. the fornices appear to be close to one reported erogenous zone, the cul-de-sac, which is near the posterior fornix.