Final answer:
The fornix is the region of the vagina surrounding the cervix, playing a vital role in connecting the vagina to the cervix and allowing for expansion during intercourse and childbirth.
Step-by-step explanation:
The region of the vagina that surrounds the cervix is known as the fornix. The vagina is a muscular canal approximately 10 cm long, which serves as the entrance to the reproductive tract as well as the exit during menses and childbirth. The superior portion of the vagina forms the fornix, which meets the protruding uterine cervix. The walls of the vagina consist of an outer fibrous adventitia, a middle layer of smooth muscle, and an inner mucous membrane with transverse folds called rugae. The fornix allows the connection between the vagina and the cervix, and its structure is essential for the expansion of the vagina to accommodate intercourse and childbirth.