The cervix is the lowest of the three portions of the uterus and projects downward into the vagina through the upper end of the anterior wall. It is cylindrical in form and constricted at each end. Its surface may be divided into a supravaginal portion, a, zone of vaginal attachment, and an intravaginal portion. The supravaginal portion composes two thirds of the cervix anteriorly and about one-half of it posteriorly. Anteriorly it is in relation with the bladder, posteriorly it is covered by peritoneum, and laterally is attached to the broad ligaments and is in relation with the uterine vessels and the ureter. The anterior wall of the intravaginal portion is less than one-third of the anterior wall of the cervix, although on the posterior wall the intravaginal portion is one-half the length of the cervix. The intravaginal portion of the cervix is a cone-shaped body, the extremity of which presents the external opening of the cavity of the uterus, the external os. In the virgin the external os is a rounded opening, but after childbirth it takes the form of a transverse slit. A smooth mucous membrane, similar to that of the vagina, covers the intravaginal portion of the cervix.

Cervix uteri

Canalis cervicis uteri

Col de l'utérus

Canal du col utérin

Cervix der Gebärmutter