This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The vagina is about 7.5 cm. (3 in.) long; its posterior wall is longer than the anterior, being 8.75 cm. (3 1/2 in.) long. It will thus be seen that if the uterus is slightly-depressed, as it often is, the cervix is within easy reach of the examining finger, if, however, it is drawn up, as by an abdominal growth, it may only be reached with difficulty. The hollow formed by the anterior wall of the vagina blending with the anterior lip of the cervix is. called the anterior fornix. The depression behind the posterior lip is the posterior fornix, behind which is Douglas' s pouch. At the vulvar outlet the lumen of the vagina is anteroposterior in direction, it then changes to lateral and at the cervix becomes round. Its walls are in contact. In nulliparae the tube is more uniform in size, but in multiparae it is small at each end but large in the middle. It is much more dilatable and larger in the latter, hence operations in nulliparae are comparatively rarely done through the vagina. Anteriorly the vagina in its upper portion is in relation with the bladder. In its lower portion (about one-third) it is in intimate relation with the urethra except at the upper portion of the latter. Posteriorly its upper 1 or 2 cm. (1/4 to 3/4 in.) is in front of the peritoneum and Douglas's pouch, below this lies the rectum, and between it and the surface is the perineal body. Laterally the ureters are close to the vagina and about half way up they empty into the bladder. In its lower portion the vagina is joined by the insertion of the levator ani muscle. The connection of the vagina to the bladder in front and rectum behind is loose, so that in performing operations it is readily separated from these organs. The Ureter in the Female. - The pelvic portion of the ureter in the female is about 10 cm. (4 in.) long. It crosses the pelvic brim at a level with the first piece of the sacrum and passes over either the common iliac artery at its bifurcation or the external iliac at its commencement. It then follows the wall of the pelvis downward just posterior to the ovary and, near the floor of the pelvis, bends forward to pass through the base of the broad ligament, traversing the loose connective tissue (parametrium) and being about 1.5 to 2 cm. (1/2 to 3/4 in.) outside of the cervix. At that point it is crossed by the uterine artery. It then inclines somewhat inward and forward along the sides and anterior wall of the vagina to enter the bladder. Its opening in the bladder is about 2.5 cm. (1 in.) below the level of the external os, which is almost as far down as the middle of the anterior vaginal wall. The ureters run in the bladder wall obliquely for about 2 cm. (3/4 in.) and their openings are from 2.5 cm. to 5 cm. (1 to 2 in.) apart according to the amount of vesical distention (Fig. 460).
Fig. 460. - The ureter, ovarian artery, and uterine artery; showing their relation to the pelvic organs.