Uterine artery

Origin and course

The uterine artery is a branch of the anterior division of the internal iliac artery, arising below the obturator artery. It runs inferiorly and medially along the lateral wall of the lesser pelvis, coursing into the inferior part of the broad ligament of uterus called the cardinal ligament.

During its initial course, the uterine artery is found lateral and superior to the ureter for about 2.5 cm and then crosses the ureter anteriorly to its medial side in order to reach the cervix of the uterus. The relationship between the uterine artery and the ureter has important clinical significance, and is remembered by the phrase “water (ureter) under the bridge (uterine artery)”.

Upon reaching the cervix of the uterus on each side, the uterine arteries give off an ascending branch, that courses superiorly alongside the uterus, and a descending branch that runs inferiorly towards the vagina.

Branches and supply

At the level of the cervico-uterine junction, the uterine artery divides into an ascending and descending branch. The uterine artery and its branches constitute the majority of the blood supply of the uterus, playing an important role during processes such as the menstrual cycle and pregnancy.

• Ascending branch: passes superiorly in a tortuous manner along the lateral wall of the body of the uterus towards the uterine tube. Along its course, the ascending branch gives off multiple small branches entering the lateral uterine wall, and ramifies in the myometrium of the uterus into helicine, arcuate, radial, spiral, and basal arteries. The ascending branch continues superiorly until it reaches the uterine tube in the region of the ovarian hilum, where it divides into ovarian and tubal branches. These branches anastomose with the ovarian and tubal branches of the ovarian artery. In summary, the ascending branch supplies the lateral margin of the uterus, medial portion of the ovary and uterine tube.
• Descending branch: passes inferiorly towards the vagina. This vaginal branch anastomoses with branches of the vaginal artery forming two median longitudinal arteries called the azygos arteries of the vagina, which descend along the anterior and posterior wall of the vagina. Along its course, the descending branch supplies the cervix and the vagina.

Anatomical variations

Although it most commonly arises directly from the internal iliac artery, the uterine artery can also arise from the umbilical artery. The uterine artery can also arise as a common trunk with the vaginal, internal pudendal, inferior vesical or middle rectal arteries.