Internal iliac artery is short thick vessel, a branch of common iliac artery. It arises from the bifurcation of the latter. It forms the major blood supply of the organs and structures within the pelvis. It also supplies the perineum, the pelvic walls and the buttocks.
The internal iliac artery arises from the bifurcation of the common iliac artery in front of the sacroiliac and lumbosacral joints of the pelvis.
It passes down into the pelvis to the upper margin of the greater sciatic foramen. At this point, the artery divides into anterior and posterior divisions, each of which gives a number of branches to supply pelvic viscera, perineum, pelvic walls and buttocks.
The artery ends by dividing into anterior and posterior division, at the upper margin of the greater sciatic foramen. Each division gives a number of branches as described below.
Branches of anterior division:
- Umbilical artery:
It represents the patent part of the embryonic umbilical artery (Note: The non patent part forms the median umbilical ligament). It gives rise to the superior vesical arteries. In males, it also gives rise to the artery of vas deferens.
- Obturator artery:
It runs along the lateral wall of the pelvis along the obturator nerve and leaves the pelvis through obturator canal.
- Inferior vesical artery:
It supplies the base of the bladder. In addition, it also supplies the prostate and seminal vesicle.
- Middle rectal artery:
It supplies the lower rectum and anastomoses with the superior and inferior rectal arteries.
- Internal pudendal artery:
This artery leaves the pelvis through the greater sciatic foramen and enters the gluteal region. It then enters the perineum by passing through the lesser sciatic foramen. It then supplies the muscles of anal canal and perineum. It also supplies the skin of perineum.
- Inferior gluteal artery:
This artery leaves the pelvis through the greater sciatic foramen and supplies the muscles of gluteal region.
- Uterine artery:
It runs on the floor of the pelvis and passes above the lateral fornix of vagina to supply the uterus. During its course, it crosses the ureter superiorly.
- Vaginal artery:
In females, the inferior vesical artery is replaced by the vaginal artery, which supplies the vagina and the base of bladder.
Branches of posterior division:
- Iliolumbar artery:
It ascends across the pelvic inlet and supplies the iliolumbar region.
- Lateral sacral artery:
This artery ascends in front of the sacral plexus. It gives branches to neighboring structures.
- Superior gluteal artery:
It leaves the pelvis through the greater sciatic foramen and supplies the gluteal region.