Internal iliac artery

At a glance

English

Internal iliac artery

Latin (TA2)

Arteria iliaca interna

System

Artery

Region

Trunk

Side

Paired, left and right

About the internal iliac artery

The internal iliac artery, once called the hypogastric artery, is the chief pelvic artery. It begins where the common iliac artery forks, in front of the sacroiliac joint at about the level of the lumbosacral disc. It is short and stout, usually around 3 to 4 cm long and narrower than its partner, the external iliac artery, which carries on into the lower limb.

From its origin it drops into the pelvis towards the top of the greater sciatic foramen, where it normally splits into an anterior and a posterior trunk. The ureter crosses in front of it. Behind it lie the internal iliac vein, the lumbosacral trunk and piriformis, and near its start the external iliac vein lies lateral to it, between the artery and psoas major. The obturator nerve runs below and lateral to it. Its length varies and is inversely related to that of the common iliac artery; the level of division ranges from the upper sacrum to the top of the sciatic foramen.

The branching pattern is variable, so a vessel may arise directly or from another branch. As a rule the posterior trunk gives the iliolumbar, lateral sacral and superior gluteal arteries, which go to the pelvic wall and buttock. The anterior trunk supplies the bladder, the rectum and the other pelvic organs, and gives the obturator, inferior gluteal and internal pudendal arteries to the medial thigh, buttock and perineum. Its first branch, the umbilical artery, stays open only in its first part, which gives the superior vesical arteries; beyond them it becomes the fibrous medial umbilical ligament.

When the artery is tied, for example to control pelvic bleeding, blood still reaches the pelvis through several links: middle rectal with superior rectal branches from the inferior mesenteric artery, iliolumbar with the last lumbar artery, and lateral sacral with the median sacral artery. It is also a common site for treating pelvic bleeding by blocking the vessel through a catheter.

Course and supply

Arises from

Begins where the common iliac artery forks, in front of the sacroiliac joint at the level of the lumbosacral disc.

Ends in

Splits close to the top of the greater sciatic foramen into an anterior trunk (visceral, obturator, inferior gluteal and internal pudendal branches) and a posterior trunk (iliolumbar, lateral sacral and superior gluteal arteries).

Supplies

Supplies the pelvic walls and organs, the buttock, the perineum and the adductor compartment of the thigh.