It is a short, thick vessel, smaller than the external iliac artery, and about 4 cm in length.
The following are relations of the artery at various points: it is posterior to the ureter, anterior to the internal iliac vein, the lumbosacral trunk, and the piriformis muscle; near its origin, it is medial to the external iliac vein, which lies between it and the psoas major muscle; it is above the obturator nerve.
The following are the branches of internal iliac artery. Because it is variable, a listed artery may not be a direct branch, but instead might arise off a direct branch.
|Posterior||Iliolumbar artery||lumbar and iliac branches||psoas major muscle, quadratus lumborum muscle, iliacus muscle|
|Posterior||Lateral sacral arteries||superior and inferior branches||anterior sacral foramina|
|Posterior||Superior gluteal artery||-||greater sciatic foramen|
|Anterior||Obturator artery (occasionally from inferior epigastric artery)||-||obturator canal|
|Anterior||Inferior gluteal artery||-||greater sciatic foramen|
|Anterior||Umbilical artery||superior vesical artery (usually, but sometimes it branches directly from anterior trunk)||medial umbilical ligament|
|Anterior||Uterine artery (females) or deferential artery (males)||superior and vaginal branches||uterus, vas deferens|
|Anterior||Vaginal artery (females, can also arise from uterine artery)||-||vagina|
|Anterior||inferior vesical artery||-||urinary bladder|
|Anterior||Middle rectal artery||-||rectum|
|Anterior||Internal pudendal artery||many branches - see article for details||greater sciatic foramen|
At birth, when the placental circulation ceases, the pelvic portion only of the umbilical artery remains patent gives rise to the superior vesical artery (or arteries) of the adult; the remainder of the vessel is converted into a solid fibrous cord, the medial umbilical ligament (otherwise known as the obliterated hypogastric artery) which extends from the pelvis to the umbilicus.
The lengths of the common iliac and internal iliac arteries bear an inverse proportion to each other, the internal iliac artery being long when the common iliac is short, and vice versa.
The right and left hypogastric arteries in a series of cases often differed in length, but neither seemed constantly to exceed the other.