Common iliac aa.

The common iliac arteries are two large arteries that originate from the aortic bifurcation at the level of the fourth lumbar vertebra. They bifurcate into the external iliac artery and internal iliac artery.

They are about 4 cm long in adults and more than a centimeter in diameter. The arteries run inferolaterally, along the medial border of the psoas muscles to their bifurcation at the pelvic brim, in front of the sacroiliac joints.

The common iliac artery, and all of its branches, exist as paired structures (that is to say, there is one on the left side and one on the right).

The distribution of the common iliac artery is basically the pelvis and lower limb (as the femoral artery) on the corresponding side.