Common iliac artery

The common iliac arteries are large, paired blood vessels located in the iliac region. They serve as the terminal branches of the abdominal aorta, forming at its bifurcation at the level of the fourth lumbar vertebra (L4). These arteries are responsible for supplying blood to the pelvis and lower limbs.

After branching from the aorta, each common iliac artery descends posterolaterally in an oblique manner along the medial border of the psoas major muscle (Read more!). They terminate at the level of the pelvic brim anterior to the sacroiliac joints by dividing into two terminal branches:

• External iliac artery (Read more!) - continues to descend, traveling along the medial border of the psoas major; it primarily supplies blood to the lower limb and gives only two side branches; it becomes the femoral artery after passing beneath the inguinal ligament;
• Internal iliac artery (Read more!) - originates posteromedially from the common iliac artery; travels within the pelvic cavity and branches into the anterior trunk and posterior trunk, each giving numerous side branches; supplies blood to the tissue and organs in and around the pelvic cavity.

In adults, the common iliac artery is about 0.3 to 0.4 inches (8 to 10 millimeters) in diameter and 1.18 to 2.36 inches (3 to 6 centimeters) in length. However, the right common iliac artery is usually 0.4 inches (1 centimeter) longer than the left common iliac artery. This is because the aortic bifurcation is positioned slightly to the left side.

The common iliac arteries are crossed by the ureters (Read more!) at the level where they divide into the terminal branches. The common iliac veins are found posterior to the common iliac arteries. The external iliac artery is found lateral to the external iliac vein on the right side. In contrast, on the left side, the external iliac artery lies anteromedial to the external iliac vein.

Although these arteries are major conducting vessels and do not have major side branches, they can give off small side branches to the surrounding tissues, including the local lymph nodes, peritoneum, kidneys, psoas major muscles, and ureters.

If a small artery branches from the common iliac artery and ascends into the abdomen, it is most likely an accessory renal artery supplying the lower pole of the kidney. The middle sacral artery may also originate from the common iliac artery in rare cases.