Coloured 3D computed tomography (CT) angiogram scan of the pelvis of a patient showing healthy iliac arteries. The two common iliac arteries branch from the aorta (not seen), the body's main artery. Each common iliac artery then further divides into the internal and external iliac arteries at upper centre. The internal iliac artery supplies blood to the viscera and walls of the pelvis, while the external iliac artery supplies the legs. At lower left and right the external iliac arteries branch into the femoral (thigh) arteries.