Coloured 3D computed tomography (CT) angiogram scan of the abdomen of a patient showing healthy arteries. The aorta, the body's main artery, runs from upper centre to centre, where it branches into the two common iliac arteries. Each common iliac artery then further divides into the internal and external iliac arteries just below 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.