The common iliac vein is the vein connected to the pelvic region and the leg. It is composed of the internal iliac vein and external iliac vein. These veins transport deoxygenated blood from the pelvic region and legs to the heart via the inferior vena cava.
The abdominal aorta, a major artery that extends into the abdomen from the aorta, divides into the right and the left common iliac artery. These arteries supply oxygenated blood to the pelvic and the legs (lower limbs).