The aorta is the largest artery in the human body. It carries oxygen-rich blood from the heart and travels downward, behind the lower abdomen where it splits into the common iliac arteries which carry blood to the right and left side of the lower body. Each common iliac artery, then splits again, into an external and internal iliac artery and becomes the two common iliac arteries. The internal iliac artery supplies blood to the pelvis and buttocks while the external iliac artery continues to the groin and becomes the femoral artery.

