The abdominal aorta is the largest artery in the abdomen, extending from the diaphragm to the pelvis. It is a continuation of the thoracic aorta and supplies oxygenated blood to the lower parts of the body, including the organs in the abdomen and the legs. As it descends, the abdominal aorta branches into several important arteries, such as the renal arteries that supply the kidneys and the iliac arteries that lead to the legs. This artery plays a crucial role in maintaining proper blood flow and delivering essential nutrients throughout the lower body.