The abdominal aorta is a continuation of the descending thoracic aorta as it passes through the diaphragmatic aortic aperture, behind the median arcuate ligament.  It begins at the lower border of the twelfth thoracic vertebra and descends over the lumbar vertebrae and associated anterior longitudinal ligament to terminate over the body of the fourth lumbar vertebra, a little left of the mid-line, by dividing into right and left common iliac arteries.

The abdominal aorta gives rise to anterior visceral (coeliac trunk, superior and inferior mesenteric arteries), lateral visceral (inferior phrenic, suprarenal, renal and gonadal arteries) and posterior parietal (lumbar and median sacral arteries) branches.

NB
Due to the the lumbarization of the first sacral vertebra in this individual, the abdominal aorta atypically terminates at the level of the body of the fifth lumbar vertebra.