descending aorta descending aorta in human anatomy, the descending aorta is part of the aorta, the largest artery in the body. the descending aorta begins at the aortic arch and runs down through the chest and abdomen. the descending aorta anatomically consists of two portions or segments, the thoracic and the abdominal aorta, in correspondence with the two great cavities of the trunk in which it is situated. within the abdomen, the descending aorta branches into the two common iliac arteries which serve the pelvis and eventually legs. descending aortaplan of the branches.the thoracic aorta, viewed from the left side.detailsprecursordorsal aortasourceascending aortabranchesthoracic aortaabdominal aortaidentifierslatinaorta descendens, pars descendens aortaeta98a12.2.10.001ta24185fma3784anatomical terminology the ductus arteriosus connects to the junction between the pulmonary artery and the descending aorta in foetal life. this artery later regresses as the ligamentum arteriosum.