The descending aorta is the part of the aorta which begins at the aortic arch and then runs down through the chest and abdomen. The descending aorta extends to a point in the lower abdomen where it splits into the common iliac arteries which supply the legs.
The descending aorta is subdivided into two sections: the thoracic aorta and the abdominal aorta. The thoracic aorta travels from the arch of the aorta to the diaphragm, giving off several branches that supply oxygenated blood to the chest cage and the organs within the chest. The second section of the descending aorta, the abdominal aorta, begins at the diaphragm as a continuation of the thoracic aorta and runs down to where the aorta ends by splitting into the two leg arteries. The abdominal aorta supplies oxygenated blood to all of the abdominal and pelvic organs and the legs.