Descending aorta: The descending aorta is the part of the aorta, the largest artery in the body, that runs down through the chest and the abdomen. The descending aorta starts after the arch of the aorta and ends by splitting into two great arteries (the common iliac arteries) that go to the legs.
The descending aorta, by convention, is subdivided into the thoracic aorta and the abdominal aorta.
The thoracic aorta, the part of the aorta that runs from the arch of the aorta to the diaphragm, gives off numerous branches that supply oxygenated blood to the chest cage and the organs within the chest.
The other part of the descending aorta, the abdominal aorta, is the final section of the aorta. It 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.
Like other sections of the aorta (the ascending aorta and aortic arch), the descending aorta is an arbitrary anatomic entity. The aorta is one continuous conduit that stems from the left ventricle of the heart to carry blood to most of the body. The descending aorta is nonetheless a hallowed and convenient division of the aorta.
The descending aorta is known in medical Latin variously as the aorta descendens and the pars descendens aortae (under which headings it is often concealed in print medical dictionaries).