The structure indicated is the descending aorta.
consist of the ascending aorta
, the aortic arch
, and the descending aorta
. The descending aorta is the largest artery
in the human body and consists of a thoracic part
and an abdominal part
. The descending aorta passes through the aortic hiatus
of the diaphragm
together with the azygos vein
and thoracic duct
to enter the abdominal cavity where it is then referred to as the abdominal aorta
. The abdominal aorta terminates by dividing at the aortic bifurcation
into the common iliac arteries
at the level of the fourth lumbar vertebra.