The thoracic aorta is part of the
descending aorta, which has different parts named according to their structure or location. The thoracic aorta is a continuation of the descending aorta and becomes the
abdominal aorta when it passes through the
diaphragm. The initial part of the
aorta, the
ascending aorta, rises out of the left ventricle, from which it is separated by the
aortic valve. The two
coronary arteries of the heart arise from the aortic root, just above the cusps of the
aortic valve. The aorta then arches back over the right
pulmonary artery. Three vessels come out of the
aortic arch: the
brachiocephalic artery, the left
common carotid artery, and the left
subclavian artery. These vessels supply blood to the
head,
neck,
thorax and
upper limbs. Behind the descending thoracic aorta is the
vertebral column and the
hemiazygos vein. To the right is the
azygos veins and
thoracic duct, and to the left is the left
pleura and lung. In front of the thoracic aorta lies the root of the left
lung, the
pericardium, the
esophagus, and the diaphragm. The
esophagus, which is covered by a nerve
plexus lies to the right of the descending thoracic aorta. Lower, the esophagus passes in front of the aorta, and ultimately is situated on the left. ==Function==