Thoracic aorta

The thoracic aorta (Latin: aorta thoracica, pars thoracica aortae) is the portion of the descending aorta located within the thorax.

Course

The thoracic part of the aorta begins at the lower edge of the 4th thoracic vertebra as the continuation of the aortic arch. The thoracic aorta descends through the posterior mediastinum. It ends anterior to the lower edge of the 12th thoracic vertebra, where it enters the abdomen via the aortic hiatus of the diaphragm. After entering the abdominal cavity, it continues downward as the abdominal aorta. 

Superiorly, the thoracic aorta is situated to the left of the vertebral column, but as it descends, it approaches the midline, and its inferior portion then lies directly anterior to the lower thoracic vertebral bodies.

Branches

On its course, the thoracic aorta gives off a number of branches, including visceral branches to the internal thoracic organs, as well as parietal branches to supply the thoracic muscles.

The visceral branches of the thoracic aorta include the following:

• pericardial branches - supply the dorsal portion of the pericardium;
• bronchial branches - supply the lungs;
• esophageal branches - supply the esophagus;
• mediastinal branches - supply lymph nodes and other tissue in the posterior mediastinum.

The parietal branches include:

• posterior intercostal arteries - supply the intercostal spaces;
• subcostal artery - mainly supplies the flat muscles of the abdominal wall;
• superior phrenic arteries - supply the diaphragm and the suprarenal glands.