aorta aorta thoracica BTO:0000157 BrendaTissueOBO Thoracic part of aorta: the proximal portion of the descending aorta, which proceeds from the arch of the aorta and gives rise to the bronchial, esophageal, pericardiac, and mediastinal branches, and the superior phrenic, posterior intercostal III to XI, and subcostal arteries; it is continuous through the diaphragm with the abdominal aorta. aorta thoracalis pars thoracica aortae thoracic aorta thoracic part of aorta