The parts around the thoracic aorta are the oesophagus and left intermediate bronchus. The oesophagus, with its accompanying plexus of nerves, lies on the right side of the aorta above. but at the lower part of the thorax it is placed in front of the aorta, and, close to the diaphragm, is situated on its left side. There are branches arising from the thoracic aorta (oesophageal branches) that contribute towards the major supply of blood to the oesophagus. The left bronchial arteries are generally two in number and arise from the thoracic aorta. These provide supply to the left intermediate bronchus.
The parts around the ascending aorta are the right auricle, which lies to the right of the root of ascending aorta. The right auricle is a small conical muscular pouch attached to the right atrium of the heart (as visible in the image). The pulmonary trunk lies to the top left of the ascending aorta. The part visible here is the surrounding the beginning part (it begins at the base of the right ventricle). It is associated with the ventricle just like the aorta is associated with the left atrium, i.e., the outlet vessel.
Coarctation of the aorta involves narrowing of the aorta and it is a heart defect. In order to treat this the part of the aorta can be removed or valves may be replaced. A contraction of the aortic part visible in the axial plane might suggest pneumonia in a child.
The parts around the left atrium are the ascending aorta, superior vena cava and oesophagus. In a certain case of respiration infection, there might be anomalous drainage of the right superior vena cava to the left atrium. The relation of the oesophagus to the aorta and that of the aorta and the left atrium has been mentioned before.