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The ascending aorta and arch of aorta with their branches
pars ascendens aortae
|Supplies||The entire body, with exception of the respiratory zone of the lung|
|Left coronary artery, right coronary artery and continues as the arch of aorta|
|Combination of superior and inferior vena cava and coronary sinus|
The ascending aorta (AAo) is a portion of the aorta commencing at the upper part of the base of the left ventricle, on a level with the lower border of the third costal cartilage behind the left half of the sternum; it passes obliquely upward, forward, and to the right, in the direction of the heart’s axis, as high as the upper border of the second right costal cartilage, describing a slight curve in its course, and being situated, about 6 centimetres (2.4 in) behind the posterior surface of the sternum. The total length is about 5 centimetres (2.0 in).
The aortic root is the portion of the ascending aorta beginning at the aortic annulus and extending to the sinotubular junction. Between each commissure of the aortic valve and opposite the cusps of the aortic valve, three small dilatations called the aortic sinuses.
The sinotubular junction is the point in the ascending aorta where the aortic sinuses end and the aorta becomes a tubular structure.
At the union of the ascending aorta with the aortic arch the caliber of the vessel is increased, owing to a bulging of its right wall.
This dilatation is termed the bulb of the aorta, and on transverse section presents a somewhat oval figure.
The ascending aorta is covered at its commencement by the trunk of the pulmonary artery and the right auricula, and, higher up, is separated from the sternum by the pericardium, the right pleura, the anterior margin of the right lung, some loose areolar tissue, and the remains of the thymus; posteriorly, it rests upon the left atrium and right pulmonary artery.
The only branches of the ascending aorta are the two coronary arteries which supply the heart; they arise near the commencement of the aorta from the aortic sinuses which are opposite the aortic valve.