Ascending aorta

At a glance

English

Ascending aorta

Latin (TA2)

Aorta ascendens

System

Artery

Region

Trunk

Side

Single, on the midline

About the ascending aorta

The ascending aorta is the short opening stretch of the body's main artery. It leaves the left ventricle at the aortic valve, lying behind the sternum's left half at about the third costal cartilage, and climbs upwards, forwards and to the right, following the long axis of the heart. Some 5 cm long, it ends behind the right side of the sternum, level with the top edge of the right second costal cartilage, where it continues as the arch of the aorta.

Its lowest part is the aortic root, which runs from the ring that anchors the aortic valve (the annulus) to the sinotubular junction. Behind each of the three valve cusps the wall bulges outwards to form an aortic sinus; above them, at the sinotubular junction, the vessel becomes a plain tube. Higher up, the right wall bulges again where the aorta meets the arch, giving the bulb of the aorta. The diameter is normally under about 3.5 to 4 cm in adults, larger with age and body size; anything clearly above that is regarded as dilated, and further widening as aneurysm.

The ascending aorta lies within the fibrous pericardium and shares a sleeve of serous pericardium with the pulmonary trunk. At its start it is covered in front by the pulmonary trunk and the right auricle; higher up, the pericardium, right pleura and lung edge, loose tissue and what is left of the thymus lie between it and the sternum. Behind it lie the left atrium and the right pulmonary artery. On its right are the right atrium and the superior vena cava, and on its left the pulmonary trunk. Its only branches are the right and left coronary arteries, which arise from the right and left aortic sinuses.

Disease here is important. Aneurysm of the ascending aorta and the root, sometimes linked with a bicuspid valve or connective tissue disorders, risks dissection and rupture and is monitored by scans until surgery is needed. Type A aortic dissection starts here and is a surgical emergency. Heavy calcification of the wall, called porcelain aorta, makes clamping during heart surgery hazardous.

Course and supply

Arises from

Leaves the left ventricle at the aortic valve, behind the sternum's left half, level with the third costal cartilage.

Ends in

Continues as the aortic arch level with the top edge of the right second costal cartilage.

Supplies

Carries all the blood leaving the left ventricle into the systemic circulation; through its coronary branches it supplies the heart itself.