Ascending aorta

Last revised by Assoc Prof Craig Hacking on 22 Apr 2021

The ascending aorta is the first part of the aorta and begins at the sinotubular junction (the junction of the aortic root and ascending aorta) and terminates as it exits the fibrous pericardium where it becomes the aortic arch, in the transthoracic plane (of Ludwig). It is located obliquely just to the left of the midline at the level of the third intercostal space.

Gross anatomy

It normally has only two branches (although technically these usually arise form the aortic root), the right coronary artery and the left coronary artery. These arise from the right and left aortic sinuses (of Valsalva) respectively, which (along with the non-coronary sinus) are out-pouchings of the aortic wall above each cusp of the aortic valve. Immediately above the three aortic sinuses, the normal tubular configuration of the aorta is attained - at the sinotubular junction.

The ascending aorta ascends slightly towards the right of midline where it can be seen as part of the mediastinal outline on a chest radiograph. This should only be the case in the older ectatic or dilated artery. In a young patient, a prominent ascending aorta, especially when combined with signs of left ventricular hypertrophy should raise suspicion of aortic stenosis.

With the pulmonary trunk, the ascending aorta is invested in a common sheath of serous visceral pericardium, anterior to the transverse pericardial sinus.

Related pathology

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Cases and figures

  • Figure 1: diagram - aorta
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  • Figure 2: thoracic aorta
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  • Figure 3: mediastinum (Gray's illustration)
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