Fact-sheet: Normal variant - Cardiac and vascular
Updated on 09/17/2021 at 12:16 PM
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Definition
Right-sided aortic arches occur in 0.05 to 0.1% of adults.
When a right-sided aortic arch is associated with an aberrant left subclavian artery, this is referred to as Neuhauser anomaly (15 to 20% of symptomatic aortic arch anomalies).
Embryologic recall:
Aortic arches are numbered from the cephalic end of the embryo (I to VI).
Bilateral connections (paired ventral and dorsal aortas).
Fusion of the dorsal aortas to form a single vessel.
During embryogenesis: modification of these aortic segments (regression, change in length, change in position).
- I and II are atrophic.
- III and IV give rise to the aortic arch and great vessels.
- V degenerates.
- VI is the origin of the pulmonary arteries and ductus arteriosus.
The regression or persistence of these segments may explain the various anomalies:
- Complete involution of the left arch between the left subclavian artery and the descending aorta.
- Formation of a double aortic arch due to persistence of the right dorsal artery and the right 4th aortic arch.
- Formation of an aberrant right subclavian artery due to persistence of the right dorsal aorta.
- Etc.