An elderly man reports difficulty swallowing solid food. Barium swallow shows a vessel compressing the oesophagus from behind at the level of the thoracic inlet. This aberrant right subclavian artery (arteria lusoria) arises embryologically from:

• A Persistence of the second arch (stapedial) artery
• B Persistence of the right sixth arch artery
• C Enlargement of the right seventh intersegmental artery connected to a persistent right aortic arch
• D Regression of the proximal right fourth arch with persistence of the distal right dorsal aorta ✓

Explanation

Normally the right fourth arch persists proximally as the proximal right subclavian while the distal right dorsal aorta regresses. If the right fourth arch segment between the common carotid and subclavian origins regresses abnormally, the right subclavian arises instead as the last branch of the aortic arch from the distal right dorsal aorta and seventh intersegmental artery, passing behind the oesophagus to cause dysphagia lusoria. The right sixth arch normally regresses entirely, and the stapedial artery relates to the middle ear.

Reference: Langman's Medical Embryology, 14th ed.

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Written and medically reviewed by the StethoPrep medical team.