Arteria lusoria, truncus bicaroticus, variant left vertebral artery

Francis LSB, Gardner MT, Loden

Abstract

The normal aorta has three branches from its arch, the brachiocephalic trunk, the left common carotid and the left subclavian artery. Variations in the branching pattern of the aortic arch are not uncommon. We report a case of aberrant branching of the aortic arch involving 3 variants. This case was observed during cadaveric dissection and a review of the literature indicates that this pattern of branching is uncommon. There was a right retro-oesophageal subclavian artery (arteria lusoria). The right and left common carotid arteries arose from the arch by a short common trunk (truncus bicaroticus). Also, the left vertebral artery arose directly from the aortic arch between the common trunk of the right and left common carotid arteries and the left subclavian artery. In a seminal study done by Liechty et al. they reviewed the branching pattern of the aortic arch in 1000 cadavers, finding thirteen cases of arteria lusoria; eight of these had associated truncus bicaroticus and only one had all three variants. We will be discussing the embryology of these variants and their clinical importance.