Variants of anatomy of the aortic arch and/or of the epiaortic vessels are congenital malformations depending upon an incorrect embryonic development of one or more components of the pharyngeal arches.

These variants could be found in symptomatic patients undergoing CT examination (with tracheal, bronchial or esophageal compression, alterations in the blood flow) as well as collateral asymptomatic finding.

The knowledge of these aberrations should be mandatory in the planning of endovascular as well as surgical treatments in order to reduce procedural complications.

Aortic development takes place during the third week of gestation [1]. The two ventral aortae fuse to form the aortic sac, while the dorsal aortae fuse together to form the descending aorta; between the ventral and dorsal aortic segments, arise and develop six paired pharingeal vascular arches: the proximal segments of the third pair contribute to the formation of the common carotid artery, whereas the distal portions, together with the cranial segments of the dorsal aortae, contribute to form the internal carotid arteries. The artery arising from the left fourth arch forms the segment of the normal and definitive aortic arch; the right fourth arch gives birth to the proximal segment of the right subclavian artery, while the distal segment arises from the distal (cranial) tract of the right root of the dorsal aorta (Fig. 1) [2].

In about 70% of cases, the proximal tract of the right root of the dorsal aorta regresses, leaving a left-descending aorta with a normal branching pattern (from right to left: brachiocephalic trunk (BT), left common carotid artery (LCC) and left subclavian artery (LS)) (Fig. 2, 3) [2].