Anatomical variation in the branching pattern of the aortic arch: a literature review

Background
Many anatomical variations of the branching pattern of the aortic arch have been documented in the literature. These find their origin in alterations to the embryological development of the arch and have significant implications for surgical and radiological interventions.

Methods
Embase and Medline database searches were carried out in June 2021 and identified 1197 articles, of which 24 were considered eligible.

Results
Twenty-eight variations were found. The prevalence of the six main variations found is as follows: normal configuration (61.2–92.59%); bovine arch type 1 (4.95–31.2%); bovine arch type 2 (0.04–24%); origin of left vertebral artery (0.17–15.3%); aberrant right subclavian artery (0.08–3.33%); thyroid ima artery (0.08–2%). Concomitant variations present in conjunction with these variations are also documented, as were other variations which could not be classified into these six groups.

Conclusions
Anatomical variations in the branching pattern of the aortic arch are present in over one-third of individuals in some populations. These are important pre- and intra-operatively during thoracic, neck and thyroid surgery. A greater effort should be employed to construct an official classification to facilitate greater understanding among clinicians.