Geometric morphometric study of anterior branches of external carotid artery and carotid bifurcation by 3D-CT angiography

Purpose The aim of our study was to determine the variations of the anterior branches of the external carotid artery (ECA) and investigate the morphometric and geometric features of the anterior branches of the ECA and carotid bifurcation (CB). Methods A total of 563 ECAs were included from 288 patients in the study. Classification and exit angles of anterior branches of ECA and determination of vertebral levels of CB and anterior branches were performed. Results The anterior branch variants of the ECA were observed in 8 different subgroups. The most common variations were type Ia 42.3% (n = 120) on the right and type Ib 40.9% (n = 114) on the left. When looking at the vertebral levels, CB was detected at C4 level in 32.9% of total ECAs (n = 185), STA was at C4 level in 33.4% of total ECAs (n = 188), LA was at C3 level in 50.1% of total ECAs (n = 282), and FA was at C2 level in 37.3% of total ECAs. The mean CB angle in all cases was 59.93 degrees +/- 16.04. In the anterior branches of the ECA in cases belonging to the Type I group, the widest angle belonged to FA (R = 116.88 +/- 27.04 degrees, L = 110.32 degrees +/- 25.94). Conclusion In conclusion, a new classification of the variations of the anterior branches of the ECA was made on the basis of the CTA images to gain more practicality in surgical procedures. This study revealed for the first time the angular and level relationship between CB and ECA anterior branches.