Eur J Anat, 16 (2): 150-156 (2012)

Individual variability and marginal types of the human vertebral artery (V3) subject to the skull shape

Maryna Alfaouri-Kornieieva¹, Azmy M. Hadidy², Maher T. Hadidi¹, Darwish H. Badran¹

¹Department of Anatomy and Histology, Faculty of Medicine, University of Jordan, Amman, Jordan ²Department of Diagnostic Radiology and Nuclear Medicine, Hospital of University of Jordan, University of Jordan, Amman, Jordan

ABSTRACT Variability of the third segment (V3) of vertebral artery (VA) in correlation with individual shape of skull was studied by analyses of 32 MRI and angiograms of 64 arteries. According to value of cranial index, the group under research was divided into three subgroups: dolichocephalic (15.6%), mesocephalic (43.8%), and brachycephalic (40.6%). The V3 was studied according to its conventional division into three sections: vertical (vV3), horizontal (hV3), and oblique (oV3), with proximal and distal loop formations along its length. The mean diameter and length of vV3 and hV3 had minimal value in the patients with brachycephalic shape of skull. The angle between bends of proximal loop of V3 progressively increased from 67.5 } 0.75 degree in the dolichocephalic group to 77.1}0.44 degree in the brachycephalic group, while the angle between bends of distal loop was decreasing from the dolichocephalic group (79.6 } 4.7 degree) to the mesocephalic group (74.85}2.4), reaching the minimal value in the brachycephalic group (79.6 } 4.7 degree). In the dolichocephalic group downward deviation of hV3 was more in evidence than in all the rest groups, with inclination to minimal or zero-deviation in brachycephalic group. The results have showed that the anatomical variability of V3 significant correlates with the shape of skull. The findings open up possibilities for primary diagnosis and prognosis of acute and chronic disorders in posterior circulation enabling to choose the individual surgical approach to the craniocervical junction and base of skull.

Keywords: Vertebral artery, V3 segment, Variability, Cranial index, Shape of skull