Course Dependent Variation of the Vertebral Artery: A Computed Tomography Angiography Studs

Introduction: The primary objective of this study is to determine the variations exhibited by the vertebral artery in the Turkish population when it branches off from the subclavian artery and reaches the cervical vertebrae.
Methods: A retrospective review of computed tomography angiography images from the picture archiving and communication systems (PACS) archive system in the Department of Radiology, between 2000 and 2024, was performed. Digital imaging and communications in medicine (DICOM) format images selected from the PACS archive system according to the exclusion criteria were transferred to Radiant DICOM Viewer (Version 2023.1). The anatomical course of the vertebral artery (right and left) and variations during this course were recorded on the scanned images.
Results: A total of 258 individuals and 516 vertebral arteries (right and left) were analyzed. After analyzing 516 vertebral artery, 3 (0.58%) vertebral artery (1 left, 2 right) entered the transverse foramen at the grade of the 3rd cervical spine, 2 (0.39%) vertebral artery (2 right) at the grade of the 4th cervical spine, 13 (2.52%) vertebral artery (3 left, 10 right) at the grade of the 5th cervical spine, and 498 (96.51%) vertebral artery (254 left, 244 right) at the grade of the 6th cervical spine. As a result of our study, it was observed that the vertebral artery entered the transverse foramen of the 4th and 5th cervical spine, mainly the 3rd cervical spine, outside the normal anatomical course.
Discussion and Conclusion: We believe that our work will contribute to the fundamental anatomical knowledge and treatment approaches in this region.

Keywords: Anatomical variation; Cervical vertebra; Transverse foramen; Vertebral artery