Relation of the vertebral artery segment from C1 to C2 vertebrae: An anatomical study

Introduction: The anatomy of the vertebral artery (VA) at the cranio-vertebral junction is significantly different from the straightforward course in the transverse foramina from C6 to C2vertebrae. Recent methods of fixation of C1 and C2 vertebrae due to different pathologies (trauma,tumors, or infection) are based on trans-articular procedures or direct screws for C1 and C2. Thesemethods of fixation depend on a detailed knowledge of the osseous anatomy of C1 and C2 vertebrae, in addition to their relation to the vertebral artery. Aim: The aim of this work was to obtain anatomical measurements of the vertebral artery segment between C1 and C2 to be considered during cranio-vertebral approaches. Materials and methods: Twenty five osseous specimens of C1 and C2 vertebrae were obtained from anatomy museum and ten adult cadaveric specimens were also studied. The anatomical measurements of vertebral artery were tabulated and graphically presented. The anatomical measurements obtained from C1 and C2 vertebra were statistically analyzed. Results: Twenty five osseous specimens of C1 and C2 vertebrae were examined carefully. The anatomical measurements obtained from C1 vertebra were statistically analyzed. Different measurements of the vertebral artery groove including its length and diameter in addition to the distance between each of the medial and lateral edges of the inner and the outer cortices of the vertebral groove to the posterior tubercle of atlas respectively were measured and tabulated. The segment of VA between C1 and C2, the third and the fourth parts of vertebral artery were dissected in ten adult cadaveric specimens. The anatomical measurements of vertebral artery were tabulated and graphically presented. Conclusion: The vertebral artery adopts a serpentine course in relationship to C1 and C2 vertebrae, making it susceptible to injury during surgical procedures in this region. Comprehensive knowledge of the surgical anatomy is essential before performing surgery around the vertebral artery.