Objective: In this study, forty dried specimens of atlas and axis vertebrae were examined using direct anatomical measurements. Methods: Various dimensions of the atlas and the axis vertebrae were quantitatively measured, with special emphasis on their relationship with the vertebral artery foramen. Results: As the vertebral artery foramen was present entirely in the transverse process of all specimens, screw implantation in the facet of atlas proved relatively safe. Conclusions: The anatomy of the atlas and axis vertebrae exhibits complex, three-dimensional structures, showing extensive variability in morphology. Characteristics of the atlas and axis vertebrae must be noted before any spinal operation such as transpedicularscrewfixation,transarticularscrewfixation,screwfixationofdensaxis,interspinouswiring,andinterlaminarclamp.