Aim:The study aimed to describe the morphometry of the atlas vertebrae regarding sex and age in posterior cervical surgery, provide a data source for surgery, and compare with other populations. In surgical operations, the morphology and morphometry of the atlas must be known.Material and Methods:Computed tomography images of 300 individuals aged 20–69 and referred to the hospital between 2020 and 2023 were used in retrospective research. The 14 parameters determined were examined in five groups formed by dividing ages into decades. The following parameters were measured: the transverse foramen area (TFA), length of the lateral mass (LLM), weight of the lateral mass (WLM), anteroposterior diameter of the left transverse foramen (ADTF), transverse diameter of the left transverse foramen (TDTF), posterior arch area (PAA), distance from the nearest point of the lateral mass on the posterior arch to the occipital condyle (OLM), posterior arch length (PAL), height of the lateral mass (HLM), and the height of the anterior tubercle of the atlas (HAT). In statistical analysis, the two-sample T-test, one-way ANOVA, and eta-squared (η²) tests were used.Results:The HLM, WLM, PAA, PAL, OLM, HAT, TFA, ADTF, and TDTF were more considerable and statistically significant in males. It was statistically significant that the HAT and OLM were lower in the 2nd decade compared to other decades in females (p < 0.05). In males, the LLM was smaller in the 3rd decade compared to individuals in the 2nd and 5th decades, which was statistically significant (p < 0.05).Conclusion:Based on the data presented, the present study will guide individuals in producing more appropriate screws (diameter, length) and safe surgical mediolateral angulation for the anatomical distinction between individuals’ sexes and ages.