BACKGROUND: The aim of the present study was to characterize the anatomy of the posterior inferior cerebellar artery (PICA) in a Polish Caucasian population by assessing its presence, origin pattern, and selected morphometric features, as well as evaluating possible side-, sex-, and age-related differences. MATERIALS AND METHODS: In the present study, a retrospective analysis of 168 of 200 sides from consecutive patients who underwent head and neck computed tomography angiography (CTA) was performed. Morphometric characteristics of the PICA and adjacent anatomical structures were assessed across 14 categories. RESULTS: The PICA was observed in 142 cases (84.5%), whereas in the remaining 26 cases (15.5%), the PICA was not visualized on CTA. The PICA originated from the vertebral artery (VA) in 132 cases (93.0%) and from the basilar artery (BA) in 10 cases (7.0%). The median diameter of the PICA at its origin was 2.35 mm (LQ = 2.05; UQ = 2.63), whereas its median cross-sectional area was 3.35 mm² (LQ = 2.65; UQ = 3.94). CONCLUSIONS: The PICA demonstrates considerable anatomical variability in terms of its presence and origin. In the studied population, the VA constituted the predominant source of this vessel, whereas BA origin represented a less common configuration. Morphometric analysis revealed measurable differences between sides and sexes for selected parameters, whereas age did not appear to significantly influence PICA dimensions. The measurements obtained provide additional quantitative data regarding the proximal morphology and trunk configuration of the artery in a CTA-based cohort. Such information may contribute to a more precise anatomical understanding of the posterior circulation. These findings highlight the importance of recognizing PICA variability during radiological evaluation and in surgical procedures involving the posterior fossa and craniovertebral junction.