The anatomy of the posterior cerebral artery - a detailed analysis

The aim of this study was to comprehensively characterize posterior cerebral artery (PCA) anatomy by assessing the prevalence of adult, transitional, and fetal PCA configurations, as well as evaluating side- and sex-related differences and age-related correlations.

Computed tomography angiography (CTA) examinations of the head and neck from 100 consecutive patients were evaluated.

The final study group included 176 sides. In all analyzed cases, the PCA was present and originated from the basilar artery (BA). Posterior communicating artery (PCoA) was observed in 130 cases (73.9%). In the remaining 46 cases (26.1%), the PCoA was aplastic. A duplicated PCoA was identified in five cases (2.8%). The median diameter of the PCA at its origin was 3.20 mm [lower quartile (LQ) = 2.90; upper quartile (UQ) = 3.47], while its median cross-sectional area was 6.12 mm² (LQ = 5.10; UQ = 7.05). The most common variation of the PCA, according to the classification by Nas et al., was the adult type (n = 103; 82.4%). The fetal and transitional types occurred in 17 (13.6%) and 5 (4.0%) cases, respectively.

The present study emphasizes that variability of the PCA and PCoA is the rule rather than the exception and should be regarded as a clinically meaningful feature of cerebral circulation. The high prevalence of incomplete or atypical posterior circle configurations highlights the need for careful, individualized interpretation of neuroimaging, particularly in the context of ischemic stroke mechanisms, collateral capacity, and treatment planning. Demographic influences on vascular morphology further support the importance of considering patient-specific factors rather than relying on simplified anatomical models. Overall, consistent definitions and population-based data are essential for translating anatomical knowledge of the posterior circulation into reliable clinical and radiological practice.