Abstract
The circulus arteriosus cerebri (CAC) has been a subject of anatomical study for over three centuries and remains a structure of anatomical and clinical interest due to its highly variable nature. This review highlights how differences in nomenclature, classification systems, sample sizes, and methodologies have contributed to the variability observed in the literature. These factors complicate direct comparisons across studies and may influence the interpretation of clinically relevant data. Of note, such anatomical variations can directly impact clinical diagnosis, surgical planning, and patient outcomes, which highlights the need for accurate and consistent classification of these variations. A historical perspective of the study of the CAC illustrates how evolving technologies and terminology have shaped the current understanding of this structure. Future research may benefit from clearly defined variation criteria, detailed methodological reporting, and careful consideration as to which data are appropriate for comparison. These practices could support more consistent and interpretable findings in the continued study of the CAC and its anatomical variations.