Morphological Variations of the Circle of Willis in Adult Nigerians: A Cadaveric Study at the University of Nigeria Teaching Hospital, Enugu

The Circle of Willis is a critical anastomotic arterial ring at the base of the brain that ensures collateral cerebral circulation. Variations in its configuration have been associated with increased susceptibility to cerebral ischaemia and aneurysm formation. Despite the clinical significance of these variations, data specific to Nigerian populations remain limited, with most existing literature derived from Western and Asian cohorts. This study aims to describe and classify the morphological variations of the Circle of Willis among adult cadavers at the University of Nigeria Teaching Hospital, Enugu, in the South East geopolitical zone. Using fresh cadaveric specimens sourced from the hospital's anatomy department, detailed dissection and photographic documentation will be conducted. Each arterial component, including the anterior communicating artery, posterior communicating artery, and their tributary vessels, will be measured and classified using the established Kamath classification system. Findings will be compared with published data from West African populations to identify any population-specific trends. The expected outcome is a descriptive profile of Circle of Willis variants applicable to neurosurgical planning and stroke risk stratification in this region. Understanding these anatomical variants is essential for clinicians interpreting angiographic findings and performing cerebrovascular procedures on Nigerian patients. This study contributes foundational morphological data to the growing body of Nigerian anatomical research.

Keywords: Circle of Willis, morphological variation, cerebrovascular anatomy, cadaveric study, Nigeria