Anatomical variations of posterior cerebral and posterior communicating artery of circle of willis – a cadaveric study

Introduction: The Circle of Willis is a vascular network formed at the base of skull in the interpeduncular fossa. Its anterior part is formed by the anterior cerebral artery, from either side. Anterior communicating artery connects the right and left anterior cerebral arteries. Posteriorly, the basilar artery divides into right and left posterior cerebral arteries and each joins to ipsilateral internal carotid artery through a posterior communicating artery. Anterior communicating artery and posterior communicating arteries are important component of circle of Willis, acts as collateral channel to stabilize blood flow. In the present study, anatomical variations in the circle of Willis were noted.
Material and Methods: 75 apparently normal formalin fixed brain specimens were collected from human cadavers. 54 Normal anatomical pattern and 21 variations of circle of Willis were studied. The Circles of Willis arteries were then coloured, photographed, numbered and the abnormalities, if any, were noted.
Result: Twenty one (21) variations were noted. The most common variation observed is in the Posterior communicating arteries, and posterior cerebral artery was found in 21 specimens.
Conclusion: Knowledge on of variations in the formation of Circle of Willis, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in the neurovascular procedures.