RÉSUMÉ
Background: The Circle of Willis plays an important role as cerebral collateral channel. Aneurysms are commonlyarising in the anterior half of the circle of Willis, those originating on the anterior communicating artery areregarded as the most complex. This complexity is caused by the frequent variants of normal anatomy. The twoanterior cerebral arteries, Anterior communicating artery, Artery of Heubner and perforating vessels arisingfrom these vessels are called the anterior cerebral- anterior communicating complex. The anatomy of thiscomplex is characterized by numerous anomalies &variations, so it gains a great surgical importance.AIM: To study the microanatomy of anterior portion of Circle of Wills in south Indian cadavers.Materials and Methods: This study done in 100 formalin fixed human brains obtained from routine dissectionfrom cadavers with 10x magnification. The length, various anomalies noted in the following arteries: A1, A2segments of anterior cerebral artery, anterior communicating artery and photographed for documentation.Results: The mean length of right and left A1 segments of anterior cerebral artery (ACA), anterior communicatingartery (ACoA) was 14.44 mm, 13.61 mm, 2.73 mm. Standard deviation was 2.53, 1.69, 1.16 respectively. HypoplasticA1 segment noted in 6% of right side. In A2 segment of ACA, the Median anterior cerebral artery found in 2% andazygous artery found in 2%. Anterior communicating artery duplicated in 10%, hypoplastic in 6%, fenestrated in16% . ACoA was absent in 2% of specimens.Conclusion: The variations found in our study was more in the ACoA and A2 segment of ACA rather than A1segments of ACA. The knowledge of anatomical variations in this region is essential for neurosurgeons toplanning the neurosurgical procedures to avoid unexpected neurological complications.