AIMS AND OBJECTIVE : A major part of brain is supplied by the branches of two internal carotid arteries and two vertebral arteries. A significant anastomosis, the Circle of Willis exist between the carotid and vertebral arterial systems. An understanding of the distribution of the arteries is very important.As the neurological signs depends on the site of lesion.

Material and methods: The study was conducted on 45 adult brain specimens of  both sexes in human cadavers.The collected specimens were preserved in 10% formalin.The Circle of Willis of each brain was dissected with care.

Results: Variations in anterior segment of  Circle of  Willis in brain specimens includes – duplicity, fenestration, trifurcation and absence of arteries.

Conclusion: Various diseases of  arteries of brain like cerebro – vascular attack, aneurysm, haemorrhage etc. are related to the anatomic patterns of  the Circle of Willis.The knowledge of which is of considerable help to neurosurgeons.