Study of variations in posterior communicating artery in human brain

Introduction: Brain is normally supplied by two internal carotid arteries and two vertebral arteries which unite to form the circle of Willis. The danger of intracranial vascular lesion has increased, so a thorough knowledge of arterial circulation of brain is essential. There are variations in the length, diameter and branches of vessels forming the circle of Willis. Posterior communicating arteries are important arteries connecting the carotid and vertebral systems. Materials and Methods: One hundred and four brain specimens were studied. The major blood vessels forming the circle of willis were traced by dissection. Their length, origin, branching pattern and anastomosis were studied, painted and photographed. Results: It was observed that the variations in arteries forming circle of Willis was 54%. Maximum variations were observed in the communicating arteries (29%), of these the variations were more (15%) in the posterior communicating arteries. Conclusion: A gross anatomical study of arteries forming the circle of willis was conducted. The origin course and branching pattern of major arteries forming the circle was studied and tabulated. Maximum numbers of variations were observed in the posterior communicating artery.