RESUMO
Background: Atherosclerosis of cerebral arteries particularly basilar artery has become common today. Theatherosclerosis of BA can lead to loss of memory, depression and also cerebrovascular accidents. Variations ofthe BA are main cause in the occurrence of cerebrovascular diseases.Context and purpose of study: The knowledge of occurrence of variation of BA can help in early diagnosis andsuccessful surgical intervention. Most of the western studies are mainly based on the radiology. An anatomicalmorphological study of BA and variations will enhance the existing knowledge of BA.Results: The average length of BA is 26.7 mm (with the range of 17.4 mm to 45mm) and the mean diameter is 3.8mm (with the range of 2.1mm to 5.2 mm). The mean angle of formation is 58.6° (with the range between 45° to 70°).In 80% of the specimens the level of formation is normal i.e. at the pontomedullary junction. The position oftermination is normal in 75% of specimens i.e. at the pons midbrain junction.Conclusion: Variations of BA are common both in respect of angle of formation and termination of BA intobranches. Knowledge of the vascular variations will increase the success of the surgical procedures andradiological procedures used in the treatment of vertebro -basilar cerebrovascular pathology.