Applied anatomy of A1 segment of anterior cerebral artery

Objective:To study the A1 segment of anteriorg cerebral artery(ACA) via pterional approach under the operative microscope,we expect to provide useful anatomic data for the surgical operation in this area.Method:10 adult cadaveric heads in which the arteries were injected with the colored emulsion were dissected,exposing the A1 segments of anterior cerebral artery via pterional approach under the operative microscope step by step.Making an observation and measuring its structures,perforating branch and adjacent vessel.Result:A1 segment of ACA was found in each cerebral hemisphere.The difference of bilateral A1 segment diameter and length was not significant in the same cadaver heads.Many anatomical variations related to shapes、perforating artery and adjacency were found in A1 segment of ACA.A lot of perforating branches arose from the inferior wall within 3mm distance near the original of all A1 segments Most Heubner's recurrent arteries coursed companying with the distal A1 segments.Conclusion:The variations of A1 segments of anterior cerebral artery are not only related to the formation of anterior communicating artery aneurysms but also provide the difficulty to clip the aneurysms.A1 segment send out a lot of important perforating branches which should be discerned and protected carefully during operation.Well understanding of the microanatomy of A1 segments can provide guidance to the operation,protect the important vessel and nerves,reduce the serious operative complications.