MATERIAL and METHODS: The origin and branching pattern of AChAs were observed intraoperatively in 130 patients who were operated via a pterional approach at our center.

RESULTS: AChAs arose from the internal carotid artery (ICA) and distal to the posterior communicating artery (PCoA) at a ratio of 70%, from just distal to the original point of the PCoA in 20%, and from just proximal to the ICA bifurcation in 10% of the patients. In 95 cases, AChAs arose from the inferolateral aspect of the ICA in the posterolateral aspect in 27 and from its lateral part in 8 cases. AChAs were found as a single branch at the origins from ICA in 110 patients, as double in 17 cases and as triple in 3 patients.

CONCLUSION: Recognition of anatomical variations and microvascular relationships of AChA will allow neurosurgeons to construct a better and safer microdissection plan, to save time and can prevent postoperative neurological deficits. Keywords : Anatomy, Anterior chorodial artery, Microsurgery, Pterional approach, Variation