Basilar artery fenestration.

The posterior circulation of the brain constitutes the vertebrobasilar system and its branches, which are responsible for about 30% of the brain's blood supply. The aim of this study was to describe the anomalies of the basilar artery, especially fenestrations. For that purpose, we examined 50 patients with computed tomography (CT) angiography during an 8-month period. In the CT reports of 2 (4%) patients of the 50 analysed, fenestration was found at the proximal basilar trunk. The two fenestrations in our series were not associated with aneurysms. No collateral branches originated from the two limbs of the fenestration. In conclusion, basilar artery fenestrations are a rare finding. The data derived from this study are useful teaching material for anatomists, and for the radiologists and neurosurgeons they are important for diagnostic and intervention procedures such as CT, magnetic resonance imaging, angiography, and surgical and endovascular procedures.