The anatomy of the median branches of the basilar artery.

The aim of study was the examination of the median branches (MB) of the basilar artery (BA). 783 MB were found in 100 human brainstems injected with coloured latex. The attachment of the MB to the quadrants of the BA's trunk, their structural shape, length of trunks, topographical arrangement (on three vascular levels) and the clinical importance of this vascular pattern was evaluated. The MB arise from Pr and Pl quadrants of the BA's trunk in 100% cases, represent 37.7% of BA's branches and are mostly located in the foramen caecum area (56%). The MB confine the BA's stem mobility on the V CN area and above, because of their shortest trunks especially on these vascular levels. In the examined specimens the MB varied in number from 0 to 22 (mean, 8).