FIG 3.

DSA, showing segments and branches of the MMA. A and B, show selective MMA injection from a lateral (A) and frontal (B) view. The MMA bifurcates at the pterional region (green circle) into 2: an anterior (red arrow) and posterior (blue arrow) division. Before its bifurcation, the MMA gives the petrosal branch (Pb), which courses on the petrous apex. The posterior division gives 2 principal branches: the petrosquamosal branch (PSb) and the parieto-occipital branch (POb). The anterior division ends with 2 kinds of terminal branches, visible after common carotid artery injection: the falcine arteries (yellow arrow) (C), which anastomose with branches of the anterior falcine artery from the OA, and contralateral branches (purple arrow) (D) that cross the midline to anastomose with a contralateral MMA.