A rare case of ruptured aneurysm associated with multiple $A_1$ fenestrations resembling plexiform network was demonstrated by 3D angiography. A 56-year-old female presented with a ruptured aneurysm in the $A_2$ segment of the left distal anterior cerebral artery associated with the right $A_1$ fenestration. The ruptured aneurysm was occluded with surgical neck clipping via interhemispheric approach without neurological deficit. Plexiform fenestrations of the right distal $A_1$. opposite side to the left ruptured $A_2$ aneurysm, were clearly visible on postoperative 3D angiography. Our case may strongly support the theory described by Paget, namely that a remnant of the plexiform anastomosis between the primitive olfactory artery and $A_1$ segment is the source of such fenestration.