Figure 2: Persistent primitive olfactory artery (PPOA) as a side branch of the precommunicating part (A1) of the right anterior cerebral artery (ACA). It originates from the anterior wall of the A1 (a) and courses to the medial surface of the frontal lobe, where the PPOA gave off a bihemispheric branch (b). Cerebral part (C4) of the right internal carotid artery (1); left C4 (2); right A1 (3); right PPOA (4); right recurrent artery of Heubner (RAH) (5)); anterior communicating artery (ACoA) (6); left A1 (7); left RAH (8); right postcommunicating part (A2) of the ACA (9); left A2 (11).