Postcommunicating part; A2 segment

The postcommunicating part of anterior cerebral artery (A2 segment) extends from the anterior communicating artery (AComm) to the bifurcation forming the pericallosal and callosomarginal arteries. The recurrent artery of Heubner (distal medial striate artery), which irrigates the internal capsule, usually arises at the beginning of this segment near the AComm. Two branches arise from this segment:

• Orbitofrontal artery (medial frontal basal): Arises a small distance away from the AComm
• Frontopolar artery (polar frontal): Arises after the orbitofrontal, close to the curvature of A2 over the corpus callosum. It can also originate from the callosal marginal.