Posterior cerebral artery

Last revised by Craig Hacking on 15 Apr 2023

The posterior cerebral arteries are the terminal branches of the basilar artery and supply the occipital lobes and posteromedial temporal lobes.

The posterior cerebral artery is divided into four (or sometimes five) segments 8,11:

  • P1: pre-communicating segment

  • P2: post-communicating segment

    • from the PCOM around the midbrain

      • P2A (anterior): sub-segment courses through the crural cistern

      • P2P (posterior or ambient): sub-segment courses through the ambient cistern

    • terminates as it enters the quadrigeminal cistern

  • P3: quadrigeminal segment

  • P4: cortical segment

    • ​within the sulci of the occipital lobe

    • e.g. calcarine artery, within the calcarine fissure

  • P5: terminal branches

    • terminal branches of the calcarine artery and parieto-occipital artery 11

The posterior cerebral artery curls around the cerebral peduncle and passes above the tentorium to supply the posteromedial surface of the temporal lobe and the occipital lobe. The visual cortex responsible for the contralateral field of vision lies in its territory. The macular part of the visual cortex often receives a dual blood supply from the PCA and the MCA, which explains the "macular sparing" phenomenon in some patients following a PCA infarct.

The fetal posterior cerebral artery arises as the posterior division of the internal carotid artery. These then fuse in the midline to form the superior most of the basilar artery 9. The proximal portion of the fetal posterior cerebral artery then reduces in caliber remaining as the posterior communicating artery. As such, from an embryologic point of view, the posterior communicating artery is a branch of the internal carotid artery even though in a minority of individuals normal flow in the posterior communicating artery is from posterior to anterior 10.

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