Posterior cerebral artery (PCA)

P1 - Precommunicating segment

Arises from basilar bifurcation, courses in the interpeduncular cistern superiorly to the oculomotor nerve and ends at the posterior communicating artery junction.


Branches:

  1. Thalamoperforating (posteromedial ganglionic) arteries
    • Penetrate the posterior perforated substance
    • Supply:
      • Medial thalamus
      • Hypothalamus
      • Subthalamus
      • Parts of the midbrain tegmentum
      • Walls of the third ventricle

  1. Short Circumferential Arteries
    • Short perforating arteries supply parts of the crus cerebri and adjacent midbrain
    • Supply:
      • Midbrain tectum
      • Superior and inferior colliculi
      • Parts of midbrain tegmentum
      • Medial part of thalamus
      • May supply the subthalamus

  1. Long Circumferential Arteries - typically arise from P2 but may arise from P1
    • Supply:
      • Midbrain tectum
      • Pineal region
      • Quadrigeminal plate
      • Posterior commissure
      • Periaqueductal grey matter
      • May contribute to posterior thalamus and roof of 3rd ventricle

P2 - Ambient segment

Extends from PCom junction to the quadrigeminal cistern. Curves around the cerebral peduncle within the ambient cistern. Runs above the trochlear nerve parallel to basal vein of Rosenthal and optic tract.


Branches:

  1. Thalamogeniculate (posterolateral ganglionic) arteries
    • Perforate posteromedially into the midbrain.
    • Supply:
      • Thalamus including the geniculate bodies and pulvinar

  1. Medial posterior choroidal artery
    • Enters tela choroidea and runs along the roof of the 3rd ventricle.
    • Anastomoses with branches of the lateral posterior choroidal artery
    • Supplies:
      • Small branches to midbrain tegmentum
      • Posterior thalamus
      • Pineal gland
      • Ipsilateral choroid plexus
      • Posterior commissure
      • Roof of 3rd ventricle
      • Habenular nuclei
      • Fornix
      • Part of superior colliculus

  1. Lateral posterior choroidal artery
    • Arises distal and lateral to medial posterior choroidal artery. Passes from the ambient cistern into the choroidal fissure.
    • Anastomoses with branches of the medial posterior choroidal artery
    • Supplies:
      • Ispilateral choroid plexus
      • Posterior thalamus including the pulvinar, lateral geniculate nucleus, and mediodorsal nucleus
      • Hippocampus, especially the fimbia and dentate gyrus
      • Posterior columns and crus of the fornix
      • May supply part of the tail of the caudate nucleus
      • Stria terminalis

  1. Inferior temporal and posterior temporal arteries
    • May anastomose with the middle temporal and angular arteries from MCA territory
    • Supply:
      • Inferior surface of temporal lobe including parts of the fusiform gyrus
      • Inferior surface of occipital lobe
      • Posterior temporal a. may contribute branches to visual cortex

P3 - Quadrigeminal segment

The PCA segment within the quadrigeminal cistern. Extends to calcarine fissure.

No distinct named branches but sometimes the lateral occipital artery may arise from it.


P4 - Calcarine segment

Terminal branches of PCA, above tentorium, in calcarine fissure.


Named branches:
  1. Medial occipital artery
    • Courses along or inside the parietooccipital sulcus and the distal part of the calcarine fissure. Divides into calcarine and parietooccipital and occipitotemporal branches:
      1. Calcarine artery
        • Courses deep in the calcarine fissure
        • Supplies:
          • Cuneus
          • Lingual gyrus
      2. Parietooccipital artery
        • Courses aong the parietooccipital sulcus.
        • Supplies:
          • Upper part of the cuneus
          • Posterior part of the precuneus
      3. Lingual artery
        • Often branch of the calcarine artery, sometimes arises separately
        • Supplies:
        • Lingual gyrus inferior to calcarine sulcus

  1. Lateral occipital artery
    • Lateral terminal branch of the PCA. Passes to the basilar surface of the posterior part of the temporal lobe.
    • Supplies:
      • Lateral occipital lobe
      • Posterior inferior temporal lobe

  1. Occipitotemporal artery
    • Courses laterally and inferiorly along the ventral surface of the occipitotemporal region
    • Travels between the posterior fusiform gyrus and inferior occipital gyrus.
    • May anastomose with branches of the inferior temporal artery or lateral occipital artery.
    • Supplies:
      • Posterior fusiform gyrus
      • Posterior part of the inferior temporal gyrus
      • Occipitotemporal junction
      • Occasionally the lingual gyrus or adjacent inferior occipital gyri

  1. Posterior pericallosal artery
    • Usually a continuation branch near the parietooccipital junction
    • Supplies:
      • Splenium of the corpus callosum
      • Precuneus
      • Posterior part of cingulate gyrus
      • Parieto-occipital sulcus region