Posterior Cerebral Artery

Overview

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

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Origin

Terminal branches of the basilar artery

Segments & Course

P1 – Pre-communicating segment

• Origin: The termination of the basilar artery located within the interpeduncular fossa
• Course: Courses anterolaterally to the posterior communicating artery, passing over the oculomotor nerve.
• Gives off small paramedian arteries that supply the rostral midbrain and thalamoperforating arteries which supply part of the thalamus
• Termination: Terminates at the posterior communicating artery

P2 – Post-communicating segment

• Origin: Segment begins at the posterior communicating artery
• Course: Curves around the ambient cistern of the midbrain and courses posteriorly, running above the tentorium cerebelli.
• The significant branches of this segment are the posterior choroidal arteries, supplies the tela choroidea of the third ventricle and the choroid plexus
• Also gives rise to peduncular perforating arteries that supply the lateral midbrain, as well as thalamogeniculate arteries that supply the ventrolateral portion of the thalamus.
• Further subdivides into:
  • P2A (anterior) sub-segment located within the crural cistern
  • P2P (posterior or ambient) sub-segment located in the ambient cistern.
• Termination: As it enters the quadrigeminal cistern

P3 – Quadrigeminal segment

• Course: Runs posteromedially through the quadrigeminal cistern
• Gives off anterior and posterior inferior temporal arteries
• Termination: As it enters the sulci of the occpital lobe

P4 – Cortical segment

• Most commonly gives rise to the parieto-occipital branches and the calcarine artery, which supplies areas bordering the calcarine sulcus and the medial surface of the occipital lobe.
• Termination: calcarine sulcus.

P5

• The terminal branches of the parieto-occipital and the calcarine arteries are included as the P5 segment.

Branches

• Posterior communicating artery
• Collicular (quadrigeminal) artery
• Choroidal branches (from P2)
  • Medial posterior choroidal arteries
  • Lateral posterior choroidal arteries
• Perforators
  • Anterior thalamoperforator (from PCOM)
  • Posterior thalamoperforator (from P1)
  • Thalamogeniculate perforator (from P2)
  • Peduncular perforator (from P2)
  • Circumflex (long and short)
• Cortical branches
  • Temporal branches
    • Anterior temporal artery
    • Posterior temporal artery
  • Lateral occipital artery
    • Anterior inferior temporal artery
    • Middle inferior temporal artery
    • Posterior inferior temporal artery
  • Medial occipital artery
    • Calcarine artery
    • Parieto-occipital artery
  • Splenial artery

Supply

• Occipital lobe
• Posteromedial temporal lobe
• Midbrain
• Thalamus
• Choroid plexus
• Part of the lateral and third ventricles

Variant Anatomy

• Fetal origin of PCA – PCOM is larger than P1 (unilateral incidence 10%, bilateral incidence 8%)
• PCA fenestration (rare)
• Duplicated PCA (rare, fetal origin and normal origin on same side)
• Common trunk with superior cerebellar artery
• Artery of Percheron