Posterior cerebral artery

At a glance

English

Posterior cerebral artery

Latin (TA2)

Arteria cerebri posterior

System

Artery

Region

Head

Side

Paired, left and right

About the posterior cerebral artery

The two posterior cerebral arteries are formed where the basilar artery divides at the upper border of the pons. Each one sweeps laterally and backwards around the cerebral peduncle of the midbrain, above the oculomotor nerve and the tentorium, to reach the medial and lower surfaces of the hemisphere. Near its start it is joined by the posterior communicating artery from the internal carotid, so it forms the back of the arterial circle at the base of the brain and links the vertebrobasilar and carotid systems.

Its branches fall into central, choroidal and cortical groups. The central or perforating branches arise close to the origin. Posteromedial branches, together with similar twigs from the posterior communicating artery, pass through the posterior perforated substance to the medial thalamus and the lining walls of the third ventricle; posterolateral branches, given off once the artery has rounded the peduncle, including the thalamogeniculate arteries, supply much of the rest of the thalamus. Medial posterior choroidal branches run forwards under the splenium to the tela choroidea and choroid plexus of the third ventricle, while lateral ones serve the lateral ventricle's choroid plexus along with the fornix, thalamus, caudate nucleus and cerebral peduncle.

The cortical branches supply the occipital lobe and the inferior surface of the temporal lobe. Temporal branches reach the uncus and the fusiform and inferior temporal gyri. The medial occipital artery divides into the calcarine branch, for the cuneus, lingual gyrus and the primary visual cortex, and the parieto-occipital branch to the cuneus and precuneus. In the embryo the vessel grows mainly from the posterior communicating artery; in most adults the basilar origin dominates, but in about a fifth the posterior communicating artery stays the main source, a so-called fetal origin.

Blockage produces varied pictures depending on which branches are hit. Loss of the cortical territory typically causes a homonymous hemianopia on the opposite side, often sparing central vision because the occipital pole also receives middle cerebral blood. Bilateral damage may give cortical blindness, sometimes with denial of the deficit. Medial temporal involvement can affect memory. Occlusion of the central branches gives thalamic syndromes with sensory loss and pain on the opposite side, and midbrain branches may produce a third-nerve palsy with weakness of the opposite limbs (Weber's syndrome).

Course and supply

Arises from

The terminal bifurcation of the basilar artery at the upper border of the pons.

Ends in

Ends in cortical branches, chiefly the calcarine and parieto-occipital arteries, on the medial surface of the occipital lobe.

Supplies

Supplies the occipital lobe including the visual cortex, the inferior and medial temporal lobe, the thalamus, the midbrain and the choroid plexus of the third and lateral ventricles.