The two posterior cerebral arteries are the end branches of the basilar artery, at the top of the brainstem. Each curves back around the midbrain to the underside of the temporal lobe and the inner face of the occipital lobe; it supplies the occipital lobe, the inner and under faces of the temporal lobe and, through small branches near its start, much of the thalamus. [1]
Lit: both posterior cerebral arteries, left and right: the precommunicating part (P1, also a link of the circle of Willis), the postcommunicating part, the lateral and medial occipital arteries with the anterior and middle temporal branches, and the posteromedial central, thalamogeniculate and posterior medial choroidal branches. Every other artery shows in a darker colour. [2][1]
The 3D brain needs JavaScript. The text below still says where the posterior cerebral artery is and what it does.
Slice
Opens with the blood-supply layer on (about 0.8 MB) and a side (sagittal) slice, so the artery is seen curving back from the top of the basilar under the temporal lobe to the inner face of the occipital lobe. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
The two arteries arise from the end of the basilar artery, where it divides at the top of the brainstem. [1][3]
That basilar artery is formed where the two vertebral arteries merge; they enter the skull through the foramen magnum, so the posterior cerebral arteries carry the back (vertebral) blood supply rather than the carotid one. [4]
Its course is divided into four segments: P1 (precommunicating) from the basilar to the posterior communicating artery; P2 (postcommunicating) around the midbrain; P3 (quadrigeminal) back through the quadrigeminal cistern; and P4 (cortical) in the sulci of the occipital lobe. [1]
Before birth it begins as a continuation of the posterior communicating artery; in most adults it draws mainly on the basilar, but in about 19% the posterior communicating artery stays the main source. [1]
What it does
It supplies the occipital lobe and the medial (inner) and inferior (under) faces of the temporal lobe. [1]
Deep: small thalamoperforating branches from its start supply the inner surfaces of the thalami and the walls of the third ventricle; branches from where it turns around the cerebral peduncle supply a considerable part of the thalamus. [1]
Its posterior choroidal branches run forward beneath the back (splenium) of the corpus callosum to the choroid plexus of the third and lateral ventricles, with small branches to the cerebral peduncle, fornix, thalamus and caudate nucleus. [1]
Cortex: its temporal branches feed the uncus, the fusiform gyrus and the inferior temporal gyrus; the calcarine branch the cuneus, the lingual gyrus and the back of the outer occipital lobe; the parieto-occipital branch the cuneus and precuneus. [1]
Other names
Often shortened to PCA (Latin: arteria cerebri posterior). Its parts are named P1 to P4, from the basilar out to the occipital cortex. [1]
Size
On this model the left and right posterior cerebral arteries with their branches fit in a box about 112 mm front to back, 114 mm side to side and 66 mm top to bottom (the box they fit in, not their volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.