What is the neurovascular anatomy relevant to posterior cerebral artery (PCA) stroke?

Updated: Jul 30, 2018
  • Author: Erek K Helseth, MD; Chief Editor: Helmi L Lutsep, MD  more...
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The posterior cerebral arteries (PCAs) are paired vessels, usually arising from the top of the basilar artery and curving laterally, posteriorly, and superiorly around the midbrain. The PCAs supply parts of the midbrain, subthalamic nucleus, basal nucleus, thalamus, mesial inferior temporal lobe, and occipital and occipitoparietal cortices. In addition, the PCAs, via the posterior communicating arteries (PCOM), may become important sources of collateral circulation for the middle cerebral artery (MCA) territory.

Various nomenclature methodologies have been used to describe PCA vascular anatomy. The PCA is divided into P1 and P2 segments by the PCOM. Penetrating branches to the mesencephalon, subthalamic, basal structures, and thalamus arise primarily from the P1 segment and the PCOM. These penetrating arteries include the thalamogeniculate, splenial (posterior pericallosal artery), and lateral and medial posterior choroidal arteries.

The P2 segment bifurcates into the posterior temporal artery and the internal occipital artery. The posterior temporal artery further divides into anterior, middle, posterior, and hippocampal branches. The internal occipital artery divides into calcarine and occipitoparietal branches.

Anatomic localization of the point of vascular occlusion in PCA infarcts may be simplified into the following 2 categories: (1) deep or proximal PCA strokes, causing ischemia in the thalamus and/or midbrain, as well as in the cortex; and (2) superficial or distal PCA strokes, involving only cortical structures. [2, 3]

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