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Posterior communicating artery

The posterior communicating artery (PCOM) makes up the posterior linkage in the circle of Willis.

Gross anatomy


The PCOM originates from the posterior aspect of the C7 (communicating) segment of the internal carotid artery and extends posteriormedially to anastomose with posterior communicating artery and form part of the circle of Willis


The PCOM gives off many fine, scarcely visible, perforating branches. The largest perforating branch is called the premamillary (or anterior thalamoperforating) artery. 

Vascular territory

Perforators from the PCOM supply:

  • posterior part of the optic chiasm and optic tract
  • posterior part of the hypothalamus and mamillary body
  • part of the thalamus

Variant anatomy

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