The Posterior Communicating Artery arises from the internal carotid internal to the choroid; it is a small but constant branch: from its origin it takes a direction backwards and inwards to anastomose with the posterior artery of the cerebrum, which is a branch of the basilar trunk.

After having given off the posterior communicating artery, the internal carotid divides into two considerable branches, viz., the anterior and middle arteries of the cerebrum.