Posterior communicating artery
The posterior communicating artery (latin: arteria communicans posterior) is a branch of the internal carotid artery that participates in forming the circle of Willis.
The posterior communicating artery arises from the posterior aspect of the internal carotid artery. It passes backwards above the oculomotor nerve and anastomoses with the posterior cerebral artery, forming the circulus arteriosus or the circle of Willis around the interpeduncular fossa. The posterior communicating artery connects the internal carotid artery, anterior cerebral and middle cerebral arteries and the posterior cerebral artery with each other.
Small side branches arise from the posterior communicating artery that supply the posterior perforated substance.
The posterior communicating artery provides blood supply to the medial thalamic surface and the walls of the third ventricle.