TRUE about posterior communicating aery is ?

Posterior communicating arises from the internal carotid aery before it bifurcates into anterior and middle cerebral aery. It communicates with the posterior cerebral aery and is a pa of the circle of Willis. Circle of willis: it is an anastomosis of internal carotid and veebral aery seen at the base of the brain. This communicating pathway allows equalization of blood-flow between the two sides of the brain, and permits anastomotic circulation, should a pa of the circulation be occluded. Vessels of circle of willis: it is formed in front by the anterior cerebral aeries, branches of the internal carotid, which are connected together by the anterior communicating; behind by the two posterior cerebral aeries, branches of the basilar, which are connected on either side with the internal carotid by the posterior communicating aery. Anterior cerebral aery (left and right) Anterior communicating aery Internal carotid aery (left and right) Posterior cerebral aery (left and right) Posterior communicating aery (left and right) Ref: Thieme atlas of anatomy: Head and neuroanatomy. Vol. 3, By Michael Schunke, Erik Schulte, Udo Schumacher, Jurgen Rude, page 246