Anterior communicating These two are interconnected in Cerebral arterial circle Anterior cerebral the cranial cavity to produce a Posterior Middle cerebral communicating cerebral arterial circle (of Willis), Ophthalmic which surrounds the hypophysial fossa(pituitary gland). Posterior cerebral Basilar Right internal carotid Left internal carotid Middle clinoid process Chiasmatic sulcus Optic canal Tuberculum sellae Foramen rotundum Superior orbital fissure Greater wing (of sphenoid) .Opening of carotid canal Hypophysial Groove for tossa middle meningeal Posterior artery Dorsum sellae clinoid process Foramen lacerum Groove and Foramen ovale hiatus for Trigeminal impression Foramen These two are interconnected in the cranial cavity to produce a cerebral arterial circle (of Willis), which surrounds the hypophysial fossa (pituitary gland)