an artery of the brain that arises from the terminal bifurcation of the basilar artery and passes above the oculomotor nerve to curve around the midbrain above the level of the tentorium cerebelli. Its branches supply blood to the region of the third ventricle, including the thalamus and choroid plexus, the occipital lobe and the inferior surface of the temporal lobe, and the lingual, fusiform, and inferior temporal gyri.