The union of the choroid plexus of the lateral ventricle with that of the third ventricle at the interventricular foramen (of Monro). ... (05 Mar 2000) ... 
Type: Term Pronunciation: pōr′ti-plek′sŭs Definitions: 1. The union of the choroid plexus of the lateral ventricle with that of the third ventricle at the interventricular foramen (of Monro).