term originally used to describe a longitudinal elevation of the rhomboid fossa extending throughout the length of the rhombencephalon and made up of named elevations such as the facial colliculus and the hypoglossal and vagal trigones; now used to describe only the medial elevation in the floor of fourth ventricle immediately rostral to the facial colliculus, the other elevations being separately named. SYN: eminentia medialis, eminentia teres, funiculus teres, round eminence.