第だい四よん脳のう室しつだいよんのうしつMeanings1nounfourth ventricleanatomyAnatomical term for the fourth ventricle of the brain.第だい四よん脳のう室しつは脳のう幹かんの背はい側そくに位い置ちする。The fourth ventricle is located on the dorsal side of the brainstem.