See hydrocephalusMeaning “water on (or in) the brain”, this word refers to an anatomical state in which there is an abnormally large volume of cerebrospinal fluid within the head. Most often this excess fluid accumulates within the ventricles of the brain and the word ventriculomegaly may be used synonymously. Some authorities teach that the word ventriculomegaly simply describes large ventricles and that the word hydrocephalus should be reserved to indicate that the enlarged ventricles are generating symptoms. Cerebrospinal fluid may also accumulate over the surface of the brain but inside the dura, in which case the term “external hydrocephalus” is sometimes used. Read more.