communicating hydrocephalus /kəmyo̅o̅″nikā′ting/ [L, communicans + Gk, hydor, water, kephale, head] , a form of hydrocephalus in which there is an increase in cerebrospinal fluid that involves the entire ventricular system and the subarachnoid space. It is caused by an abnormality in the ability to absorb fluid in the subarachnoid space. No obstruction exists in the ventricular pathways.
