Communicating hydrocephalus associated with deficient dysplastic parasagittal arachnoidal granulations

✓ Marked diminution of arachnoidal granulations with abnormality of those remaining is presented as a cause of communicating hydrocephalus in two children. Although this underlying abnormality has been alluded to in the past, it has not been adequately documented. The authors believe their observations constitute sufficient evidence to warrant consideration of this entity as one of the causes of communicating hydrocephalus.