Hydrocephalus, or ventricular enlargement, may involve some or all of the ventricles, depending on whether there is a specific site of obstruction to CSF flow. The ventricles appear enlarged (ex vacuo) also if there is significant loss of brain tissue.
Clinical:
F-54 with delayed milestones, S/P occipital decompression of Chiari malformation, with progressive gait ataxia, adduction paresis of eyes, nystagmus and dementia