hydrocephaly
- n an abnormal condition in which cerebrospinal fluid collects in the ventricles of the brain; in infants it can cause abnormally rapid growth of the head and bulging fontanelles and a small face; in adults the symptoms are primarily neurological
- The Aleutian skull appeared perfectly normal, with no evidence of giantism which would have thickened it, or of hydrocephaly ("water on the brain") which would have deformed it.