Gliosis and aqueductule formation in the aqueduct of Sylvius.

A study was made of the cerebral aqueducts of 30 children with hydrocephalus but without myelomeningocele. A sequence of events is demonstrated which suggests a mechanism of aqueductule formation and burial of ependymal cells. The cellularity of areas of gliosis may normally decrease and resemble normal neural tissue, but occasionally activity is perpetuated by continuing irritants. The only evidence of gliosis long after the event may be the presence of buried ependymal cells or aqueductules, The presence of a small aqueductal 'ghost' and ciliated columnar epithelial lining suggests an intra-uterine timing of the insult.