Membranous occulusion of the aqueduct of Sylvius.

Two cases of membranous occlusion of the aqueduct of Sylvius are presented. The role of Conray ventriculography in the precise diagnosis of this condition is stressed. Both cases have been operated upon, and the membranes perforated by catheterisation. The catheter was left in the aqueduct in one case. One of the patients was cured, the other died. Membranous occlusion of the aqueduct of Sylvius is a rare cause of hydrocephalus. Occurrence of two cases within a four-month period attracted our attention to this disorder.