Definition of Aqueduct of Sylvius

Aqueduct of Sylvius: A canal between the third and fourth ventricles in the brain within the system of four communicating cavities that are continuous with the central canal of the spinal cord. The ventricles are filled with cerebrospinal fluid, which is carried by the aqueduct of Sylvius.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=9175
Last Editorial Review: 3/19/2012