Fig. 7From: Measurements of cerebrospinal fluid production: a review of the limitations and advantages of current methodologiesDirect CSF Production Measurement in Cats. A cannula is placed into the aqueduct of Sylvius through the tunnel inside the cerebellar vermis, the outer surface of the cannula is covered by cyanoacrilic gel glue to prevent CSF leakage and the entry of air. The tip of extracranial part of the cannula is used to collect the CSF and measure the ICPBack to article page