[[Cerebrospinal fluid]] (CSF) [[external drainage]] devices are used to drain CSF and to monitor the flow of CSF from the [[ventricular system]] in order 

(1) to control intracranial pressure (ICP)

(2) to evaluate CSF chemistry and cytology

(3) to provide temporary egress for CSF in patients with infected or malfunctioning CSF shunts.

[[External lumbar cerebrospinal fluid drainage]]