CSF is located in all four ventricles. Fluid flows from the two lateral ventricles via the foramen of Monro into the third ventricle, then through the aqueduct of Sylvius into the fourth ventricle.

Since the CSF opening pressure was slightly elevated, a computed tomography scan was performed immediately after the spinal tap which revealed an inclusion of air within the fourth ventricle ...

This fluid circulates through the ventricles of the brain, the central canal of the spinal cord and the subarachnoid space surrounding the brain and spinal cord. CSF has several critical functions.