KEY POINTS

1. Cerebrospinal fluid has many functions.

2. Most cerebrospinal fluid is formed at the choroid plexus of the ventricles.

3. Cerebrospinal fluid flows down a pressure gradient through the ventricular system into the subarachnoid space.

4. Cerebrospinal fluid is absorbed into the venous system.

5. Hydrocephalus is an increased volume of cerebrospinal fluid in the skull.

6. Permeability barriers exist between blood and brain.