The brain has hollow fluid-filled cavities called Ventricles. Inside the Ventricles is a structure that makes clear colorless Cerebrospinal Fluid (CSF). CSF flows within and around the Brain and Spinal Cord to help cushion it from injury. This circulating fluid is constantly being absorbed and replenished.
A balance is maintained between the amount of CSF that is absorbed and the amount that is produced. A disruption or blockage in the system can cause a buildup of CSF, which can cause enlargement of the ventricles (Hydrocephalus) or cause a collection of fluid in the Spinal Cord (Syringomyelia).