CEREBRAL SPINAL FLUID (CSF)

• CSF is formed by the choroid plexus of the lateral ventricles and 3rd ventricle.
• CP generates approximately 400-500 ml of CSF per day.
• Total volume at one time is about 150 ml, equally distributed between the brain and cord

Path of CSF throughout the CNS:

CSF flows from the lateral ventricles (1st & 2nd) through the Foramen of Monroe to the 3rd ventricle through the Aqueduct of Sylvius to the 4th ventricle.  From the 4th ventricle the CSF enters the subarachnoid space through several openings.  In the middle, CSF travels through the Foramen of Magendie to the Cisterna magna.  In the sides/lateral, CSF travels through the Foramen of Luschka to the Cerebellopontine Angle Cistern. From there the CSF distributes to the spinal cord and around the brain.  It is reabsorbed by the arachnoid villi (smaller) and the arachnoid granulations  (larger).  These are apart of the arachnoid membrane.

Normal ICP: 5-15 mmHg (some institutions up to 20 mmHg)