Cerebrospinal fluid

Cerebrospinal fluid is the clear fluid that surrounds the brain and spinal cord. Its primary function is to act as a shock absorber for the brain and spinal cord, but it also plays a role in preventing infection from entering the brain case or the spine. In a normal person, the CSF is created and drained between 3 and 4 times a day.
Because CSF is being continuously created, if it does not drain properly, it can quickly increase pressure in the skull and prevent the correct flow of blood to the brain.
A lumbar puncture is a procedure where a surgeon draws CSF from the spinal column by inserting a syringe between two of the vertebrae. The CSF can then be tested for a number of diseases.
Cerebrospinal fluid at Wikipedia
Category:Anatomy