Understanding Cerebrospinal fluid

Cerebrospinal fluid (CSF) is a clear, colourless liquid that bathes the brain and spinal cord.  It is incredibly important to our health and wellbeing but what do we know about it and what mysteries does it hold?

The primary function of CSF is to cushion the brain within the skull and serve as a shock absorber for the central nervous system but it also circulates nutrients and chemicals filtered from the blood and removes waste products from the brain. 

​How is it made?
CSF is produced by the choroid plexus in the brain and then reabsorbed into the bloodstream. What is amazing is that the fluid is continually produced and completely replaced every few hours. Interestingly, the exact method of the formation of the CSF is uncertain. After originating in the ventricles of the brain, it is believed to be filtered through the nervous-system membranes.

The fluid is eventually absorbed into the veins; it leaves the cerebrospinal spaces in a variety of locations, including spaces around the spinal roots and the cranial nerves. 

Movement of the CSF is affected by the downward pull of gravity, the continual process of secretion and absorption, blood pulsations in contingent tissue, respiration, pressure from the veins, and head and body movements.

What is it made of?
CSF is slightly alkaline and is about 99 percent water. There are about 100 to 150 ml of CSF in the normal adult human body.

Why is it so important?
When an individual suffers a head injury, the fluid acts as a cushion, dulling the force by distributing its impact. The fluid also helps to maintain pressure within the cranium at a constant level.  So if there is an increase in the volume of blood or brain tissue, the amount of CSF will decrease to balance this. Conversely, if there is a decrease in the volume of matter within the cranium, as occurs in atrophy of the brain, the CSF compensates with an increase in volume. 

What happens if CSF doesn’t flow well?
When CSF flow is hindered then brain cells can’t receive essential nutrients nor cleanse themselves well. This can cause cell stress that may lead to cell dysfunction. Alzheimer’s and Parkinson’s are associated with a build-up of toxic material in the brain but there is still so much unknown about this area.

Improving the flow
It is interesting that sleep opens the brain-cleansing pathways, kind of an inbuilt detox rhythm!  During sleep the brain’s extracellular space enlarges. This allows more CSF to flow throughout the brain and is a very important reason why we need to sleep.

One primary intent of Craniosacral work is to encourage the flow of CSF. Whilst it is hard to measure the flow of CSF during a treatment, it it interesting to note that many clients often feel like they are falling asleep during treatment, thus indicating another possible way to optimize the size of the space through which CSF flows. As craniosacral work also helps relax the nervous system, another consequence is that people sleep better, which is nature's sure way of improving our CSF flow!

What I do know for sure is that this amazing fluid, that is in direct contact with our brain and spinal cord, that we continually make and replace, holds some mysteries that science has not yet unlocked.....