Photo by Robina Weermeijer on Unsplash

Cerebrospinal fluid (CSF): Meaning, production, circulation and function

 

What is CSF?

CSF is an abbreviation for cerebrospinal fluid. This cerebrospinal fluid is a clear, colourless watery body fluid that surrounds the brain and spinal cord. It also acts as a liquid cushion for the brain and spinal cord. The brain and spinal cord make up your central nervous system.

Your central nervous system controls and coordinates everything you do including, muscle movement, organ function, and even complex thinking and planning. CSF is an ultrafiltrate of blood plasma and is contained within the subarachnoid space and the central canal of the spinal cord.

 

CSF PRODUCTION

CSF is produced by specialized ependymal in the choroid plexus which can be found in the two lateral ventricles, and in the roof of the third and fourth ventricles of the brain. Around 500 ml is generated each day, with around 125-150ml being present in the body at any one time.

 

CSF CIRCULATION

CSF is produced continuously which keeps the fluid in circulation around the central nervous system. CSF circulates within the ventricular system of the brain but an abnormal accumulation of CSF in the ventricles of the brain or obstruction of the passage of CSF is known as Hydrocephalus. So Basically, the fluid will move from the lateral ventricle to the third and then to the fourth ventricle. From the fourth ventricle, the fluid moves out into the subarachnoid space and/or the central canal of the spinal cord.

 

FUNCTIONS OF CSF

Four Main Functions of CSF:

Protection – CSF protects the brain and spinal cord from trauma. It acts as a shock absorber preventing damage from occurring to the brain when the cranium is jolted/hit.

Homeostasis – regulates the distribution of metabolites surrounding the brain keeping the environment ideal to prevent any damage to the nervous system.

Nourishment – CSF supplies nutrients to nervous system tissue.

Clearing waste – CSF removes waste products from cerebral metabolism. How? -waste products produced by the brain move into the CSF which then clears out through the arachnoid granulations into the venous sinus so it can be absorbed into the bloodstream.

 

HOW CSF SAMPLE IS TAKEN

• CSF sample is taken using a lumbar picture method which takes less than 30min if the doctor knows what he is doing.
• A lumbar puncture involves taking the CSF from the lower back
• You would be asked to lean over so your spine can be curled forward or you may have to lie on your side curling your spine forward
• After staying in the right position, your back would be properly sterilised with iodine to reduce the risk of infection
• You would be injected with anaesthetic so you won’t feel pain.
• A numbing cream or spray could also be applied to your skin.
• Once the area is fully numb, your doctor inserts a thin spinal needle between two vertebrae. {A special type of X-ray called fluoroscopy is sometimes used to guide the needle}

PS: Try not to move during the procedure to avoid trauma to the spine,

• A manometer is used to measure the pressure inside the skull
• The doctor will withdraw a small amount of cerebrospinal fluid for testing. This will take about five minutes.
• When the fluid collection is complete, the needle is removed. The puncture site is cleaned again. A bandage is applied.

 

• You’ll be asked to remain lying down for about an hour or two. This reduces the risk of a headache, which is a common side effect of the procedure.

 

WHAT DO WE NEED CSF ANALYSIS FOR?

You may need a CSF analysis if you have symptoms of an infection of the brain or spinal cord, or of an autoimmune disorder, such as multiple sclerosis.

check out CSF analysis