Anatomy And Physiology Of Cerebrospinal Fluid

Anatomy And Physiology Of Cerebrospinal Fluid

Describe the cerebrospinal fluid under the following headings: (1) formation, (2) circulation, (3) absorption, (4) functions and (5) applied anatomy.

Answer. The cerebrospinal fluid (CSF) is a modified tissue fluid similar to blood plasma and interstitial tissue fluid. It is present in the ventricles of the brain and subarachnoid space around the brain and spinal cord.

Formation Of Cerebrospinal Fluid

• The bulk of the CSF (80%–90%) is formed by choroid plexuses of lateral ventricles.
• The small amount is formed by the choroid plexuses of the 3rd and 4th ventricles.
• In an adult, the total quantity of CSF is about 150 mL, out of which only 30 mL lies in the ventricular system.

Read And Learn More: Selective Anatomy Notes And Question And Answers

Circulation Of Cerebrospinal Fluid It is given in the form of a flowchart given below:

Absorption Of Cerebrospinal Fluid

• The CSF is chiefly absorbed through the arachnoid villi and arachnoid granulations into the superior sagittal sinus.
• It is also absorbed partly by the perineural lymphatics around the cranial and spinal nerves and also via pial veins.

Functions Of Cerebrospinal Fluid

• Provides protection to the CNS.
• Provides nutrition to the CNS.
• Removes waste products from the CNS.

Applied Anatomy Of Cerebrospinal Fluid

• Withdrawal of CSF: The CSF can be obtained by lumbar puncture, cisternal puncture, and ventricular puncture for diagnostic and therapeutic purposes.
• Hydrocephalus: The excessive accumulation of CSF within the skull due to either obstruction to the flow of CSF in the ventricular system or impairment of its absorption into the intracranial dural venous sinuses through arachnoid granulations, leads to hydrocephalus in children and raised intracranial pressure in adults.

The characteristic clinical features of hydrocephalus are as follows:

• Abnormally large head
• Bossing of forehead
• Wide, tense anterior fontanelle
• ‘Setting-sun appearance’ of the eyes
• Thin scalp with dilated scalp veins
• Cracked-pot sound on skull percussion
• Dementia