Cerebrospinal Fluid
Specialised extracellular fluid
Present in
- Ventricles of brain
- Central canal of spinal cord
- Subarachnoid space
Formation & Circulation of CSF
- Choroid plexus of lateral and third ventricle forms CSF by filtration and secretion
- Passes through fourth ventricle and central canal in spinal cord
- Flows through foramens of Magendie and Luschaka to arachnoid space
- Gets absorbed through the arachnoid villi present in the sagittal sinus
Composition & Properties of CSF
- Colourless, transparent fluid
- Specific gravity: 1005
- Alkaline (pH>7)
- Volume: 150 ml (500 ml produced per day)
- 99% water and 1% solids
Functions of CSF
- Acts as a cushion between the brain and rigid cranium
- Supports weight of the brain: Net weight of brain in CSF is 50g as compared to its weight of 1400g in air
- Distributes force of blows on the head
- Maintains intracranial pressure by balancing the volume of blood and CSF
- Drains metabolites from the brain
- Supplies nutrients and oxygen to the brain
Applied Aspects
Hydrocephalus
- Condition of increased intracranial pressure due to defective absorption or circulation of CSF
- Enlargement of cranial cavity and associated damage to the brain because of pressure effect
Lumbar puncture
- Procedure by which CSF is taken out from the subarachnoid space
- CSF drawn by introducing a needle between 3rd and 4th lumbar vertebrae
- Histological and biochemical study of CSF gives indication about various disease process affecting CNS
