CSF Physiology, Pressure & Dynamics
CSF volume
CSF volume is the total amount of cerebrospinal fluid present, normally about 150 mL, which increases when fluid accumulates in hydrocephalus.
In short: CSF volume
- The total volume is normally about 150 mL.
- Roughly 25 mL is in the ventricles and 125 mL around the brain and spine.
- It increases when CSF accumulates in hydrocephalus.
- It is kept stable by the balance of production and absorption.
What it is
CSF volume is the total amount of cerebrospinal fluid present in the brain and spinal cord at any given time, normally about 150 mL. It is distributed between the ventricles and the spaces around the brain and spinal cord.
Understanding CSF volume
Of the roughly 150 mL of CSF, only a portion (about 25 mL) is within the ventricles, with the larger share (about 125 mL) in the subarachnoid spaces around the brain and spinal cord. This volume is normally kept stable by the balance between continuous production (about 500 mL per day) and absorption. In hydrocephalus, the volume within the ventricles increases as fluid accumulates, enlarging these spaces. (These figures are general and vary among individuals; volume can also increase with brain atrophy in hydrocephalus ex vacuo.)
Why it matters
Understanding CSF volume helps families see that the brain normally holds a small, stable amount of fluid, and that hydrocephalus involves an increase in this volume within the ventricles as the balance is disrupted.
Common questions
What is the normal CSF volume?
About 150 mL.
Where is it located?
Roughly 25 mL in the ventricles and 125 mL around the brain and spine.
What happens in hydrocephalus?
Ventricular volume increases as fluid accumulates.
Bottom line
CSF volume is the total fluid present, normally about 150 mL, which increases in the ventricles when hydrocephalus develops.
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