Cerebrospinal fluid (CSF) is produced primarily by the choroid plexus. What is the approximate rate of CSF production and total volume in an adult?
- A Production 500 mL/day; total volume 500 mL
- B Production 150 mL/day; total volume 500 mL
- C Production 500 mL/day; total volume 150 mL (with complete turnover ~3.3 times/day) ✓
- D Production 50 mL/day; total volume 50 mL with daily replacement
Correct answer: C. Production 500 mL/day; total volume 150 mL (with complete turnover ~3.3 times/day)
Explanation
The choroid plexus (mainly in the lateral, third, and fourth ventricles) produces CSF at approximately 500 mL/day (0.35 mL/min). Total CSF volume in the adult is approximately 150 mL (70 mL intraventricular, 80 mL in the subarachnoid space and spinal canal), meaning the entire CSF volume turns over about 3–4 times per day. CSF is absorbed primarily by arachnoid granulations into the dural venous sinuses, and a smaller proportion via lymphatics.
Reference: Guyton & Hall, Textbook of Medical Physiology, 14th ed.
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