Normal intracranial pressure (ICP) ranges from which of the following?

• A. 5-15 mm Hg
• B. 20-25 mm Hg
• C. 0-5 mm Hg
• D. 15-25 mm Hg

Answer: (A)

Normal intracranial pressure in a resting adult is about 5 to 15 mmHg. This range reflects a brain with normal volume, venous drainage, and cerebrospinal fluid dynamics, allowing adequate cerebral perfusion. Values above around 20 mmHg are considered intracranial hypertension and can compromise blood flow to the brain, increasing the risk of herniation and other complications. Among the options, 5–15 mmHg is the only one that sits within the normal range. The other ranges either imply hypotension below normal or indicate elevated ICP.