Neuroanatomy: ventricular system and CSF: practice question

A Anatomy question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Anatomy · Neuroanatomy: ventricular system and CSF

Sample item

An 8-month-old infant recovering from bacterial meningitis develops enlarging head size and bulging fontanelle. CT shows dilatation of all ventricles including the fourth. Which mechanism explains this communicating hydrocephalus?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Impaired absorption of CSF at the arachnoid granulations into the superior sagittal sinus

CSF is produced mainly by the choroid plexus and flows through the ventricles and subarachnoid space, being absorbed through arachnoid granulations into the dural venous sinuses, mainly the superior sagittal sinus. Post-meningitic fibrosis of the subarachnoid space and granulations blocks absorption, so all ventricles dilate, including the fourth.

Option by option

  • A. Impaired absorption of CSF at the arachnoid granulations into the superior sagittal sinus (correct)

    Correct. Failure of absorption through the arachnoid granulations causes dilatation of all ventricles.

  • B. Obstruction of the cerebral aqueduct

    Aqueduct obstruction would dilate the lateral and third ventricles but spare the fourth.

  • C. Overproduction of CSF by the ependymal lining of the central canal

    The central canal is not the main CSF source; the choroid plexus is.

  • D. Blockage of the interventricular foramen by the choroid plexus

    Foramen blockage would dilate only the lateral ventricle on that side.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, Impaired absorption of CSF at the arachnoid granulations into the superior sagittal sinus. CSF is produced mainly by the choroid plexus and flows through the ventricles and subarachnoid space, being absorbed through arachnoid granulations into the dural venous sinuses, mainly the superior sagittal sinus.

Why is "Obstruction of the cerebral aqueduct" not the answer?

Aqueduct obstruction would dilate the lateral and third ventricles but spare the fourth.

Why is "Overproduction of CSF by the ependymal lining of the central canal" not the answer?

The central canal is not the main CSF source; the choroid plexus is.

Why is "Blockage of the interventricular foramen by the choroid plexus" not the answer?

Foramen blockage would dilate only the lateral ventricle on that side.

What concept does this question test?

It tests Neuroanatomy: ventricular system and CSF in Anatomy. Post-meningitic fibrosis of the subarachnoid space and granulations blocks absorption, so all ventricles dilate, including the fourth.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Neuroanatomy: ventricular system and CSF?

Learn every nerve by its route, its muscles and what a lesion looks like at the bedside. That one habit answers a large share of questions. Then use the flashcards and the other Anatomy questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.