Head and neck: spread of dental infection to the cavernous sinus: 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 · Head and neck: spread of dental infection to the cavernous sinus

Sample item

A man with an infected upper molar develops swelling in the face, then proptosis and ophthalmoplegia. Through which route did infection most likely reach the cavernous sinus from the infratemporal fossa?

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

The answer and the reasoning

C. Pterygoid plexus through the foramen ovale

The pterygoid venous plexus in the infratemporal fossa drains the upper teeth and communicates with the cavernous sinus through emissary veins that pass via the foramen ovale and foramen lacerum. The veins are valveless, so infection can spread backwards into the sinus.

Option by option

  • A. Occipital veins to the sigmoid sinus

    Occipital veins drain the back of the scalp and do not connect with the pterygoid region.

  • B. Anterior jugular vein to the subclavian

    The anterior jugular vein is a superficial neck vein and does not communicate with the pterygoid plexus.

  • C. Pterygoid plexus through the foramen ovale (correct)

    Correct. Emissary veins through the foramen ovale link the plexus to the cavernous sinus.

  • D. Retromandibular vein to the external jugular

    This pathway drains blood away from the head to the neck and does not lead to the cavernous sinus.

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 C, Pterygoid plexus through the foramen ovale. The pterygoid venous plexus in the infratemporal fossa drains the upper teeth and communicates with the cavernous sinus through emissary veins that pass via the foramen ovale and foramen lacerum.

Why is "Occipital veins to the sigmoid sinus" not the answer?

Occipital veins drain the back of the scalp and do not connect with the pterygoid region.

Why is "Anterior jugular vein to the subclavian" not the answer?

The anterior jugular vein is a superficial neck vein and does not communicate with the pterygoid plexus.

Why is "Retromandibular vein to the external jugular" not the answer?

This pathway drains blood away from the head to the neck and does not lead to the cavernous sinus.

What concept does this question test?

It tests Head and neck: spread of dental infection to the cavernous sinus in Anatomy. The veins are valveless, so infection can spread backwards into the sinus.

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 Head and neck: spread of dental infection to the cavernous sinus?

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.