Head and neck: facial nerve: 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: facial nerve

Sample item

A 35-year-old man has lower motor neuron facial palsy, hyperacusis and loss of taste over the anterior two-thirds of the tongue, but normal tear production. Where is the lesion?

AIn the facial canal between the geniculate ganglion and the origin of the nerve to stapediusBAt the stylomastoid foramenCAt the geniculate ganglionDIn the internal acoustic meatus

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

The answer and the reasoning

A. In the facial canal between the geniculate ganglion and the origin of the nerve to stapedius

In the facial canal the greater petrosal nerve leaves at the geniculate ganglion, then the nerve to stapedius, and finally the chorda tympani. Hyperacusis and loss of anterior tongue taste with preserved lacrimation place the lesion between the geniculate ganglion and the origin of the stapedius branch. A lesion at the stylomastoid foramen gives only facial weakness.

Option by option

A. In the facial canal between the geniculate ganglion and the origin of the nerve to stapedius (correct)
Correct. Stapedius and chorda tympani fibres are affected while the greater petrosal branch is spared.
B. At the stylomastoid foramen
Only motor fibres remain at this level, so there would be no hyperacusis or taste loss.
C. At the geniculate ganglion
A lesion at the ganglion would also reduce lacrimation because the greater petrosal nerve is involved.
D. In the internal acoustic meatus
A lesion in the meatus would be proximal to all branches and usually affects hearing and balance as well.

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.

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is A, In the facial canal between the geniculate ganglion and the origin of the nerve to stapedius. In the facial canal the greater petrosal nerve leaves at the geniculate ganglion, then the nerve to stapedius, and finally the chorda tympani.

Why is "At the stylomastoid foramen" not the answer?

Only motor fibres remain at this level, so there would be no hyperacusis or taste loss.

Why is "At the geniculate ganglion" not the answer?

A lesion at the ganglion would also reduce lacrimation because the greater petrosal nerve is involved.

Why is "In the internal acoustic meatus" not the answer?

A lesion in the meatus would be proximal to all branches and usually affects hearing and balance as well.

What concept does this question test?

It tests Head and neck: facial nerve in Anatomy. Hyperacusis and loss of anterior tongue taste with preserved lacrimation place the lesion between the geniculate ganglion and the origin of the stapedius branch. A lesion at the stylomastoid foramen gives only facial weakness.

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: facial nerve?

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.