Ear and audiology: facial canal dehiscence in stapes surgery: practice question

A ENT 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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ENT · Ear and audiology: facial canal dehiscence in stapes surgery

Sample item

A surgeon planning a stapedotomy notes that the tympanic segment of the facial nerve is exposed and bulging over the oval window niche. Why is this relevant?

AThe nerve lies below the round window, so it is safeBThe nerve runs through the stapes footplateCThe chorda tympani crosses over the oval window and prevents accessDThe nerve lies directly above the oval window and is often dehiscent, so it can be injured or herniate into the operative field

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

The answer and the reasoning

D. The nerve lies directly above the oval window and is often dehiscent, so it can be injured or herniate into the operative field

The tympanic (horizontal) segment of the facial nerve runs in the medial wall just above the oval window and below the lateral semicircular canal. The bony Fallopian canal is dehiscent in a sizeable minority of ears. A prolapsed nerve can obstruct access or be damaged during stapes surgery.

Option by option

A. The nerve lies below the round window, so it is safe
The nerve lies above, not below, the oval window, and the round window is not related to it.
B. The nerve runs through the stapes footplate
The nerve does not pass through the footplate, which is part of the stapes.
C. The chorda tympani crosses over the oval window and prevents access
The chorda tympani crosses the middle ear laterally and does not block the oval window.
D. The nerve lies directly above the oval window and is often dehiscent, so it can be injured or herniate into the operative field (correct)
Correct. The tympanic segment lies right above the oval window, often with a bony defect.

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 ENT question

What is the answer to this ENT question?

The best answer is D, The nerve lies directly above the oval window and is often dehiscent, so it can be injured or herniate into the operative field. The tympanic (horizontal) segment of the facial nerve runs in the medial wall just above the oval window and below the lateral semicircular canal.

Why is "The nerve lies below the round window, so it is safe" not the answer?

The nerve lies above, not below, the oval window, and the round window is not related to it.

Why is "The nerve runs through the stapes footplate" not the answer?

The nerve does not pass through the footplate, which is part of the stapes.

Why is "The chorda tympani crosses over the oval window and prevents access" not the answer?

The chorda tympani crosses the middle ear laterally and does not block the oval window.

What concept does this question test?

It tests Ear and audiology: facial canal dehiscence in stapes surgery in ENT. The bony Fallopian canal is dehiscent in a sizeable minority of ears. A prolapsed nerve can obstruct access or be damaged during stapes surgery.

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 Ear and audiology: facial canal dehiscence in stapes surgery?

Learn tuning fork results and audiogram patterns by sketching them. Then use the flashcards and the other ENT 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.