Complications and emergencies: lithotomy position nerve injury: practice question

A Anaesthesia 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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Anaesthesia · Complications and emergencies: lithotomy position nerve injury

Sample item

After a four-hour operation in the lithotomy position with the leg holders pressing behind the lateral knee, a patient cannot dorsiflex the foot and has numbness over the dorsum. Which nerve is injured?

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

The answer and the reasoning

C. Common peroneal nerve

The common peroneal nerve is compressed against the fibular head by leg supports, producing foot drop and loss of sensation over the dorsum of the foot. Femoral and obturator injuries come from other mechanisms such as stretch or retractors.

Option by option

  • A. Tibial nerve

    Tibial injury causes inability to plantarflex and loss of sole sensation.

  • B. Femoral nerve

    Femoral injury weakens knee extension.

  • C. Common peroneal nerve (correct)

    Correct. Compression at the fibular head gives foot drop.

  • D. Obturator nerve

    Obturator injury weakens hip adduction.

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 Anaesthesia question

What is the answer to this Anaesthesia question?

The best answer is C, Common peroneal nerve. The common peroneal nerve is compressed against the fibular head by leg supports, producing foot drop and loss of sensation over the dorsum of the foot.

Why is "Tibial nerve" not the answer?

Tibial injury causes inability to plantarflex and loss of sole sensation.

Why is "Femoral nerve" not the answer?

Femoral injury weakens knee extension.

Why is "Obturator nerve" not the answer?

Obturator injury weakens hip adduction.

What concept does this question test?

It tests Complications and emergencies: lithotomy position nerve injury in Anaesthesia. Femoral and obturator injuries come from other mechanisms such as stretch or retractors.

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 Complications and emergencies: lithotomy position nerve injury?

Make a table of each agent, its key advantage and its main side effect. Then use the flashcards and the other Anaesthesia 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.