Leprosy: posterior tibial nerve involvement: practice question

A Dermatology 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.

Try it

Dermatology · Leprosy: posterior tibial nerve involvement

Sample item

A man with long-standing leprosy has an anaesthetic, dry sole and clawing of the toes from paralysis of the small muscles of the foot. Which nerve is mainly involved?

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

The answer and the reasoning

B. Posterior tibial nerve

The posterior tibial nerve passes behind the medial malleolus and divides into the medial and lateral plantar nerves. Its damage causes plantar anaesthesia, anhidrosis and clawing of the toes, and makes the sole prone to painless ulcers.

Option by option

  • A. Sural nerve

    The sural nerve is purely sensory over the lateral foot and does not paralyse intrinsic muscles.

  • B. Posterior tibial nerve (correct)

    Correct. Plantar sensory loss with paralysis of the intrinsic foot muscles points to the posterior tibial nerve.

  • C. Common peroneal nerve

    Common peroneal damage causes foot drop and sensory loss over the dorsum of the foot and lateral leg.

  • D. Saphenous nerve

    The saphenous nerve is a sensory branch of the femoral nerve over the medial leg and does not supply the sole.

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.

More Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is B, Posterior tibial nerve. The posterior tibial nerve passes behind the medial malleolus and divides into the medial and lateral plantar nerves.

Why is "Sural nerve" not the answer?

The sural nerve is purely sensory over the lateral foot and does not paralyse intrinsic muscles.

Why is "Common peroneal nerve" not the answer?

Common peroneal damage causes foot drop and sensory loss over the dorsum of the foot and lateral leg.

Why is "Saphenous nerve" not the answer?

The saphenous nerve is a sensory branch of the femoral nerve over the medial leg and does not supply the sole.

What concept does this question test?

It tests Leprosy: posterior tibial nerve involvement in Dermatology. Its damage causes plantar anaesthesia, anhidrosis and clawing of the toes, and makes the sole prone to painless ulcers.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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 Leprosy: posterior tibial nerve involvement?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.