Lower limb: sciatic nerve injury: 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 · Lower limb: sciatic nerve injury

Sample item

A front-seat passenger in a road crash has a limb that is shortened, flexed, adducted and internally rotated. After reduction she has foot drop and loss of sensation on the dorsum of the foot, with plantar flexion preserved. Which nerve component is most likely injured in this injury?

ACommon fibular division of the sciatic nerveBTibial division of the sciatic nerveCFemoral nerveDSuperior gluteal nerve

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

The answer and the reasoning

A. Common fibular division of the sciatic nerve

This is a posterior hip dislocation, which can stretch the sciatic nerve against the posterior acetabular rim. The common fibular division is more often injured than the tibial because it is more lateral, tethered at the fibular neck and has fewer connective tissue supports. This causes foot drop and loss of dorsal foot sensation with preserved plantar flexion.

Option by option

A. Common fibular division of the sciatic nerve (correct)
Correct. The common fibular division is the more vulnerable part and its loss gives foot drop.
B. Tibial division of the sciatic nerve
The tibial division controls plantar flexion and sole sensation, which are preserved here.
C. Femoral nerve
The femoral nerve supplies the quadriceps, so its loss impairs knee extension.
D. Superior gluteal nerve
The superior gluteal nerve injury causes a Trendelenburg gait, not foot drop.

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, Common fibular division of the sciatic nerve. This is a posterior hip dislocation, which can stretch the sciatic nerve against the posterior acetabular rim.

Why is "Tibial division of the sciatic nerve" not the answer?

The tibial division controls plantar flexion and sole sensation, which are preserved here.

Why is "Femoral nerve" not the answer?

The femoral nerve supplies the quadriceps, so its loss impairs knee extension.

Why is "Superior gluteal nerve" not the answer?

The superior gluteal nerve injury causes a Trendelenburg gait, not foot drop.

What concept does this question test?

It tests Lower limb: sciatic nerve injury in Anatomy. The common fibular division is more often injured than the tibial because it is more lateral, tethered at the fibular neck and has fewer connective tissue supports. This causes foot drop and loss of dorsal foot sensation with preserved plantar flexion.

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 Lower limb: sciatic nerve injury?

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.