Lower limb: posterior hip dislocation: 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: posterior hip dislocation

Sample item

After a head-on car collision, a 30-year-old man lies with his right leg shortened, flexed, adducted and internally rotated at the hip. Which nerve is most at risk from this injury?

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

The answer and the reasoning

C. Sciatic nerve

This is the classic attitude of posterior hip dislocation, in which the femoral head lies behind the acetabulum. The sciatic nerve passes directly behind the hip joint, below piriformis, and is stretched or contused, causing foot drop and weak knee flexion. It occurs in a minority of cases and needs urgent reduction.

Option by option

  • A. Femoral nerve

    The femoral nerve lies in front of the joint, so it is more at risk in anterior dislocation.

  • B. Obturator nerve

    The obturator nerve lies at the obturator foramen and is more at risk in anterior (obturator) dislocation.

  • C. Sciatic nerve (correct)

    The sciatic nerve lies posterior to the hip joint and is displaced by the head of the femur.

  • D. Superior gluteal nerve

    The superior gluteal nerve passes above piriformis and is not usually stretched by the femoral head.

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 Anatomy questions

Questions about this Anatomy question

What is the answer to this Anatomy question?

The best answer is C, Sciatic nerve. This is the classic attitude of posterior hip dislocation, in which the femoral head lies behind the acetabulum.

Why is "Femoral nerve" not the answer?

The femoral nerve lies in front of the joint, so it is more at risk in anterior dislocation.

Why is "Obturator nerve" not the answer?

The obturator nerve lies at the obturator foramen and is more at risk in anterior (obturator) dislocation.

Why is "Superior gluteal nerve" not the answer?

The superior gluteal nerve passes above piriformis and is not usually stretched by the femoral head.

What concept does this question test?

It tests Lower limb: posterior hip dislocation in Anatomy. The sciatic nerve passes directly behind the hip joint, below piriformis, and is stretched or contused, causing foot drop and weak knee flexion. It occurs in a minority of cases and needs urgent reduction.

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 Lower limb: posterior hip dislocation?

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.