Lower limb: lateral femoral cutaneous nerve: 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: lateral femoral cutaneous nerve

Sample item

A 45-year-old obese man who wears a tight belt has burning pain and numbness over the anterolateral thigh with no weakness. Reflexes and power are normal. Where is the responsible nerve most likely entrapped?

AObturator nerve in the obturator canalBIlioinguinal nerve in the inguinal canalCLateral femoral cutaneous nerve at the inguinal ligamentDFemoral nerve in the femoral triangle

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

The answer and the reasoning

C. Lateral femoral cutaneous nerve at the inguinal ligament

This is meralgia paraesthetica, entrapment of the purely sensory lateral femoral cutaneous nerve (L2 and L3) as it passes under or through the inguinal ligament near the anterior superior iliac spine. Obesity, pregnancy and tight belts are risk factors. Because it is purely sensory there is no weakness.

Option by option

A. Obturator nerve in the obturator canal
Obturator nerve compression affects the medial thigh and adductor power.
B. Ilioinguinal nerve in the inguinal canal
The ilioinguinal nerve supplies the groin and genital skin, not the anterolateral thigh.
C. Lateral femoral cutaneous nerve at the inguinal ligament (correct)
Correct. Compression at the inguinal ligament produces sensory symptoms over the anterolateral thigh only.
D. Femoral nerve in the femoral triangle
Femoral nerve injury would weaken knee extension and reduce the knee jerk.

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 C, Lateral femoral cutaneous nerve at the inguinal ligament. This is meralgia paraesthetica, entrapment of the purely sensory lateral femoral cutaneous nerve (L2 and L3) as it passes under or through the inguinal ligament near the anterior superior iliac spine.

Why is "Obturator nerve in the obturator canal" not the answer?

Obturator nerve compression affects the medial thigh and adductor power.

Why is "Ilioinguinal nerve in the inguinal canal" not the answer?

The ilioinguinal nerve supplies the groin and genital skin, not the anterolateral thigh.

Why is "Femoral nerve in the femoral triangle" not the answer?

Femoral nerve injury would weaken knee extension and reduce the knee jerk.

What concept does this question test?

It tests Lower limb: lateral femoral cutaneous nerve in Anatomy. Obesity, pregnancy and tight belts are risk factors. Because it is purely sensory there is no weakness.

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: lateral femoral cutaneous nerve?

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.