Lower limb: obturator canal: 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: obturator canal

Sample item

An emaciated 80-year-old woman has small bowel obstruction. She also has pain along the medial thigh and knee that worsens on extension and medial rotation of the thigh, and a tender fullness high on the medial thigh. Which nerve compression in which opening explains the thigh pain?

ALateral femoral cutaneous nerve under the inguinal ligamentBFemoral branch of the genitofemoral nerve at the femoral ringCIlioinguinal nerve in the inguinal canalDObturator nerve in the obturator canal

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

The answer and the reasoning

D. Obturator nerve in the obturator canal

An obturator hernia passes through the obturator canal, beneath the pectineus, and compresses the obturator nerve, producing pain along its cutaneous distribution on the medial thigh (Howship-Romberg sign). It is typical of elderly, thin multiparous women and often presents as obstruction.

Option by option

A. Lateral femoral cutaneous nerve under the inguinal ligament
The lateral femoral cutaneous nerve supplies the lateral thigh and compression gives meralgia paraesthetica.
B. Femoral branch of the genitofemoral nerve at the femoral ring
The genitofemoral nerve supplies skin below the mid-inguinal point and is not in the obturator canal.
C. Ilioinguinal nerve in the inguinal canal
The ilioinguinal nerve supplies the groin and upper scrotum or labium, not the medial thigh.
D. Obturator nerve in the obturator canal (correct)
Correct. The obturator nerve runs in the canal, and its compression gives medial thigh pain.

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 D, Obturator nerve in the obturator canal. An obturator hernia passes through the obturator canal, beneath the pectineus, and compresses the obturator nerve, producing pain along its cutaneous distribution on the medial thigh (Howship-Romberg sign).

Why is "Lateral femoral cutaneous nerve under the inguinal ligament" not the answer?

The lateral femoral cutaneous nerve supplies the lateral thigh and compression gives meralgia paraesthetica.

Why is "Femoral branch of the genitofemoral nerve at the femoral ring" not the answer?

The genitofemoral nerve supplies skin below the mid-inguinal point and is not in the obturator canal.

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

The ilioinguinal nerve supplies the groin and upper scrotum or labium, not the medial thigh.

What concept does this question test?

It tests Lower limb: obturator canal in Anatomy. It is typical of elderly, thin multiparous women and often presents as obstruction.

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: obturator canal?

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.