Dislocations: posterior shoulder dislocation: practice question

A Orthopaedics 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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Orthopaedics · Dislocations: posterior shoulder dislocation

Sample item

A man has a shoulder locked in internal rotation after an epileptic seizure, and an AP radiograph shows the light-bulb sign. What is the diagnosis?

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

The answer and the reasoning

D. Posterior shoulder dislocation

Seizures and electric shock cause strong internal rotator contraction that dislocates the humeral head posteriorly. The arm is fixed in internal rotation and cannot be externally rotated, and the AP film shows a light-bulb head with the rim sign. An axillary or scapular Y view confirms it.

Option by option

  • A. Luxatio erecta

    Luxatio erecta has the arm held fully abducted overhead.

  • B. Anterior shoulder dislocation

    Anterior dislocation holds the arm in abduction and external rotation.

  • C. Frozen shoulder

    Frozen shoulder does not follow an acute seizure and shows no dislocation.

  • D. Posterior shoulder dislocation (correct)

    Correct. Fixed internal rotation with a light-bulb sign is posterior dislocation.

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.

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Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, Posterior shoulder dislocation. Seizures and electric shock cause strong internal rotator contraction that dislocates the humeral head posteriorly.

Why is "Luxatio erecta" not the answer?

Luxatio erecta has the arm held fully abducted overhead.

Why is "Anterior shoulder dislocation" not the answer?

Anterior dislocation holds the arm in abduction and external rotation.

Why is "Frozen shoulder" not the answer?

Frozen shoulder does not follow an acute seizure and shows no dislocation.

What concept does this question test?

It tests Dislocations: posterior shoulder dislocation in Orthopaedics. The arm is fixed in internal rotation and cannot be externally rotated, and the AP film shows a light-bulb head with the rim sign. An axillary or scapular Y view confirms it.

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 Dislocations: posterior shoulder dislocation?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.