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Posterior shoulder dislocation — ABFM Board MCQ

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HardMusculoskeletal/Sports medicinePosterior shoulder dislocationABFM Board

A 23-year-old man develops severe right shoulder pain after a seizure. The arm is held adducted and internally rotated, and anteroposterior shoulder radiograph shows a lightbulb appearance of the humeral head. Which of the following is the most likely diagnosis?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: D — Posterior shoulder dislocation

Posterior shoulder dislocation is classically associated with seizures or electrical injury. The arm is held adducted and internally rotated, and AP radiograph can show a lightbulb sign.

Reference: AAOS Shoulder Dislocation Guidance