HSS Ultrasound of the Month Case 129

Clinical History 16 month old boy with refusal to move elbow after arm was inadvertently pulled by mother.

Ultrasound of the Month – Case 129

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Ultrasound of the Month – Case 129

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Diagnosis: Nursemaid’s Elbow Nursemaid’s elbow refers to subluxation of the annular ligament, which becomes interposed between the capitellum and the radial head.

Mechanism of injury is sudden longitudinal traction to the hand or forearm with the elbow extended and forearm pronated.

The person pulling the arm may have heard a pop or click at the time of injury, and the child will present with refusal to move the elbow.

Radiographs usually are normal (in 25%, the radiocapitellar line may project lateral to the center of capitellum).

On ultrasound, presence of soft tissue interposed between the radial head and capitellum, representing the subluxed annular ligament, is diagnostic.

Ultrasound has the advantages of being quick, radiation-free, and being able to easily scan the contralateral elbow for comparison.

Treatment is conservative, consisting of casting with the forearm in supination or hyperpronation.

Ultrasound of the Month – Case 129

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