HSS Ultrasound of the Month Case 115

Clinical History 22 year old male with snapping sensation over the medial side of the elbow.

Ultrasound of the Month – Case 115

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Ultrasound of the Month – Case 115

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Diagnosis: Ulnar Nerve Dislocation at the Elbow Discussion Dislocating ulnar nerve is the most common source of a snapping sensation along the medial aspect of the elbow.

The ulnar nerve normally courses posterior to the medial epicondyle of the distal humerus, but in approximately 15% of the population, the nerve can dislocate anterior to the medial epicondyle, causing a snapping sensation.

May otherwise be asymptomatic or may be associated with ulnar neuritis.

A less common cause of snapping along the medial aspect of the elbow is snapping of the medial head of the triceps.

Ultrasound is the best modality for assessing the source of a snapping sensation of the medial aspect of the elbow.

Ultrasound, compared to MRI, is more easily tolerated, more accessible, and quicker.

But the greatest advantage of ultrasound over MRI is the ability to perform dynamic maneuvers, which is necessary to diagnose either a dislocating ulnar nerve or medial head of the triceps.

Treatment is usually conservative, although patients with symptomatic neuritis may require surgical transposition of the ulnar nerve.

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