HSS Ultrasound of the Month Case #99

Clinical History 29 year old female with numbness along the ulnar aspect of the thumb since laceration with glass over the 1st web of the hand.

Ultrasound was requested to evaluate the ulnar digital nerve to the thumb

Ultrasound of the Month – Case 99

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Ultrasound of the Month – Case 99

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Ultrasound of the Month – Case 99

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Diagnosis: Neuroma-in-continuity of the Ulnar Digital Nerve to the Thumb Post-traumatic neuromas can occur either as a stump neuroma if the nerve is amputated or a neuroma-in-continuity if the nerve is transected but the two ends of the nerve are not retracted from each other. “Neuroma� is a misnomer as it does not represent a neoplasm but rather scar formation around the injured nerve.

Both ultrasound and MRI are useful modalities for identifying post-traumatic neuromas, although ultrasound is more accurate for small neuromas immediately beneath the skin such as in this case.

On ultrasound, post-traumatic neuromas manifest as areas of focal thickening and disorganized architecture of the nerve.

Ultrasound is also useful for guiding therapeutic injections or ablations of the neuroma, and for preoperative mapping.

Ultrasound of the Month – Case 99

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