WHAT IS INVOLVED

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Ulnar Nerve


LOCATION

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Most frequently at the Elbow from leaning on it or trauma


COMMON SYMPTOMS

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- Weak hand, dropping objects, difficulty turning keys, ignition, doorknobs

- Numbness/tingling fourth, fifth fingers

- Wasting of the interosseii muscles

- Occasional elbow soreness

- Symptoms not related to night/daytime

- Frequently on both sides


ONSET

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Usually slow, insidious over months/years


RISK FACTORS

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- Men>Women, Diabetes or family history, Alcoholism, HIV infection, leaning on elbows

- Occupational (telephone operators, receptionists)

- Trauma (hitting elbow), or following a long surgery


EXAM

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- Look for First Dorsal Interosseous (FDI) and/or other Interosseii atrophy (looking at the back of the hand)

- Test First Dorsal Interosseous and Interosseii strength (ask patient to spread fingers against resistance)

- Decreased sensation to touch and pinprick over fourth and fifth fingers

- Positive and painful Tinel sign (tingling upon tapping nerve) at the Elbow with appropriate radiation to arm and fourth/fifth digits


EMG

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Very good for showing Ulnar slowing or conduction block at the elbow

Good for localizing lesions to Guyon's canal (in bike riders)

Findings:
- Low Ulnar sensory amplitudes and slowed Ulnar motor conductions across the elbow

- Normal Median Sensory/Motor distal latencies

- If Ulnar and Median Conductions are abnormal, test the lower extremity to rule out Peripheral Neuropathy

- Active/Chronic denervation in Ulnar muscles (FDI, Flexor Carpi Ulnaris) on Needle Examination


RECOMMENDATIONS

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- Stop/decrease cause (leaning on Elbow, repetitive trauma)

- Elbow pads not helpful (except maybe for reminding patients not to lean on elbows!!)

- Ulnar Nerve rubbing at Elbow (rub nerve in the groove up and down for 5 minutes three times a day to see if improvement)

- Surgery (Ulnar nerve transposition) for severe lesions and for atrophy with active denervation in interosseii

- Surgery not always successful; Patients can be left with Elbow pain from surgery and not infrequently, with injury to the Ulnar branch of the Flexor Carpi Ulnaris muscle in the vicinity, with subsequent weakness and elbow pain.


WHAT ELSE COULD IT BE?

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- Cervical root lesion (C8-T1), usually accompanied by neck and arm pain

- WATCH OUT FOR Amyotrophic Lateral Sclerosis (ALS), if symptoms are in more areas than just the Ulnar Nerve, or if accompanied by speech and swallowing problems and fasciculations

- Could be Syringomyelia but then would be accompanied by dissociated pain/temperature sensory loss

- Thoracic outlet syndrome (very rare)