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A 38-year old gentleman starts working for a moving company.  One month following the date of employment, while carrying a heavy dresser down the stairs, he slips and falls.  However, he’s able to maintain control of the dresser as he goes to the ground.  His right elbow forcibly strikes the stairway.  There is acute bruising at the elbow.  He is aware of numbness involving the fourth and fifth digits of the right hand. 

He is seen in evaluation.  An ulnar sensory deficit is noted.  He is treated conservatively.  Over time he is aware of increasing numbness as well as weakness of the hand.  He is sent for EMG and nerve conduction studies three months following the injury because of a failure to respond to conservative treatment. 

Nerve conductions reveal a drop in amplitude when comparing the ulnar potential obtained following stimulation below the elbow to the potential above the elbow.  There is ulnar motor conduction slowing following stimulation above the elbow.  Sensory studies reveal small sensory potentials of both the ulnar sensory measured from digit 5 and the ulnar dorsal cutaneous potential.  Needle EMG reveals acute changes limited to right ulnar muscles.

Discussion:

 A diagnosis of ulnar neuropathy is made based on a number of changes including slowing of conduction through the elbow, a decrease in the amplitude obtained following stimulation above the elbow compared to the potential below the elbow, motor and sensory amplitude changes, and abnormalities noted on needle examination. 

In this case, localization is clearly made by the nerve conduction studies which show slowing at 29 meters per second (normal greater than 50) through the elbow and a decrease in the motor amplitude from 7.6 to 4.1.  With mild ulnar neuropathies, slowing might be the only changes.  However in this case, we also have small sensory potentials noted when recorded from the fifth digit and the ulnar dorsal cutaneous branch.  This is a sign of “nerve damage”.  Severe changes are also characterized by increased insertional activity. 



Given the degree of changes seen here, it is unlikely that conservative treatment would be helpful in providing clinical improvement.  Signs of “nerve damage” indicate that a more aggressive treatment would be indicated.  This patient underwent ulnar nerve transposition.  Symptomatology cleared in 12 weeks.  Repeat EMG and nerve conduction study was normal.