Compression of the ulnar nerve at the elbow by an intraneural ganglion.

A rare cause of ulnar nerve compression at the elbow is presented in this report. A 42 year old right-handed mechanic developed subacute, progressive numbness, tingling and weakness in his right hand. Electrophysiologic studies demonstrated a severe conduction block affecting the ulnar nerve in the retrotrochlear groove but without any sign of major axonal loss. His hand functions were carefully studied prior to surgery. While fine motor tasks were not affected, the hand strength was markedly diminished. At surgery, a 1-cm diameter intraneural ganglion at the site of the conduction block was found and excised. The patient made a dramatic recovery within 6 weeks post-surgery. The conduction block completely resolved and the hand functions also returned to normal. This and other reported cases point to the importance of early diagnosis and intervention.