Ulnar nerve stimulation at the palm in diagnosing distal ulnar nerve entrapment.

Distal entrapment of the ulnar nerve at the wrist and hand (Guyon's syndrome) is a relatively uncommon condition. It may present with a confusing permutation of sensory and motor symptoms, depending on which branches of the ulnar nerve are involved Electrodiagnostic test procedures are often helpful in sorting out this quandary. Electrophysiologic studies that include electrical stimulation of the nerve at the palm, in addition to stimulation of the ulnar nerve at other locations, are useful in demonstrating the focal nerve conduction abnormality that is involved in the entrapment. Sensory and motor recordings from palmar stimulation of the ulnar nerve are not technically difficult procedures, and can be performed routinely.