title: Spread to the dorsal ulnar cutaneous branch: a pitfall during the routine antidromic sensory nerve conduction study of the ulnar nerve.
abstract: OBJECTIVE
  To document the incidence and effects of a previously unreported pitfall during routine antidromic sensory nerve conduction study (SCS) of the ulnar nerve: the spread of the wrist stimulation to the dorsal ulnar cutaneous (DUC) branch.
  
  
  METHODS
  The subjects consisted of 20 healthy volunteers. An antidromic sensory nerve action potential (SNAP) was recorded over the proximal interphalangeal joint of the little finger, and the DUC response was monitored over the dorsum of hand to check for the occurrence of this spread.
  
  
  RESULTS
  The spread occurred in all subjects, which caused a 4-87% increase in the SNAP amplitude. The likelihood that this spread may occur during routine SCS varied among the subjects, and also within an individual subject depending on minute shifts of the stimulating site. Selective stimulation of the ulnar main trunk up to maximal intensity without spread to the DUC was not achieved despite every effort in two subjects.
  
  
  CONCLUSIONS
  This spread phenomenon may occur frequently during routine antidromic SCS, but would not be recognized without monitoring the DUC response.
  
  
  CONCLUSIONS
  This pitfall may interfere with the reproducibility of the SNAP amplitude, and also with the diagnosis of ulnar neuropathy at the wrist.
authors: Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan.
authors: Hideharu
authors: H
authors: Murashima
authors: Masahiro
authors: M
authors: Sonoo
authors: Hiroshi
authors: H
authors: Tsukamoto
authors: Shingo
authors: S
authors: Kawakami
authors: Yasuomi
authors: Y
authors: Kawamura
authors: Keiichi
authors: K
authors: Hokkoku
authors: Yuki
authors: Y
authors: Hatanaka
authors: Teruo
authors: T
authors: Shimizu
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D004558:Electric Stimulation / Q000379:methods*; D004576:Electromyography; D005260:Female; D006225:Hand / Q000294:innervation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D012867:Skin / Q000294:innervation*; D014459:Ulnar Nerve / Q000502:physiology*; D014953:Wrist / Q000294:innervation; D055815:Young Adult