title: A new pitfall in a sensory conduction study of the lateral antebrachial cutaneous nerve: spread to the radial nerve.
abstract: BACKGROUND
  We describe a previously unreported pitfall, spread of the stimulus at the elbow to the radial nerve, in an antidromic sensory nerve conduction study of the lateral antebrachial cutaneous (LAC) nerve.
  
  
  METHODS
  Subjects consisted of 80 healthy volunteers, and both sides were examined for each subject. Besides routine recording of the LAC nerve, sensory nerve action potentials (SNAPs) of the radial nerve were recorded distally.
  
  
  RESULTS
  The spread phenomenon occurred in 73 of 160 arms (46%), and the SNAP amplitude increased due to contamination of the radial SNAP up to 6.7 times the genuine LAC SNAP. In 10 arms (6%), the spread started before the LAC SNAP was saturated, and the genuine LAC SNAP was unknown due to an anatomical variation in at least 1 arm.
  
  
  CONCLUSIONS
  Without monitoring distal radial SNAPs, the spread phenomenon will remain unrecognized. This pitfall undermines the reliability of the test.
authors.affiliation: Department of Neurology, Faculty of Medicine, Kyorin University, Tokyo, Japan.
authors.forename: Chizuko
authors.initials: C
authors.lastname: Oishi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sonoo
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kurono
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hatanaka
authors.forename: Teruo
authors.initials: T
authors.lastname: Shimizu
authors.forename: Atsuro
authors.initials: A
authors.lastname: Chiba
authors.forename: Manabu
authors.initials: M
authors.lastname: Sakuta
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001703:Biophysics; D004558:Electric Stimulation; D004576:Electromyography; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D011826:Radial Nerve / Q000502:physiology*; D012867:Skin / Q000294:innervation*; D055815:Young Adult
keywords: lateral antebrachial cutaneous nerve; pitfall; radial nerve; sensory nerve conduction study; spread phenomenon