title: Relative sparing of the second lumbrical muscle in carpal tunnel syndrome is not associated with regional differences in axonal membrane potential.
abstract: OBJECTIVE
  Regional differences in nerve resting membrane potential have been associated with susceptibility to entrapment neuropathy. The aim of this study was to test whether the different susceptibilities to carpal tunnel syndrome (CTS) of median nerve motor axons supplying the second lumbrical (L2) and abductor pollicis brevis (APB) muscles could be explained in this way.
  
  
  METHODS
  Computerized nerve-excitability testing was used to examine the excitability properties of the median motor axons of both L2 and APB in 24 healthy volunteers.
  
  
  RESULTS
  Although some excitability measurements differed between the L2 and APB motor axons, estimates of resting membrane potential (RMP) by model fitting indicated no significant difference between the two groups.
  
  
  CONCLUSIONS
  Differences in RMP cannot account for the relative sparing of L2 axons in severe CTS.
  
  
  CONCLUSIONS
  L2 sparing in CTS most likely has an anatomical rather than a biophysical basis.
authors.affiliation: Department of Neurosurgery, Busan Paik Hospital, Inje University College of Medicine, Busan, Republic of Korea.
authors.forename: Sung Hwha
authors.initials: SH
authors.lastname: Paeing
authors.affiliation: Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
authors.forename: Mi-Ri
authors.initials: MR
authors.lastname: Kang
authors.affiliation: Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
authors.forename: So-Hyeon
authors.initials: SH
authors.lastname: Ahn
authors.affiliation: Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
authors.forename: Min Woo
authors.initials: MW
authors.lastname: Lee
authors.affiliation: Department of Neurology, National Police Hospital, Seoul, Republic of Korea.
authors.forename: So Young
authors.initials: SY
authors.lastname: Pyun
authors.affiliation: Institute of Neurology, University College London, United Kingdom.
authors.forename: Hugh
authors.initials: H
authors.lastname: Bostock
authors.affiliation: Department of Neurology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea. Electronic address: lwsbae@naver.com.
authors.forename: Jong Seok
authors.initials: JS
authors.lastname: Bae
mesh_terms: D000328:Adult; D001369:Axons / Q000502:physiology; D002349:Carpal Tunnel Syndrome / Q000175:diagnosis* / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008564:Membrane Potentials / Q000502:physiology; D008875:Middle Aged; D008962:Models, Theoretical; D018482:Muscle, Skeletal / Q000503:physiopathology*
keywords: Abductor pollicis brevis; Carpal tunnel syndrome; Lumbrical; Nerve excitability; Threshold tracking