title: Reference values for median nerve conduction to the pronator quadratus.
abstract: OBJECTIVE
  To derive a normative database for nerve conduction values of the median nerve to the pronator quadratus using a large and varied subject population.
  
  
  METHODS
  Descriptive study.
  
  
  METHODS
  Private office or university-based clinic.
  
  
  METHODS
  Volunteers (N=207), recruited, without risk factors for neuropathy.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Onset latency, duration, amplitude, and area were recorded for all subjects. Side-to-side variability was calculated and the normative ranges were derived (97th percentile of observed values).
  
  
  RESULTS
  Because the latencies increased with longer distances (longer forearms), the data were divided into 3 categories. The mean latency for those subjects whose distance from stimulator to recording electrode was 23 cm or less was 3.8+/-0.4 ms; the comparable values for those subjects with distances of 23.5 to 24.5 cm was 4.0+/-0.4 ms; and for those with distances of 25 cm and more, 4.5+/-0.4 ms. The amplitude and area varied with age. The mean amplitude for those subjects under 60 years of age was 4.4+/-1.8 mV, while those 60 years and over had an amplitude of 3.7+/-1.7 mV. The upper limit of normative side-to-side variability for latency was 0.6 ms, and the upper limit decrease in amplitude from 1 side to the other was 37%.
  
  
  CONCLUSIONS
  This study establishes normative values for the median motor nerve conduction to the pronator quadratus.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine, Indianapolis, IN 46202, USA. bsfoley@iupui.edu
authors.forename: Brian S
authors.initials: BS
authors.lastname: Foley
authors.forename: Eric T
authors.initials: ET
authors.lastname: Roslonski
authors.forename: Ralph M
authors.initials: RM
authors.lastname: Buschbacher
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004558:Electric Stimulation; D004566:Electrodes; D004568:Electrodiagnosis; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000502:physiology*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology*; D012015:Reference Standards; D012016:Reference Values; D012680:Sensitivity and Specificity; D034941:Upper Extremity