title: Ultrasonography in severe carpal tunnel syndrome.
abstract: BACKGROUND
  In up to 30% of patients with carpal tunnel syndrome (CTS), the cross-sectional area (CSA) of the median nerve may not be enlarged. We hypothesize that this could be the result of secondary atrophy of the nerve in severe CTS. The aim of this study was to measure the ultrasonographic CSA of the median nerve at the wrist in patients with severe CTS.
  
  
  METHODS
  In 14 consecutive patients with clinically and electrophysiologically defined severe CTS, the CSA of the median nerve was measured and compared with that of control subjects.
  
  
  RESULTS
  CSA of the median nerve exceeded the upper limit of normal in the majority of patients with severe CTS.
  
  
  CONCLUSIONS
  Atrophy of the median nerve in severe CTS does not explain negative ultrasonographic test results. Instead, the CSA of the median nerve is enlarged in most patients with severe CTS.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Canisius Wilhelmina Hospital, P.O. Box 9015, 6500 GS Nijmegen, The Netherlands. kristel_kasius@hotmail.com
authors.forename: Kristel M
authors.initials: KM
authors.lastname: Kasius
authors.forename: Franka
authors.initials: F
authors.lastname: Claes
authors.forename: Wim Im
authors.initials: WI
authors.lastname: Verhagen
authors.forename: Jan
authors.initials: J
authors.lastname: Meulstee
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000368:Aged; D000369:Aged, 80 and over; D002349:Carpal Tunnel Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D014463:Ultrasonography / Q000379:methods*