title: Ultrasound measurements of the distance between acupuncture needle tip at P6 and the median nerve.
abstract: BACKGROUND
  Pericard 6 (P6) is one of the most frequently used acupuncture points, especially in preventing nausea and vomiting. At this point, the median nerve is located very superficially.
  
  
  OBJECTIVE
  To investigate the distance between the needle tip and the median nerve during acupuncture at P6, we conducted a prospective observational ultrasound (US) imaging study. We tested the hypothesis that de qi (a sensation that is typical of acupuncture needling) is evoked when the needle comes into contact with the epineural tissue and thereby prevents nerve penetration.
  
  
  METHODS
  The outpatient pain clinic of the Medical University of Vienna, Austria.
  
  
  METHODS
  Fifty (50) patients receiving acupuncture treatment including P6 bilaterally.
  
  
  METHODS
  Patients were examined at both forearms using US (a 10-MHz linear transducer) after insertion of the needle at P6.
  
  
  METHODS
  The distance between the needle tip and the median nerve, the number of nerve contacts and nerve penetrations, as well as the number of successfully elicited de qi sensations were recorded.
  
  
  RESULTS
  Complete data could be obtained from 97 cases. The mean distance from the needle tip to the nerve was 1.8 mm (standard deviation 2.2; range 0-11.3). Nerve contacts were recorded in 52 cases, in 14 of which the nerve was penetrated by the needle. De qi was elicited in 85 cases. We found no association between the number of nerve contacts and de qi. The 1-week follow-up showed no complications or neurologic problems.
  
  
  CONCLUSIONS
  This is the first investigation demonstrating the relationship between acupuncture needle placement and adjacent neural structures using US technology. The rate of median nerve penetrations by the acupuncture needle at P6 was surprisingly high, but these seemed to carry no risk of neurologic sequelae. De qi at P6 does not depend on median nerve contact, nor does it prevent median nerve penetration.
authors.affiliation: Department of Anaesthesiology and Intensive Care B, Medical University of Vienna, Vienna, Austria. konrad.streitberger@insel.ch
authors.forename: Konrad
authors.initials: K
authors.lastname: Streitberger
authors.forename: Urs
authors.initials: U
authors.lastname: Eichenberger
authors.forename: Antonius
authors.initials: A
authors.lastname: Schneider
authors.forename: Steffen
authors.initials: S
authors.lastname: Witte
authors.forename: Manfred
authors.initials: M
authors.lastname: Greher
mesh_terms: D015669:Acupuncture Points; D015670:Acupuncture Therapy / Q000295:instrumentation* / Q000379:methods; D000328:Adult; D001317:Austria; D005260:Female; D005542:Forearm / Q000000981:diagnostic imaging* / Q000294:innervation*; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000000981:diagnostic imaging*; D009339:Needles; D019413:Qi; D012016:Reference Values; D012107:Research Design; D014463:Ultrasonography