title: The accuracy of needle placement in lower-limb muscles: a blinded study.
abstract: OBJECTIVE
  To assess the accuracy of common anatomic guides for electromyographic needle placement in muscles.
  
  
  METHODS
  Blinded study. The dissector identified different needle placements by a random number attached to a wire in the insertion site.
  
  
  METHODS
  A university anatomy laboratory.
  
  
  METHODS
  Ten cadaver lower limbs.
  
  
  METHODS
  By using techniques published in texts by Gieringer and Delagi and Perotto, clinical electromyographers palpated and measured appropriate locations for needle placement. A thin wire was inserted through the needle into 36 different muscles in 10 cadavers, resulting in 263 targeted muscles. An anatomist blinded to intended location dissected and recorded muscles and other tissues that the wire pierced or passed near.
  
  
  METHODS
  Targeted muscle penetration, final resting place of the wire tip, and proximity to vital structures.
  
  
  RESULTS
  Fifty-seven percent of insertions penetrated the intended muscle. The wire tip was in the intended muscle 45% of the time. Seventeen percent of insertions penetrated or passed within 5mm of an important structure, including nerve (9.1%), tendon (3.0%), named artery (2.7%), vein (2.7%), or joint (0.8%). Specific muscle accuracy was highly variable, from 0% for 12 tries in various deep hip muscles to 100% of 10 tries in the vastus medialis.
  
  
  CONCLUSIONS
  The accuracy of blind needle placement varied according to muscle. With the blind insertion technique, more accurate and safe needle placement strategies can be developed.
authors.affiliation: Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor 48108, USA. Andyhaig@umich.edu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Haig
authors.forename: Craig W
authors.initials: CW
authors.lastname: Goodmurphy
authors.forename: Albert R
authors.initials: AR
authors.lastname: Harris
authors.forename: Alejandro Perez
authors.initials: AP
authors.lastname: Ruiz
authors.forename: Jeffery
authors.initials: J
authors.lastname: Etemad
mesh_terms: D002102:Cadaver; D004311:Double-Blind Method; D004567:Electrodes, Implanted / Q000592:standards*; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*; D009339:Needles; D015588:Observer Variation; D015203:Reproducibility of Results; D012449:Safety