title: Internal Carotid Artery Strains During High-Speed, Low-Amplitude Spinal Manipulations of the Neck.
abstract: OBJECTIVE
  The primary objective of this study was to quantify the strains applied to the internal carotid artery (ICA) during neck spinal manipulative treatments and range of motion (ROM)/diagnostic testing of the head and neck.
  
  
  METHODS
  Strains of the ICA (n = 12) were measured in 6 fresh, unembalmed cadaveric specimens using sonomicrometry. Peak and average strains of the ICA obtained during cervical spinal manipulations given by experienced doctors of chiropractic were compared with the corresponding strains obtained during ROM and diagnostic testing of the head and neck.
  
  
  RESULTS
  Peak and average strains of the ICA for cervical spinal manipulative treatments were significantly smaller (P < .001) than the corresponding strains obtained for the ROM and diagnostic testing. All strains during ROM and treatment testing were dramatically smaller than the initial failure strains of the ICA.
  
  
  CONCLUSIONS
  This study showed that maximal ICA strains imparted by cervical spinal manipulative treatments were well within the normal ROM. Chiropractic manipulation of the neck did not cause strains to the ICA in excess of those experienced during normal everyday movements. Therefore, cervical spinal manipulative therapy as performed by the trained clinicians in this study, did not appear to place undue strain on the ICA and thus does not seem to be a factor in ICA injuries.
authors.affiliation: Killam Memorial Chair, Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; Canada Research Chair (Tier 1) in Molecular and Cellular Biomechanics, Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; Professor in Kinesiology, Medicine, Engineering and Veterinary Medicine, Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada. Electronic address: walter@kin.ucalgary.ca.
authors.forename: Walter
authors.initials: W
authors.lastname: Herzog
authors.affiliation: Chiropractor, Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Conrad
authors.initials: C
authors.lastname: Tang
authors.affiliation: Research Associate, Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Leonard
mesh_terms: D001696:Biomechanical Phenomena; D020212:Carotid Artery Injuries / Q000209:etiology*; D002343:Carotid Artery, Internal; D006801:Humans; D020393:Manipulation, Spinal / Q000009:adverse effects* / Q000379:methods*; D009333:Neck
keywords: Biomechanics; Carotid Artery Injuries; Cervical; Chiropractic; Manipulation; Safety; Stroke