title: The effect of rotational head and neck movements on the afferent cerebral blood flow.
abstract: OBJECTIVE
  To determine the effect of lateral rotational head and neck movements on the afferent cerebral blood flow in healthy adult humans so as to increase our knowledge of the relationship between arterial resistance and blood flow in the afferent cerebral arteries and in the arterial segments of the circle of Willis.
  
  
  METHODS
  Prospective, experimental study.
  
  
  METHODS
  Department of Radiology and Department of Functional Anatomy, Utrecht University, Utrecht, The Netherlands.
  
  
  METHODS
  Nine healthy adult male human volunteers aged between 24 and 52 years participated in this study with informed consent.
  
  
  METHODS
  The changes in the afferent cerebral blood flow between the neutral (face to the front) and the rotated head positions (turn to the right and turn to the left). The relationship between the changes in the afferent cerebral blood flow and the angle of the head rotation.
  
  
  RESULTS
  There were no significant differences between the changes in the afferent cerebral blood flow of the neutral and of the rotated head positions (p = 0.930 and p = 0.508 for the right and left head turns respectively). The correlation coefficients between the changes in the afferent cerebral blood flow and the angle of head rotation which ranged between 44.5 degrees and 72 degrees for the right turn and between 45 degrees and 72 degrees for the left turn were also not statistically significant (p = 0.191 for the right turn and p = 0.570 for the left turn).
  
  
  CONCLUSIONS
  The most likely explanation for these observations was that the changes in resistance in the afferent cerebral arteries of these healthy volunteers were too small to produce significant blood flow changes. Therefore, we conclude that normal physiological lateral rotational head and neck movements do not produce any significant blood flow changes in the afferent cerebral arteries of healthy adults.
authors.affiliation: Department of Anatomy, University of Zimbabwe, Harare, Zimbabwe. gmawe@zimbix.uz.zw
authors.forename: G
authors.initials: G
authors.lastname: Mawera
authors.forename: B
authors.initials: B
authors.lastname: Hillen
authors.forename: C J
authors.initials: CJ
authors.lastname: Bakker
authors.forename: W P
authors.initials: WP
authors.lastname: Mali
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002536:Cerebral Arteries / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009333:Neck / Q000098:blood supply / Q000502:physiology*; D011446:Prospective Studies; D012399:Rotation; D014655:Vascular Resistance