title: Relationship between the thickness and hemodynamics of the erector spinae muscles in various lumbar curvatures.
abstract: BACKGROUND
  There is little information about the relationship between the changes of hemodynamics and the morphologic changes of the erector spinae muscle.
  
  
  METHODS
  Fifty healthy male volunteers participated. Ultrasonography was used to measure muscle thickness, and near-infrared spectroscopy was used to measure tissue blood volume and its oxygenation in the erector spinae muscle at L3 in six different relaxed trunk postures (flexed 20 degrees , flexed 40 degrees, flexed maximum, neutral posture, extended 20 degrees, and extended maximum of the lumbar spine). We also evaluated the reproducibility of the near-infrared spectroscopy measurements.
  
  
  RESULTS
  Near-infrared spectroscopy gave highly reproducible measurements. The thickness of the erector spinae muscle and the total and oxygenated hemoglobin were simultaneously increased during relaxed extension and decreased during relaxed flexion. Changes in the thickness of the erector spinae muscle with various lumbar curvature were similar in pattern to the changes in tissue blood volume and its oxygenation.
  
  
  CONCLUSIONS
  The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as demonstrated by non-invasive near-infrared spectroscopy and ultrasonography. These findings might afford a better understanding of the pathomechanics of posture-related back symptoms.
  
  
  CONCLUSIONS
  The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as shown by non-invasive near-infrared spectroscopy and ultrasonography. Changes in hemodynamics and morphology of the erector spinae muscles in asymptomatic subjects are given for further research on the pathomechanism of back pain.
authors.affiliation: Department of Orthopaedic Surgery, Gifu University School of Medicine, Yanagido 1-1, Gifu City, Gifu 501-1194, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Masuda
authors.forename: Kei
authors.initials: K
authors.lastname: Miyamoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Oguri
authors.forename: Toshio
authors.initials: T
authors.lastname: Matsuoka
authors.forename: Katsuji
authors.initials: K
authors.lastname: Shimizu
mesh_terms: D000328:Adult; D001810:Blood Volume / Q000502:physiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D011187:Posture / Q000502:physiology*; D013223:Statistics as Topic; D014463:Ultrasonography
chemical_list: D010100:Oxygen