title: The spinal curvature of three different sitting positions analysed in an open MRI scanner.
abstract: Sitting is the most frequently performed posture of everyday life. Biomechanical interactions with office chairs have therefore a long-term effect on our musculoskeletal system and ultimately on our health and wellbeing. This paper highlights the kinematic effect of office chairs on the spinal column and its single segments. Novel chair concepts with multiple degrees of freedom provide enhanced spinal mobility. The angular changes of the spinal column in the sagittal plane in three different sitting positions (forward inclined, reclined, and upright) for six healthy subjects (aged 23 to 45 years) were determined using an open magnetic resonance imaging (MRI) scanner. An MRI-compatible and commercially available office chair was adapted for use in the scanner. The midpoint coordinates of the vertebral bodies, the wedge angles of the intervertebral discs, and the lumbar lordotic angle were analysed. The mean lordotic angles were 16.0 ± 8.5° (mean ± standard deviation) in a forward inclined position, 24.7 ± 8.3° in an upright position, and 28.7 ± 8.1° in a reclined position. All segments from T10-T11 to L5-S1 were involved in movement during positional changes, whereas the range of motion in the lower lumbar segments was increased in comparison to the upper segments.
authors.affiliation: Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
authors.forename: Daniel
authors.initials: D
authors.lastname: Baumgartner
authors.forename: Roland
authors.initials: R
authors.lastname: Zemp
authors.forename: Renate
authors.initials: R
authors.lastname: List
authors.forename: Mirjam
authors.initials: M
authors.lastname: Stoop
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Naxera
authors.forename: Jean Pierre
authors.initials: JP
authors.lastname: Elsig
authors.forename: Silvio
authors.initials: S
authors.lastname: Lorenzetti
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology*; D013121:Spinal Curvatures / Q000503:physiopathology; D055815:Young Adult