title: In vivo three-dimensional kinematics of the cervical spine during head rotation in patients with cervical spondylosis.
abstract: METHODS
  Kinematics of the cervical spine during head rotation was investigated using 3-dimensional (3D) magnetic resonance imaging (MRI) in patients with cervical spondylosis (CS).
  
  
  OBJECTIVE
  To demonstrate in vivo 3D kinematics of the spondylotic cervical spine during head rotation.
  
  
  BACKGROUND
  Several in vivo studies have identified kinematic differences between normal and spondylotic subjects, but only two-dimensional flexion/extension motion has been investigated. Differences of in vivo 3D cervical motion during head rotation between normal and spondylotic subjects have yet to be clarified.
  
  
  METHODS
  Ten healthy volunteers (control group) and 15 patients with CS (CS group) underwent 3D MRI of the cervical spine with the head rotated to 5 positions (neutral, ±45° and ±maximal head rotation). Relative motions of the cervical spine were calculated by automatically superimposing a segmented 3D MRI of the vertebra in the neutral position over images for each position using volume registration. The 3D motions of adjacent vertebra were represented with 6 degrees of freedom by Euler angles and translations on the coordinate system.
  
  
  RESULTS
  Compared with the control group, the CS group showed significantly decreased mean axial rotation and mean coupled lateral bending at C5-C6 and C6-C7 and significantly increased mean coupled lateral bending at C2-C3 and C3-C4, although both the groups showed the same pattern of coupled motions.
  
  
  CONCLUSIONS
  The in vivo 3D kinematics of the spondylotic cervical spine during head rotation was accurately depicted and compared with those of healthy cervical spines for the first time.
authors.affiliation: Department of Orthopaedic Biomaterial Science Osaka University Graduate School of Medicine, Suita, Osaka, Japan. 7gam0to@gmail.com
authors.forename: Yukitaka
authors.initials: Y
authors.lastname: Nagamoto
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishii
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sakaura
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Hisao
authors.initials: H
authors.lastname: Moritomo
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kashii
authors.forename: Takako
authors.initials: T
authors.lastname: Hattori
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Kazuomi
authors.initials: K
authors.lastname: Sugamoto
mesh_terms: D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000503:physiopathology*; D005260:Female; D019416:Head Movements; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D012399:Rotation; D055009:Spondylosis / Q000503:physiopathology*; D055815:Young Adult