title: Effects of whole spine alignment patterns on neck responses in rear end impact.
abstract: The aim of this study was to investigate the whole spine alignment in automotive seated postures for both genders and the effects of the spinal alignment patterns on cervical vertebral motion in rear impact using a human finite element (FE) model.
  
  
  
  Image data for 8 female and 7 male subjects in a seated posture acquired by an upright open magnetic resonance imaging (MRI) system were utilized. Spinal alignment was determined from the centers of the vertebrae and average spinal alignment patterns for both genders were estimated by multidimensional scaling (MDS). An occupant FE model of female average size (162 cm, 62 kg; the AF 50 size model) was developed by scaling THUMS AF 05. The average spinal alignment pattern for females was implemented in the model, and model validation was made with respect to female volunteer sled test data from rear end impacts. Thereafter, the average spinal alignment pattern for males and representative spinal alignments for all subjects were implemented in the validated female model, and additional FE simulations of the sled test were conducted to investigate effects of spinal alignment patterns on cervical vertebral motion.
  
  
  
  The estimated average spinal alignment pattern was slight kyphotic, or almost straight cervical and less-kyphotic thoracic spine for the females and lordotic cervical and more pronounced kyphotic thoracic spine for the males. The AF 50 size model with the female average spinal alignment exhibited spine straightening from upper thoracic vertebra level and showed larger intervertebral angular displacements in the cervical spine than the one with the male average spinal alignment.
  
  
  
  The cervical spine alignment is continuous with the thoracic spine, and a trend of the relationship between cervical spine and thoracic spinal alignment was shown in this study. Simulation results suggested that variations in thoracic spinal alignment had a potential impact on cervical spine motion as well as cervical spinal alignment in rear end impact condition.
authors: a Japan Automobile Research Institute , Tsukuba , Ibaraki , Japan.|b Chalmers University of Technology , Göteborg , Sweden.
authors: Fusako
authors: F
authors: Sato
authors: c Tokyo Institute of Technology , Meguro-ku , Tokyo , Japan.
authors: Mamiko
authors: M
authors: Odani
authors: c Tokyo Institute of Technology , Meguro-ku , Tokyo , Japan.
authors: Yusuke
authors: Y
authors: Miyazaki
authors: a Japan Automobile Research Institute , Tsukuba , Ibaraki , Japan.
authors: Kunio
authors: K
authors: Yamazaki
authors: b Chalmers University of Technology , Göteborg , Sweden.
authors: Jonas
authors: J
authors: Östh
authors: b Chalmers University of Technology , Göteborg , Sweden.
authors: Mats
authors: M
authors: Svensson
mesh_terms: D000063:Accidents, Traffic / Q000706:statistics & numerical data*; D000328:Adult; D001696:Biomechanical Phenomena; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D019838:Neck Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011187:Posture; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014911:Whiplash Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055815:Young Adult
keywords: Rear impact; finite element analysis; spinal alignment; whiplash