Event

Welcome to the Licenciate seminar by Fusako Sato:

Female and Male Whole Spinal Alignment and Cervical Kinematic Responses in Rear Impacts

Thesis submitted for the degree of Licentiate of Engineering in Machine and Vehicle Systems at the Department of Mechanics and Maritime Sciences, Chalmers University of Technology, Gothenburg, Sweden.

Abstract
The susceptibility of women to Whiplash Associated Disorders (WADs) has been the focus of
numerous epidemiologic studies. Summarising the epidemiologic WAD studies, women were
found to be at three times higher risk of sustaining WADs than men. Analysis of insurance
claims records indicate that certain whiplash protection seats have reduced the risk of
sustaining WADs more effectively for men than for women. However, many aspects of
WADs are still unknown, including what role gender differences play in the risk of sustaining
WADs.

In order to obtain fundamental knowledge to understand the gender difference involved in
the risk of sustaining WADs, this thesis reanalysed previous rear impact sled test series
comprising female and male volunteers to clarify the dynamic characteristics of inertiainduced
cervical vertebral kinematics during rear impacts for women and men. Furthermore,
cervical spinal alignment has been suggested as one of several possible causes of the gender
differences seen in the risk of sustaining WADs. In addition, it has been reported that the
initial position of the thoracolumbar spine against a seatback affects vertebral kinematics as
well as the cervical spine. Therefore, this study also investigated whole spinal alignments in
one automotive seated posture using an upright open MRI system for both genders, and
estimated average gender specific spinal alignment patterns.

During rear impacts, the female subjects presented with a more pronounced S-shape in the
cervical spine than the male subjects, beyond the voluntary muscle-induced cervical
kinematics range for female subjects. In contrast, for the male subjects, the peak S-shape
appeared within the voluntary muscle-induced cervical kinematics range. The estimated
average spinal alignment pattern in the automotive seated posture was slight kyphotic, or
almost straight cervical spine with less-kyphotic thoracic spine for the female subjects, and
lordotic cervical spine with more pronounced kyphotic thoracic spine for the male subjects.
The findings support previous studies which have indicated influences of cervical spinal
alignment on cervical vertebral kinematics. Potential impacts of any gender differences in
whole spinal alignment on cervical vertebral kinematics can be investigated with a wholebody
human FE model in future work based on this thesis.

Facilitator
Assoc. Prof. Kai-Uwe Schmitt
Department of Health Sciences and Technology
ETH Zurich
Switzerland

Link to thesis: chalmersuniversity.box.com/s/h5j1udn8wb2dn1y6d7mgz0n84srfhua2