A Study of Cervical Spine Kinematics and Joint Capsule Strain in Rear Impacts Using a Human FE Model

Recently, the cervical facet joint capsules have been focused on as a potential site of whiplash injury. An experimental approach has been taken to analyze the vertebral motion and to estimate joint capsule stretch. This study analyzed the kinematics of the cervical facet joint using a human finite element (FE) model in order to better understand the injury mechanism. The Total Human Model for Safety (THUMS) was used to visually analyze the local and global kinematics of the spine. A model of the soft tissues of the neck was introduced into THUMS for estimating the loading level in rear impacts. The model was validated against human test data in the literature. Joint capsule strain was estimated from a maximum principal strain output from the elements representing the capsule tissues. A rear-end collision was then simulated using THUMS and a prototype seat model. The trajectory of the vertebrae was analyzed in a local coordinate system defined along the joint surface. Strain growth in the joint capsules was explained with regard to contact events between the occupant and the seat. A new seat concept was proposed to help lessen the loading level to the neck soft tissues. It included softening of the foam material of the seat back, reducing the initial gap behind the head, stiffening the head restraint, and reinforcing the lower seat back frame to withstand the impact severity. Another rear impact simulation was conducted using the new seat concept model. The joint capsule strain was found to be relatively lower with the new seat concept. The study also discusses the influence of seat parameters on the vertebral motion and the resultant strain in the joint capsules.


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  • Accession Number: 01046258
  • Record Type: Publication
  • ISBN: 139780768018295
  • Files: TRIS
  • Created Date: Apr 19 2007 10:14AM