Citation

Ejima S, Ono K, Yamazaki K. Proc. IRCOBI 2004; 32.

Copyright

(Copyright © 2004, International Research Council on Biomechanics of Injury)

DOI

unavailable

PMID

unavailable

Abstract

One of the important problems that needed to be investigated is the effect of muscle activity on the mechanisms of the neck injuries resulting from collision at low speeds. It has been experimentally indicated by that the cervical muscles can react fast enough to significantly reduce the head angular displacement during the impact. Because of it the modified finite element model of cervical spine which implements the Hill-type multi-bar muscle, was analyzed to study the mechanisms of the neck injuries. The activation of the neck musculature was determined using EMG data from the volunteer tests. The result from this analysis is to understand the mechanisms of injury to cervical facet joints. The finite element model of the cervical spine called THUMS was applied to the neck injury analysis for the base model. This was validated against the results of the experiments using volunteers. Validation against the modified model of the general head-neck complex kinematics indicates that modeling of unexpected impacts at speeds of 8 km/h yielded angular displacement and resultant and angular accelerations of the head gravity center COG either inside or very close to the corridors obtained in the experiments using volunteers. Comparing it to the original model, results from the modified model shows good agreement with the experimental result. The present model of cervical spine well represented both the general kinematics of the head-neck complex and motion of cervical vertebrae in unexpected impact at speed of 8km/h. This, in turn, indicates that the reflex time of cervical muscles are significantly influenced by the cervical motion, since all these variables are directly measured from the volunteer test. This model is currently in the improvement stage toward its practical application, and several problems remain to be solved.