In the present study, the effects of cervical spine initial alignment, muscle activity, and the selected properties of trachea, vena cava and inactivated muscles on the responses of a finite element model of a cervical spine (H-Model by the ESI Group) under direct head loading were investigated. The modelling results were compared with those of volunteers. The present results suggest the following: Properties of inactivated muscles, vena cava and trachea greatly affect the general head motion; Maximum isometric force plays an important role in resisting neck extension; and Reflex time determining the start of generation of active muscle force considerably affects the angular displacement of cervical vertebrae. Based on these findings, the modifications of the cervical spine H-Model were introduced. The modified model well represented the head-C7 motion, although it underestimated the head-atlas extension. For the covering abstract see ITRD E825082.
Abstract