Finite Element Analysis of Head–Neck Kinematics in Rear-End Impact Conditions with Headrest

Abstract

A detailed three-dimensional (3D) head–neck (C0–C7) finite element (FE) model was developed and used to dictate the motions of each cervical spinal segment under static physiological loadings of flexion and extension with a magnitude of 1.0 Nm and rear-end impacts. In this dynamic study, a rear-end impact pulse was applied to C7 to create accelerations of 4.5 G and 8.5 G. The predicted segmental motions and displacements of the head were in agreement with published results under physiological loads of 1.0 Nm. Under rear-end impact conditions, the effects of peak pulse acceleration and headrest angles on the kinematic responses of the head–neck complex showed rates of increase/decrease in the rotational motion of various cervical spinal segments that were different in the first 200 ms. The peak flexion rotation of all segments was lower than the combined ROM of flexion and extension. The peak extension rotation of all segments showed variation compared to the combined ROM of flexion and extension depending on G and the headrest angle. A higher acceleration of C7 increased the peak extension angle of lower levels, but the absolute increase was restricted by the distance between the head and the headrest. A change in the headrest angle from 45° to 30° resulted in a change in extension rotation at the lower C5–C6 segments to flexion rotation, which further justified the effectiveness of having distance between the head and the headrest. This study shows that the existing C0-C7 FE model is efficient at defining the gross reactions of the human cervical spine under both physiological static and simulated whiplash circumstances. The fast rate of changes in flexion and extension rotation of various segments may result in associated soft tissues and bony structures experiencing tolerances beyond their material characteristic limits. It is suggested that a proper location and angle of the headrest could effectively prevent the cervical spine from injury in traumatic vehicular accidents.

Efficient 2D Neck Model for Simulation of the Whiplash Injury Mechanism

“…The ENM-2D’s efficiency makes it ideal for optimization processes requiring a high number of simulations. Therefore, this model enables more efficient computational analysis in comparison to using 3D finite element models, such as for the seat design position and angle of the headrest conducted by Wang et al [ 35 ].…”

Abnormal Static Sagittal Cervical Curvatures following Motor Vehicle Collisions: A Retrospective Case Series of 41 Patients before and after a Crash Exposure

“…During exposure to an MVC, the cervical spine is subjected to complex inertial loading where bending, shear, and compression loads act on the column. During the skull translation phase, many authors have described an S-Curve (first-order buckled mode) of the cervical lordosis [29][30][31][32][33]. Similarly, Matsunaga et al [34] described altered static cervical curvatures, including S-curves and retrolistheses, as buckled modes or shapes.…”

“…In MVC's acceleration/deceleration events, during the skull translation phase, many authors have described an S-Curve (first-order buckled mode) of the cervical lordosis [29][30][31][32][33]. Furthermore, altered geometry of the static cervical curvatures of patients has been previously described as buckled modes/shapes [34], but to our knowledge no study has shown that MVC's cause or contribute to altered geometry of the cervical curve post-crash.…”

Experimental Validation of a Driver Monitoring System

“…Numerous investigation reports can be found in the literature that have attempted to characterize the cervical spine biomechanical response. Many of these investigations have tested animals [5], human volunteers [6], human cadavers [7], crash-test dummies [8], articulated artificial necks [9], and computational models [10][11][12].…”