Publication Details

Methods: A detailed finite element head–neck model was enhanced and evaluated against literature data, then used to investigate HFI response at a 2 m/s vertical drop impact velocity. A reposturing procedure achieved graded head-forward eccentricity from 0 to 50 mm in 5 mm increments, reflecting postures observed during anticipatory neck bracing. A matched cadaveric HFI experiment was subsequently performed with 30 mm eccentricity.

Results: Simulations demonstrated that eccentricities of 15 mm or more produced an S-shaped neck deformation during impact, as observed in prior experiments that produced CFD, accompanied by marked increases in anterior intervertebral shear and flexion bending at C7/T1. The matched cadaveric experiment produced bilateral C7/T1 dislocation, consistent with the predicted loading and deformation trends. However, complete CFD was not reproduced computationally because current intervertebral soft-tissue failure formulations did not capture the observed failure progression.

Conclusions: Preimpact head-forward eccentricity can substantially increase lower-neck loading and susceptibility to CFD under the inverted-drop conditions studied.