A com putational head-neck model was developed to efficiently study dynam ic responses of the head and neck to near-vertex head im pact. The model consisted of rigid vertebrae interconnected by assemblies of nonlinear springs and dashpots, and a finite element shell model of the skull. Q uasi-static flexion-extension characteristics of ten human cadaveric cervical spines were measured using a test frame capable of applying pure moments. The cadaveric m otion segments dem onstrated a nonlinear stiffening response without a no-load region, or neutral zone. Com putational model param eters were based upon these measurements and existing d a ta reported in the literature. Geometric and inertial characteristics were derived from three-dimensional reconstructions of skull and vertebral CT images. The model reproduced the shape and timing of the cervical spine buckling deformations observed in high speed video of cadaveric studies of near-vertex head impact. Head and neck force histories and head acceleration histories agreed with those reported in the cadaveric studies. A sensitivity analysis of the model parameters revealed that head and neck responses were most sensitive to changes in head stiffness, head mass, and flexion-extension properties, suggesting th a t an appropriately configured deformable head and accurate experimental characterization of motion segment flexion-extension behavior are critical to reliable model predictions. Increases in the coefficient of friction between the head and a rigid im pact surface over a range from 0.0 to 1.0 resulted in increases of up to 40%, 113%, and 9.8% in peak postbuckled resultant neck forces, peak moment at the occiput-C l joint, and peak resultant head accelerations, respectively. A param etric study of padding characteristics demonstrated that a pad with optimized characteristics can produce up to 23% less peak resultant neck force, 87% less peak resultant head acceleration, 97% less HIC value, and 33% less peak occiput-Cl moment than a rigid im pact surface. However, a pad with unfavorable characteristics produced up to 36% higher peak resultant neck forces than a rigid impact surface, substantiating cadaveric experimental findings that padded surfaces can result in a higher incidence of neck injury than rigid surfaces. The present study has characterized the relationships between several padding variables and various measures of injury potential, providing the safety engineer w ith general guidelines for designing injury-reducing impact surfaces.