Dynamic Characteristics of the Human Cervical Spine

This paper presents the experimental dynamic tolerance and the force-deformation response corridor of the human cervical spine under compression loading. Twenty human cadaver head-neck complexes were tested using a crown impact to the head at speeds from 2.5 m/s to 8 m/s. The cervical spine was evaluated for pre-alignment by using the concept of the stiffest axis. Mid cervical column (C3 to C5) vertebral body wedge, burst, and vertical fractures were produced in compression. Posterior ligament tears in the lower column occurred under flexion. Anterior longitudinal ligament tears and spinous process fractures occurred under extension. Mean values were: force at failure, 3326 N; deformation at failure, 18 mm; stiffness, 555 N/mm. The deformation at failure parameter was associated with the least variance and should describe the most accurate tolerance measure for the population as a whole.