Biomechanics of Lateral Skull Fracture

This study was designed to investigate the biomechanics of human head injury with a focus on skull fracture due to side impact loading. Temporo-parietal impact tests were conducted using specimens from ten unembalmed post mortem human subjects. The specimens were isolated at the occipital condyle level, and pre-test x-ray and computed tomography images were obtained. They were prepared with multiple triaxial accelerometers and subjected to increasing velocities (ranging from 4.9 to 7.7 m/s) using free-fall techniques by impacting onto a force plate from which forces were recorded. A 40durometer padding (50-mm thickness) material covering the force plate served as the impacting boundary condition. Computed tomography images obtained following the final impact test were used to identify pathology. Four out of the ten specimens sustained skull fractures. Peak force, displacement, strain, acceleration, energy, and head injury criterion variables were used to describe the biomechanics, and probability curves were developed using the Kaplan-Meier method to establish tolerance limits.