Whole-Body Response to Pure Lateral Impact

The objective of the current study was to provide a comprehensive characterization of human biomechanical response to whole-body, lateral impact. Three approximately 50th-percentile adult male PMHS were subjected to right-side pure lateral impacts at 4.3 ± 0.1 m/s using a rigid wall mounted to a rail-mounted sled. Each subject was positioned on a rigid seat and held stationary by a system of tethers until immediately prior to being impacted by the moving wall with 100 mm pelvic offset. Displacement data were obtained using an optoelectronic stereophotogrammetric system that was used to track the 3D motions of the impacting wall sled; seat sled, and reflective targets secured to the head, spine, extremities, ribcage, and shoulder complex of each subject. Kinematic data were also recorded using 3-axis accelerometer cubes secured to the head, pelvis, and spine at the levels of T1, T6, T11, and L3. Chest deformation in the transverse plane was recorded using a single chestband. Following the impact the subject was captured in an energy-absorbing net that provided a controlled non-injurious deceleration. The wall maintained nearly constant velocity throughout the impact event. One of the tested subjects sustained 16 rib fractures as well as injury to the struck shoulder while the other two tested subjects sustained no injuries. The collected response data suggest that the shoulder injury may have contributed to the rib fractures in the injured subject. The results suggest that the shoulder presents a substantial load path and may play an important role in transmitting lateral forces to the spine, shielding and protecting the ribcage. This characterization of whole-body, lateral impact response provides quantified subject responses and boundary condition interactions that are currently unavailable for whole-body, lateral impacts at impact speeds less than 6.7 m/s.