THORACIC DEFORMATION AND VELOCITY ANALYSIS IN FRONTAL IMPACT

The objective of the present study was to measure dynamic chest deform ations and compute chest velocity and viscous criterion during real wo rld frontal impacts conducted on a horizontal sled. Four unembalmed hu man cadavers were restrained using a three-point belt restraint in the driver seat of a sled buck. Two chest bands (each with a 24 gauge cap ability) were placed on the thorax to record the temporal deformation patterns during impact. All tests were conducted at a velocity of appr oximately 50 kph. Biomechanical data were gathered digitally at a samp ling rate of 12,500 Hz. Multiple rib fractures were identified in all specimens at autopsy. Analysis of approximately 800 temporal deformati on contours of the thorax demonstrated regional differences. The overa ll mean maximum normalized chest deflections, maximum chest compressio n velocities, and peak viscous response variables ranged from 0.15 to 0.51, 1.79 to 4.87 m/s, and 0.15 to 1.95 m/s, respectively. These find ings clearly illustrate the potential use of the chest band output to correlate injury with biomechanical variables and establish thoracic i mpact tolerance.