Practical Method for Forensic Testing of Fall Impact Effects on the Human Spine

Abstract

The purpose of this study was to develop a safe, inexpensive, and practical method for estimating the force on the human spine during simulated fall landings for forensic investigations. Although the injury tolerances for the spine are known, the mechanics of spinal loading during fall landing are not well-established and thus limit the use of injury tolerances in establishing risk in landing injury cases. Measuring these spinal forces directly using live subjects would be invasive and unsafe; cadaver and animal models are expensive and do not capture the true mechanics of human spinal loading. As an alternative, this study proposed the use of a heavy duty punching bag to simulate the semi-rigid properties of the human body during a fall landing. The heavy bag was instrumented with accelerometers and dropped from various heights to measure impact acceleration. A live test subject instrumented with accelerometers on the foot and low back performed feet-first fall landings at relatively low heights to establish data for comparison. The impact acceleration for the heavy bag and back acceleration of the live subject matched well at corresponding heights. The measured foot accelerations did not correlate directly with those of the bag, possibly due to additional limb acceleration during landing. These preliminary results suggest that a heavy bag could be used to estimate the acceleration experienced by the back during simulated fall landings in forensic investigations.