Author(s): Hayes WC, Erickson MS, Power ED
Forensic injury biomechanics is the science that relates mechanical forces to disruption of anatomical regions of the human body. In this review, we introduce (a) how scaling techniques can be used to describe injury severity and probability of death; (b) how a simple ratio, the factor of risk, and more sophisticated injury risk functions can be used to determine the probability of injury; and (c) how injury criteria (also known as tolerance limits) are defined for the head and neck. Methods for establishing injury causation are then illustrated by real-world examples drawn from litigation involving motor vehicle collisions and slips, trips and falls. Those factors that distinguish litigation from basic and applied research are also discussed, including the criteria for admissibility of expert opinions and the level of certainty used as the basis for these opinions. The criteria that must be met to support opinions on causation at both epidemiological and individual levels are also noted. If the expert appreciates the difference between the demands of ligation and those of basic and applied research, expert opinion can play a crucial role in the decision-making process that characterizes litigation. Because forensic injury biomechanics is central to opinions on injury causation, and because causation is often the key to determinations of who is at fault, forensic injury biomechanics can be the deciding factor in many personal injury, products and premises liability, wrongful death, and criminal cases.