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North American Congress on Biomechanics Canadian Society for Biomechanics - American Society of Biomechanics University of Waterloo Waterloo, Ontario, Canada August 14-18, 1998 |
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The science of biomechanics is relatively unknown within the judicial systems of the U.S. and Canada. While engineers, orthopedists, economists, chemists, psychologists and scientists in other areas routinely serve as expert witnesses, biomechanists have been less active in thc forensic arena. However, in recent years this has begun to change as more scientists from this discipline have been called upon to provide their unique contribution in personal injury and product liability cases. Unfortunately, these activities which I describe as the 'underground science' are seldom shared among biomechanists since their work is hidden in written reports, deposition transcripts and trial testimony records. As a result, there is little exchange of information among biomechanists as to the activities and responsibilities of an expert witness. Consequently, those who enter this area of application of our science must learn by 'trial and error' as they develop the necessary skills to become effective expert wġitnesses. The fact that "Forensic Biomechanics" was selected as one of the topics for a Keynote Address at this Congress reflects the growing interest in this professional activity.
My first experience as an expert witness occurred in 1980 at which time I received a call from an attorney regarding an accident in which a woman fell on a dance floor. Over the next decade I served as an expert on five to ten cases a year during which time it became clear that the biomechanist was uniquely qualified to reconstruct accidents of all types.
The combined knowledge of human anatomy and physiology, basic mechanics and human motion cannot be duplicated by researchers in other fields. For exainple, reconstruction of automobile crashes is typically done by accident reconstruction engineers who examine evidence secured at the scene to determine the motion of the vehicle(s), impact speed, Delta V values, etc. Meanwhile medical and rehabilitation specialists testify as to the nature of the injuries sustained bv the occupants, predict recovery times and estimate the degree of permanent disability. The forensic biomechanist "fills the gap" between these two groups of professionals by reconstucting the accident taking into account the physical features of the occupants, their motion during the accident while linking the injuries sustained to their location in the vehicle. Of the over ninety automobile accident cases I have worked on eleven have involved single car crashes with two occupants, one of whom dies during the crash. Since alcohol was a factor in each case the question of who was driving was of major importance. Typically, the survivor (who may not remember anything due to a head injury) claims to have been the front seat passenger in order to avoid prosecution for DUI homicide. In each of these cases my biomechanical reconstruction determined conclusively which of the two occupants had been driving at the time of the accident.
The fact that biomechanists possess unique skills makes it possible to analyze and reconstruct accidents of all kinds. Included among my cases have been industrial and farm accidents involving tractors, a front loader, forklift rollovers, conveyor belts, corn grinder, chain saws, pig feeder, factory machinery, railroad switch operation, table and skill saws, salt and coal mining environments and many others. A number of snow sledding accidents involving sleds and snow tubes have been analyzed to determine whether the device was defective, thereby placing the injured rider at risk. Softball accidents involving fixed and 'breakaway' bases, collision with the back stop fence and a torn astroturf seam have also been investigated. Other sport related accidents have involved a scalp wound suffered by a football player, two severe brain injuries resulting from defective boxing headgear, ski accidents involving binding release issues and many others. In all of these cases the purpose of the biomechanical reconstruction has been to determine precisely how the accident occurred which can then be used to either support or refute the plaintiffs version.
Finally, a number of professional issues will be discussed includng the following: the role of the expert witness (or, why get involved?), contractual arrangements, plaintiff versus defense, deposition and court testimony, promoting your services, ethical considerations, conflicts of interest and other matters.