Article

This article discusses the process by which it is possible to reconstruct an incident by examining injury data. In this instance, our biomedical engineer, Dr. Williams was tasked with determining the manner in which the deceased encountered the electrical source.

AN UNWITNESSED ELECTROCUTION

A woman is found lying on the ground in her own yard while in contact with a live power line that had fallen. The event is unwitnessed and the female later dies of 3rd and 4th degree burns to over half of her body. Did she grab the power line? Did the power line fall on her? There was no dispute that the injuries were related to the incident, but our client’s legal strategy required knowledge of the manner in which the person encountered the power source.

This type of injury causation analysis falls under the purview of biomedical engineering. Biomedical engineering is the application of classical mechanical, electrical and chemical engineering toward the understanding of the human body as a whole system as well as the individual systems, organs, tissues and cells.

Electricity is the flow of electrons across a potential gradient from high to low concentration through a conductive material. Current is comprised of electrons and is what can kill or hurt people. The mechanism, extent, and depth of an electrical injury are determined by:

  • The voltage
  • The amount of current
  • The duration of current
  • The pathway of the current
  • The resistance
  • The type of current (ie. direct current – DC or alternating current – AC)

Low voltage is considered 380 volts or less and high voltage is above 380 volts. High voltage exposure greater than 1000V does not cause loss of consciousness but instead causes devastating thermal burns.1,2 Alternating current causes muscle tetany (involuntary contraction of muscles) due to the cyclic flow of electrons. This muscle tetany can cause prolonged exposure to the source because the muscle fibers are stimulated causing contraction. In addition to skeletal muscle and nerve damage, injuries from electrical contact can include bone fractures and joint dislocations.

Burns from electric current present as entrance and exit wounds. Entrance wounds occur at the point of contact with the source and exit wounds occur between the person and the grounding location. Entrance and exit wounds have specific appearances and create a particular injury pattern. The current pathway through the body can also leave a path of destruction with the contact points suffering the greatest damage.

An injury causation analysis can often determine what happened in an unwitnessed event and can also verify whether or not events took place as described by witnesses. It can also be used to determine if the use/misuse of protective equipment played a role in the cause of an injury.

In the case of the fatal electrocution, our expert was able to investigate the injury pattern described and depicted in the medical records and autopsy and apply knowledge of the mechanisms of electrical injuries to demonstrate that the person did not grab the live power source with either hand. Instead, the power line had fallen onto the person’s left upper arm. This, in turn, enabled our client to show that the deceased was not liable.

An injury causation analysis can be applied to any type of incident, whether it involves sports, automobile crashes, industrial mishaps, or slips and falls. If your case strategy calls for an understanding of the injury mechanisms, our biomedical experts at Robson Forensic can discuss your case with you to determine how we can help.

BIOMEDICAL/BIOMECHANICAL ENGINEERING INVESTIGATIONS

The biomedical experts at Robson Forensic provide scientific and analytical evaluation of injuries to determine causation. Our experts are engaged when the cause or mechanism of an injury is not known, is not understood, or is in dispute.

Injuries tell a story. Could a fall have occurred as testified? Were the forces high enough to have caused the injuries claimed? Was the known mechanism (direction and type of loading) of injury provided in the event? Is the injury consistent with the physical evidence? These are examples of questions our biomedical/biomechanical experts can help investigate.

For more information visit our Biomechanical Engineering practice page.

 

Featured Expert

Valentina Ngai, Ph.D., P.Eng.

Biomedical Engineer & Biomechanics Expert

Dr. Ngai is an expert in biomechanical engineering. She provides investigations, reports, and testimony toward the resolution of disputes and litigation involving traumatic injuries including medical implants and devices, motor vehicle crashes, premises liability, in addition to workplace and sports injuries.

Dr. Ngai holds a Ph.D. in Bioengineering from the University of Illinois at Chicago. She has been published in the Journal of Biomechanics, Wear, and the Journal of Engineering in Medicine. She has presented her research at numerous international conferences including the Orthopaedic Research Society, Wear on Materials, World Congress of Biomechanics and was an invited speaker at the 10th International Essen Symposium in Germany. Dr. Ngai is a licensed professional engineer in Ontario, Canada and also holds degrees in Civil and Mechanical Engineering.

Robson Forensic offers highly skilled biomechanical engineers throughout the country to meet the technical and geographical needs of each assignment.

Sources:

  1. Cushing TA, Wright RK, Electrical Injuries in Emergency Medicine, Medscape, April 12, 2010 (http://emedicine.medscape.com/article/770179-overview).
  2. Hunt JL, Soft tissue pattern in acute electric burns, Chapter 4 in Electrical Trauma: The Pathophysiology, Manifestations and Clinical Management, RC Lee, EG Cravalho, JF Burke. New York: Cambridge University Press, 2011. 84-86. Print.