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CED Investigative Technologies Inc. has engineering expertise in many different areas but one that most people haven’t heard about is called “ring avulsion.” Ring avulsion occurs when someone catches a band such as a wedding ring or jewelry on moving machinery or on a protrusion from a surface as they jump or move away from that object. Numerous people have been seriously injured when their ring was caught in this manner, some even losing fingers in the process. Many companies have instituted safe working practices requiring workers such as machinists, welders, mechanics and other labor intensive occupations to remove rings when they are on the job.
The biomechanics involved in the research and study of ring avulsion are fascinating. The Journal of Hand Surgery published an article titled “Ring Avulsion Injuries: A Biomechanical Study”. In this study a cadaveric simulation model was used. A weight was attached to the ulna while the finger was suspended by an attachment of the ring to a hook. As it is more common to snag a ring on the palm side of the hand, a hook was attached to the palm side of the ring and then high speed cinematography was used to evaluate the amount of force necessary to result in amputation. Following the application of various forces, each finger was inspected and the type and extent of damage was assessed. Injuries were categorized according to Urbaniak’s classification on a scale of class I to class III. A class I injury was defined as a soft tissue injury while a class III injury resulted in complete digital amputation. The average maximum force applied that resulted in a class I injury was less than 18 pounds while the force applied in a class III amputation was around 35 pounds. This force was much lower than expected.
Recently, CED experts were retained on a ring avulsion case concerning a piece of industrial equipment in a processing plant. The first thing that the CED engineers performed was a site inspection to obtain crucial measurements such as the length of the subject’s arms relative to the placement of the equipment. Secondly, the CED engineers designed and conducted testing to calculate the amount of potential force that occurred during the proposed ring avulsion. Results of these tests were then compared to published research for causation. Based upon the testing and research, CED engineers were then able to provide a comprehensive opinion as to causation or potential causation.
Ring avulsion is a widely unknown subject to the general public but one where CED can help should a loss occur. CED biomechanical engineers have education and training in such areas as finger joint manipulation, prosthesis research and human tissue and skeletal testing. These engineers have also been retained for cases concerning ring avulsion in such areas as industrial equipment, worker safety practices and consumer products including car doors, bicycles, electrical equipment, etc. If you would like more information on ring avulsion or to talk to one of our case managers, please feel free to contact us at 800.780.4221 or at casemanager@cedtechnologies.com.
