Biomechanical Analysis of Head and Neck Injury Risk from a Falling Object
Background
A woman (the plaintiff) was shopping at a convenience store when an empty plastic storage bin fell from the top shelf and allegedly struck her on the head. Surveillance video footage of the incident showed the woman bending over to look at an object on the ground when the bin began sliding off the front edge of the shelf. Unfortunately, the video footage cut out before the bin made contact with the plaintiff. Plaintiff alleged she sustained injuries to her head and neck as a result of the incident.
Process
Explico biomechanical engineers Steve Rundell and Shaun Jeffs were tasked with determining injury risk by computing forces and accelerations of plaintiff’s head and neck resulting from the impact. As the video did not show the precise moment of impact, they investigated a range of possible impact scenarios. The position of the plaintiff’s body was determined through analysis of the surveillance video. A female surrogate was used to quantify the plaintiff’s posture. An exemplar bin was then dropped from an exemplar shelf in the same manner as seen in the surveillance video, and the velocity of the bin was determined via video tracking software. To characterize the impact duration, the exemplar bin was dropped onto a force plate.
Using this data, Explico simulated the incident in MADYMO, a software package designed to calculate the human body’s response to external forces. To account for potential variability in plaintiff’s position and the orientation of the bin, a sensitivity study of 10 separate impact scenarios were analyzed. The results showed that the accelerations and forces plaintiff would have experienced in her head and neck were considerably less than those associated with acute injury and were consistent with those experienced during common, benign activities of daily living.
Results
Explico communicated the findings to the client, who was able to achieve a favorable outcome at mediation.
