Biomechanics Expert Opines on Neck Injuries Suffered in Rear-End Collision

This kinesiology case involves a car accident that allegedly caused chronic, debilitating neck pain. The Plaintiff was driving his car when he was rear-ended by a large garbage truck operated by a private garbage removal service. While the damage to the Plaintiff’s vehicle was fairly minor, the force of the impact caused serious injuries to the patient’s neck, which required a fusion surgery and additional supportive care. The Plaintiff believes the impact caused the neck pain resulting in the subsequent surgery.

Question(s) For Expert Witness

1. Can you discuss on how the impact of a collision may have an effect on the human body?

Expert Witness Response E-007211

It is possible that such an accident could cause an injury to the neck. As two bodies collide, in this situation it would be the two vehicles making contact, momentum will be transferred from one body to the other. If the Plaintiff's vehicle was stationary, the impact would be greater than if it were moving in the same direction as the striking vehicle. In addition, if the Plaintiff's vehicle was pushed forward due to the contact, and the striking vehicle stopped abruptly due to the impact, the transfer of momentum to the Plaintiff's vehicle would be much greater. Another item that will affect the amount of momentum transferred during the impact would be the difference in masses of the two vehicles. Upon impact, the momentum would be transferred from the striking vehicle to the Plaintiff's vehicle, and simultaneously to the Plaintiff. At initial impact, the Plaintiff's upper body and/or their head would be driven backwards into the seat and headrest if their body was not previously in contact with said objects. If the Plaintiff was already applying the brakes while stopped, the vehicle will slide forward due to the impact and momentum transfer, allowing the Plaintiff's vehicle to overcome the coefficient of friction. Within a few moments, the coefficient of friction will resist the forward movement and cause the vehicle to stop abruptly. This sudden stop would then cause the Plaintiff's body to travel forward, hopefully being restrained by their seatbelt. If the seatbelt is working properly, the torque latch would engage as the upper body pushes forward and begins to unravel the wound seatbelt. This would immediately stop the upper body from flexing forward about the hips, and transfer the angular momentum to the head about the neck. As we transfer angular momentum from one segment to another, angular velocity will increase as the radius of rotation decreases. This transfer will cause the neck to rotate forward at a violent rate, creating a large flexion torque at the neck. Such a motion and concurrent torque have the potential to cause traumatic injury to the bones and soft tissue at the neck.