Yale News reports that persons whose heads are turned when in a rear impact collision are at risk for a much more serious whiplash injury, and potentially chronic symptoms. And a Yale School of Medicine study shows why.
Manohar Panjabi, a professor in the departments of Orthopedics and Mechanical Engineering, said, “We believe this is the first study to identify, quantify and determine the mode of cervical spine injury sustained during a rear impact collision when a person in the vehicle has their head turned.”
The article said that “previous clinical studies…show that the rotated head posture was the major factor causing more severe chronic symptoms, even when considering the presence of a head restraint and the state of preparedness.”
The study Panjabi performed along with his co-authors used six human cervical spine specimens and a sled apparatus. They performed rear impact simulations with the head turned at the time of the impact.
“The researchers,” the article goes on to say, “directly compared their findings with those obtained in their previous study of rear impact with head facing forward at the time of impact. Rotated head posture at the time of rear impact caused significantly greater neck injury severity and more complex injuries.”
The article says that researchers hypothesize this is true for two reasons: “First, there is an initial stretch in the neck ligaments, which is not present when the head is facing forward. During the rear impact, the ligaments are stretched further. This over-stretching of the ligaments can cause ligament tears and spinal instability, leading to neck pain. Second, rear impact with rotated head posture causes three-dimensional head and neck motions, as compared to only two dimensional motions in the head forward posture. The three-dimensional head motions cause more complex types of neck injuries.”