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Chiropracitc and Physical Therapy Clinic
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Whiplash Injury      

For the people who really want to know what is going on....

 

4 Phases of a Whiplash Injury
     by Andrew S. Choi, D.C.

Half of a second is not a long time but long enough to stretch nerves, tear ligaments and tendons, herniate disks, and slap the brain into the side of the skull. This all happens through 4 stages of acceleration. Each one is distinct and has its own damaging effects on the body. Even more disturbing is that the body received substantially more acceleration than the vehicle.

Well known specialist Dr. Guy says," There is no doubt that the practice of comparing vehicle damage to the degree of human injury is naïve."

 

As you can see the head and neck experiences over 3 times the G force of the car itself, meaning just because the car isn't totaled doesn't mean you're not.

PHASE I

The car is struck and begins to move underneath you. Your mid back is flattened into the seat. Your body lifts towards the roof of the car. The neck and the low back flatten and the disks compress. The head violently moves backward. The neck restraint will protect you some; reducing injury by 11-20% (if adjusted properly) but most of the injury will occur before your head hits the seat. The axial compressive force on the spine is in the range of 33 pounds.

PHASE II

Your head reaches full acceleration but continues to move forward. This produces a shearing force on the neck. An S-curve develops in the spine. The foot is drawn away from the brake, resulting in more acceleration. This is a dangerous situation that can result in disk, ligament, muscle, and facet damage. This facet damage is often difficult to see on imaging and can result in pain years after the accident.

PHASE III

Both the head and shoulders are at peak acceleration while the vehicle is slowing down. The head and shoulders are moving forward and the torso is forced into the seat. The feet press back down on the brake which makes the deceleration more violent. The shoulder restraint protects you from being ejected from the vehicle but can cause contusions across the chest and ribs. 

PHASE IV

This is the most damaging phase. The seat belt causes a violent flexion of the neck. The muscles and ligaments are strained and the fibers of the disks can tear. Vertebrae can misalign at this phase. As your head is jerked forward the brain can smack the inside of your skull resulting in brain damage. This damage can manifest in the form or memory loss and head aches. If you are not restrained properly, this can result in further damage by hitting the windshield and steering wheel.

"At an impact speed of 20 mph the human head reaches a peak acceleration of 12 G during extension."
Hanley & Belfus