Dr David McGrath

Spine Physician

MB BS (Hons) FAFOM, RACP, FAFMM
Master of Pain Medicine

Motor Vehicle Accidents

The current evidence, indicates that worse injuries occur, when people are unprepared. In other words lack of preparedness, is a risk factor for injury.
When a collision is anticiptaed, we instinctively brace. Combining, those two bits of information,we would be led to the conclusion,that voluntary bracing , is likely to reduce injury.
Biomechanically, this makes sense. The neck is protected by ligaments and passive elements within muscles. The time duration of an impact, is too short to create an active reponse from muscles. When we anticipate a collision, active contraction of the muscles (bracing), contributes to the overall neck stiffness, and reduces the impact of forces to the joints.
Although head rests, will limit the backward extension of head travel,their contribution to safety has been minimal. Damage can occur, long before the head hits the backrest. The shockwave resulting from a rear end collision, forces the neck joints into an abnormal rotation and joint movement. Placing the head hard against the rest, will only prevent some of this occuring, plus any impact injury against the rest. The head will rebound foward, creating a flexion injury to the neck.
Pressing hard on the brake, is a useful manouver,when anticipating a collision. This transfers momentum into the earth,rather than the vehicle,and hence the occupants.
In summary, people who want to protect themselves, from injury, particularly rear end collision damage, could do the following.
1. Check rear vision when braking to a stop.
2. If a collision is anticipated, press hard on the brake pedal.
3. Brace for the collision (tightening all muscle groups)
4. Place the head close to or touching the headrest.(but not pressing backwards)