Whiplash is the term used to describe neck pain and stiffness following a violent collision; usually a car accident. It can also be accompanied by headaches, dizziness, fatigue, jaw pain (TMJ), numbness and tingling in the upper extremities. Whiplash, if not treated properly soon after the injury, can set the stage for long-term (chronic) neck problems.

Technically, whiplash occurs when the body is suddenly accelerated then decelerated, which is precisely what happens in a "rear-fender" car accident: upon impact from behind, the torso accelerates rapidly to the same speed as the colliding car. Because of the neck's flexibility, the head simultaneously arcs backward, injuring soft tissue structures (muscle, ligaments and tendons) around the neck and upper shoulders. When the force of the collision stops (within one second), the torso suddenly stops, but the head accelerates forward and over corrects, causing the neck to sharply flex (bend) forward resulting in further soft tissue injury. In severe cases, ligaments rupture causing joint instability; nerve injury may occur, as well as fractures.

Immediately after a whiplash event that results in soft tissue injury, swelling starts very gradually. The injured tissues release a variety of inflammatory products which irritate nerve endings and cause pain. As the swelling progresses, it increases internal pressure in the joints, causing them to stiffen. Typically, swelling following a whiplash accident peaks 72 hours after the accident. This explains why your neck hurts the most several hours after the accident, instead of immediately after the accident.

It is important to know that whiplash can occur from even low velocity collisions. The reason is that the kinetic energy (force) of a car is very high, even at five miles per hour, due to the large mass of the car. The non suspecting passenger is also completely relaxed at the neck which allows for more “non-guarded” range of motion. This energy is transferred to the occupants of the vehicle and is actually more violent if the cars do not deform (dent), which is often the case in low impact collisions. Therefore, even if you were in a low-impact accident that was enough to cause a whiplash effect, It is advisable to get checked to make sure problems don’t develop later on.