Whiplash occurs when the head is rapidly thrust backward and then forward, subjecting the cervical spine to extreme forces. It is medically known as cervical acceleration-deceleration syndrome.
Whiplash can be caused by various high-impact events, ranging from falls to sports collisions, but it most commonly happens when a person is rear-ended in a motor vehicle accident.
Initially, the accelerating seatback pushes against the person’s back, which sends forces up the cervical spine, compressing it against the head.
The torso is accelerated forward but the head is not because it has yet to contact the accelerating headrest. This causes the cervical spine to temporarily lose its C-shape lordosis curve and become an unnatural S-shape. These forces put extreme stress on the facet joints and intervertebral discs before the muscles have any chance to stabilize and protect the cervical spine.
Then the head rotates backward and goes into extension before bouncing off the headrest and accelerating forward, whipping into full flexion.
There are numerous potential sources of pain following whiplash. Some that are thought to be more common include:
- The protective cartilage at the tips of the facet joint could become damaged or the capsule holding the joint together could tear.
- Tears in a disc could become painful. If a disc herniates, inflammatory proteins could leak and cause pain outside the disc.
- Ligaments and muscles can get tears from being stretched too far or too quickly.
Neck pain from whiplash can range from mild and dull to severe and sharp. Other symptoms could include headache, dizziness, reduced coordination, and many others. If a nerve root becomes pinched, cervical radiculopathy symptoms of pain, tingling, numbness, and/or weakness could radiate down the arm.
Whiplash symptoms may start immediately after the accident, or in some cases can take about 24 hours to develop. A whiplash injury typically heals within 3 months, but sometimes symptoms can become chronic and last much longer.