Our seven cervical vertebrae (neck bones) include a spinal canal to protect the spinal cord, the bundle of nerves running from the brain to all parts of our body. If a broken vertebra injures the cord, the person could be paralyzed from the arms on down. Sometimes even the breathing muscles can be damaged, causing death.

In the context of major trauma, the most important thing a first responder on the scene can do is immobilize the neck — hold the victim’s head still until paramedics can arrive with equipment. This might be difficult, since accident victims may be disoriented or in pain, & pay no attention until it’s too late. But we do the best we can.
If there are multiple victims, and one is in cardiac arrest (no heartbeat), attend to the others. Don’t do CPR!!! Data show that with cardiac arrest from major trauma, literally 0% survive. Cardiac arrest from a heart attack is completely different; heart damage may be minimal, but an electrical short circuit caused it to stop. But when trauma is the cause, nothing will help. Better to attend others, one of whom may have a broken neck.
Another common error is to be drawn to a person with blood streaming down their face. Nobody past infancy can bleed to death from the head; its arteries and veins don’t carry much blood. But anyone with head injury may also have a neck fracture, which is what will do them in!
How do we tell if someone may have a broken neck? We push gently one by one on the neck bones, in the center (not the muscles on the side). If pushing doesn’t hurt, we tap on them one by one; then tap harder. The 7th vertebra is easy to find, since it sticks out. Continuing on up the neck, bones may be less distinct, but we focus in the middle. If we can tap hard without pain, there’s no broken neck.

The only time this exam doesn’t work is if the patient is unconscious, or disoriented, panicked, or drunk or high on drugs. Then they can’t concentrate on how we examine them. Similarly, a large arm or leg fracture may hurt worse than a small one in the neck. That’s called a “distracting injury;” the victim doesn’t notice the neck pain. Whenever we’re in doubt, for anyone who may possibly have sustained head or neck trauma, we do what we can to make sure they don’t move the neck.
And if they’re in the middle of the road? We direct traffic around them, until the ambulance arrives. Don’t let anyone move the victim, please!