Why is a broken neck fatal? It isn’t always fatal. It depends on the break.
Breaking a neck is a very broad term. There are 33 bones in the spine of the average person. 7 of those bones are in the neck. They are called cervical vertebrae and they have three main jobs. The first is to support the head. It obviously varies from person to person, but the average human head weighs about 5 kg. This is a lot of weight. The top vertebrae is called the atlas, because it holds the head upright in the same way that Atlas holds the world on his shoulders. It is ring shaped ad is at the base of the skull. The vertebrae beneath that is called the axis and its job is to let the head move from side to side. The five vertebrae underneath the axis are for support, shock absorption, and to allow the neck to move in every direction. They are controlled and supported by muscles, tendons, and ligaments. There is a soft disk between each vertebrae called cervical disks. They allow the neck to flex more and they also act as shock absorbers.
The second job of the cervical vertebrae is to protect the spinal cord. The brain is connected to the rest of the body by the spinal cord, which is a column of soft tissue and nerves. 8 nerves exit the spinal cord between the 7 cervical vertebrae, and they are responsible for the movement of your neck, shoulders, arms, hands, diaphragm, and upper body sensation. The rest of the nerves exit the spine lower down. All of the vertebrae in the spine have a hole that the spinal cord fits through. They protect it from damage.
The third job is to protect the blood supply to the brain. The vertebral arteries carry blood up to the brain and they pass through holes in the cervical vertebrae. The vertebrae protect them and make sure the brain has a constant supply of blood.
So, why is a broken neck fatal? A broken neck isn’t necessarily fatal, but it can be. When we suffer an injury to the neck that is greater than a sprain or bruising, there are two possibilities. The first is that the cervical bones are broken. Our body can heal broken bones pretty easily and if that is the only problem then it is not a problem. The second is that the spinal cord is injured. This is a whole different kettle of fish.
It is not easy to break the neck and it requires a lot of force. Broken necks are usually called by a fall or a traffic accident. Suddenly twisting the neck can also provide enough torque to break it. When the neck is broken, the bones can damage the spinal cord. Swelling can occur at the site of the injury, causing even more damage. With extreme breaks, the bones can even sever the spinal cord. Depending on where it is severed, this can be fatal. If the spinal cord is severed, the brain can no longer control any of the muscles in the body. That might not sound too bad, but the heart and the diaphragm are both muscles. If your heart cannot beat and you cannot breathe, your brain will run out of oxygen in a very short amount of time and that will be fatal. If the blood vessels to the brain are also squashed or severed, it will cut off the blood supply to the brain, but it also means that the brain can’t be drained and fluids will build up.
When someone is executed by hanging, the knot in the rope is placed on the left of the person, between the second and third cervical vertebrae. When the person goes through the trapdoor and the rope goes tight, it jerks the head up and to the right, creating enough force to dislocate these vertebrae and crush the spinal cord. Unconsciousness is supposed to be almost instantaneous. Studies carried out on people who were executed by the state have shown that only about one sixth of people executed by hanging died because their spinal cord was crushed in the way it was supposed to. If the jolt isn’t strong enough to crush the spinal cord, death can come from suffocation or when the brain fills with fluid. None of which sound very pleasant.
So, a broken neck isn’t necessarily fatal, but if the break is bad enough to sever the spinal cord, it can be. And this is what I learned today.
Sources
https://orthoinfo.aaos.org/en/diseases–conditions/cervical-fracture-broken-neck/
https://www.self.com/story/heres-exactly-what-happens-when-you-break-your-neck
https://en.wikipedia.org/wiki/Cervical_fracture
https://en.wikipedia.org/wiki/Cervical_vertebrae
https://my.clevelandclinic.org/health/body/21946-spinal-cord
https://my.clevelandclinic.org/health/articles/22278-cervical-spine