Why are hits on the back of your head so dangerous?

Question by: Victor

There is a typical way to die accidentally in movies: slipping and hitting the back of your head. What makes that area so dangerous?

Depending on where in your head you hit your head, you will get a different brain injury.

Some areas of your brain can take some damage, but you will still survive. Others, not so much.

Let’s take the frontal lobes. 

If you hit the front of your head, you’ll get damage to your frontal lobes. However, you have two frontal lobes–right and left—so even if you get injured, you still have the other one.

Also, the frontal lobes are in charge of personality, decisions, and impulses. They are important, but we can live without them. There are many examples of people living with frontal lobe damage:

• Phineas P. Gage was a railroad construction foreman. One day, he had a work accident. There was an explosion, and a heavy metal bar pierced through his head. His mates looked at him in horror. He was talking and standing–with a hole on top of his head.
  Doctors removed the bar, and Phineas survived, dying 12 years after the accident. His personality changed, yes, but he survived. You can still see his skull in Warren Anatomical Museum, Boston

• Patients with lobotomies: some 100 years ago, we didn’t know how to treat psychiatric patients in an effective, humane way. Instead, doctors performed lobotomies: they pierced through the patient’s skull to damage their frontal lobes.
  That way, they changed their personality and, hopefully, cured their madness. Most patients survived.

The back of your head is different, though. Getting hit on the lower back of your head may damage your brainstem, which is a vital structure.

First, you only have one. Second, its role is very important for our survival. It transmits every order from your brain to your body. It also harbors several control centers without which we cannot live, like the breathing, sleep-awake, and cardiac centers.

Consequently, if your brainstem gets severely injured, your brain won’t be able to send signals to your body.

Remember, your breathing and cardiac centers lie in your brainstem. If your breathing center gets injured, your body will no longer know how to breathe. The same goes for your heart–a malfunction of your cardiac center will cause a cardiac arrest, leading to death in a few minutes.