Giz Explains: What Happens when You Get Shot in the HeadS

You may or may or may not see it coming, but it doesn't really matter. You're not going to have time to react. Because a bullet can travel at speeds exceeding 3200 feet per second, which is too fast to duck or yell or plead. Hang in there. Taking a cap to the dome means that it will be over faster than a fatal wound anywhere else.

The bullet with your name on it slides past hair, skin and muscle before it smashes into one of eight cranial bones engineered to keep your brain safe. Unfortunately, it's too late for that now. Bullets beat bones. The projectile's entrance into your skull makes easy shrapnel of your calcium, phosphorus, sodium, and collagen case. As a souvenir of the opening, you gain a circular hole rimmed with abraded skin. Distance matters, too: The closer you are to the bullet, the more the gun's smoke and powder could burn your flesh.

But enough about the blemish; the real work happens deeper. The connective tissue and fibrous membranes that act as internal cushioning are split open just before the bullet dives into your cerebrospinal fluid. This fluid serves as a shock absorber. It, with some other structures, allows you to ride roller coasters and join mosh pits without injury. But again, because your 3.4-pound control system is being taken out, this will be your last head bang.

The bullet travels through your brain faster than the speed at which your tissues tear. This means that it's actually pushing tissues out of the way, stretching them beyond their breaking points. When high velocity long arms are responsible, bullets traveling at thousands of feet per second will exit your body before your tissues have a chance to rip.

The ability to process information and solve problems? All gone when the bullet shoves its way through your prefrontal cortex. Your ability to index memories? Gone with your hippocampus. In the bullet's wake, a long temporary cavity is left. When the tearing finally does happen, your tissues will snap back toward the initial opening and overshoot their original position. You know that back and forth thing that happens when you kick one of those springy door stops? Well that's what your tissues do when the shock waves kick them.

Then the passage collapses. The high-speed firearm that produced the bullet created a disruption in your brain 10 times its diameter.

But you're lucky, relatively speaking. If you were shot in the heart, your blood pressure would quickly drop, but it would take 10 to 15 seconds to lose brain function. In that time you could draw your gun, utter last words, or spend some time thinking about your unfortunate situation. But a shot to the brain is different. Your brain stops functioning almost immediately. In just a fraction of a second, you're gone.

Rachel Swaby is a freelance writer living in San Francisco.

Image credit Shutterstock


Giz Explains is where we break down whatever science or tech questions are scratching at the backs of our noggins. Got questions of your own? Email them to us at explains@gizmodo.com and we'll see about answering them.