mechanics / biology of getting hit in the chin and KO'd

What is it about getting hit in the chin that causes a knockout? It seems like there is more to it than a concussion, because I believe you can get punched just as hard in the side or back of the head without getting KO’d.

That movie taught me some important lessons in life. 1. I can build a robot that loves me. 2. I can reanimate my dead girlfriend by jamming bits of metal and silicon into her skull. Both are lessons I use on a daily basis…

Most KOs aren’t really knock outs in the sense of unconciousness. Most KOs are an exhausted fighter being knocked down and being too tired to get back up. Because of the way most of us stand (boxers included) it is easier to be knocked on your ass then it is to be knocked down sideways, thus a direct blow to the face (or chin) will be more likely to knock you down than a blow to the side of your head.

Well, Ursa, I don’t have much to back me up on this other than what I’ve seen…but when a boxer’s eyes roll back into his head, and his legs get rubbery, I think that is more than just being “too tired to get back up”. I think there is a brief period of unconsciousness going on. Anyone boxers here to verify/refute that?

That movie taught me some important lessons in life. 1. I can build a robot that loves me. 2. I can reanimate my dead girlfriend by jamming bits of metal and silicon into her skull. Both are lessons I use on a daily basis…

I read “somewhere” that a knockout results from a blow to the head because: The brain is not rigidly fixed inside the skull. The force of the blow causes the skull to move very abruptly to the length of its tether. (the neck) The skull then begins to rebound and collides with the brain which is traveling in the original direction of the skull, but at a slower rate. The impact is something the brain does not know how to deal with and so it calls the whole thing off by shutting down very briefly.

I repeat that I do not know where I heard or read this, whichever, and I have no idea if it is accurate or not. It is an explanation that seems to work.


Here’s an explanation from Hemo the Magnificent, one of the 50’s Bell Science Series tv programs. It might be out of date.

The brain controls how much blood goes to different parts of your body. If you’re exercising, more blood goes to those muscles and less elsewhere, including the brain itself. If you’ve just eaten, more blood goes to the digestive system. That’s why you can get cramps if you do heavy exercise after eating. This is also part of the reason you feel sleepy after a big meal.

When you get hit on the head, the physical shock to the brain upsets this control and blood goes to all areas at once. There’s not enough blood to fully supply these areas and the brain at the same time, so you lose consciousness.

For business reasons, I must preserve the outward signs of sanity. - Mark Twain

      • Discover magazine said that a knockout is caused by a sidways hit to the head, that causes the skull to spin. Because the brain is soft, it stays still for a moment and during this time, many small blodd vessels between the brain and skull are torn open. They clot (usually safely) pretty quick and the remaining untorn vessels swell up to make up the deficiency, but this all takes a couple minutes. The article also noted that this damage (torn blood vessels) is assumed to be cumulative over the length of the fight leading up to the KO; even among heavyweight pro fighters, it is very difficult to actually knock someone unconcious this way - using only one blow of your hand against their head. You can put someone under by hitting their noggin with a baseball bat or tire iron, but that involves an additional type of damage; you can’t really equate the two. Most of the vessels will regrow in a couple weeks - not all of them, but most of them. It is the repeated tearing of these blood vessels that is suspected to lead to the mental condition that old boxers usually end up in, due to the fact that eventually those blood vessels give up and stop trying to regrow. This condition is often called “trauma-related Parkinson’s disease”.
  • Boxing is also very tiring, and that is also a factor, but boxing is still lots easier now than it used to be. In the early part of the century, rounds lasting a half-hour and longer weren’t uncommon. Boxers from back then would laugh at the three-minute rounds we have today. - MC

Then there are those few unlucky people with glass jaws . . . .

If you follow your jaw back to where it joins the skull, the mandibular joint, you will see that it joins the head near the base of the ears (well, kinda near). If you place your fingers below the joint, you should be able to feel your pulse quite strongly.

Your fingers are directly over the carotid arteries. The carotids are the main arteries into the head, though you also have vertebral arteries going up your spine. But the carotids are the ones that are really interesting.

One carotid goes up each side, and branches near where your fingers are located into the inferior and superior carotid. At the junction, there is a physiologically important area that contains a large quantity of nerve endings.

These nerve endings sense some critical information about the blood before it goes gushing into your skull. It senses the oxygen content, possibly carbon dioxide content, and definitely blood pressure.

The receptors that check blood pressure at this branching point are called the carotid baroreceptors, and they are responsible for making sure you get plenty of the vino vitae into your brain. If blood pressure drops, they signal for an increase in heart rate and contractility, if the blood pressure rises, they signal the heart to slow down.

It just so happens that they really don’t measure just blood pressure, but pressure on the notch. If you jab your finger right on top of this sensor, you can fool the sensor into thinking that it is your blood pressure that went through the roof, not that you’re just pushing on the sensor itself. Then the body compensates by dropping blood pressure, which happens fairly rapidly.

Heart output drops, and you pass out from the pressure reduction in the brain.

Go ahead. Try it. Push real hard.

It is believed that a glass jawed person has a loose mandibular joint that allows a good solid thwack to cause a pressure wave that sets off the baroreceptor, lowering blood pressure, and down they go.

Grabbing the baroreceptor is also a common trick that the military and police use to subdue the proles. Punch a thumb into that area, and you’ll put them to sleep right fast.

But . . .

There is a critical nerve that runs right next to this branching point of the carotid. This nerve, called the vagus nerve, is important for controlling heart rate and damn near everything else that happens below your neck. If this nerve is damaged, the immediate damage can cause the nerve to stop the heart, and if the nerve is permanantly damamged, you’ll never shit right again, if ever.

Just thought you ought to know that before the teeming millions start thumb punching each other in the neck.

:::faints on the ground as his blood pressure drops:::



I’d like to mention that WIPSS markets a mouthpiece that is supposed to lower the jaw and open the mandibular joint. In doing so, they supposedly eliminate the chance of the mandibular joint slamming up and causing a knockout. They also claim easier-breathing benefits. If the benefit is that significant, within a few years, this mouthpiece may become a standard in many contact sports.