Now people say you can use pressure points to do some pretty amazing things like cause peoples hearts to stop, organs to die, by tapping certain areas a person can fall unconscious and also that if you touch certain areas you can heal people.
A lot of this is based around the ancient practice of acupuncture which is honestly an outdated, pre-scientific form of medicine. There has been some minor correlation that acupuncture can aid in back pain, but as far as healing? I believe that more has to do with the placebo effect and having conditions that will heal on their own anyway. But hey, burden of proof and all that maybe I'm wrong?
With that said though, in regards to knockouts there are places a person can hit that will seriously destroy a persons ability to continue fighting. These may be the true pressure points.
We as humans are pretty tolerant to low and moderate forms of blunt trauma. Our bones are living and flex, our skin and muscles are stretchy, indeed we're mostly water. A stick swung on the skin at most will usually leave a bruise...but..certain places are prime targets for attack.
You can knock someone out in three different ways;
1. Concussion (Making the brain bang against the inside of the skull). You see this a lot in boxing and football. The person is hit so hard and fast that their brain is slammed up into the skull causing a lost of consciousness and possible damage.
2. Pain Knockouts (These are hits on places that cause horrible, crippling pain that lead to unconsciousness or a state of helplessness. The Liver, The Groin, The Kidneys, The Solar Plexus, The Eyes). The liver is a huge network of nerves and chemicals. Hitting it floods your body and hurts horribly. The Groin, well that's easy to understand. The Kidneys are similar to the liver and the Solar Plexus can cause great pain and knock all of the air from a persons body (remember to yell or exhale sharply when struck to avoid this).
3. Spiking the blood pressure (Choking someone unconcious, striking the throat, etc anything that stops the ability for blood to reach the brain quickly and efficiently.) A person struck hard enough in the throat/artery's can experience a spike in blood pressure and lose consciousness. Not as common as 1 or 2.
The Best Targets:
Head:
Side of the Jaw: Run your finger along it, you'll feel a groove right by the back edges. This is home to a Vein/Artery cluster. Hitting here will spike the blood pressure. You can also push your thumb in there to relieve the pain of a headache.
Chin: Ask your dad where to hit someone and he'll likely say "Right on the tip of the chin!" This is a weak point in the facial bones. Hitting here can split/break the jaw and also rocks the head back hard causing a concussion.
Eyes: Enough said.
Temples: A favorite for knockout artists. Feel the side of your head above and a little forward from your ears. You'll feel two little bumps. These are a nice cluster of veins/artery's and nerves. Striking them causes blood spikes, concussions and pain.
Ears: You can cup your hands (like swimming) and clap hard over someones ears. Doing this forces the air into their ear canals and causes massive levels of unbalance, pain and possibly ruptured eardrums. According to my Sensei a 4 year old nearly toppled his dad when asked to demonstrate it.
Side of the Neck: You'll see police hit this target often. Your neck is home to your big artery's, nerves and your spine. Crack a forearm, knife edge hand or fist into this spot and you can cause an instant knockout from a combination of spiked blood and pain. A great place in self defense if you can hit it.
Torso:
Solar Plexus: Find the hard bone of your sternum and go a little down below it. You'll feel a nice soft, squishy area about as big as your fist. Behind the skin is a muscle that helps you breathe. Hitting it causes the air to be knocked out of you and is painful. Search youtube for videos, I saw a petite lady bring a grown man to his back with a proper punch to that spot.
Liver: The liver is on the right side of your body inside and just below your ribs. It wraps slightly around your side. This can be struck with a front, roundhouse, a straight punch or a hook punch. Hitting here causes horrible pain. Go ahead and have a friend slug you there if you don't believe me.
Kidneys: Located on your lower back nestled slightly on the side. They are sensitive bags of nerves. Hitting them is horrible.
Groin: Enough said
Other Spots:
I don't recommend them because they are hard to get too usually but your inner thighs (Right up by the champ) and your armpits have big arterys nestled inside of them. Strong blows to these spots can spike your blood pressure and cause horrible pain.
There are other ways to knock people out I'm sure, but these are the ones I'm aware of.
Thanks for reading, and remember..use this information appropriately. Don't go whacking on your brother or whipping out the ear claps for a school yard fight. Save these for self defense only.