Combative Anatomy: Using a knife for self defense

After writing the post about how to fight a dog, I got to thinking about how little information is freely available about using weapons in self defense against humans. Many people carry a pocket knife daily (I’ve carried one every day since I was nine years old), many of them with thoughts of using it as a defensive weapon if they needed to. But almost no one gives the actual how to use it part more than a passing thought. This is some basic information on how to use a knife as a defensive weapon.

Before I get started I need to get something out of the way.

  1. Using a knife against another human is considered use of deadly force (even showing a knife is a crime in most places if it is not a clear cut case of self defense). If you would not be justified in shooting and killing the other person, don’t pull out the knife.
  2. If you pull a knife in self defense, you need to be 110% committed to using it, quickly and violently. If you are not, do not pull out the knife.

WARNING:

This post is going to cover some very graphic information about causing massive trauma to another human with a sharp and pointy weapon. If you are at all squeamish, you probably don’t want to read any further.

DISCLAIMER:

I am not telling you to do anything here. This does not constitute legal advice. If you use any of this information in a situation other than self defense, you will go to prison.

Notice that the title of this post is “Using a knife for self defense”, not “How to fight with a knife”. Self defense is something you do when everything else has failed, and you are now in a fight for your life. Fighting with a knife is something you do just before going to prison. Even if you are 100% justified in using a knife as a defensive weapon, you are probably going to have legal troubles because of it, and you are definitely going to have psychological troubles because of it.

This is not a post about conflict resolution, or violence deterrence or avoidance. These are your first lines of defense. This post covers what to do when everything has failed, and you are in a fight for your life against another human (or multiple attackers). This is not going to be nice, it is going to be extremely graphic.

If you’re still reading, I hope this information can be used to save your life if you are ever in the unenviable situation of having to fight for your life, but the information in this post is not going to do it all by itself. Physical combat is something that must be trained and practiced if you want to perform any better than half-assed (at best). If you carry a knife for self defense, I highly urge you to get some training on how to use it properly. In the realm of knife use I think Tom Sotis’ AMOK! system is about the best training you can find.

If you carry a knife for self defense you need to ask yourself a very serious question; can I cut/stab another human, possibly resulting in their death?

Using a knife as a weapon is very intimate, you are going to be very close to the damage you cause. You are going to be traumatized by it.

You need to know that if you use a knife on a human, you are going to see a LOT of blood, and probably a good sliced open chunk of meat. If you want to know what a real knife wound looks like (this is really, really graphic) take a look at some of the images here.

Could you do that to another human if your life is on the line? Only you can answer that question, but you must answer that question if you are going to carry a knife as a defensive weapon.

It is rather easy to think that you could, but I know men who have shot people and tell me that they could never use a knife on another person.

The concept I am trying to convey is very difficult to communicate correctly. There is a lot of macho “I could totally cut that guy up” crap that you need to put aside, and really consider what the consequences of you actions (or potential actions) are. Marc MacYoung (who knows a thing or two about self defense) really sums it up well in this post on his website. I really urge you to read that and understand that there are rather steep costs to using a knife against another person.

Just something to think about.

Let’s get started with some basic anatomy:

Click to enlarge

Anyone who has taken anatomy in college (or in high school even) will be able to tell that this is not 100% accurate and to scale, but it is close enough for our purposes. If you really want to get a strong grasp of where vital targets are on a human, pick up a copy of Gray’s Anatomy (paperback is your best bet here).

Unlike when fighting a dog, humans have a deep and instinctive fear of knives. It is possible that simply brandishing a blade will cause your attacker to have a change of mind, and suddenly remember that he has something else that urgently requires his immediate attention, but I would not rely on that. I prefer that an attacker not know that I am armed until I am using whatever weapon it may be on them. Just be aware that brandishing, while it may effectively deter the attack, is generally also a crime.

If you decide to show the attacker that you are armed and they back off, you should do two things immediately:

  • Leave the area.
  • Call the police to report what just happened.

You need to leave because criminals have a funny way of deciding that your knife wasn’t quite so scary when they get somewhere where they can get reinforcements or other weapons, neither of which is usually far away from where they choose to commit their crimes.

You need to call the police and report the incident so that the attacker who you just scared off doesn’t have a stroke of “genius” and decide to call the police and report that you threatened him with a knife while he was helping an old lady to cross the street (which has happened more than once).

When using a knife for self defense you have two basic strikes; slash and stab.

Slashing targets

Figure 1 – Click to enlarge

Figure 2 – Click to enlarge

Figure 3

Since the human body is (more or less) symmetrical, the targets shown are in the same place (roughly) on either the left or right side of the body.

Point A in Figure 1 is the Superficial Temporal Artery which runs along the outside of the skull across the temple (shown better in Figure 2). If cut this will bleed profusely.

Point B in Figure 1 is the side of the neck and throat just about even with the adam’s apple. This area contains the Carotid Artery and Jugular Vein. If either is cut the attacker will bleed to death very rapidly. The Carotid is approximately 1.5″ below the surface of the skin, so a powerful slash will be needed to reach it, however if severed unconsciousness will result in approximately 5-15 seconds (assuming no chemical stimulation). Be wary, as drugged up attackers may continue to fight on for up to a full minute.

Point C in Figure 1 is the trapezius muscle. This muscle is responsible for much of the shoulder movement.

Point D in Figure 1 is a cut to the outer side of the pectoral muscle. This should be a powerful slash. If done horizontally and continued out to the arm it can potentially sever the cephalic vein which will bleed profusely.

Point E in Figure 1 is a cut across the front of the deltoid muscle. If done powerfully it may sever the cephalic vein.

Point F in Figure 1 is a slashing cut across the biceps. This muscle is responsible for much of the motion of the arm and contains multiple veins.

Point G in Figure 1 is a slashing cut across the inside of the elbow joint. In addition to the numerous veins (shown as point B in Figure 3), this area also contains the ligaments that enable motion in the forearm.

Point H in Figure 1 is a horizontal cut across the forehead. This area is dense with veins, and will bleed profusely when cut, potentially blinding your attacker.

Point I in Figure 1 is a vertical cut across the cheek and jaw. This area contains some of the major nerves in the face and will be extremely painful.

Point J in Figure 1 is a horizontal cut across the neck and throat. This area contains not only the Jugular Vein, but the trachea and ligaments that control movement of the head.

Point K in Figure 1 is the trapezius muscle closer to the neck.

Point L in Figure 1 is a powerful slash across the pectoral muscle. A deep cut here will destroy the attacker’s ability to throw punches with any power behind them.

Point M in Figure 1 is a powerful vertical slash to the abdomen. Successful penetration of the abdominal wall here will result in loss of motion, and possible disembowelment.

Point N in Figure 1 is a powerful horizontal slash to the abdomen. Successful penetration of the abdominal wall here will result in loss of motion, and possible disembowelment.

Point O in Figure 1 is a penetrating slash to the inside of the forearm between the radius and ulna bones. Penetration of more then one inch will sever a great deal of veins (shown as Point C in Figure 3)and result in rapid blood loss.

Point P in Figure 1 is a slash across the back of the head starting at the top rear of the ear and ending near the center of the skull. There is a group of minor arteries that run across the outside of the skull here (shown in Figure 2), and will bleed profusely if severed.

Point Q in Figure 1 is a slash across the outside edge of the shoulder blade, and will result in loss of motion in the shoulder.

Point R in Figure 1 is a vertical slash down the back between the spine and shoulder blade. This group of muscles is responsible for much of the motion of the upper torso.

Point S in Figure 1 is a vertical slash across the rib cage and kidney area. This will be extremely painful and result in loss of motion.

Point T in Figure 1 is a horizontal slash across the back of the neck. In addition to the numerous veins here, these muscles control much of the motion of the head.

Point U in Figure 1 is a slash to the rear of the trapezius muscle which will result in loss of motion in the shoulder.

Point V in Figure 1 is a slash through the muscles in the back between the lower edge of the shoulder blade and spine, curving to follow the shoulder blade. This will be extremely painful and result in loss of motion in the upper torso.

Point W in Figure 1 is a horizontal cut across the lower back. This area is highly dense with nerves and will result in massive pain and loss of motion in the upper torso.

Figure 2 gives a better view of arterial structure in the head and neck.

Point A in Figure 3 is the brachial artery that runs along the inside of the arm. This artery is deep, but severing it will result in unconsciousness in as little as 15 seconds, and death in as little as 90 seconds.

Point C in Figure 3 is the radial artery (this artery runs across the top of the radius bone 2-4 inches behind the base of your thumb). Severing the radial artery can result in unconsciousness in as little as 30 seconds, and death in as little as two minutes.

Stabbing targets

Figure 4 – Click to enlarge

Point A in Figure 4 is the side of the neck just behind the adams apple, approximately 2-2.5 inches from the front of the throat. This is ideally a thrust with the blade perpendicular to the spine, and cutting out the front of the neck. If done correctly this will sever the carotid and trachea, resulting in loss of consciousness in as little as 5 seconds and death in as little as 12 seconds.

Point B in Figure 4 is the inside of the right armpit, with the blade parallel to the ribs. If done correctly this will pass between the 3rd and 4th rib perforating the right lung. This is a risky target due to potential for the blade to bind in the ribcage.

Point C in Figure 4 is a thrust up and under the right side of the ribcage, done at a 45 degree angle into the liver. Depending on the severity of the damage to the liver this can result in unconsciousness in as little as 1 minute, and death in as little as 5 minutes.

Point D in Figure 4 is the subclavian artery located approximately 2.5 inches below the point shown, just behind the collar bone. Severing of the subclavian artery will result in unconsciousness in as little as 2 seconds, and death in as little as 3.5 seconds.

Point E in Figure 4 is the inside of the left armpit, with the blade parallel to the ribs. If done correctly the thrust will pass between the 3rd and 4th rib perforating the left lung and the heart if the blade is of sufficient length (documented cases of blades as small as 3.5 inches successfully piercing the heart exist). Piercing the heart can result in instant unconsciousness and death in as little as 3 seconds. This is a risky target due to potential for the blade to bind in the ribcage.

Point F in Figure 4 is the center of the abdomen, approximately 1 to 4 inches above the navel. Approximately 5 inches below the skin is the Descending Aorta (the largest artery in the body) and Inferior Vena Cava (the largest vein in the body). Severing either can result in unconsciousness in as little as 1-2 seconds and death in as little as 3-5 seconds.

Point G in Figure 4 is just behind the bottom of the ear. This hollow is the only point that an average person may be able to pierce the skull with a knife. Long narrow blades have the best chance of reaching the brain. A solid thrust here can result in instantaneous death. This is a risky target due to potential for the blade to bind in the skull (or jaw if done incorrectly).

Point H in Figure 4 is a thrust to either kidney. Puncturing a kidney can cause near instant unconsciousness, and death within as little as one minute. The Kidneys are connected to the body by the Suprarenal veins, which are rather large, so even if the kidney is not punctured, a thrust here may still sever one of these and result in rapid loss of consciousness.

Considerations

Carrying a pocket knife, and carrying a pocket knife with the express intent to be able to use it as a self defense tool are two completely different things. Until I was about 15 I carried a swiss army type of knife in the bottom of one of my pockets. This is going to be almost useless in a situation where you will need a knife as a self defense tool. Chances are, if you need to use a knife in self defense, you are going to need to have the knife open and in your hand about 5 seconds ago.

Some things you’ll want to consider if you are carrying a knife for self defense:

  • How quick can you get the knife open and in your hand?
  • Can you open the knife with one hand?
  • Can you reach the knife with either hand?
  • Can you deploy the knife if someone grabs you from behind and pins both of your arms to your sides?

In another post I’ll cover the criteria that I use to select a knife that may be used as a defensive tool.

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27 Responses to Combative Anatomy: Using a knife for self defense

  1. Great information. Read the “Don pentecost knife fighting” it’s very nice fotrcomplement your publication.

  2. Troy Riser says:

    This article is a good, well-presented reference on knife targeting; however, the times given for incapacitation (and death) from this or that slash or stab are simply not true, and seem to be derived from W.E. Fairbairn’s estimates dating back to the SOE/OSS days of WWII. For example, the statement, “Severing of the subclavian artery will result in unconsciousness in as little as 2 seconds, and death in as little as 3.5 seconds…” is simply not true. For more up-to-date information regarding knife strike incapacitation times, I recommend the study by Janich and Grosz, “Contemporary Knife Targeting: Modern Science vs. W.E. Fairbairn’s Timetable of Death”.

    It would be a bad day, I think, to deliver a strike or series of strikes to an opponent while believing such a strike will bring about near-instantaneous results, especially when the guy trying to kill you stubbornly refuses to cooperate. The best strategy, I think, is to have no expectations, to just keep going until the threat is removed.

    • dragonhawk1959 says:

      Army doctors in Korea and in World War 2 was surprised to find men coming into camp with wounds which should have killed them instantly only to have them die shortly thereafter.

  3. This is a great resource. Thank you! Now, with lots of practice, the slahes and stabs will be commited to muscle memory.

  4. Ali Garrison says:

    Thank you for posting this information. Especially the photographs of real knife wounds. The most important things about making the choice to carry a knife as a means of self defense 1) you are comfortable and familiar with it. I have been carrying a knife with me since I was a teenager. I use it all the time for everything. It is a legal size and fits comfortably in my hand. I can open it easily with my thumb, it is familiar and I don’t need to look at it or fumble to open it 2) if you choose to pull your knife to defend yourself, open it, grip it firmly, strike IMMEDIATELY with the intent to harm or even possibly kill. 3) if you hesitate there is a good chance your attacker will use your own knife against you. Pulling your knife is not a display of the fact you have a weapon. IF YOU PULL YOUR KNIFE IT IS TO USE IT, IMMEDIATELY AND WITH THE INTENT TO TAKE A LIFE IF NECESSARY. 4) be ready for the damage your knife will do. Most people have never stabbed or slashed another person. The effect is instantaneous, extremely gorey and can be frightening. BE SURE. Once you have cut someone open, you cannot take it back. Its possible you will stand there and watch another human being bleed to death within a minute, right there in front of you, and likely, all over you. 5) ONCE AGAIN, YOU TAKE THIS ACTION IN DEFENSE OF YOUR LIFE, POSSIBLY WITH THE COST OF TAKING A LIFE. Be ready, be fast, be sure. 6) Unfortunately, my familiarity with my weapon of choice, my knowledge of self defense, and my ease and familiarity of the use of my knife as a weapon comes to me through my history. I am severely bipolar, from about age 13. I have also been a self cutter from that time. Not only has my knife always been with me, I have maintained it, and used it. Unfortunately I have had some bad accidents caused by this. A few bad enough to have killed me quickly if not for fast and correct intervention of family members and my fiancée. I have seen up close the damage a knife causes, and I am comfortable with it. I am not posting this to brag or for shock value. This is the truth of my life. I fight with my mental illness every day, and I’m happy to say I havent cut myself in almost 3 years. But the knife is still in my pocket, as familiar to me as my own hand. I realize my situation is somewhat unique and most people have no remotely similar experiences to draw from. This, as well as the added experience of being a battered woman, sadly, one who came very close to death at the hands of a man, caused me to make the decision to learn self defense, and then become a teacher for other women.
    Which is why I talk about my experiences. And why I try to help all women learn to keep themselves, their children, and their loved ones safe. I need to stress again: IF YOU USE A KNIFE AS A WEAPON, BE FAST, ATTACK WITH THE INTENT TO HARM, THIS IS THE ACTION OF LAST RESORT: BE SURE. Obviously this is not going to be a good choice for everyone. Probably most everyone. Choosing to carry a weapon comes with very serious consequences. I don’t recommend it. If you do choose to carry, please, consider your local laws, choose a weapon you are prepared to use and accept the consequences of it’s use. Get proper training in the use of your weapon, whether its a knife, a pistol, a baton, or pepper spray. I also recommend some type of self defense training. Your goal isn’t to use your weapon. Your goal is to have the knowledge and be prepared to get away safely, as fast as possible. For most women, I recommend learning how to get away from an attacker with no or minimal contact at all. Also, learn from various martial arts traditions how a smaller, weaker women can use the knowledge of pressure points and leverage to escape from a larger, stronger attacker. And how to deliver a few blows which could slow or disable him to allow you to get away. Be alert to your surroundings especially at night alone. Be prepared. Panic is your enemy. It will rob you of your knowledge and your strength and your chances to get away safely. TAKE A CLASS. BRING YOUR DAUGHTERS, YOUR FRIENDS, AND YOUR MOTHER. PRACTICE WHAT YOU LEARNED. Its better to stay out of places and situations which could be dangerous in the first place, if at all possible. I also recommend that women carry a flashlight with them at night. The kind with the brand name MagLite, the kind that operates on several D batteries. It will keep you from tripping on the sidewalk. It will illuminate your surroundings. It is 100% legal. It is large enough and heavy enough to serve as a good weapon if you are in extreme need. A good blow to the temple will stun, or more likely disable an attacker. If you’re shaky and unsure, a strong, quick, localized attack of blows to the region of the head and face will break bones, take eyesight, badly hurt and likely disable. MOST OF ALL, BE PREPARED, PRACTICE WHAT YOU LEARN. KNOWLEDGE OF WHAT TO DO IN A GIVEN SITUATION WILL PREVENT PANIC, ALLOW YOU TO GET AWAY, AND IF NECESSARY, ALLOW YOU TO DEFEND YOUR LIFE. Thanks for sticking with me through all this. If you were interested enough to read all of this, I hope you are interested enough to go learn more. Blessings to you and the women and children you love. Be well, and be safe. (If you want or need, you can contact me on Facebook @ Ali Garrison. )

  5. JM says:

    I grew up with the Butterfly knife as part of my family’s heritage and had been taught about knives from when I was little. I will take a life if I can in a situation where I have to defend my family, like I have my little girl with me and there’s an attacker. I think any mother will die defending their children. I agree that the opponent/attacker should only know about my knife when it is already stuck into him or the last moments when he feels the hot blood spurting out of him before he dies… I can deal with psychological stress later after I have protected my child/children/family….

  6. Yash says:

    Nice….

  7. Whoflungpoo says:

    These skills have a shelf life. Practice, practice, practice.

  8. Information on this is…hard to find? Nope. Not at all. (Oh and yes, the WW II bleed out rates are really wrong, as the Grosz book above indicates. And, there are many excellent knife course available with a very quick search on the net. Whether one is “better” than another depends on how very small your search world is on the subject.

    • Sandman says:

      Yes this was written using the timetable I could find at the time with the thought “well I know that’s inaccurate, I’ll go back and rewrite later.”

      And like with everything, stuff came up.

      I suppose I really should make time to correct it.

  9. Marcilio Silva says:

    Great explanation.

  10. Winston J.Wingo says:

    I enjoyed the article
    Thank you

  11. As person that deploys regularly to places where the possibility and threat of being attacked is damn near constant I must say this is good stuff. I actually learned a few things here,and that doesn’t happen often. I’m not claiming to be some big super soldier I’m only saying most of what it put out these days is straight up bullshit.

  12. Dave from San Antonio says:

    Good article. Well presented. IF a person is going to use a knife in self defense…they must be utterly committed when they do. Very fast and completely violent…to the max…or it will fail.

  13. Logan says:

    Great information , thank you. Best defensive tactic is a a stab to the throat area. A solid puncture to this area will disable you attacker instantly.

  14. Alexander says:

    About time this subject came up. I am Alexander in ohio. I have been a martial arts instructor a long time n most has been geared as a combative concept. Besides my martial arts background I have been a big knife tactics instructor. This information is very good except for how fast the human body shuts down. But of importance is knife selection. Blade type, grip material is very important but most of all it must be very sharp. Do not use it for any general cutting at all. If u carry it for protection treat it like a gun. Alot of knives on the market n it’s very personal n it’s what feels good to you . You must be able to deploy it under 1.5 seconds from the draw to the first cut or stab. Really 1 second or less is the norm with a knife instructor. Trauma is severe as mentioned n do not talk just react. A good knife fighter is more dangerous than a gun up close so be prepared mentally for the tissue damage it causes. All blades are dangerous some more that others due to design. I personally carry the civilian from spyderco only cuz it’s only purpose is for killing. Made for undercover LEOs this curved serrated blade is so intimidating n it’s very sharp blade will slice through 6 water bottles like butter n bottles never move. No knife like it on market made for defense. Card with it says DO NOT USE AS A UTILITY BLADE. Choose wisely

  15. Alejandrina Valdez says:

    Very helpful, I’m a single mom n have a 12 yr old daughter, we live alone. 4 yrs ago we where victims of a home invasion, the criminals beat my 18 yr old son w a gun, held us hostage in the restrm while they stole everything we owned including our family dog, an English bulldog. I couldn’t defend my kids at the time I was sick battling breast cancer n was weak. 5 guys victimized my kids n myself. My daughter n I moved into an apt complex n a couple of nights ago we where pulling into my parking space an a man only wearing pajama pants no shirt or shoes was walking in the middle of the street, n waved @ us. I didn’t know him, he looked extremely coked up on crack Meth, idk he looked scary n I didn’t want him to see what apt we where in. So I drove away. We pulled in after he was gone n only hada pocket knife, my daughter was extremely scared n brought back memories of that night. I didnt sleep, n kept my gun on the night my stand n my daughter slept w me. Thank you

  16. Roland says:

    Great article , what would you say is the best size blade for self defense ? I understand a 12″ bowie or dagger is nice but few will carry such a large heavy blade around. Most EDC pocket folders will be somewhere between 2.5″ to 4″ it looks like thats plenty of blade to kill someone. But I welcome your insight.

    • Sandman says:

      There isn’t really a singular answer to this. Personally I carry a Benchmade 710 (have for 18 years now), and usually something big in the other pocket like a Cold Steel Voyager X2 or Rajah II, though I’ll occasionally carry a Fox Kerambit or a Spyderco Endura with the Emerson opener.

      Really it comes down to how much training do you have with edged weapons, and how comfortable are you with using them?

      I would prefer a small fixed blade, but any fixed blade concealed in California is a felony (which is retarded).

      With training you could kill someone with a pencil, but is that the tool you WANT when you’re in a life or death fight? Probably not.

      Ideally? I’d like to have my Recon Scout, but that’s a pretty beefy knife to tote around, so I compromise with a largish utility folder (the 710) and a 5″+ defensive folder.

      More important than the knife though is your competency with it. Get training.

      In a real fight you’re going to be grappling and clenching, and having a tool in one hand greatly changes that dynamic, especially if you have judo or jiu jitsu experience.

  17. Church says:

    Great article. Well thought out and written. My students got a lot out of it.

  18. Gary Perkins says:

    Hey Guys, GP here in Illinois, Liberal bastion of stupidity that it be. Absolutely superb article. How to article,if you will. However, Just like with concealed carry of a firearm make DAMN sure you want to follow thru. I you kill someone KNOW UP FRONT THAT YOU ARE IN FOR THE HASSLE OF YOUR LIFE. I shit you not. I realize some situations happen so fast you have barely time to act–let alone think. But talk this over in your head numerous times B/4 that INSTANT bad stuff happens. THANKS GUYS + Be prepared.

  19. James Keller says:

    Are there techniques for a knife attack on successive unarmed people in an office setting? Self defense, of course …

    • Sandman says:

      I wasn’t going to approve your comment, but I’ll leave it to the readers to judge. This information is already available for anyone who would use it as you suggest, in fact some of it has been found in documents seized from bad guys (talk to Ed at Ed’s Manifesto about the kind of training materials the narcos are found with, or a door kicker about the training materials that daesh are found with.

      I present this to the public for two reasons: to get the good guys thinking about the dangerous reality a knife presents as a threat, and to get the good guys thinking about them as viable useful tools of self defense (despite their drawbacks).

      You can snark all you like, but to answer your question, yes such “training” exists and can be found with a little searching of the deep web. Which serves to illustrate my earlier point about this information already being available to the bad guys.

  20. syzito says:

    Good article , however my “knife” comes in .45 cal. 230 gr.

    • Sandman says:

      Yeah gun usually beats knife, just don’t assume that the gun is some sort of magic talisman or that it is the right tool for every need 🙂

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