Place your hands side by side. Both hands should be in horizontal fists. Now rotate each hand outward (with thumb knuckles touching) until you form a "bottomless triangle" on the in side of your hands. Each fist should roughly be at a 45 degree angle. Which makes a 90 degree angle hence the phrase "bottomless triangle". Now pull one hand back to your jaw line. This the way your fist should makr contact. This is the safest position for your wrist. Now on to the contact surface. If you punch as stated before; aim for the center line of your attacker and you will make contact with your bottom 3 knuckles only. this is the best KO postion as for as the target, the wrist/hand structure and contact surface. The old-time pugilism punched with a vertical fist. The horizontal fist only came into popular use in sport boxing after the introduction of thickly padded gloves. There was a good reason for this. A vertical fist protects the hand from injury. Two biomechanical principles are key. First is the idea of spreading the force of the strike over as large a portion of the surface of the knuckles as possible. This keeps any one bone of the hand from being subjected to excessive stress. Second is keeping the wrist aligned in as "squared" a position as possible so that when the force of your strike is reflected back, it travels through the center of your wrist and up the middle or "long-axis" of your forearm. If your wrist is not aligned properly, force will be reflected off an at angle rather than through the center of your forearm and your wrist is more likely to bend and suffer damage. Get up from your computer and try this simple experiment. Face the wall and extend your arm completely straight out in front at your own chin level. Make a horizontal fist (palm down) and place it against the wall. Now lean your weight onto your fist so that it is as flat against the wall as possible. You will find that not only will your wrist bend upward, it will bend outward as well in order to keep the fist flat against the wall. Now pivot so that you have a vertical fist (palm inward) while rolling your elbow inward and do the same thing. Your wrist should stay "squared" and your fist should be in good contact with the wall at the same time. The vertical punch keeps the wrist aligned to prevent it from being injured, and allows force to be spread over the surface of the knuckles as much as possible to avoid a fracture of the hand. Think of aiming with the "middle" knuckle of the hand when punching. This is the one that is most in line with the long-axis of your forearm and so will help you keep your wrist properly aligned. Also try and keep the elbow of your punching arm rolled inward as if pointing toward your opposite foot. This not only helps to keep the wrist aligned, but also aligns your forearm with your shoulder for maximum delivery of force when punching. THANKS TO Keith P. Myers FOR ALL THE HELP ON THIS SUBJECT. Without him I might still be punching WRONG!!!!!