Ok, you've all heard about the ninja death touch -- you know, the one where a ninja can instantly kill a person by striking a certain pressure point. Well, the superlative straightdope.com ran a column on this, and here's how they explain it:
Full Version: Ninja Death Touch Deconstructed
| QUOTE |
| Commotio cordis, also known as cardiac concussion [is] a syndrome in which a nonpenetrating impact to the chest causes heart failure but little or no structural damage. The classic victim is a kid or young adult who takes a baseball, hockey puck, or other hard object in the chest, but a 44-year-old teacher died when she caught an elbow while breaking up a fight at school. About half the time the victim collapses immediately, and in the balance of cases within a minute or two. Death is thought to result from ventricular fibrillation, a state in which the lower heart chambers start fluttering and stop pumping blood. One study of 128 cases found that 84 percent of the victims died, and nearly all the survivors received prompt defibrillation. Relatively little force is required for the killing blow--one researcher estimates that the blunt instrument need be moving at only 30 mph. Don't think this is something you'll be able to pull on the next ninja who leaps from the shadows, though. Animal experiments suggest that you’d have to strike within a 15-20 millisecond window in the heartbeat cycle to have a reasonably good chance of taking down your attacker. |
Just as Cecil Adams mentions, this *is* a well-established cause of death -- more information for the curious can be found at emedicine.com. However, it's rather interesting to see *just* how hard it is to pull off such a technique.
Ok, first off, here's a picture of heart, framed by the ribs
In order to initiate defibrillation, you've got to give a direct hit to the heart itself -- not to the inner ribs, nor to the sternum. Although it's difficult enough to bypass the shock-absorbing bone, there's yet another hurdle to overcome.
Here's an electrocardiogram:
The only place where defibrillation can be initiated is in the ST segment (highlighted in yellow). The heart is susceptible to attacks in this frame, since it has just finished contracting (R spike), but hasn't started relaxing yet (T bump). However, as you can see, this window is just forty milliseconds long. In comparison, humans have normal reaction times around 100-130 milliseconds.
So, I guess there's not a lot to fear from the ninja death touch. In order to pull it off properly, the ninja would have to find your pulse (either from your neck/wrist arteries), compensate for the fluid lag between the heart beat and the pulse, and strike within an obscenely short window. Although the mantra "When you fail, try, try again" does have it's merits, it's probable that the ninja in question would quickly abandon this method and resort to the tried and true "use-palm-to-drive-nasal-bone-through-braincase" technique.
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