Capt. Kirk's karate chop...

[Gord.T]

...to the neck is legit I guess. I never would have guessed it was possible.

http://video.ca.msn.com/watch/video/hand-knife-knockout/1gl4x4qjp

 

[HorseFilms]

It's absolutely possible. Potentially fatal, as well. He shouldn't be messing around with it.

 

[Gord.T]

So what's causing the knock out? Is it a spike in nerve signals , like a pain signal? And 2nd question is why is it potentially lethal?

 

[Jawa Ex Machina]

So what's causing the knock out? Is it a spike in nerve signals , like a pain signal? And 2nd question is why is it potentially lethal?

Depends on what you're aiming for, the artery with oxygen to the brain or just the muscle.
The muscle isn't so bad, but the artery is worse. Doesn't hurt much but blacks you out for a second, which is why you go down.

Unlike say, a strong punch to the jaw, which would send your head in a rapid turn and shakes your brain.


EDIT: and Yes, don't try this at home.
At least not without filming it for YouTube.

 

[Gord.T]

Ah, cool. It just surprised me because I always thought of a karate chop to the neck as going something like this...

...A few grabs from a scene in 'The Ghost and Mr.Chicken" where Don Knotts attempts to karate chop a guy in the neck from behind only to crush his own hand on impact. The guy is totally unaware than Don tried to hit him.
It's a funny scene.

 

[Jawa Ex Machina]

The neck is a pretty fragile place. Last week, I was hit in the back of my neck by my 150cm IGUS rail when it fell over as I was picking something up from the floor. Nearly decapitated me.
Luckily, it landed on the neck muscle, and not on the spine or the head.