I started studying pressure points about three years ago as i suffered from really bad migraines. I found that they really help with them. i have aslo done karate and judo for ten years. There are two things i would like to ask to the very experienced people. Firstly, by striking someone hard across the back of the neck, on the top of the spinal cord, can this knock someone out or will it kill them, i dont want to find out the hard way. Secondly, i heard from a firend who also practices the Martial arts, if you place your thumb in the valley at the back of the head also at the top of the spinal cord, then snap the persons head back the person will be paralysed for about an hour. Is this true or am i just been naive?