Knifehand strike
In martial arts, a knifehand strike is a strike using the part of the hand opposite the thumb, familiar to many people as a karate chop. Suitable targets for the knifehand strike include the carotid sinus at the base of the neck, mastoid muscles of the neck, the jugular, the throat, the collar bones, ribs, sides of the head, temple, jaw, the third vertebra, the upper arm, the wrist, the elbow, and the knee cap.
In many Japanese, Korean, and Chinese styles, the knifehand is used to block as well as to strike.
Japanese martial arts
Tegatana is a term from Japanese martial arts like aikido and Chinese-Okinawan martial arts like karate and Shorinji Kempo referring to a hand position that resembles that of the blade of a sword. This can be in a high, middle or low position but is usually extended outwards at about eye level.During practice, uke and tori will often stand opposite each other with their respective tegatana touching each other. From this position, considered by some the ideal combative distance for two unarmed opponents, many balance-breaking, striking and throwing techniques can be applied. In karate, the handsword collarbone chop, the handsword collarbone strike and the handsword face chop all use this fundamental strike as a basis for attack.
The knifehand strike can be used with either side of the hand. Having the thumb tucked in, leaving the fore finger side of the hand free, allows that side of the hand to be used as a striking surface. This is called an inside knifehand where as the pinkie finger side is called an outside knifehand.