"Thai boxing fights get won at first with the head and then with fists or feet's."

Muay Thai originates from art of war of Thai soldiers.
Stylistic noticeable characteristics of Muay Thai are elbow and knee techniques as also clinching. Because of the very high risk of injuries, caused by elbow or knee techniques, Muay Thai is designated as one of the most dangerous martial art sports in the world.

The punch techniques are similar to European boxing, but there are also punches out of a turn allowed, where the head of the opposite gets hit with the back of the fist. Some styles allow to drop the opposite.

Because drops are very dangerous, most regulations prohibit them.
Other Asian martial arts never had a big influence on Thai martial art, because their own was mature enough, so there was no sense for them to add foreign techniques.