I am very surprised that no one had their throat crushed on ufc by now as many elbows in throats that Ive seen. the elbows in temples could also pop eyes out so maybe thats why theyre banned too. headbutts are effective and I enjoy watching them and I hate watching a grapple fight drag on when there are so many headbutt openings that arent taken. I do not think they should be banned when knees are allowed since they can do similar damage.