At first, in the late 70s/early 80s, this was part of the heavy metal revival of early 70s styles. By the late 70s, though, as heavy metal melded with thrash punk, the style got more exaggerated and lethal-looking, with a forest of nails protruding from wristband and neckband instead of just medieval-looking studs. More a stage style than a street style, though you did occasionally see it on punks and the like.

Sorry, the second sentence in the above comment should read "By the late 80s," instead of "By the late 70s." Typo, dontchaknow.

I bought my first spiked wrist band in New Orleans during the world's fair. For years i wanted to go back and buy the wrist plates. I had one neck band that was too tight, still managed to put it on even though i couldn't breathe.