User blog comment:IamJakuhoRaikoben/Chapter 457: Naked Battle, Review./@comment-4999650-20151019120400/@comment-7418318-20151019134206

Yes, but to cut an artery you don't pull your arm up and back like that. You just try to put your hand close to the artergy and then do a little twist of the wrist and it's over.

What Lucy did was a very clear stabbing motion.