I say the "torso" is the head above the eyes... but I think it really should be called 'Center of Mass' because Military Personell with ANY firearms training are told to fire at Center of Mass, not the Head, or Arm.
It even pertains to our military, with the exception of the Sniper Corp., who recieve training on exactly where a killing shot can happen, and even they are told to aim for the rib cage area, where they are far more likely to score a killing hit.
If they miss the heart, they puncture/deflate/break a rib of the lung unless they miss completely.
I hear that stomach and shoulder wounds are usually life threatening if not tended to soon.
Sorry for the in-depth rant about that, I know its uncalled for...
But hey, I was bored and wanted to type something.
(I don't claim to know everything about this, however, and this has only been my experience with retired military personell and things I've read. I have not, persay 'Researched it' but I do know a good bit of it.)