question for the medically-inclined or particularly klutzy folks on the flist
say someone grabs your head and slams you face-first into the side of a building. and say they grab you in such a way that you don't end up with a broken nose but instead hit the wall with your forehead. and say there's jagged bit(s) of stucco or brick or a nail or something sticking out of said wall, such that it cuts your head open. how deep is such a cut likely to be, and how deep does it have to be before you'll need stitches, and if you do need stitches and the cut's a few inches long, how many stitches would that be? (and you can't get a concussion from that, can you?) i'm guessing there will be ancillary scraping and bruising and a general headache and ow, but i'm mostly interested in the stitches and the scarring.