Actually, it would have been better if Zidane headbutted him in the head. A blow even have as bad as that to the chest can send the heart into cardiac arrest.
I thought about this but then rather about the breast bone breaking and piercing the lung, but I think it is besides the point. I imagine that the initial idea will be to hit someone against the head.
I think Materazzi was just knocked off his feet. Not all itallians are divers. They are eather divers or slayers, for the lack of a better word, and Materazzi is clearly the last having a long list of potentional careerending tackles and intentionally damaging the opponent. But Materazzi usually does this in the heat of the battle and he never argues with the ref. Just like Gatuzzo also isn't a diver.
If you review the video you will see Materazzi making a gesture with his head. I think it means 'Ooh, come one. Don't be a wuss' since to me this is the typical non-verbal language that fits a line like this. Then Zidane walls away, turns around and he says one more thing, and then he get the provocing reaction.
And for the people that want to forget this incident. We have also 'forgotten' his headbut against HSV and his kick outside the duel in 1998 against Saudi Arabia. He collected a total of 13 red cards during his career. The problem now is that this red card was in the final and in his final match. Kind of like last impressions last.
Topic: World Cup