[quote name='E-Z-B']I saw this earlier, but I think it's his thumb. However, at the press briefing today, Scott McClellan refused to say what happened, only mumbling "I refuse to dignify that question". If it was totally false, why didn't he just come out and say so?[/QUOTE]
No way it was his thumb, try making a similar shape out of your hand by raising your thumb. There's a large area on the right of his hand, and a smaller one of the left. While the middle finger would fit perfectly, raising you index finger may also create a similar shape. I would assume it's one of those two.