Well, everything on the left is just the face and ears, then on the upper right, that's the back of the head. In the lower right is the neck, and I can never seem to remember what's in the middle...I want to say it was something to do with the forehead...? Don't quote me on that, if you need help, I tend to look at the preset files that are already in-game to help me get a basic idea of what is what, the head markings also help too if you can remember where exactly they are on the character model.
But yeah, like Ulti said, I believe Ven posted something about that asking about which was which, I'd have to try and find it though, it was quite some time ago.
