These were brought to my attention by Bay Raitt, creator of Gollum. Check this out HERE. It includes his Mask diagram (below) that can be used for virtually any humanesque head and follows the muscle structure
Quote "An Edge Loop is an interlocking series of continuous mesh edges used to accurately control the smoothed form of an animated subdivision surface." - Bay Raitt
These are the basic edgeloops and geometry flow for a human head....yes I know it's Hellboy.
Remember... If, as a kid, you were made to walk the plank, it's probably because your folks couldn't afford a dog!