Youre right, ominousplay. That bones came from the head bone. As you can see at this image, I allways start whit the hip bone. Its a skeleton structure similar at the Posers figures. And the eyebrowns and the helmet makes all those movements too.

bluetone wrote:
"I'm not clear on how your bones are related so that when you rotate the eyelid, it doesn't through the whole head out of wack."

To avoid this, bluetone, I allways name the part of the mesh before attach the bone, selecting all the polygons of the head, for an example, and naming it. After attach the skeleton, is much more easy select the polygons by the name and work with the weight of the bone.