while we wait for themilum to weigh in with a definitive answer, here are some interesting things to ponder:
1) the levator is a muscle that serves to raise some body part, as the lip or the eyelid
2) the source of supercilious (showing haughty disdain) is Latin supercilium, eyebrow
3) to raise one's eyesbrows (or an eyebrow) is shown as a phrase in OED under eyebrow (and raise).

edit:
4) a search of W3 yields risus sardonicus, a facial expression characterized by raised eyebrows and grinning distortion of the face resulting from spasm of facial muscles especially in tetanus; this is, of course, no help whatsoever but nicely rounds out my research.

-joe (pride goeth before a fall) friday

Last edited by tsuwm; 06/21/2007 4:26 PM.