corrugator muscle
n.
A muscle with origin from the orbital portion of the orbicular muscle, with insertion to the skin of the eyebrow, with nerve supply from the facial nerve, and whose action draws the medial end of the eyebrow downward and wrinkles the forehead vertically.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.