The document discusses the anatomy of the forehead and brow region. It describes the fascial planes, muscles, nerves and blood supply involved. It discusses Ellenbogen's criteria for the ideal brow position and how different muscles affect brow shape and position. Specifically, it notes that the frontalis muscle is the primary brow elevator, while the procerus and corrugators are primary brow depressors. It provides tips on how to surgically address different types of rhytids or wrinkles in the glabellar region based on the underlying muscles.