It's produced mainly by the corrugator muscle, which lowers & pulls together the eyebrows
The procerus helps to pull that part of the skin between the eyebrows
... [DOC] [TLE] Chapter 10 muscle tissue Flashcards | Quizlet [PAR] Insertion: Skin of eyebrow ... Insertion:lower margin of mandible; and skin and 
muscle at corner of mouth ... helps depress mandible; pulls lower lip back and 
down, produces downward ... Action: Depresses tongue and draws its sides 
inferiorly ... rotates head to opposite side; Contraction of both sides together: 
flexes neck [DOC] [TLE] CHAPTER 10 Anatomy of the Muscular System - coursewareobjects ... [PAR] Fingers, 372.