Posted On May 24 2022. Updated On May 24 2022.
The Zygomaticus muscle is innervated by the facial nerve (the seventh cranial nerve). The Zygomaticus Major is a muscle of facial expression which draws the angle of the mouth superiorly and posteriorly (smile). However, the Zygomaticus Minor draws the upper lip backward, upward, and outward (used in making sad facial expressions).