The depressor anguli oris (triangularis) muscle is a triangular muscle that originates from the mandible at its broad base and is inserted in the angle of the mouth. It is innervated by the facial nerve (VII cranial nerve) and is supplied by the facial artery. This muscle depresses the angle of the mouth and pulls it backward, the direct opposite of the levator anguli oris and the zygomaticus major, and is used when expressing sadness. Research Depressor Anguli Oris
The zygomaticus major is a slender cheek muscle, which originates from the zygomatic bone near the temporozygomatic suture and extends downward and inward, and is inserted into the angle of the mouth. It is innervated by the facial nerve and supplied by the facial artery. This muscle draws the upper lip upward and outward and is used in smiling. Research Zygomaticus Major
The zygomaticus minor (caput zygomaticum quadrati labii superioris) muscle is a slender cheek muscle, which originates from the zygomatic bones and extends downward and inward, and is inserted into the orbicularis oris muscle along the upper lip. It is supplied by the facial artery and innervated by the facial nerve (VII cranial nerve) This muscle lies just in front of the zygomaticus major muscle and draws the upper lip backward, upward and outward and is used in expressing sadness. Research Zygomaticus Minor
 
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Matt and Leela Probert