Zygomaticus major muscle

The zygomaticus major muscle is a muscle of the face. It arises from either zygomatic arch (cheekbone); it inserts at the corner of the mouth. It is innervated by branches of the facial nerve (cranial nerve VII). It is a muscle of facial expression, which draws the angle of the mouth superiorly and posteriorly to allow one to smile. Bifid zygomaticus major muscle is a notable variant, and may cause cheek dimples. (Wikipedia)