Zygomaticus major is one of the muscles of facial expression.
On each side, it originates from the anterior and inferior surface of the zygomatic bone. It inserts into the modiolus at the angle of the mouth. As it passes anteroinferior from its origin, the facial artery and vein lie deep.
Its blood supply is derived from the facial artery.
Primarily, it is innervated by the buccal branch of the facial nerve (VII). However, it can also receive innervation from the zygomatic branch of VII.
Zygomaticus major acts to raise the corner of the mouth superolaterally, as in smiling.