occipitofrontalis

noun

oc·​cip·​i·​to·​fron·​ta·​lis äk-ˌsip-ət-ō-frən-ˈtā-ləs 

: a fibrous and muscular sheet on each side of the vertex of the skull that extends from the eyebrow to the occiput, that is composed of the frontalis muscle in front and the occipitalis muscle in back with the galea aponeurotica in between, and that acts to draw back the scalp to raise the eyebrow and wrinkle the forehead

called also epicranius