The occipital belly of epicranius muscle (also known as the occipitalis muscle) helps extend the scalp so that the eyebrows can come up and the forehead may wrinkle. This, along with the frontalis muscle is one of two parts, or bellies, of the epicranius. The epicranius is a musculofibrous layer that is wide and spreads across one entire side of the vertex of the skull, from the occipital bone to the eyebrow. The occipital belly is close to the occipital bone. This muscle takes on a thin, quadrilateral form and begins with tendinous fibers at the lateral two-thirds of the superior nuchal line of the occipital bone, and from the mastoid part of the temporal bone. The occipitalis ceases in the galea aponeurotica. The occipital belly exchanges information with the frontal belly by an intermediate tendon.