Which two parts constitute the epicranius?

The epicranius is a muscle structure located on the skull that plays a crucial role in facial expressions, particularly in raising the eyebrows or wrinkling the forehead. It is composed of two primary muscle groups: the frontalis and the occipitalis.

The frontalis muscle is situated at the front of the forehead and aids in moving the eyebrows upward and creating horizontal forehead wrinkles. The occipitalis muscle is found at the back of the head and pulls the scalp backward. Together, these muscles form the epicranius, which is responsible for movements involving the scalp and forehead.

This anatomical relationship is essential for understanding how facial expressions work, especially in esthetics, where expressions can influence customer interactions and service delivery. The other options do not accurately reflect the composition of the epicranius, as they include muscles that do not contribute directly to the skulp's muscle structure associated with the epicranius complex.