What is the broad muscle that covers the top of the skull called?

The broad muscle that covers the top of the skull is known as the epicranius. This muscle is significant because it comprises two main parts: the frontalis, which sits at the forehead, and the occipitalis, which is located at the back of the skull. These parts are interconnected by a structure known as the galea aponeurotica.

The epicranius plays a crucial role in facial expressions; for example, the frontalis is responsible for raising the eyebrows and creating horizontal forehead wrinkles. This muscle's wide coverage over the skull allows for the coordinated movement necessary for such expressions. Understanding the anatomy and functions of the epicranius is essential for estheticians, as it can influence techniques in facial treatments and the overall aesthetic results for clients.