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

The broad muscle that covers the top of the skull is known as the epicranius, which is a two-part muscle consisting of the occipitofrontalis. This muscle plays an important role in various facial expressions, as well as the movement of the scalp. It includes the frontalis muscle, which raises the eyebrows and wrinkles the forehead, and the occipitalis muscle, which pulls the scalp backward. The epicranius is vital for expressing surprise and other emotions, reflecting its functional significance in facial communication.

Other muscles, such as the trapezius, primarily extend over the upper back and neck, and are involved in movements like shrugging the shoulders or tilting the head. The frontalis is a part of the epicranius but does not encompass the entire muscle. The temporalis muscle, located on the side of the skull, is involved in chewing rather than covering the top of the skull. Thus, the epicranius is the most accurate answer, emphasizing its broad coverage over the cranial region.