Which muscle is involved in raising the eyebrows and wrinkling the forehead?

The muscle primarily responsible for raising the eyebrows and wrinkling the forehead is the epicranius. This muscle has two main parts: the frontal belly and the occipital belly. The frontal belly, in particular, plays a crucial role in elevating the eyebrows, which is an action often associated with surprise or curiosity. When the frontal belly contracts, it pulls the skin of the forehead upwards, resulting in forehead wrinkles that are commonly observed during expressions of surprise or concern.

Understanding the epicranius’s function highlights its importance not only in facial expressions but also in how our emotions are communicated through muscle movements. This muscle's ability to perform these actions makes it a key player in the dynamics of facial expression.