The primary muscles directly associated with your skull are the frontalis muscle located on your forehead and the occipitalis muscle at the back of your head.
Scalp Muscles: The Occipitofrontalis
While we might think of muscles covering the entire skull, it's more accurate to describe these as scalp muscles. The occipitofrontalis (or epicranius) muscle is the main muscle in this region, comprised of two parts:
- Frontalis: This muscle is located in the forehead. Its primary function is to raise the eyebrows and wrinkle the forehead skin. Since it doesn't attach to bone directly (it attaches to the skin of the eyebrows and nose), it's responsible for facial expressions of surprise or concern.
- Occipitalis: Situated at the back of the head, the occipitalis muscle pulls the scalp backward.
Epicranial Aponeurosis (Galea Aponeurotica)
Importantly, there's no muscle covering the top of the head between the frontalis and occipitalis. Instead, these two muscle bellies are connected by a broad, strong sheet of fibrous tissue called the epicranial aponeurosis, also known as the galea aponeurotica. This aponeurosis allows the frontalis and occipitalis to work together to move the scalp and eyebrows. Think of it as a tendon that spans the top of your head connecting the two muscle bellies.
Summary
In essence, the muscles directly associated with your skull's exterior are the frontalis (forehead) and occipitalis (back of the head), connected by the epicranial aponeurosis. These muscles primarily control facial expressions and scalp movement.
