Which muscle covers the uppermost back portion of the skull and, when it acts, lifts the eyebrows to create a surprised expression?

• A. Occipitalis
• B. Frontalis
• C. Occipitofrontalis Muscle
• D. Procerus Muscle

Answer: (C)

Think of the big scalp muscle that crosses the top of the head with two parts: one at the back and one at the forehead. This muscle, called the occipitofrontalis, spans the top of the skull and is made of two bellies joined by the galea aponeurotica. When the frontal belly contracts, it lifts the eyebrows, producing a surprised expression. The part at the back mainly pulls the scalp backward and doesn’t raise the eyebrows by itself, while the procerus is involved in frowning between the brows. So the muscle that fits both parts of the description—covering the upper back of the skull and helping lift the eyebrows when it acts—is the occipitofrontalis muscle.