Which muscle forms the fibrous sheet over the frontal and parietal bones and helps move the scalp forwards?

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

Answer: (B)

The scalp is moved by the epicranius, or occipitofrontalis, which has two parts that are connected by a broad tendon called the galea aponeurotica. This fibrous sheet runs over the top of the skull, covering the frontal and parietal bones. Contraction of the frontalis part raises the eyebrows and moves the scalp forward, while the occipitalis part pulls the scalp backward. Because the fibrous sheet is formed by this muscle as a whole, the occipitofrontalis is the structure that creates that sheet and enables forward movement of the scalp. The frontalis alone would not form the sheet, the occipitalis alone pulls the scalp back, and the temporalis is a chewing muscle, not involved in moving the scalp.