Final answer:
The C. frontalis muscle, part of the occipitofrontalis muscle, is responsible for producing horizontal wrinkles in the forehead by causing the skin to move anteriorly and superiorly when it contracts.
Step-by-step explanation:
To produce horizontal wrinkles in the forehead, the muscle involved is the C. frontalis muscle. This muscle, along with the occipitalis muscle, comprises the occipitofrontalis muscle that makes up the scalp, with a frontal belly and an occipital belly.
The frontalis muscle is responsible for raising the eyebrows and wrinkling the forehead. Contraction of the frontalis muscle pulls the skin of the forehead anteriorly and superiorly, causing the characteristic horizontal wrinkles.
The occipitofrontalis muscle has two parts: the frontal belly (frontalis muscle), which covers the forehead and the dome of the skull, and the occipital belly (occipitalis muscle), which is located on the posterior aspect of the skull.
The two bellies are connected by a broad tendon known as the epicranial aponeurosis, or galea aponeurosis.