What muscle located above the ear assists in opening and closing the mouth during chewing?

The temporalis muscle, located above the ear, plays a crucial role in the process of chewing by assisting in both the opening and closing of the mouth. This fan-shaped muscle originates from the temporal fossa and temporal fascia of the skull, extending down to the coronoid process of the mandible.

When the temporalis contracts, it primarily functions to elevate the mandible, which is essential for closing the mouth during chewing. Moreover, it also contributes to the retraction of the mandible, aiding in the intricate movements required for grinding food. Understanding the role of the temporalis in these movements highlights its importance in the mechanics of mastication, making it a key muscle involved in the overall function of the jaw.

Other options do not fit this function as closely: the masseter, while also involved in chewing, is positioned more at the angle of the jaw and primarily focuses on elevating the mandible without the same lateral and retracting actions provided by the temporalis. The orbicularis oris is primarily responsible for movements around the mouth, such as pursing and closing lips, rather than the mechanics of chewing. Lastly, the sternocleidomastoideus is primarily involved in head movement and neck stabilization, rather than