What muscle is responsible for chewing and is known as the masseter?

The masseter muscle is primarily responsible for the action of chewing, which is known as mastication. This powerful muscle is located in the jaw and plays a crucial role in elevating the mandible (lower jaw) to bring the teeth together, enabling the grinding and crushing of food.

The masseter's anatomical position allows it to generate significant force, which is essential for effective chewing. It originates from the zygomatic arch (cheekbone) and inserts into the angle and ramus of the mandible, making it ideally positioned to exert the forces needed for this function.

In contrast, the other muscles listed perform very different roles. The frontalis muscle is involved in raising the eyebrows and wrinkling the forehead. The zygomaticus minor is associated with facial expressions, particularly smiling, as it elevates the upper lip. The orbicularis oris surrounds the mouth and enables actions such as pouting and kissing but does not play a direct role in the chewing process. Thus, the masseter is the only muscle among the choices that directly facilitates chewing.