Which muscle inserts on the mandibular ramus?

• A. Masseter
• B. Temporalis
• C. Zygomaticus
• D. Orbicularis Oris

Answer: (A)

The main idea here is which muscle attaches to the vertical portion of the mandible, the ramus, so it can influence how the jaw moves. The masseter originates from the zygomatic arch and inserts on the lateral surface of the mandibular ramus and the angle. This placement gives the masseter a strong lever to elevate the mandible, enabling the bite.

The temporalis also helps close the jaw, but its primary insertion is on the coronoid process of the mandible (with some fibers attaching to the ramus as well), so the ramus is not its main attachment site. The zygomaticus and orbicularis oris are facial expression muscles that insert into the lips or facial skin, not onto the mandible.

So the muscle that inserts on the mandibular ramus is the masseter.