Which muscle inserts at the coronoid process of the mandible?

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

Answer: (D)

Muscle attachment sites on the jaw tell you what each muscle does. The coronoid process is the insertion for the temporalis. This muscle originates from the temporal fossa and fascia, travels under the zygomatic arch, and its tendon anchors to the coronoid process of the mandible. When it contracts, it elevates the mandible to close the jaw, with some fibers capable of pulling the mandible backward to retract it. The masseter attaches to the lateral surface and angle of the mandible and mainly elevates and protrudes the jaw, not to the coronoid process. The zygomaticus and orbicularis oris are facial expression muscles that insert in the lips or the skin around the mouth, not on the mandible. So the muscle that inserts at the coronoid process is temporalis.