Which muscle mirrors the shape and position of the masseter, but is located on the medial side of the mandible?

• A. Medial pterygoids
• B. Lateral pterygoid
• C. Masseter
• D. Temporalis

Answer: (A)

Think of a muscle that closes the jaw from the inside of the mandible. The medial pterygoid fits this description because it lies on the inner (medial) surface of the mandible and runs upward to the medial surface near the ramus, effectively mirroring the masseter’s shape and role from the opposite side. Both are strong jaw elevators that work together to close the mouth. The medial pterygoid originates in areas of the sphenoid and palatine bones and inserts on the inner aspect of the mandible, so it functions as the internal counterpart to the masseter. In contrast, the lateral pterygoid sits more laterally and helps with protrusion and opening movements, while the temporalis is a broad muscle on the temporal fossa that attaches to the coronoid process, not the inner mandible.