Which muscle is primary for mandibular protrusion?

Which muscle is primary for mandibular protrusion?

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

Answer: (D)

Protruding the mandible is driven by pulling the condyles forward, which is the role of the lateral pterygoid muscles. When both sides contract, they tug the mandible and the articular discs anteriorly, moving the jaw straight forward. The lateral pterygoids also help stabilize the disc during opening, reinforcing forward movement. The other muscles mainly elevation the jaw to close the mouth (masseter and temporalis) or assist with elevation and grinding (medial pterygoid); they are not the primary drivers of forward mandible movement. So the lateral pterygoid is the key muscle for protrusion.

Protruding the mandible is driven by pulling the condyles forward, which is the role of the lateral pterygoid muscles. When both sides contract, they tug the mandible and the articular discs anteriorly, moving the jaw straight forward. The lateral pterygoids also help stabilize the disc during opening, reinforcing forward movement. The other muscles mainly elevation the jaw to close the mouth (masseter and temporalis) or assist with elevation and grinding (medial pterygoid); they are not the primary drivers of forward mandible movement. So the lateral pterygoid is the key muscle for protrusion.