What is the primary muscle that moves the jaw to the right?

What is the primary muscle that moves the jaw to the right?

• A. Left lateral pterygoid
• B. Right lateral pterygoid
• C. Masseter
• D. Temporalis

Answer: (A)

The ability to move the jaw sideways is driven by the lateral pterygoid muscles, with unilateral contraction producing a deviation toward the opposite side. When the left lateral pterygoid contracts, it pulls the condyle and articular disc forward and to the right, swinging the mandible to the right. The right lateral pterygoid would cause the jaw to deviate to the left if it acted alone. Masseter and temporalis mainly close the jaw and do not generate the directed lateral movement needed here, so they aren’t the primary movers for moving the jaw to the right.

The ability to move the jaw sideways is driven by the lateral pterygoid muscles, with unilateral contraction producing a deviation toward the opposite side. When the left lateral pterygoid contracts, it pulls the condyle and articular disc forward and to the right, swinging the mandible to the right. The right lateral pterygoid would cause the jaw to deviate to the left if it acted alone. Masseter and temporalis mainly close the jaw and do not generate the directed lateral movement needed here, so they aren’t the primary movers for moving the jaw to the right.