Which muscle is a primary mover of jaw closure during chewing?

Which muscle is a primary mover of jaw closure during chewing?

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

Answer: (A)

Jaw closure during chewing relies on the muscles that lift the mandible. The masseter is the primary mover here, delivering the strongest closing action and most of the bite force by pulling the lower jaw upward from the cheekbone to meet the upper teeth. The temporalis also helps close the jaw and can retract the mandible, adding to biting efficiency, but it isn’t the main source of closing power. The medial pterygoid assists in elevating the jaw and stabilizing the bite, working together with the masseter, while the lateral pterygoid mainly opens the jaw and moves it forward. So, the masseter is the key muscle responsible for closing the jaw during chewing.

Jaw closure during chewing relies on the muscles that lift the mandible. The masseter is the primary mover here, delivering the strongest closing action and most of the bite force by pulling the lower jaw upward from the cheekbone to meet the upper teeth. The temporalis also helps close the jaw and can retract the mandible, adding to biting efficiency, but it isn’t the main source of closing power. The medial pterygoid assists in elevating the jaw and stabilizing the bite, working together with the masseter, while the lateral pterygoid mainly opens the jaw and moves it forward. So, the masseter is the key muscle responsible for closing the jaw during chewing.