Which muscle is primarily responsible for depressing the mandible and aiding in jaw movements?

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

Answer: (C)

The lateral pterygoid muscle is primarily responsible for depressing the mandible and facilitating movements of the jaw, particularly during actions like opening the mouth and moving the jaw side to side. This muscle plays a crucial role in the complex movements of mastication, allowing for the lateral and protrusive movements of the jaw.

In contrast, the masseter and temporalis muscles primarily function to elevate the mandible, contributing to the closing of the jaw when biting or chewing. The medial pterygoid also assists in elevating the mandible and does not contribute to its depression or the lateral movements as significantly as the lateral pterygoid.

Thus, understanding the specific functions of these muscles highlights why the lateral pterygoid is considered the main muscle responsible for the depression of the mandible and for aiding in its movements.