Which of the following DOES NOT cause depression of the mandible?

The contraction of the temporalis muscle does not cause depression of the mandible, making this option the correct choice. The temporalis muscle primarily functions to elevate the mandible and assist with the retrusion of the jaw. When it contracts, it pulls the mandible upwards, contributing to the closing of the mouth, rather than lowering it.

In contrast, the lateral pterygoid muscle plays a significant role in depressing the mandible when it contracts, as it helps to move the jaw forward (protrusion) and downward. The suprahyoid muscles also facilitate the depression of the mandible by pulling the mandible downward during actions such as swallowing or opening the mouth. Lastly, relaxation of all muscles allows gravity to act, which can also contribute to the depression of the mandible. Therefore, it is clear that the temporalis muscle is not associated with the depression of the mandible during its contraction, affirming why this choice is accurate.