Which muscles are primarily involved in lateral deviation of the mandible?

Lateral deviation of the mandible is a movement that occurs when the jaw moves sideways, typically during actions such as chewing. The primary muscles involved in this action include the contralateral lateral pterygoid and medial pterygoid muscles, as they work together to move the mandible side to side. The ipsilateral temporalis muscle, particularly its posterior fibers, also aids in this movement by stabilizing the jaw during lateral deviation.

The contralateral lateral pterygoid muscles on one side pull forward the head of the mandible, while the medial pterygoids on the opposite side help bring the mandible over to that side. The posterior fibers of the temporalis assist by providing a downward and backward pull on the mandible for stabilization and complementary movement. This combination allows for effective lateral deviation as the jaw moves in a coordinated manner.

This understanding of the complex interactions among these muscles highlights why the correct answer focuses on the specific involvement of the contralateral lateral and medial pterygoids, as well as the ipsilateral posterior fibers of the temporalis in achieving lateral movement.