Which of the following is NOT a muscle of mastication?

The deltoid muscle is indeed not a muscle of mastication. It is primarily located in the shoulder and is responsible for arm movements, such as lifting the arm away from the body. In contrast, the muscles of mastication, which include the lateral pterygoid, medial pterygoid, and masseter, are specifically involved in the process of chewing. These muscles work together to allow the jaw to move up and down, as well as side to side, facilitating the breakdown of food.

The lateral and medial pterygoid muscles help to control the movement of the mandible forward and side to side, while the masseter muscle is key for the powerful closing of the jaw. Understanding the distinct functions of these muscles is crucial for anyone studying dental nursing, as it relates to both anatomy and patient care involving occlusion and dental functions.