Which of the following is NOT a muscle of mastication?

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

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the muscles of mastication. These are the muscles responsible for chewing and include the Masseter, Medial pterygoid, Temporalis, and Lateral pterygoid. They are innervated by the mandibular branch of the trigeminal nerve (cranial nerve V).
2. Step 2: Recognize the Buccinator muscle. The Buccinator is not a muscle of mastication; instead, it is a facial muscle that assists in manipulating food within the oral cavity and is involved in actions like blowing air or sucking. It is innervated by the facial nerve (cranial nerve VII).
3. Step 3: Compare the functions of the listed muscles. The Masseter, Medial pterygoid, and Temporalis are directly involved in the movement of the jaw for chewing, while the Buccinator is primarily involved in maintaining tension in the cheeks and does not contribute to jaw movement.
4. Step 4: Identify the key distinction. The Buccinator is categorized as a muscle of facial expression rather than mastication, which is why it is not part of the group responsible for chewing.
5. Step 5: Conclude that the Buccinator is the correct answer to the question, as it does not belong to the group of muscles of mastication.