Which of the following is NOT a muscle of mastication?
(A.) Masseter
(B.) Medial pterygoid
(C.) Temporalis
(D.) Lateral pterygoid
(E.) Buccinator
Answer: (E.) Buccinator
This is what you can see with StudentRDH National Boards Review Package, in Head and Neck Anatomy:
MUSCLES OF MASTICATION
4 muscles: masseter, medial pterygoid, temporalis, and lateral pterygoid. These muscles work with the TMJ to accomplish jaw movement.
All muscles of mastication are innervated by the fifth (V) cranial nerve.
- Masseter: two heads, deep and superficial. The superficial head is the bigger one.
- O: zygomatic arch. I: angle of the mandible.
- Action: elevates the mandible.
- Temporalis: fan-shaped muscle.
- O: temporal fossa. I: coronoid process of mandible.
- Action: elevates and retracts the mandible with the posterior portion of the muscle.
- Medial pterygoid: two heads, deep and superficial. The deep head is the bigger one.
- O: medial surface of the lateral plate of the pterygoid process (deep head), and the maxillary tuberosity (superficial head). I: angle of the mandible.
- Action: elevates the mandible.
- Runs vertically, compared to the lateral pterygoid that runs horizontally.
- Lateral pterygoid: two heads, upper and lower.
- O: infratemporal crest of the greater wing of the sphenoid bone (upper head), lateral surface of the pterygoid process (lower head).
- Action: depresses the mandible.
MUSCLES OF FACIAL EXPRESSIONS
- Buccinator: thin muscle between the maxilla and mandible in the cheek area.
- O: alveolar process of the maxilla/mandible and pterygomandibular raphe. I: corner of the mouth.
- Action: keeps the food pushed back when chewing, compresses cheeks against the teeth, helps the sucking action, and expels air (also called as the trumpet muscle for this reason).
- Pierced by the parotid duct.
As you can see above, the buccinator is a muscle of facial expression and is NOT considered a muscle of mastication.
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