Which of the following is NOT a muscle of mastication?

Add commentMarch 14, 20162 min read

(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.