The muscles of mastication are the powerful muscles that enable us to chew. There are four primary muscles responsible for the intricate movements of the jaw:
The Primary Muscles of Mastication
- Masseter: This strong, superficial muscle originates from the zygomatic arch (cheekbone) and inserts onto the mandible (lower jaw). It's a powerful elevator of the mandible, crucial for closing the jaw. Learn more about the Masseter muscle
- Temporalis: A fan-shaped muscle originating from the temporal fossa (side of the skull) and inserting onto the coronoid process of the mandible. It also elevates the mandible and assists in retraction (pulling the jaw backward). Explore the Temporalis muscle in detail
- Medial Pterygoid: Located deep within the face, this muscle originates from the pterygoid plates of the sphenoid bone and inserts onto the mandible. It acts as a powerful elevator and assists in protrusion (pushing the jaw forward).
- Lateral Pterygoid: Also deep within the face, this muscle originates from the pterygoid plates and inserts onto the condylar process of the mandible and articular disc. Uniquely, it is the primary muscle responsible for depressing (opening) the mandible. Understand the Lateral Pterygoid's role
Secondary or Accessory Muscles of Mastication
While the four muscles above are the primary players, several other muscles contribute to the complex process of chewing:
- Buccinator: This muscle helps keep food between the teeth during chewing.
- Suprahyoid muscles: These include the digastric, mylohyoid, and geniohyoid muscles, supporting the tongue and assisting in jaw opening.
- Infrahyoid muscles: These muscles (sternohyoid, sternothyroid, thyrohyoid, and omohyoid) help stabilize the hyoid bone and indirectly influence jaw movement.
Understanding these muscles provides a comprehensive view of the mechanics of mastication. The coordinated actions of these primary and secondary muscles allow for the precise and powerful movements required for efficient chewing.
