The masseter and temporalis muscles are two key muscles that control the movement of the mandible.
Muscles Involved in Mandible Movement
The mandible, or lower jaw, is moved by several muscles, but the masseter and temporalis play the most significant roles in mastication (chewing). These muscles work together to allow for the complex movements required for biting and chewing food.
Masseter Muscle
- Origin: The masseter muscle starts at the zygomatic arch, located on the side of the skull.
- Insertion: It inserts along the angle and lateral surface of the mandible.
- Function: This muscle provides the primary force for the elevation and protrusion of the mandible, essential for biting and grinding food. The masseter is one of the strongest muscles in the human body, due to its role in chewing.
Temporalis Muscle
- Origin: The temporalis muscle originates from the floor of the temporal fossa, a depression on the side of the skull.
- Insertion: It inserts onto the coronoid process of the mandible, a bony projection that extends upwards from the jaw.
- Function: The temporalis muscle primarily elevates the mandible and also helps with retraction (moving the jaw backward). In addition, it assists with side-to-side movements of the jaw during chewing.
| Muscle | Origin | Insertion | Function |
|---|---|---|---|
| Masseter | Zygomatic arch | Angle and lateral surface of the mandible | Powerful elevation and protrusion of the mandible |
| Temporalis | Floor of the temporal fossa | Coronoid process of the mandible | Elevation and retraction of the mandible; some side movement |
These two muscles work synergistically to control the complex movements of the jaw, and contribute to mastication. Understanding the function of each muscle offers insight into jaw biomechanics and clinical conditions affecting the temporomandibular joint.
