Answer
This is a description of the identifying characteristics of the temporalis, the masseter, and the medial and lateral pterygoid muscles.
1. Temporalis; Location along the side of the head(skull) above the ears.
The origin of the temporalis is on the temporal lines and temporal fossa of the cranium. Its insertion is on the coronoid process and anterior border of the mandibular ramus. The temporalis elevates and retracts the mandible and also moves it medially and laterally. Innervation of this muscle is by the mandibular branch of the trigeminal nerve ( CN V).
2. The Masseter: Location : On each side of the skull (face) in the back of the jaw near the ears.
The masseter originates on the zygomatic arch. Its insertion is on the lateral surface of the mandibular arch and angle. Its major action is the elevation of the mandible, but it also protracts, retracts, and moves the mandible laterally and medially The masseter is innervated by the mandibular branch of CN V.
The masseter is arguably the strongest muscle in the body.
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3. Medial pterygoid. Located on the surface of the mandible
This muscle has its origin on the medial surface of the lateral pterygoid plate. It inserts on the medial surface of the mandibular ramus and angle. It elevates and protracts the mandible, and also moves it laterally and medially. Innervation is by mandibular branch of CN V.
4. The lateral pterygoids are located on the inner surface of mandible. They depress the mandible in the action of opening the mouth wide. They also protract the mandible and move it laterally and medially. They originate on the lateral surface of the lateral pterygoid plate and the greater wing of the sphenoid bone.
This muscle also is innervated by the mandibular branch of CN V.
