Mastication Muscles: Origin, Insertions, Innervation, and Action

Temporalis: Origin

• Temporalis fossa

Temporalis: Insertion

• Coronoid process

• Anterior border of ramus of mandible

Temporalis: Innervation

• Mandibular division of trigeminal nerve

Temporalis: Action

• Closes jaw

• Posterior portion retracts mandible

Masseter: Origin

• Inferior zygomatic arch

• Zygomatic process of maxilla

Masseter: Insertion

• Angle and ramus of mandible

Masseter: Innervation

• Mandibular division of trigeminal nerve

Masseter: Action

• Closes jaw

Lateral Pterygoid: Origin

• Superior head: Infratemporal surface of greater wing of sphenoid

• Inferior head: Lateral surface of lateral pterygoid plate

Lateral Pterygoid: Insertion

• Neck of mandible

• Articular capsule and disc of TMJ

Lateral Pterygoid: Innervation

• Mandibular division of trigeminal nerve

Lateral Pterygoid: Action

• Protrudes mandible

• Side to side mandible

Medial Pterygoid: Origin

• Medial surface of lateral pterygoid plate

Medial Pterygoid: Insertion

• Medial surface of ramus and angle of mandible

Medial Pterygoid: Innervation

• Mandibular division of trigeminal nerve

Medial Pterygoid: Action

• Closes jaw

• Acting alone pulls chin to opposite side

• Acting alternately causes grinding