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Muscles of Mastication

Muscles of mastication are involved in chewing.
  • Originates on the temporal fossa of the temporal bone and inserts on the coronoid process and anterior ramus of the mandible; it elevates and retracts the mandible.
  • Originates on the zygomatic bone and arch and inserts on the angle and lateral ramus of the mandible, which it elevates.
Medial pterygoid has two heads:
  • The deep head originates on the medial aspect of the lateral pterygoid process of the sphenoid and inserts on the medial surface of the angle and ramus of the mandible.
  • The superficial head originates on the tuberosity of the maxilla and inserts with the deep head on the mandibular angle.
  • The medial pterygoid elevates the mandible and moves it laterally.
The lateral pterygoid also has two heads:
  • The upper head originates from the infratemporal fossa of the sphenoid and inserts on the temporomandibular joint capsule and mandible.
  • The lower head originates from the lateral surface of the lateral pterygoid plate and inserts with the upper head.
  • The lateral pterygoid protrudes the mandible and moves it laterally.
Movements of the mandible at the temporomandibular joint:
  • Protrusion moves the mandible anteriorly; the lateral pterygoid muscles produce this movement.
  • Retraction moves the mandible posteriorly; the masseter produces this movement.
  • Elevation moves the mandible superiorly towards the upper teeth; temporalis, masseter, and the medial pterygoid produce this movement.
  • Depression moves the mandible inferiorly.