Muscles of Mastication Flashcards
What are the 4 main muscles of mastication?
Temporalis
Masseter
Medial Pterygoid
Lateral Pterygoid
Which osteological regions are relevant for muscles of mastication?
Temporomandibular joint
Temporal fossa
Infratemporal fossa
What two bony landmarks articulate at the temporomandibular joint?
Mandibular fossa of temporal bone
Head of condyloid process of mandible
What movements are associated with the temporomandibular joint?
Elevation (close mouth) Depression (open mouth) Protrusion (protrude chin) Retrusion (retrude chin) Lateral movements (grinding and chewing)
Describe the temporal fossa.
Depressed area on side of skull
Superior to infratemporal fossa
Which muscle occupies the temporal fossa?
Upper portion of temporalis muscle
Where is the infratemporal fossa located?
Medial/deep and inferior to zygomatic arch
Which osteological landmarks are relevant to the infratemporal fossa?
Ramus of mandible
Lateral pterygoid plate
Maxilla
Inferior surface of greater wing of sphenoid
Mastoid and styloid processes of temporal bone
What makes up the medial wall of the infratemporal fossa?
Lateral pterygoid plate
What makes up the anterior wall of the infratemporal fossa?
Maxilla
What makes up the roof of the infratemporal fossa?
Greater wing of sphenoid bone
Squamous part of temporal bone
What makes up the lateral wall of the infratemporal fossa?
Ramus of mandible
What is the significance of foramen ovale in the infratemporal fossa?
Root which nerve that innervates muscles of mastication passes through to the infratemporal fossa
Which nerve innervates muscles of mastication?
Trigeminal nerve - mandibular division (V3)
Where is the foramen ovale found in the infratemporal fossa?
Deep and posterior
Where is the tuberosity of the maxilla found?
Lateral to hard palate, posterior to alveolar processes
Where does masseter originate?
Zygomatic bone
Zygomatic arch
Where does masseter insert?
Ramus of mandible: angle and lateral surface
What are the two heads of masseter?
Deep and superficial heads
How does the deep head of masseter run?
Vertically
How does the superficial head of masseter run?
Oblique
What functions does masseter perform?
Elevate and protrude mandible
Which head of masseter elevates the mandible?
Deep head
Which head of masseter protrudes the mandible?
Superficial head
Where does temporalis originate?
Temporal fossa (superior temporal line)
Where does temporalis insert?
Coronoid process of mandible (apex and medial surface)
What functions does temporalis do?
Elevate and retract mandible
What are the two heads of the lateral pterygoid muscle?
Superior and inferior heads
What are the two heads of the medial pterygoid muscle?
Superficial and deep heads
Where does the superior head of lateral pterygoid muscle originate?
Greater wing of sphenoid bone
Where does the inferior head of lateral pterygoid muscle originate?
Lateral surface of lateral pterygoid plate
Where do the 2 heads of lateral pterygoid muscle insert?
Region of temporomandibular joint
Neck of condyloid process of mandible
Together, what do the two heads of the lateral pterygoid muscle do?
Protrude mandible
Acting alone and alternatively, what do the two heads of the lateral pterygoid muscle do?
Produce side to side movement
Where does the deep head of the medial pterygoid muscle originate?
Medial surface of lateral pterygoid plate
Where does the superficial head of the medial pterygoid muscle originate?
Tuberosity of maxilla
Where do the two heads of the medial pterygoid muscle insert?
Medial surface of mandible
Acting together, what do the two heads of the medial pterygoid muscle do?
Elevate and protrude mandible
Acting alone and alternatively, what do the two heads of the medial pterygoid muscle do?
Produce a grinding motion (side to side)
Which two muscles form a muscular sling around the mandible?
Medial pterygoid muscle
Masseter
