axial muscles - origins and insertions for muscles of mastication

Question 1

origin of the buccinator

Answer 1

• alveolar processes of maxilla and mandible

- pterygomandibular raphe

Question 2

insertion of the buccinator

Answer 2

• bends into fibers of orbicularis oris

Question 3

what is the upper and lower attachment of the pterygomandibular raphe

Answer 3

upper: pterygoid hamulus
lower: mandible, immediatley posterior to the third molar

Question 4

is the buccinator a muscle of mastication

Answer 4

no

Question 5

what are the muscles of mastication

Answer 5

• temporalis
• masseter
• medial pterygoid
• lateral pterygoid

Question 6

how is the lateral pterygoid divided

Answer 6

• superior and inferior

Question 7

what are the origins of the lateral pterygoid

Answer 7

superior:
- lateral surface of greater wing of sphenoid

inferior
- lateral surface of the lateral pterygoid plate

Question 8

what is the insertion for the lateral pterygoid

Answer 8

superior

• articular disc
• capsule of TMJ

inferior

• superiormedial surface of the ramus of the mandible
• condylar process of mandible

Question 9

what are the actions of the lateral pterygoid

Answer 9

bilateral

• protrudes mandible, pulls articular disk forward
• depresses mandible

unilateral
- lateral movements of chewing (mandible)

Question 10

how is the medial pterygoid divided

Answer 10

superficial and deep

Question 11

what is the origin of the medial pterygoid

Answer 11

superficial
- maxillary tuberosity of the maxilla

deep

• medial surface of lateral pterygoid plate
• lateral surface of medial pterygoid plate
• pterygoid fossa

Question 12

what is the insertion of the medial pterygoid

Answer 12

• medial surface of ramus

- angle of mandible

Question 13

what are the actions of the medial pterygoid

Answer 13

• elevates mandible
• protrudes mandible
• unilateral (lateral movements of chewing)

Question 14

what is the deepest muscle of mastication

Answer 14

medial pterygoid

Question 15

what are the portions of the temporalis, and what fibers are associated with each

Answer 15

• anterior portion: vertical fibers
• middle portion: oblique fibers
• posterior portion: horizontal fibers

Question 16

what is the origin of the temporalis

Answer 16

• inferior temporal line of the temporal fossa

- temporal fascia

Question 17

what is the insertion of the temporalis

Answer 17

• coronoid process of mandible
• anterior border of the ramus of the mandible
• **travels under the zygomatic arch

Question 18

what are the actions of the temporalis

Answer 18

• vertical/anterior fibers: elevate mandible
• middle/oblique and posterior/horizontal fibers: retrude mandible
• unilateral: lateral movement of chewing (mandible)

Question 19

how is the masseter divided

Answer 19

• superficial and deep head

Question 20

how do the fibers run in the portions of the masseter

Answer 20

• superficial: downward and slightly bakward

- deep: fibers run vertically

Question 21

what is the origin for the masseter

Answer 21

superficial
- anterior 2/3 of the zygomatic arch

deep
- posterior 1/3 of the zygomatic arch

Question 22

what is the insertion of the masseter

Answer 22

superficial
- mandibular angle and ramus

deep
- mandibular ramus and coronoid process

Question 23

what are the actions of the masseter

Answer 23

• elevate mandible (teeth brought into contact)
• protrude mandible (superficial head)
• unilateral (lateral movement of mandible or chewing)