Muscles of Mastification

Question 1

muscles of mastification are derived from

Answer 1

the first (mandibular) pharyngeal/Brachial arch during fetal development (from Meckels cartilage)

Question 2

all muscles of mastification are innervated by the

Answer 2

trigeminal nerve (CNV)

Question 3

Medial (internal) pterygoid m. O/I/A

Answer 3

O: medial portion of lat pterygoid plate
I: medial surface of ramus
A: raises mandible (closes jaw) and deviation of jaw to opposite side

Question 4

Fills pterygoid fossa

Answer 4

medial pterygoid m.

Question 5

Lateral pterygoid m. O/I/A

Answer 5

Two heads-
O: infratemporal crest/lat surface of lateral pterygoid plate
I: articulate disc of TMJ and neck of mandibular condyle
A: only muscle to depress mandible
–bilateral–> protrusion
–unilateral–> excursion

Question 6

Temporalis M. O/I/A

Answer 6

O: Temporalis lines
I: coracoid process/notch
A: elevates and retrudes mandible

Question 7

elevates and retrudes mandible

Answer 7

temporalis m.

Question 8

involved in resting tonus

Answer 8

temporalis when relaxed

Question 9

Masseter M. O/I/A

Answer 9

O: zygomatic arch
I: body/angle of ramus
A: elevates the mandible (most powerful)-can slightly retract; messenteric sling

Question 10

most powerful elevator of the mandible

Answer 10

masseter

Question 11

Buccinator m. action and nerve

Answer 11

manages food bolus; facial nerve (CN VII)