Muscles of Mastication

Question 1

Name the 4 muscles of mastication.

Answer 1

• masseter
• temporalis
• medial pterygoid
• lateral pterygoid

Question 2

Embryologically, where are the muscles of mastication derived from?

Answer 2

paraxial mesoderm of the first pharyngeal arch

Question 3

The muscles of mastication originate from ______ and insert into _____.

Answer 3

skull / mandible

Question 4

Every muscle of mastication is innervated by which cranial nerve?

Answer 4

mandibular branch of the trigeminal nerve (CN V3)

Question 5

side-to-side movement, may be lateral or medial

Answer 5

excursion

Question 6

2 parts of the masseter (origin, insertion, action)

Answer 6

Superficial
- origin: anterior 2/3rds of zygomatic arch
- insertion: lateral part of ramus and angle of mandible
- action: protrudes mandible

Deep
- origin: posterior 1/3rd of zygomatic arch
- insertion: lateral part of ramus and angle of mandible
- action: retracts mandible

Both
- action: elevates mandible, unilateral contraction leads to ipsilateral excursion

Question 7

This muscle is deep to the masseter and zygomatic process.

Answer 7

temporalis