Muscles of Mastication

Question 1

Masseter

Answer 1

Origin Zygomatic arch and zygomatic bone
Insertion Lateral surface of the ramus and angle of the mandible
Action Elevates the mandible
Innervation Nerve to the masseter, from mandibular div. of trigeminal nerve (V)
Artery Masseteric branch of maxillary a.

Question 2

Lateral Pterygoid

Answer 2

Origin Superior head: greater wing of sphenoid bone
Inferior head: lateral surface of the lateral pterygoid plate
Insertion Superior head: capsule and articular disk of the TMJ
Inferior head: neck of the mandible
Action Protracts the mandible; opens the mouth; active in grinding actions of
chewing
Innervation Lateral pterygoid branch of mandibular div. of trigeminal nerve (V)
Artery Pterygoid branch of maxillary a.

Question 3

Medial Pterygoid

Answer 3

Origin Medial surface of the lateral pterygoid plate, pyramidal process of the
palatine bone, tuberosity of the maxilla
Insertion Medial surface of the ramus and angle of the mandible
Action Elevates and protracts the mandible
Innervation Medial pterygoid branch of mandibular div. of the trigeminal nerve (V)
Artery Pterygoid branch of maxillary a.

Question 3

Temporalis

Answer 3

Origin Temporal fossa and the temporal fascia
Insertion Coronoid process of the mandible and the anterior surface of the ramus
of the mandible
Action Elevates the mandible; retracts the mandible (posterior fibers)
Innervation Anterior & posterior deep temporal nerves from mandibular div. of
trigeminal nerve (V)
Artery Anterior & posterior deep temporal aa.

Question 4

Buccinator

Answer 4

Origin Pterygomandibular raphe, mandible, and the maxilla lateral to the molar
teeth
Insertion Angle of mouth, and the lateral portion of the upper and lower lips
Action Pulls the corner of mouth laterally; presses the cheek against the teeth
Innervation Buccal branches of the facial nerve (VII)
Artery Facial a.

Question 5

Depressor Anguli Oris

Answer 5

Origin Oblique line of the mandible
Insertion Angle of the mouth
Action Pulls the corner of the mouth downward
Innervation Marginal mandibular & buccal branches of the facial nerve (VII)
Artery Inferior labial branch of the facial a., mental a.

Question 6

Depressor Labii lnferioris

Answer 6

Origin Anterior surface of the mandible
Insertion Skin of the lower lip
Action Depresses the lower lip
Innervation Marginal mandibular branch of the facial nerve (VII)
Artery Inferior labial branch of the facial a., mental a.

Question 7

Levator Anguli Oris

Answer 7

Origin Canine fossa of the maxilla
Insertion Angle (corner) of the mouth
Action Elevates the angle of the mouth
Innervation Buccal branch of the facial nerve (VII)
Artery lnfraorbital a., superior labial branch of the facial a.

Question 8

Levator Labii Superioris

Answer 8

Origin Inferior margin of the orbit
Insertion Skin of the upper lip
Action Elevates the upper lip
Innervation Buccal branch of the facial nerve (VII)
Artery lnfraorbital a., superior labial branch of the facial a.

Question 9

Levator Labii Superioris Alaeque Nasi

Answer 9

Origin Frontal process of the maxilla
Insertion Ala of the nose and skin of the upper lip
Action Elevates the upper lip and flares the nostril
Innervation Buccal branch of the facial nerve (VII)
Artery lnfraorbital a. , superior labial branch of the facial a.

Question 10

Mentalis

Answer 10

Origin Anterior surface of the mandible near the mental symphysis (midline)
Insertion Skin of the chin
Action Elevates the lower lip and skin of chin
Innervation Marginal mandibular branch of the facial nerve (VII)
Artery Mental a., inferior labial branch of the facial a.

Question 11

Orbicularis Oris

Answer 11

Origin Skin and fascia of lips and the area surrounding the lips
Insertion Skin and fascia of the lips
Action Purses the lips
Innervation Buccal branch of the facial nerve (VII)
Artery Superior and inferior branches of the facial a., mental a., infraorbital a.

Question 12

Risorius

Answer 12

Origin Fascia of the lateral cheek
Insertion Skin of the angle (corner) of the mouth
Action Draws the corner of the mouth laterally
Innervation Buccal branch of the facial nerve (VII)
Artery Transverse facial a. , facial a.

Question 13

Zygomaticus Major

Answer 13

Origin Upper lateral surface of the zygomatic bone
Insertion Skin of the angle of the mouth
Action Elevates and draws the corner of the mouth laterally
Innervation Zygomatic and buccal branches of the facial nerve (VII)
Artery Transverse facial a., facial a.

Question 14

Zygomaticus Minor

Answer 14

Origin Lower surface of the zygomatic bone
Insertion Lateral part of the upper lip
Action Elevates the upper lip
Innervation Buccal branch of the facial nerve
Artery Transverse facial a., facial a.