Muscles Of Mastication

Question 1

What are the muscles of mastication

Answer 1

Join to the mandible to allow for movement during chewing and grinding

Question 2

5 main movements of mandible allowed by muscles of mastication

Answer 2

Forwards (protrusion)
Backwards (retraction)
Up/close (elevation)
Down/open (depression)
Side to side (rotation)

Question 3

Muscles of mastication clinical relevance

Answer 3

Impact of inferior dental blocks (hematomia, trauma)
Pain during mastication
Trismus (difficultly opening)
Clenching and grinding (masseter pain)

Question 4

Principle muscles of mastication

Answer 4

Masseter
Temporalis
Lateral pterygoid
Medial pterygoid

Question 5

2 parts of masseter

Answer 5

Superficial
Deep

Question 6

Origin and insertion masseter

Answer 6

Origin - zygomatic arch.

Insertion - ramus of mandible.

Question 7

Action of masseter muscle

Answer 7

Closing of mandible (elevate)

Question 8

Innervation and blood supply for masseter

Answer 8

Nerve - masseteric nerve (anterior division of mandibular nerve).

Blood - Superficial temporal artery (facial branch)
and maxillary artery (masseteric branch)

Question 9

What gland duct passes through masseter muscle

Answer 9

Parotid gland duct

Question 10

Origin and insertion of temporalis

Answer 10

Origin - temporal fossa.

Insertion - coronoid process and ramus of mandible.

Question 11

Action of temporalis muscle

Answer 11

Closing of mandible (elevate)

Question 12

Nerve and blood supply of temporalis

Answer 12

Nerve - anterior division of mandibular nerve

Blood - superficial temporal and maxillary arteries

Question 13

Origin and insertion of upper head of lateral pterygoid muscle

Answer 13

Origin - greater wing of sphenoid bone.

Insertion - neck of mandible (pterygoid fovea)

Question 14

Origin and insertion of lower head of lateral pterygoid

Answer 14

Origin - lateral pterygoid plate of sphenoid bone.

Insertion - neck of mandible (pterygoid fovea)

Question 15

Action of the lateral pterygoid muscles

Answer 15

Bilateral contraction - opens and protrudes the mouth (depression and protrusion)

When contract alternately - lateral deviation (rotation)

Question 16

Innervation and boood supply of lateral pterygoid

Answer 16

Innervation - lateral pterygoid branch of mandibular nerve.

Blood supply - pterygoid branch of maxillary artery.

Question 17

Origin and insertion of large deep head of medial pterygoid

Answer 17

Origin - lateral pterygoid plate of sphenoid.

Insertion - ramus and angle of mandible.

Question 18

Origin and insertion of small superficial head of medial pterygoid muscle

Answer 18

Origin - maxilla and palatine bone.

Insertion - ramus and angle of mandible.

Question 19

Action of medial pterygoid muscle

Answer 19

Closing of mandible (elevates)
Along with lateral pterygoid, protrudes the mandible.

Question 20

Nerve and blood supply of medial pterygoid muscle

Answer 20

Nerve - medial pterygoid branch of mandibular nerve.

Blood - pterygoid branches of maxillary artery.

Question 21

Accessory muscles of mastication

Answer 21

Digastric
Buccinator
Geniohyoid
Genioglossus

Question 22

Origin and insertion of anterior belly of digastric muscle

Answer 22

Origin - lower border of mandible (digastric fossa).

Insertion - above hyoid bone, held with fibrous sling anchoring to body of hyoid bone.

Question 23

Origin and insertion of posterior belly of digastric muscle

Answer 23

Origin - mastoid process of temporal bone.

Insertion - above hyoid bone, held with fibrous sling anchoring to body of hyoid bone

Question 24

Action of digastric muscle

Answer 24

Opening of mouth (depression)
Elevate hyoid bone during chewing and swallowing

Question 25

Nerve and blood support of anterior belly of digastric muscle

Answer 25

Nerve - mylohyoid nerve Blood - sub mental branch of facial artery

Question 26

Nerve and blood supply of posterior belly of digastric muscle

Answer 26

Nerve - digastric branch of facial nerve Blood - posterior auricular/occipital artery

Question 27

Buccinator origin and insertion

Answer 27

Origin - Pterygomandibular raphae and buccal alveolar bone Insertion - orbicularis oris (corners of mouth)

Question 28

What muscle forms the cheek

Answer 28

Buccinator

Question 29

Action of Buccinator

Answer 29

Pulls corners of mouth back. Compress cheek against buccal surface of molars. Regulates vestibular region with tongue; keeps food in line with occlusal surfaces of teeth during mastication.

Question 30

Innervation and blood supply of Buccinator

Answer 30

Nerve - facial nerve, buccal branch Blood - facial and maxillary arteries

Question 31

Geniohyoid

Answer 31

Narrow muscle situated above medial part of mylohyoid line

Question 32

Origin and insertion of geniohyoid

Answer 32

Origin - inferior genial tubercle Insertion - body of hyoid bone.

Question 33

Action of geniohyoid

Answer 33

Aids in deglutition Opening of mouth (depression of mandible)

Question 34

Innervation and blood supply of geniohyoid muscle

Answer 34

Nerve - hypoglossal nerve Blood supply - sublingual branch of lingual artery

Question 35

Genioglossus muscle origin and insertion

Answer 35

Origin - superior genial tubercle on inner surface of mandible. Insertion - enters dorsum of tongue. Superior fibres - tip of tongue. Inferior fibres - body of hyoid bone

Question 36

Action of Genioglossus

Answer 36

Depresses the tongue Inferior fibres retract the tongue Superior fibres protrude the tongue

Question 37

Innervation and blood supply of Genioglossus

Answer 37

Innervation - hypoglossal nerve Blood supply - sublingual branch of lingual artery and sub mental branch of facial artery.

Question 38

Fan shaped muscle of either side of head.

Answer 38

Temporalis

Question 39

A thick quadrilateral muscle

Answer 39

Medial pterygoid

Question 40

Thick quadrilateral muscle Most powerful of muscles of mastication.

Answer 40

Masseter

Question 41

A short, thick muscle, triangular in shape and arises from 2 heads

Answer 41

Lateral pterygoid