2.2.2 Structures of Mastication

Question 1

What are the covered parts?

Answer 1

Question 2

What are the characteristics of the ventral surface of the tongue?

Answer 2

• Ventral surface of tongue is smooth and is attached to floor of mouth by lingual frenulum
• Deep lingual vein courses on either side of the frenulum
• Sublingual caruncles at the base of frenulum provide drainage for the submandibular duct

Question 3

What are the two types of movement accomplished by the TMJ?

Answer 3

• Hinge: between the mandibular condyle and inferior surface of articular disc
• Gliding: between the superior portion of the disc and the temporal bone

Question 4

What are the characteristics of the intrinsic muscles of the tongue?

Answer 4

• Allow change in shape and length of tongue
• Do NOT attach to bone
• All innervated by CN XII
• Consist of:
• -Superior & Inferior Longitudinal Bundles
• -Transverse Bundles
• -Vertical Bundles

Question 5

What are the two compartments of the oral cavity?

Answer 5

1) Vestibule– between teeth and cheeks
2) Oral Cavity Proper – internal to teeth

Question 6

What structures receive blood from either the 1st, 2nd, or 3rd branch of the maxillary artery?

Answer 6

1st part - Deep Auricular A to ear; Middle Meningeal A to cranial bones; Inf Alveolar A to mandibular teeth

2nd - Muscles of face

3rd - Maxillary teeth; infraorbital artery to face; nose; descending palatine artery to palate

Question 7

What are the characteristics of the buccinator muscle?

Answer 7

• NOT a muscle of mastication, but rather of facial expression
• Between maxiallar and mandible
• Receives innervation from CNVII
• Keeps food between the occlusal surface of the teeth during chewing
• Pierced by parotid duct as it enters vestibule of oral cavity

Question 8

What is the origin and insertion of the Temporalis?

Answer 8

Origin - floor of the temporal fossa and the deep surface of the temporal fossa

Insertion - Attaches to the tip of the coronoid process

Question 9

What are the contents of the oral cavity proper?

Answer 9

• Contents of Oral Cavity Proper
• Hard palate
• Soft palate
• Phalatoglossal arch
• Tongue
• Uvula: separates oral cavity from oral pharynx

Question 10

What is ankyloglossia?

Answer 10

restricted tongue movement due to short lingual frenulum

Question 11

What are the characteristics of a dislocated jaw?

Answer 11

• Occurs when there is excess contraction of the lateral pterygoid muscle
• Typically, head of mandible slides too far anteriorly over the articular tubercle
• Corrected by applying downward pressure with fingers in the vestibule of oral cavity

Question 12

What is the importance of the sphenomandibular lig?

Answer 12

holds mandible to the cranium

spine of sphenoid to lingula, above mandibular foramen

Question 13

What is the vallecula?

Answer 13

Space between the base of the tongue and the epiglottis

Question 14

What are the muscles of the soft palate?

Answer 14

Question 15

Describe the difference between the anterior and posterior dorsum of the tongue.

Answer 15

• Anterior dorsum has papillae for taste sensation
• Posterior dorsum has no papillae but lymphoid tissue known as lingual tonsil

Question 16

What is the blood supply of the tongue?

Answer 16

external carotid → lingual a → deep lingual, sublingual

Question 17

What is the function of the Pterygoid plexus?

Answer 17

venous drainage to the fossa

Question 18

What divides the anterior and posterior divisions of the dorsal tongue?

Answer 18

-Dorsum is divided into anterior 2/3 and posterior 1/3 by the sulcus terminalis

Question 19

What are the 3 valves to keep food and air separate?

Answer 19

Question 20

What are the 4 parts of the mandible?

Answer 20

1) Condylar Process: head articulates with temporal fossa
2) Mandibular Notch: where masseteric nerve & vessels enter masseter M
3) Coronoid Process: masseter & temporal m attachment
4) Angle of Mandible: where ramus meets body; insertion for medial pterygoid m

Question 21

What is the infratemporal fossa?

Answer 21

Irregular space located deep to zygomatic arch and posterior to maxillary bone

Question 22

What is responsible for the motor nerve supply to the tongue?

Answer 22

• Motor: CN XII innervates all muscles
• Except palatoglossus (CNX)

Question 23

What are the 4 muscles of mastication?

Answer 23

• Temporalis
• Masseter
• Medial Pterygoid
• Lateral Pterygoid

Question 24

What are the 4 extrinsic muscles of the tongue?

Answer 24

• Genioglossus: protrudes the tongue
• Hypoglossus: retract and depresses tongue
• Styloglossus: retracts and elevates tongue
• Palatoglossus: elevate posterior tongue and provides structure for palatoglossal arch

Question 25

What is the point at which the mandible articulates with the cranium?

Answer 25

Temporomandibular joint ( TMJ)

Question 26

What is the function of the masseter?

Answer 26

-Masseter: powerful elevator of jaw, used for clenching/crushing on molars

Question 27

What is the tongue anchored to?

Answer 27

-Muscular organ with freely mobile body and base anchored to hyoid bone

Question 28

What are two important structures within the infratemporal fossa?

Answer 28

- Medial & lateral pterygoid muscles - Maxillary artery

Question 29

The medial neck of the mandible serves as?

Answer 29

-lateral pterygoid insertion

Question 30

What are the characteristics of a broken jaw?

Answer 30

- May occur in several places - 42% at mandibular angle/body - 35% at condylar process - Typically secured with arch bars attached to neck of teeth - Head of mandible generally **receives sufficient blood,** even if broken at neck

Question 31

What are the characteristics of mandibular tori?

Answer 31

- Bony protrusions from the medial wall of the mandible toward the oral cavity - Most common in males and Asians, affecting 7-10% of the population

Question 32

What makes up the TMJ?

Answer 32

-Synovial joint whose elements include: mandible, temporal bone, and articular disc

Question 33

What are some other important aspects of the uvula - pathologies.

Answer 33

Question 34

What is the origin and insertion of the masseter?

Answer 34

- Origin: Zygomatic arch - Insertion: Lateral angle of mandible

Question 35

What carries out the general sensory innervation of the tongue?

Answer 35

- Ant 2/3: lingual nerve from CNV3 (from trigeminal nerve) - Post 1/3: CN IX

Question 36

What are the characteristics of a Uvular deviation?

Answer 36

Question 37

What is the innervation of the 4 muscles of mastication?

Answer 37

Mandibular division of the trigeminal nerve

Question 38

What is the insertion of the medial pterygoid? Lateral?

Answer 38

Medial - Origin - Medial surface of lateral pterygoid plate Insertion - Medial surface of the mandible Lateral - Origin - Infratemporal crest for superior head, lateral pterygoid plate for inferior head Insertion - Neck of the mandible

Question 39

What are the most common locations of a mandibular fraction?

Answer 39

Question 40

What are the characteristics of the Articular Disc that sits in the TMJ?

Answer 40

- Compact, dense, fibrocartilaginous plate - Between the condylar process of the mandible and the articular surface of the temporal - Peripherally, fuses with the surrounding joint capsule

Question 41

Why shouldn't infants feed on their backs?

Answer 41

Question 42

What is sleep apnea and what can be some causes of it?

Answer 42

may be due to enlarged tonsils, dropped tongue or enlarged soft palate → blocking normal airflow

Question 43

What happens to the auditory tube when swallowing?

Answer 43

Question 44

What is the importance of the mandibular foramen?

Answer 44

-tunnel for inf alveolar nerve

Question 45

What is circular breathing?

Answer 45

Question 46

What is Gleeking?

Answer 46

sudden release of saliva from the submandibular ducts as the mylohyoid muscle contracts part of the gland against intrinsic muscles of the tongue

Question 47

What is the function of the soft palate?

Answer 47

valve to prevent food/fluid from entering nasal cavity

Question 48

Describe the contents of the vestibule.

Answer 48

- Parotid duct - Labial frenula: mucosa keeping lips attached to gingiva - Mucogingival Junction: scalloped line separating the alveolar from gingival mucosa * -Alveolar Mucosa: loose gingiva covering alveolar processes of maxilla * -Gingival Mucosa: attached keratinzied stratified epithelium

Question 49

What are the characteristics of the mandible?

Answer 49

single bone forming lower jaw; horizontal U-shaped body with two vertical rami– is joined from two sites of **intramembranous ossification.**

Question 50

What is responsible for the taste nerve supply to the tongue?

Answer 50

- Ant 2/3: CN VII via the chorda tympani - Post 1/3: CN IX

Question 51

What are the characteristics of an Inferior alveolar Nerve Block?

Answer 51

anesthetize teeth, near opening of mandibular foramen (feel for lingula)

Question 52

What is the innervation of the 4 extrinsic muscles of the tongue?

Answer 52

- CN XII: Genioglossus, hypoglossus, styloglossus - CN X: Palatoglossus

Question 53

What is the function of the temporalis?

Answer 53

-Temporalis: elevation and retraction of the jaw

Question 54

What is the function of the medial and lateral pterygoids?

Answer 54

- Medial Pterygoid: elevate jaw, assists with grinding motion - Lateral Pterygoid: has superior and inferior heads; opens and protrudes jaw