Lecture 28: Oral Cavity

Question 1

What bones form the roof and floor of the oral cavity?

Answer 1

Roof - maxilla

Floor - mandible

Question 2

What does the mandible articulate with?

Answer 2

The temporal bone at condylar region of mandible - temporomandibular joint

Question 3

What are the features of the temporomandibular joint?

Answer 3

Sliding hinge joint that allows chewing

Question 4

What muscles help in chewing?

Answer 4

Masseter and temporalis

Question 5

What are the features of orbicularis oris?

Answer 5

Muscle that goes around the lips - brings lips together

Question 6

What are the features of buccinator?

Answer 6

Embedded in the cheek and closes off the space between the mandible and maxilla to form the lateral wall of the oral cavity

Question 7

Where does the temporals tendon attach and what happens when it contracts?

Answer 7

Temporalis tendon attaches to coronoid process. When temporalis contracts it pulls condyloid process and elevate mandible when chewing

Question 8

What bones form the roof of the mouth/hard palate?

Answer 8

Maxilla, palatine and horizontal process of palatine

Question 9

Where is the soft palate?

Answer 9

Connective tissue and muscle suspended from posterior end of hard palate

Question 10

What is deep to the mucosa lining the mouth?

Answer 10

Palatine glands

Question 11

Where do the lesser palatine vessels go?

Answer 11

Posterior to soft palate

Question 12

Where do the greater palatine vessels go?

Answer 12

Along hard palate

Question 13

Where is the mandible deficient and what fills this?

Answer 13

Inferiorly, mylohyoid muscle

Question 14

Where does the inferior alveolar nerve enter the mandible?

Answer 14

Mandibular foramen on medial aspect of mandibular foramen

Question 15

Where does the hyoid bone sit?

Answer 15

Crease between floor of mouth and neck

Question 16

What is the oral vestibule?

Answer 16

Space lateral to dental arches where mucosa projects upwards - space to store food

Question 17

What is significant about the vessels in the mucosa in the floor of the mouth?

Answer 17

Important for rapid absorption of drugs

Question 18

Why will there be profuse bleeding and nerve damage if the floor of the mouth is injured?

Answer 18

Lingual nerve, submandibular duct and hypoglossal nerve present here

Question 19

How is the tongue split?

Answer 19

Tongue is split into anterior 2/3 and posterior 1/3 by v-shaped groove (sulcus terminalis) - apex of the v is directed posteriorly (towards back of oral cavity) - classic landmark for sensory nerve supply

Question 20

What is the depression at the apex of sulcus terminalis and what is it remnant of?

Answer 20

Foramen caecum - remnant of thyroglossal duct in development

Question 21

What is present between the palatoglossal and palatopharyngeal arches?

Answer 21

Palatine tonsils

Question 22

Where are the papillae on the tongue?

Answer 22

Valate papillae are anterior to sulcus terminalis in a row, foliate papillae are grooves on lateral sides of tongue, fungiform papillae over rest of mucosa of tongue - scattered all over anterior 2/3 of the tongue

Question 23

Why are papillae important?

Answer 23

Papillae are important because the tastebuds are imbedded in the walls of the papillae. Tastebuds are connected to sensory nerves that run in the chordae tympani (branch of 7th cranial nerve - info about taste from tongue to CNS)

Question 24

What papillae doesn’t have tastebuds?

Answer 24

Filiform

Question 25

Why are filiform papillae important?

Answer 25

Rough, allow tongue to grip food

Question 26

What innervates extrinsic tongue muscles and what do they do?

Answer 26

Alter position of tongue, CNXII (except for palatoglossus – pharyngeal branch of CNX)

Question 27

What are the extrinsic tongue muscles?

Answer 27

- Palatoglossus - from palate towards tongue - elevate - Styloglossus - styloid process to posterior tongue (more horizontal) - retract - Hyoglossus - hyoid to tongue – depress - Genioglossus - mid mandible to back end of tongue - protract

Question 28

What nerve innervates the intrinsic tongue muscles, what are they and what do they do?

Answer 28

Alter shape of tongue, CNXII | Superior and inferior longitudinal, transverse and vertical

Question 29

What is the sensory innervation for the tongue?

Answer 29

Posterior 1/3 innervated by glossopharyngeal (taste and general sensory) Anterior 2/3 innervated by lingual nerves (general) and chorda tympani (CNVII) (special)

Question 30

How many adult teeth?

Answer 30

32

Question 31

What are the number of teeth and their type and features?

Answer 31

* 2 incisors – central and lateral, sharp flat edges for biting * 1 canine – sharp pointy edge for anchoring onto food * 2 premolars and 3 molars – flat cusps important for grinding

Question 32

What is the nerve innervation for the upper teeth?

Answer 32

Upper teeth innervated by superior alveolar nerve (branch of V2 trigeminal – maxillary)

Question 33

What is the nerve innervation for the lower teeth?

Answer 33

Lower teeth innervated by inferior alveolar nerve (branch of V3 trigeminal – mandibular) - access into mandible via mandibular foramen on medial side of ramus

Question 34

What is the structure of the tooth?

Answer 34

Outer enamel later (protective) and inner core of pulp - significant neurovascular supply - through bone and roots into pulp

Question 35

What is dentin?

Answer 35

Layer between enamel and pull - little tubules to transmit fluid, temp or electrical energy

Question 36

What is a toothache?

Answer 36

Activation of highly sensitive pulp

Question 37

What is the vascular supply to the teeth?

Answer 37

Branches of external carotid artery

Question 38

When do the teeth erupt, and how do they normally erupt?

Answer 38

Teeth erupt from about 6/7 years of age, usually anterior to posterior

Question 39

What are the exceptions to normal teeth eruption?

Answer 39

Lower canine and upper canine erupt a bit later and out of sequence, first molar erupts very early

Question 40

What are the features of the parotid salivary glands?

Answer 40

Anterior to external auditory meatus, superficial to masseter and ramus of mandible - has a single duct emerging from anterior aspect that runs over masseter and opens in oral vestibule opposite 2nd molar tooth

Question 41

What are the features of the sublingual salivary glands?

Answer 41

In floor of mouth on either side of tongue under mucosa - opens via multiple ducts into mucosa on floor of mouth

Question 42

What are the features of the submandibular salivary glands?

Answer 42

Sits on both sides of posterior oral cavity, wraps around posterior edge of diaphragm muscle (mylohyoid) - bit inside and bit outside oral cavity - duct projects all the way forward and opens via small papilla lateral to lingual frenulum