9. oral cavity and tongue (lecture)

Question 1

What are the boundaries of the oral cavity?

Answer 1

roof: hard and soft palate
floor: tongue
lateral + medial: cheeks
posterior: oropharyngeal isthmus
anterior: oral fissure (anterior to teeth, aperture)

Question 2

what is the oral vestibule?

Answer 2

space between teeth and cheeks / lips

anything within the mouth anterior to the teeth

Question 3

what is the oral cavity proper?

Answer 3

from teeth to the ring made by palatopharyngeal arch, uvula, tip of epiglottis

Question 4

what are the anterior and posterior arches of the oral cavity?

Answer 4

anterior: palatoglossal arch (palate (roof) to tongue)
posterior: palatopharyngeal arch (palate to oropharynx)
(formed by the palatoglossus (anterior) and palatopharyngeus muscles)

Question 5

what forms the hard palate?

Answer 5

maxilla and palatine bones

palatine is a continuation of the maxilla bone posteriorly

Question 6

what is the soft palate?

Answer 6

muscular (valve)

Question 7

function of the soft palate?

Answer 7

tense and elevate the soft palate during swallowing (pass food down oesophagus) - so soft palate is not in the way

Question 8

what innervates the muscles of the soft palate?

Answer 8

predominantly vagus nerve (pharyngeal branch) CN X

Question 9

what happens when the pharyngeal branch of the vagus nerve is damaged?

Answer 9

innervates soft palate
so stronger side is UNopposed (towards unaffected side)
uvula TOWARDS UNaffected side

Question 10

function of the gag reflex?

Answer 10

to prevent choking

Question 11

when is the gag reflex examined?

Answer 11

as part of the cranial nerve examination

important for assessing brainstem function

Question 12

what is the afferent limb of the gag reflex?

Answer 12

glossopharyngeal nerve (CN IX, 9)
back of tongue / throat, uvula, tonsillar area (sense)

Question 13

what is the efferent limb of the gag reflex?

Answer 13

VAGUS nerve (CN X)
pharyngeal muscles of soft palate (push down action)

Question 14

name the teeth from the front back

Answer 14

central incisor, lateral incisor,
canine,
first premolar, second premolar,
first molar, second molar, third molar

Question 15

what is the sensory supply to the lower jaw?

Answer 15

lower jaw + lower lip (mandibular prominence embryology)

inferior alveolar nerve (branch of V3)

Question 16

how can the inferior alveolar nerve (V3) be damaged?

Answer 16

can lose sensation during mandibular fracture

site of anaesthesia use in dental surgery

Question 17

what are the extrinsic muscles of the tongue?

Answer 17

genioglossus
hyoglossus
styloglossus
palatoglossus

Question 18

function of the extrinsic muscles of the tongue?

Answer 18

helps anchor the tongue (to hyoid bone and mandible)

allows the tongue to change position

Question 19

what are the intrinsic muscles of the tongue?

Answer 19

superior and inferior longitudinal
vertical
transverse
(both sides separated by septum)

Question 20

function of intrinsic muscles of the tongue?

Answer 20

help tongue to change shape

action based on the direction fibres run

Question 21

innervation to muscles of the tongue?

Answer 21

all muscles hypoglossal nerve (CN XII)

APART from palatoglossus (CN X)

Question 22

general and special sensory innervation to the anterior 2/3rd of the tongue?

Answer 22

general: lingual nerve (CN V3)

special sensation: chorda tympani (CN VII) - petrous temporal bone, then middle ear to tongue

Question 23

general and special sensory innervation to the posterior 1/3rd of the tongue?

Answer 23

glossopharyngeal nerve (CN IX) 9

Question 24

what innervates the larynx?

Answer 24

internal laryngeal nerve (branch of vagus, CN X)

Question 25

which side does the uvula deviate towards?

Answer 25

UNaffected side

Question 26

which side does the tongue deviate towards?

Answer 26

Affected side