Anatomy of the oral cavity- glands, tongue, swallowing

Question 1

Where does the oral cavity span from anteriorly–> posteriorly?

the oral cavity can be divided into 2 parts. what divides it and which 2 sections does this create?

Answer 1

anterior border of the oral cavity: oral fissure (opening between the lips)

posterior border of the oral cavity: oropharyngheal isthmus (opening of the oropharynx)

oral cavity is split into 2 parts divided by the upper and lower dental arches into the vestibule and mouth proper

Question 2

what is the vestibule of the mouth?

how does it communicate with the mouth proper?

the duct of which gland empties into the veticule behind upper molar 2?

Answer 2

• the vestibule of the mouth is the space between the lips/ cheeks and the gums/teeth
• communicates with mouth proper by gaps behind molar no*3
• duct of parotid gland empties out into the vesticule secreting salivary juices

Question 3

what are the broders of the mouth proper?

roof-

lateral walls-

floor-

Answer 3

roof- hard and soft palates

lateral walls- cheeks

floor- muscular diaphragm, geniohyoid muscles, tongue, salivary gland and duct

Question 4

Roof-

• what 2 structures make up the palate?
• what epithelium covers the hard palate?
• what is the soft palate made of/
• what is the function of the soft palate?

Answer 4

• the hard and soft palate

The hard palate

• the hard palate is found anteriorly and it seperates the oral and nasal cavities
• the hard palate is covered by respiratory mucosa (ciliated pseudostratified columnar epithelium) superiorly and by oral mucosa inferiorly (stratified squamous epithelium)

the soft palate

• continuation of the hard palate
• muscular structure
• acts as a valve to:
  
  • lower and therefore clsoe the oropharyngheal isthmus (this prevents the food bolus from entering the nasopharynx)
  • elevate and seperate the nasopharynx from oropharynx

Question 5

Cheeks- lateral wall

which msucle forms this?

what is the cheek lined by?

which nerve innervates the cheek?

Answer 5

buccinator muscle forms the wall

lined by oral mucosa (stratified squamous non-keritinsied)

innervated by buccal branches of the facial nerve

Question 6

What makes up the floor of the oral cavity

Answer 6

1. muscular diaphragm- comprised of bilateral mylohyoid muscles. this structure pulls the larynx forward during swallowing.
2. geniohyoid muscles- pulls larynx forward during swallowing
3. tongue- connected to the floor by the frenulum
4. salivary glands + ducts

Question 7

Sensory innervation of the oral cavity

largely via 2 nerves

• hard palate
• soft palate
• cavity floor
• tongue
• cheeks

Answer 7

1. hard palate- greater palatine nerve and nasopalatine nerve (both branches of the V2)
2. soft palate- lesser palatine nerve (branch of V2)
3. cavity floor- lingual nerve (branch of V3)
4. Tongue- special sensory fibres for taste via chorda tympani (branch of facial nerve)
5. Cheeks- buccal nerve (branch of facial nerve

Question 8

The tongue contains 8 muscles

how are they divided

Answer 8

by whether theyre intrinsic (4) or extrinsic (4)

Question 9

intrinsic tongue muscles

• what makes them intrinsic?
• name correlates to their direction of travel- what are their names?
• overall what do they do to the tongue?
• what does each do to the tongue?
• motor innervation to them is via?

Answer 9

intrinsic tongue muscles only attach to other tongue muscles

with all 4 of them, their name correlates to their direction of travel:

• superior longitudinal- shorten tongue
• vertical- shorten tongue
• transverse- flatten tongue
• inferior longitudinal- flatten tongue

The above is their layout within the tongue

overall thay change the shape+size of the tongue

motor innervation is via the hypoglossal nerve

Question 10

what are the 4 extrinsic tongue muscles

• where do they attach
• where do they insert
• what is their functions
• what is their innervation

Answer 10

Genioglossus

• function: inf fibres- protrude the tongue/// middle fibres- depress the tongue/// superior fibres- tip back and down
• innervation: motor via the hypoglossal nerve
• attach: mandibular symphysis and inserts: into the body of the hyoid bone

Hypoglossus

• function: depresses and retracts the tongue
• innervation- hypoglossal nerve
• attach: hyoid bone, inserts: side of the tongue

Styloglossus

function- retracts and elevates the tongue

innervation- hypoglossal nerve

attach: styloid process of the temporal bone insert: side of the tongue

Palatoglossus

function- elevates posterior part of the tongue closing the oropharyngeal isthmus

innervation- vagus nerve

attach-*** palatine aponeurosis ***insert- broadly across the tongue

Question 11

name the 4 muscles

Answer 11

yellow- geniohyoidus

blue- genioglossus

green- hyoglossus

purple- styloglossus

Question 12

innervation to the tongue

• general sensation anterior 2/3
• taste anterior 2/3
• general sensation posterior 1/3
• taste posterior 1/3

Question 13

• what is the arterial and venous supply to the tongue
• lymphatics of the anterior 2/3 and posterior 1/3

damage to the hypoglossal nerve

LMN lesion (damage to nerve itself)- curve towards the damaged side when protruding

(((((UMN lesion (damage to nerve pathway)- curve away due to action of genioglossus???)))))))

Answer 13

arterial supply to the tongue- lingual artery (majority) + tonsillar artery (both branches of ECA)

drainage- lingual vein

Question 14

The hard palate is composed of which 2 bony parts

hard palate contains (3) foramina/ canals

2 arches bind the soft palate:

what sits between these 2 arches

Answer 14

hard palate- palatine processes of the maxilla + horizontal plates of the palatine bones

1. incisive canal- transmits the nasopalatine nerve
2. greater palatine foramen- greater palatine nerve and vessels
3. lesser palatine foramina- lesser palatine nerve

palatoglossal arches anteriorly and the palatopharyngeal arches posteriorly

between these 2 arches sits the palatine tonsils

Question 15

5 muscles make up the soft palate

they are all innervated by? apart from x which is innervated by?

what are the 5 muscles that make up the soft palate and their functions and attachments

Answer 15

all innervated by the pharyngeal branch of the vagus nerve

apart from tensor veli palatini which is innervated by the medial pterygoid branch of V3

1) tensor veli palatini

• function: tenses soft palate
• attachments: origin- medial pterygoid plate of the sphenoid bone insertion: palatine aponeurosis

2) levator veli palatini

• function: elevation of the soft palate
• attachments: attach- petrous temporal bone + eustachian tube insert- palatine aponeurosis

3) palatoglossus

• function: pulls soft palate towards tongue
• atatchments: palatine aponeurosis. insert: side of the tongue

4) palatopharyngeus

• function: tenses the soft palate, drawing the pharynx anteriorly when swallowing
• attachments: poaterioer nasal spine and palatine aponeurosis to thyroid cartilage

5) muscularis uvulae

• function: shortens uvula
• attachments: post nasal spine and aponeurosis to the uvula

Question 16

innervation of the soft palate

general sensory- maxillary branch of the trigeminal

glands of the hard palate- greater palatine nerve

mucous membrane of the ant. hard palate- nasopalatine

soft palate- lesser palatine

Question 17

what is a cleft?

what is a cleft lip?

what is a cleft palate?

complications

Answer 17

a cleft refers to a gap/ split in the upper lip or the palate. it results from a defect during developemnt of the face and palate.

cleft lip- occurs when the medial nasal prominence and maxillary prominence fail to fuse.

celft palate- can occur in isolation when the palatal shelves fail to fuse in the midline, or in combination with cleft lip.

complications

• psychological and societal
• death if baby is unable to feed
• recurrent ear infections and speech impediment

Question 18

label the anatomy of the parotid gland

Answer 18

yellow- parotid gland

pink- zygomatic arch- superior border

light blue- sternocleidomastoid- posterior border

red- masseter

green- buccinator

Question 19

how many parotid glands are there

what kind of gland is it

what does it secrete

what is its anatomical structure

Answer 19

bilateral so 2 parotid glands

salivary gland

it secretes serous saliva

lobular and irregular morphology- deep and superficial lobe seperated by the fsacial nerve

Question 20

the parotid gland lies within the parotid region (deep hollow)

what are the boundaries of it?

• superior
• inferior
• anterior
• posterior

Answer 20

superior- zygomatic arch

inferior- inf border of the mandible

anterior- massester muscle

posterior- external ear and sternocleidomastoid

Question 21

what is the anatomical course of the parotid gland

Answer 21

1. secretion are via the Stenson duct
2. it arises on the anterior part of the gland
3. traverses the masseter muscle
4. moves medially
5. pierces buccinator
6. opens into the oral cavity near molar 2

Question 22

What are the anatomical relationships of the parotid gland?

why are they important to learn?

Answer 22

• facial nerve- gives rise to its 5 terminal branches in the parotid gland- facial expression
• External carotid artery- ascends within the parotid where it gives rise to the terminal branches: posterior auricalar, maxillary and superficial temporal arteries
• Retromandibular vein- formed here from the superficial temporal and maxillary veins

important as they can be severed during parotid gland surgery

Question 23

explain the

• arterial supply
• venous supply
• sensory innervation
• autonomic parasympathetic
• autonomic sympathetic

​of the parotid gland

Answer 23

• arterial supply- posterior auricular and superficial temporal bracnhes of the ECA
• venous supply- retromandibular vein
• sensory innervation - auriculotemporal nerve (gland) and the great auricular nerve (fascia)
• autonomic parasympathetic - glossopharyngeal nerve –> otic ganglion–> auriculotemporal nerve to parotid causing increase saliva secretion
• autonomic sympathetic- originates in the superior cervical ganglion (part of the paravertebral chain) –> fibres travel along the ECA–> parotid inhibiting secretion via vasocontriction

Question 24

Sublingual glands

• where are they found
• what kind of gland are they
• which nerves pass alongside the medial aspect
• how many sublingual glands are there? what is the name of the structure that they unite to form?

Answer 24

sublingual glands

• found in the sublingual fossa underneath the tongue, bordered by mylohyoid and masseter
• mostly mucous gland in nature
• submandibular and lingual nerves pass alongside the medial aspect of the glands
• there are 2 sublingual glands, they unite to form a horseshoe shape known as the the lingual frenulum

Question 25

What is the course of the sublingual gland? what is the anatomical variance in some people?

Answer 25

* secretions drain into the oral cavity by the minor sublingual ducts (of Rivinus), exits via the submandivular papilla * in some the secretions drain into a major sublingual duct (of Bartholi)

Question 26

sublingual ![]()

Question 27

what supplies x to the sublingual glands? * arterial * venous * parasympathetic * sympathetic

Answer 27

***_sublingual gland_*** * ***_arterial-_*** sublingual and submental arteries (both fed by the facial artery) * ***_venous_***- sublingual (ligual- Int. Jug.) + submental (facial- int. jug) * ***_parasympathetic_***- superior salivatory nucleus via chorda tympani--. chord tymp. unifies with the lingual branch of V3--\> synapse at submandibular ganglion--\> post synaptic innervation drives effect * ***_sympathetic_***- superior cervical ganglion--\> post synaptic vasoconstrictive fibres travel as plexus on the int. ext. carotid arteries --\> facial, submental and sublingual arteries

Question 28

submandibular glands * what do they secrete * located in which part of the submandibular triangle? what are the boundaries of the submandibular triangle? * made up of 2 arms, what determines which arm is which?

Answer 28

secrete a mix of serous and mucous saliva located in the anterior portion of the submandibular triangle boundaries of the submandibular triangle * superior- inf border of mandible * anterior- ant. belly of digastric * posterior- post belly of digastric made of 2 arms, differentiated by their relation to mylohyoid that they wrap around * **superficial arm**- sits in the submandibular fossa * **deep arm**- hooks around posterior aspect of mylohyoid

Question 29

what is the anatomical course of the submandibular gland

Answer 29

1. travels into the oral cavity via the submandibular duct (Wharton's duct) 2. emerges from the deep arm between mylohyoid, hypoglossus and genioglossus 3. duct enters into 1/3 orifices on a sublingual papilla bilaterally at the base of the lingual frenulum

Question 30

both the submandibular duct and gland share intimate relations with 3 nreves, what are they? explain these relations

Answer 30

submandibular duct and gland has intimate relations with: 1. lingual nerve 2. hypoglossal nerve 3. facial nerve ***_lingual nerve_***- begins at the submandibular duct, goes anteromedially to loop beneath the duct before branching, branches ascend over hypoglossus to provide somatic info to anterior 2/3 of the tongue ***_hypoglossal nerve_***- lies deep to the submandibular gland + runs superficial to hypoglossus + deep to digastric ***_facial nerve_*** (marginal mandibular branch)- exits anterior inferior part od the parotid gland at the nagle of the jaw and curves down inferior to the submandibular gland.

Question 31

what is the vasculature to the submandibular gland? ## Footnote arterial? venous? innervation? para and symp

Answer 31

***_submandibular gland_*** ***_arterial-_*** submental (facial) and sublingual (lingual) ***_venous-_*** facial (into IJV) + sublingual (lingual -\>IJV) ***_innervation_*** para 1. presynaptic fibres via the chorda tympani 2. superior salivatory nucleus 3. chorda tymp unifies with the lingual branch of the mandibular nerve 4. syanpse at the submandibular ganglion symp superior cervical ganglion postsynaptic vasoconstrctive firbes travel down branches of the ECA (facial, sublingual and submental)

Question 32

The pshyiology of swallowing can be split into 3 distinct sections. name and explain them.

Answer 32

1. ***_Voluntary phase_*** 1. ​mastication leads to a bolus of food being produced 2. back of tongue elevates 3. soft palate pulled anteriorly against it (keeps food in cavity allowing airway to be open) 4. inspiration inhibited 5. bolus moved to pharynx by tongue 6. stimulation of swallowing reflex 2. ***_Pharyngeal phase_*** 1. ​bolus moved to pharynx 2. pressure receptors activated in the palate and anterior pharynx 3. signals the swallowing centre which: 1. inhibits respiration 2. raises the larynx (helps block off access to the trachea?) 3. closes the glottis (prevents bolus entering resp system) 4. opens the upper oesophageal sphincter 4. soft palate raises to clsoe the nasopharynx, allowing the passage of food 5. true vocal cords close to prevent aspiration 6. bolus moved to the oesophagus via peristalsis and pharyngeal constrictor muscles 3. ***_Oesophageal phase_*** ​upper 1/3 of oesophagus is voluntary skeletal muscle and the lower 2/3 is involuntary smooth 1. larynx lowers returning to its normal position 2. cricopharyngeus contracts to prevent reflux+respiration begins