L22: Anatomy of oral cavity and pharynx

Question 1

What is the separation between the nasal and oral cavity?

Answer 1

Hard and soft palette

-tip of soft palette is the uvula

Question 2

What is the maximum amount of teeth we have?

Answer 2

32

• incisors
• canines
• premolars
• molars

Question 3

What is the vestibule?

Answer 3

The area between the teeth and the lips

Question 4

Where do you find the palatine tonsils?

Answer 4

Between the palatoglossal arch and the palatopharyngeal arch

Question 5

What is the fauces?

Answer 5

Opening to oropharynx

-connection b/w oral cavity and oropharynx

Question 6

What is the structure of the tongue?

Answer 6

Intrinsic muscles: (not attached to any other structures except other muscles in the intrinsic muscle group)

• 4 paired muscles (longitudinal, transverse, lateral)
• motor innervation: hypoglossal nerve

Extrinsic muscles: (arise from another structure and attach to intrinsic muscles)
-genioglossus
-hyoglossus
-styloglossus
(above are supplied by hypoglossal nerve)
-palatoglossus (supplied by vagus nerve)

Question 7

What is the sensory supply to the tongue?

Answer 7

Anterior 2/3

• sensation: trigeminal V3 lingual branch
• taste: facial nerve (chorda tympani)

Posterior 1/3
-sensation and taste: glossopharyngeal

Question 8

What are the main salivary glands?

Answer 8

• submandibular: produces most of the saliva, lies within the submandibular triangle (b/w mandible and the 2 bellies of the digastric muscle), empties into Wharton’s duct
• parotid: anterior to ear, in front of SCM and behind the masseter, underneath the zygomatic arch, duct opens via Stensen duct near upper 2nd molar
• sublingual: underneath the tongue, only produce 5% of saliva, lots of ducts

Question 9

What is sialolothiasis?

Answer 9

Salivary gland stones
-usually located in submandibular glands
-due to dehydration/reduced salivary flow
Symptoms: (eating stimulates)
-pain in gland
-swelling
-infection
Diagnose:
-history
-X-Ray
-sialogram (contrast dye injected into salivary gland and imaged)

Question 10

What is tonsilitis?

Answer 10

Inflammation of the palatine tonsils (central uvula)
-fever
-sore throat
-pain/difficulty swallowing
-cervical lymph node enlargement
-bad breath
(usually viral causes, some bacterial causes usually by Strep.pyogenes)

Question 11

What is a peritonsillar abcess?

Answer 11

Tissue around tonsil- deviates uvula from the swelling site
-severe throat pain
-fever
-bad breath
-drooling
-diffiulty opening mouth
(can follow on from untreated tonsilitis/arise on its won via aerobic/anaeobic bacteria)

Question 12

What are the different sections of the pharynx?

Answer 12

• nasopharynx
• oropharynx
• laryngopharynx

Question 13

Where do you find the nasopharynx?

Answer 13

-behind the nasal cavity, extends down to uvula level
Boundaries
-superior: base of skull to upper border of soft palate
-posterior: C1, C2
-anterior: nasal cavity

Contains the pharyngeal tonsil (adenoid)

Question 14

What happens when you get an enlarged adenoid?

Answer 14

• blocks entrance to eustachian tube causing recurrent/persistant middle ear infections
• snoring/sleep apnoea
• sleeping with mouth open
• nasal tone to voice
• chronic sinusitis

Question 15

Where do you find the oropharynx?

Answer 15

From tip of uvula to upper border of epiglottis when it is open

• anterior border: oral cavity
• posterior border: C2, C3

Contains palatine tonsils (between the arches, where the sections join)

Question 16

Where do you find the laryngopharynx?

Answer 16

Start at epiglottis to the cricoid cartilage

• posterior border: C4, C5, C6
• anterior border: larynx

Contains the piriform fossa

Question 17

What is the piriform fossa?

Answer 17

Epiglottis diverts the fluid/food down into the piriform fossa which then go into the oesophagus

Question 18

What muscles elevate the pharynx and larynx during swallowing?

Answer 18

3 longitudinal muscles
Stylopharyngeus
-originates from styloid process, and goes down to posterior border of thyroid cartilage
-supplied by glosspharyngeal nerve
Palatopharyngeus
-originates from hard palate and extends down to attach to the posterior border of the thyroid gland
-supplied by pharyngeal branch of the vagus nerve
Salpingopharyngeus
-originates from cartilaginous part of the eustachian tube and goes down and merge with palatopharyngeus
-suppplied by pharyngeal branch of the vagus nerve

Question 19

What are the pharyngeal constrictors?

Answer 19

3 circular muscles which constrict the walls of the phayrnx when swallowing

Superior pharyngeal constrictor:
-origin: pterygomandibular raphe
Middle pharyngeal constrictor:
-origin: hyoid bone 
Inferior pharyngeal constrictor:
Has 2 parts-
-thyropharyngeal (origin: thyroid cartilage)
-cricopharyngeal (origin: cricoid cartilage)

All insert into pharyngeal raphe (midline at the back)

All supplied by the vagus nerve

Question 20

What is the pharyngeal pouch?

Answer 20

Posteromedial outpouching of the mucosa/submucosa of the laryngopharynx

• arises between the 2 parts of the inferior constrictor
• due to anything that increases pressure around here

Present with:

• bad breath
• regurgitation of food
• choking on fluids
• difficulty swallowing

Question 21

What is the general nerve innervation of the pharynx?

Answer 21

Pharyngeal plexus- located mainly on the surface of the middle constrictor muscle (vagus, glossopharyngeal, cervical sympathetic nerves)

Question 22

What are the different phases of swalllowing?

Answer 22

Stage 1: oral

• voluntary
• prep phase: making bolus
• transit phase: bolus compressed against palate and pushed into oeopharynx by tongue and soft palate

Stage 2: pharyngeal

• involuntary
• tongue positioned against hard palate so food can’t reenter mouth
• soft palate elevated sealing off nasopharynx
• suprahyoid and longitudinal muscles shorten so pharynx widens and shortens and larynx elevates and is sealed off by vocal cords
• epiglottis closes over larynx
• bolus moves through pharynx by sequential contraction of constrictors
• relaxation of UOS

Stage 3: oesophageal

• involuntary
• upper stiated muscle of oesophagus and lower smooth muscle allows for rapid peristalsis
• LOS relaxes

Question 23

What is dysphagia?

Answer 23

Difficulty swallowing

Symptoms and signs:

• coughing and choking
• drooling (sialorrhoea)
• recurrent pneumonia (aspiration)
• change in voice/speech (wet speech as can’t clear secretions from cavity)
• nasal regurgitation

Question 24

How do you test for cranial nerve problems (IX and X)?

Answer 24

• absent gag
• uvula deviated from lesion
• dysphagia
• taste impairment (posterior tongue) (IX)
• loss of sensation in oropharynx (IX)

Question 25

What happens if you have lesion to cranial nerve XII?

Answer 25

Hypoglossal

• wasted tongue
• tongue may deviated when stuck out (damage to nerve, point to side of lesion)
• fasiculations (twitches)