L22: Anatomy of oral cavity and pharynx Flashcards
What is the separation between the nasal and oral cavity?
Hard and soft palette
-tip of soft palette is the uvula
What is the maximum amount of teeth we have?
32
- incisors
- canines
- premolars
- molars
What is the vestibule?
The area between the teeth and the lips
Where do you find the palatine tonsils?
Between the palatoglossal arch and the palatopharyngeal arch
What is the fauces?
Opening to oropharynx
-connection b/w oral cavity and oropharynx
What is the structure of the tongue?
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)
What is the sensory supply to the tongue?
Anterior 2/3
- sensation: trigeminal V3 lingual branch
- taste: facial nerve (chorda tympani)
Posterior 1/3
-sensation and taste: glossopharyngeal
What are the main salivary glands?
- 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
What is sialolothiasis?
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)
What is tonsilitis?
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)
What is a peritonsillar abcess?
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)
What are the different sections of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
Where do you find the nasopharynx?
-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)
What happens when you get an enlarged adenoid?
- blocks entrance to eustachian tube causing recurrent/persistant middle ear infections
- snoring/sleep apnoea
- sleeping with mouth open
- nasal tone to voice
- chronic sinusitis
Where do you find the oropharynx?
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)
Where do you find the laryngopharynx?
Start at epiglottis to the cricoid cartilage
- posterior border: C4, C5, C6
- anterior border: larynx
Contains the piriform fossa
What is the piriform fossa?
Epiglottis diverts the fluid/food down into the piriform fossa which then go into the oesophagus
What muscles elevate the pharynx and larynx during swallowing?
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
What are the pharyngeal constrictors?
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
What is the pharyngeal pouch?
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
What is the general nerve innervation of the pharynx?
Pharyngeal plexus- located mainly on the surface of the middle constrictor muscle (vagus, glossopharyngeal, cervical sympathetic nerves)
What are the different phases of swalllowing?
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
What is dysphagia?
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
How do you test for cranial nerve problems (IX and X)?
- absent gag
- uvula deviated from lesion
- dysphagia
- taste impairment (posterior tongue) (IX)
- loss of sensation in oropharynx (IX)
What happens if you have lesion to cranial nerve XII?
Hypoglossal
- wasted tongue
- tongue may deviated when stuck out (damage to nerve, point to side of lesion)
- fasiculations (twitches)
