9.2 Oral Cavity, Tongue, Pharynx Flashcards
What forms the lateral walls of the oral cavity?
Buccinators
What forms the roof of the oral cavity?
Hard and soft palate
What forms the floor of the oral cavity?
2 mylohyoid muscles
Tongue
Other soft tissues
Where does the oral cavity begin and end?
Begins anteriorly at oral fissure
Ends posteriorly at the oropharyngeal isthmus
What forms the sides of the oropharyngeal isthmus?
Anterior and posterior pillars of fauces
What forms the anterior and posterior pillars of the fauces?
Anterior = palatoglossus muscles Posterior = palatopharyngeal muscles
What is the function of the pillars of fauces?
Contraction during chewing pulls soft palate down towards tongue
Closes oropharyngeal isthmus to keep food in the oral cavity whilst chewing
What lies between the anterior and posterior pillars of fauces?
The palantine tonsil within the tonsillar fossa
When is the palantine tonsil visible?
Tonsillitis
How is the oral cavity important to the function of the GI tract?
Entry of food
Mastication to produce bolus
Lubrication and partial digestion of food by saliva
What is sialolithiasis?
Salivary duct stones. Causes pain and swelling of the salivary gland affected. Swelling and pain can fluctuate in relation to eating
What gland is most commonly affected in sialolithiasis?
Submandibular gland
What epithelium covers the tongue?
Squamous epithelium
How many muscles make up the tongue?
8
4 intrinsic
4 extrinsic
What is the attachment site of the intrinsic muscles of the tongue?
The extrinsic muscles of the tongue
What are the 4 extrinsic muscles of the tongue?
Palatoglossus
Hyoglossus
Styloglossus
Genioglossus
What structures anchor the tongue?
Hyoid bone and mandible below
Styloid process and soft palate above
How do we test the function of CN XII?
Hypoglossal nerve tested by testing action of genioglossus muscles. Done by protruding tongue in the midline. Derivation of the tongue from the midline of protrusion indicates weak or paralysed genioglossus muscle
What muscle of the tongue is not innervated by CN XII?
Palatoglossus - forms part of the soft palate and tongue, innervated by the vagus nerve CN X
Why does the tongue receive afferent innervation from a number of cranial nerves?
As tongue derived from a number of pharyngeal arches during embryonic development
What nerve carries general sensation from the anterior 2/3rds of the tongue?
Lingual nerve - branch of the mandibular division of the trigeminal nerve
What nerve supplies the special sensory innervation of the anterior 2/3rds of the tongue?
Chorda tympani - branch of the facial nerve CN VII
The parasympathetics to the sublingual and submandibular glands run with what nerves?
The lingual (CN V) and the chorda tympani (CNVII)
What nerve provide special sensory and general sensory innervation to the posterior 1/3rd of the tongue?
Glossopharyngeal nerve (CN IX)
What nerve provides parasympathetics to the parotid gland?
Glossopharyngeal nerve (CN IX)
How is CN X tested?
Vagus nerve tested by asking patient to open their mouth and say ‘Ahhh’
Uvula inspected for deviation to any one side, indicates weakness of the contralateral soft palate.
What cranial nerves does the gag reflex test?
CN X - vagus (efferent)
CN IX - glossopharyngeal (afferent)
What muscle protrudes the tongue?
Genioglossus
What is the pharynx?
A muscular tube that originates at the base of the skull and extends inferiorly to level C6 where it continues as the oesophagus
What are the 3 divisions of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
What covers the posterior wall of the pharynx?
Buccopharyngeal fascia, lies next to the prevertebral layer of the deep cervical fascia
Where is the nasopharynx?
Behind the nasal cavity, above the soft palate.
C1 vertebrae lies posteriorly
What is found in the nasopharynx?
Opening of the posterior nasal apertures
Orifice of the pharyngotympanic tube
Pharyngeal tonsils/adenoids
Where is the location of the oropharynx?
Beneath the soft palate to the superior border of the epiglottis.
Vertebral bodies C2 and C3 lie posteriorly
What structures lie in the oropharynx?
Palatine tonsils
Where is the laryngopharynx?
From the epiglottis to the inferior border of the cricoid cartilage. Behind the larynx. Vertebral bodies C4 C5 and C6 lie posteriorly.
What is the piriform fossa?
A small depression in the laryngopharynx on each side of the laryngeal inlet
What forms the walls of the pharynx?
Circular superior, middle and inferior constrictors
What nerve innervated the circular constrictors of the pharynx?
CN X
What is the pharyngeal raphe?
Common midline tendinous insertion of the circular muscles of the pharynx
Describe the structure of the inferior constrictor of the pharynx
two muscles bellies, thyropharyngeus and cricopharyngeus
What is Killians dehiscence?
Small area of weakness between the two bellies of the inferior constrictor muscle of the phraynx ( thyropharyngeus and cricopharyngeus)
Herniation of the oesophagus can happen here forming a pharyngeal pouch (diverticulum)
What are the symptoms of a pharyngeal pouch?
Trapped food
Dysphagia
Regurgitation of food
Lump in the neck
What are the internal muscles of the pharynx? What are their actions?
3 longitudinal internal muscles
Contract to shorten and widen the pharynx + Lift up the larynx during speaking and swallowing.
What is the voluntary phase of swallowing?
Food bolus transferred to back of oral cavity towards the oropharynx by movements of the tongue
What is the involuntary phase of swallowing?
- elevation of the soft palate
- closing off the nasopharynx from the oropharynx
- Contraction of the suprahyoid muscles and the longitudinal pharyngeal muscles also act to elevate the larynx
- automatic, sequential contraction of the three pharyngeal constrictor muscles forcing food/fluid into the oesophagus
What nerves contribute to the pharyngeal plexus of nerves?
Vagus
Glossopharyngeal
Sympathetic branches from superior cervical ganglion
What muscle of the pharynx and soft palate isnt supplied by the vagus nerve?
Stylopharyngeus - CN IX
Describe the special sensory innervation of the pharynx
The nasopharynx-the maxillary branch of the trigeminal (CN Vb)
The oropharynx (and pharyngotympanic tube…even though this is found in the nasopharynx!) - the glossopharyngeal nerve (CN IX)
The laryngopharynx- the vagus nerve (CN X).
What structures can cause non-otological Otalgia?
Nose and sinuses (V) Oesophagus (X) Cervical spine (C2 and C3) Larynx and hypopharynx (X) Oropharynx (IX) Tongue (V) Temporomandibular joint, parotid, teeth (V)
What is Waldeyer’s ring?
A lymphoid ring around the nasopharynx and oropharynx.
What structures form Waldeyer’s ring?
Nasopharyngeal tonsils
Palatine tonsils
Lingual tonsils
What happens to the nasopharyngeal tonsils after puberty?
Undergo atrophy
What is adenoiditis?
When the nasopharyngeal tonsils are chronically inflammed
What complications can adenoiditis cause?
1) obstruct passage of air through choanae into nasopharynx causing mouth breathing and nasal tone in speech
2) block the exit of the pharyngotympanic tube causing middle ear infections (acute otitis media/ otitis media with effusion)
Why is it common for upper respiratory tract infections to cause middle ear infections?
The pharyngotympanic tube also provides a potential route for infection in the pharynx to spread to the middle ear
What is a tonsillectomy?
Removal of the palatine tonsils due to recurrent inflammation
What is a common complication of tonsillectomy?
profuse bleeding from the rich blood supply to the tonsil (arterial blood supply is via the tonsillar branch of the facial artery).
What pathologies are associated with the piriform fossa?
- potential site for foreign bodies (e.g. fishbone, chicken bone, etc.) entering the pharynx to become lodged
- Pharyngeal cancers (can grow large without causing obvious symptoms
What separates the nasal cavity and the oral cavity?
Soft and half palate
What is the uvula?
The tip of the soft palate
How many teeth do adults have?
32
What are the different kinds of teeth?
Central incisor Lateral incisor Canine 1st and 2nd premolars 1st 2nd and 3rd molars
What is the vestibule of the oral cavity?
The area between the teeth and lips
Which salivary gland produces the majority of saliva?
Subamndibular (60%)
Where is the submandibular gland located?
In the submandibular triangle / digastric triangle
Under mandible between the anterior and posterior bellies of the digastric muscle
Where do the submandibular glands exit into the mouth?
Wharton’s ducts
2 paired ducts on either side of the lingual frenulum on the undersurface of the tongue.
Where does the parotid gland sit?
Sits anterior to the ear and SCM
Behind the masseter
Where does the parotid gland open into the oral cavity?
Stensen duct near upper 2nd molar
Where is the salivary gland located?
Underneath the tongue
How does the sublingual gland drain into the oral cavity?
8-20 excretory glands per duct
Located under the tongue
Where are most sialolithiasis?
Submandibular glands
When are symptoms of sialolithiasis worsened?
Before eating/when salivating
How do we diagnose sialolithiasis?
History
X-ray
Sialogram
What is a sialogram?
When contrast dye injected into salivary gland and then imaged
What are symptoms of tonsillitis?
Fever • Sore throat • Pain/difficulty swallowing /dysphagia • Cervical lymph nodes • Bad breath
What are the most common causes of tonsillitis?
Viral
Bacterial (40%) - strep pyogenes (indicated by white/yellow patches )
What is a peritonsillar abscess?
Swelling of tissue around the tonsil (quinsy).
If unilateral causes deviation of the uvula
How do patients with peritonsillar abscesses present?
Severe throat pain • Fever • Bad breath • Drooling • Difficulty opening mouth
What causes peritonsillar abcsess?
Ca follow from untreated/ partially treated tonsillitis
Can arise on its own (aerobic/anaerobic)
What does the larynx consist of?
Vocal folds
Thyroid cartilage
Cricoid cartilage
What are the 3 longitudinal muscles that elevate the pharynx and larynx during swallowing?
Stylopharyngeus
Palatopharyngeus
Salpingopharyngeus
Describe the attachment and innervation of Stylopharyngeus
- Styloid process- posterior border of thyroid cartilage
* Glossopharyngeal nerve (CN IX)
Describe the attachment and innervation of the palatopharyngeus
- Hard palate- posterior border of thyroid cartilage
* Pharyngeal branch of vagus (CN X)
Describe the attachment and innervation of salpingopharyngeus
- Cartilaginous part of ET- merges with palatopharyngeus
* Pharyngeal branch of vagus (CN X)
Where does the the superior pharyngeal contractor originate?
Pterygomandibular raphe
Where does the middle pharyngeal constrictor originate?
Hyoid bone
What is a pharyngeal pouch?
Posteromedial outpouching of the mucosa and submucosa of the laryngopharynx in Killian’s dehiscence
What causes a pharyngeal pouch?
- Failure of the UOS to relax
- Abnormal timing of swallowing
- Essentially there is a higher pressure in laryngopharynx
- Weakness in Inferior constrictor muscle produces outpouching
How can we image pharyngeal pouch?
Barium swallow.
What can cause dysphagia?
Neurological (fluids hard to swallow
Mechanical (solids hard to swallow)
What are the signs and symptoms of dysphagia?
- Coughing & choking
- Sialorrhoea (drooling)
- Recurrent pneumonia (aspiration of food into respiratory tract)
- Change in voice/speech (wet voice)
- Nasal regurgitation
How might CN IX and CN X be injured?
Medullary infarct
Jugular foremen issue (foramen)
What are the signs of hypoglossal nerve lesion?
Wasted tongue • Stick tongue out- tongue may deviate • Damage to nerve itself (LMN) -point to side of lesion • Muscle wasting • Fasiculations
What are Fasiculations?
Involuntary muscular contractions that is more intense than fibrilllation