2 Pharynx Flashcards
What does the pharynx lie posterior to?
- Nasal cavity (nasopharynx)
- Oral cavity (oropharynx) - common pathway for air and food + fluid
- Larynx (laryngopharynx)
What does nasopharynx transport and how is it divided from oropharynx?
- Transports air
* Soft palate divides nasopharynx from oropharynx
What does oropharynx transport?
Transports air plus flood + fluid
Must be separated:
• Air –> larynx
• Food + fluid –> laryngopharynx
Where does auditory tube open into?
Nasopharynx
Name the 3 folds/arches raised by the longitudinal muscles that elevate the pharynx and larynx
- Palatoglossal fold (margin of oropharyngeal isthmus)
- Salpingopharyngeal fold
- Palatopharyngeal arch (overlies palatopharyngeus muscle)
What is the piriform fossa between?
- Quadrangular membrane of larynx
* Side wall of pharynx
What is the laryngeal inlet between?
Aryepiglottic folds
Where are foreign bodies like fish bones easily stuck in?
Piriform fossa
What holds the nasopharynx open?
Pharyngobasilar fascia
What is the function of the 3 pharyngeal constrictors (superior, middle and inferior)?
Squeeze bolus towards oesophagus
What is the function of elevators?
Lift pharynx and receive bolus
What does simultaneous laryngeal elevation do?
For closure and airway protection during swallowing
What are the 4 points of pharyngeal attachment (base of skull)?
- Medial pterygoid plate of sphenoid
- Pharyngobasilar fascia attaches to the cartilage of the auditory tube
- Levator Palati arises from the apex of the petrous temporal bone, inside is the pharyngeal attachment
- Pharyngobasilar fascia, and the posterior midline pharyngeal raphe formed by the constrictors attach to the pharyngeal tubercle
Attachments of stylohyoid ligament
Lesser horn to suspend the hyoid (therefore pharynx and larynx) from the styloid process of the skull
Attachment of pharyngobasilar fascia?
Medial pterygoid plate (posterior nasal china) internal to the attachment of the superior pharyngeal constrictor
What does superior pharyngeal constrictor continue and form?
Form pterygomandibular raphe with the buccinator - continuity between oral cavity and pharynx
Attachments of middle pharyngeal constrictor?
- Hyoid bone (greater and lesser horns)
2. Stylohyoid ligament
Attachments of inferior pharyngeal constrictor?
- Oblique line of thyroid cartilage (thyropharyngeus)
- Cricoid cartilage
- Fascia on cricothyroid
Nerves and vessels pierce … membrane in pharynx
Thyrohyoid membrane
Function of palatopharyngeal sphincter?
Separates the nasopharynx from oropharynx during swallowing
What structures enter the oral cavity, pharynx and larynx through potential spaces/ “gaps”?
- Internal branch of superior laryngeal nerve with superior laryngeal vessels
- Recurrent laryngeal nerve with inferior laryngeal vessels
What does the glossopharyngeal cranial nerve (IX) supply?
- Stylopharyngeus
2. Sends a branch deep to hyoglossus (doesn’t supply it) to reach posterior 1/3 of tongue and oropharynx
What 2 nerves and duct enter between mylohyoid and hyoglossus in the pharynx?
- Lingual nerve (V3)
- Hypoglossal cranial nerve (XII)
- Submandibular duct
What does the internal branch of superior laryngeal nerve supply?
Sensation to larynx above vocal folds
Whats does the external branch of superior laryngeal nerve supply?
Cricothyroid muscle
What does the recurrent laryngeal nerve pass deeply to and supply?
Passing deeply to inferior pharyngeal constrictor to reach larynx
What is the nerve supply of pharyngeal constrictors?
Pharyngeal branch of vagus cranial nerve (X) via pharyngeal plexus
What is the function of pharyngeal constrictors?
When contracting sequentially there force a food bolus downwards to oesophagus
What is the lower circular part in inferior pharyngeal constrictor called? Function?
Cricopharyngeus
-forms a sphincter around upper oesophagus to prevent air being drawn into the stomach during inhalation
What may uncoordinated contraction of cricopharyngeus result in?
Excessively raise pressure in pharynx
Palatopharyngeal sphincter or Passavant’s muscle (ridge)
• Coincides with?
• Derived from?
• Function?
- Coincides with inferior edge of pharyngobasilar fascia
- Muscular ring derived from superior pharyngeal constrictor or the palatopharyngeus
- Provides a “socket” into which the soft palate can move into when it’s tensed and elevated during swallowing
At which point does the superior constrictor layer end?
What is it’s importance?
- Just above cricopharyngeal sphincter (which leaves only 2 layers, the middle and inferior constrictor)
- Allows a potential weakness (the dehiscence of Killian) through which a pharyngeal diverticulum may occur, particularly in cricopharyngeal uncoordination
What are the points of insertion of the pharyngeal elevators?
Importance?
• From skull to fan out into the inner surface of pharynx
• May send some fibres to the thyroid cartilage as well
- Ensures simultaneous elevation of pharynx and larynx
Name the pharyngeal elevators?
- Palatopharyngeus
- Stylopharyngeus
- Salpingopharyngeus
Palatopharyngeus:
• Function?
• Nerve supply?
- Elevates the pharynx & larynx
- Draws the soft palate downwards & brings the palatopharyngeal arch towards the midline to help palatoglossus (pillars of the fauces) separate the oral cavity from the pharynx
• Supplied by vagus cranial nerve (X)
Stylophayngeus:
• Attachments?
• Nerve supply?
- Descends from styloid process to pass between the superior & middle pharyngeal constrictors & fan into the internal pharyngeal surface
- Only pharyngeal muscle supplied by glossopharyngeal cranial nerve (IX)
Salpingopharyngeus:
• Attachment?
• Function?
• Nerve supply?
• Descends into pharynx from cartilage of auditory tube
- Elevator of pharynx and larynx
- Helps to open the auditory tube during swallowing for pressure equalisation in the middle ear
• Supplied by vagus cranial nerve (X)
Nervous supply of palatine tonsil (referred pain)?
- Via glossopharyngeal cranial nerve (IX)
* Referred pain to middle ear
What are tonsils?
Clusters of lymphocytes around an invagination of overlying epithelium (crypts)
What tonsils make up Waldeyer’s ring?
- Palatine (x2) - between palatoglossal and palatopharygneal arches
- Lingual - posterior 1/3 of tongue
- Pharyngeal (adenoid) - roof of nasopharynx
- Tubal (x2) - opening of auditory tube
The bed of which tonsils are highly vascular and bleeding may be a problem during surgical removal?
Palatine tonsils
Swelling of which two tonsils may cause obstruction of the airway and auditory tube?
Causing?
- Swelling of pharyngeal and tubule tonsils
* Causing mouth breathing and middle ear infection
What is the vallecula?
- Pit or fossa between tongue and epiglottis
* Waiting for foreign bodies
Where is the pharyngeal recess?
Behind auditory tube
A catheter intended for the auditory tube may miss and enter _____? What happens if the pharynx is pierced?
- Pharyngeal recess
* If pharynx pierced, catheter could enter internal carotid artery
What is the main arterial supply to palatine tonsil?
Tonsillar branch of facial artery
Arterial supply of the upper and lower pharynx?
- Upper pharynx - branches of external carotid artery
* Lower pharynx - branches of inferior thyroid branch of thyrocervical from subclavian artery
Venous drainage of the pharynx?
Pterygoid plexus but essentially converges on:
- Facial vein
- Internal jugular vein
Lymph drainage of pharynx?
• Retropharyngeal
• Paratracheal
• Infrahyoid nodes
—> Essentially converges on the deep cervical nodes
• Palatine tonsils drain –> jugulodigastric
Which part of the pharynx receives their sensory supply by maxillary (V2) division of trigeminal cranial nerve (V)?
Nasopharynx
Which part of the pharynx receives their sensory supply by Glossopharyngeal cranial nerve (IX)? Referred pain?
- Oropharynx
- Palatine tonsil
- Inferior aspect of soft palate • Posterior 1/3 tongue
• Referred pain to middle ear
Which part of the pharynx receives their sensory supply by Vagus cranial nerve (X)?
- Laryngopharynx
- Vallecula
- Epiglottis
What is the sensory supply of soft palate?
Combination of:
• Maxillary (V2)
• Glossopharyngeal (IX)
Motor supply of pharynx?
• Parasympathetic secretomotor: -Vagus (X) & facial (VII) cranial nerves
• Musculature:
- All by vagus cranial nerve (X) except stylopharyngeus - glossopharyngeal cranial nerve (IX)
• The pharyngeal plexus lies on the external pharyngeal wall & includes branches of IX, X & cervical sympathetics
What is the motor supply of gag reflex?
- Afferent IX
* Efferent X
6 stages of swallowing
- Bolus pushed towards the back of oral cavity by raising the tip & body of tongue upwards towards the palate: mylohyoid & tongue intrinsic muscles
- Styloglossus pulls tongue upwards & backwards to tip the bolus through the oropharyngeal isthmus & into pharynx
- The soft palate is tensed (tensor veli palatini) & elevated (levator veli palatini) to sit within Passavant’s ridge & separate the nasopharynx from the oropharynx
- Palatoglossal & palatopharyngeal arches relax moving laterally
- Pharynx & larynx have already been elevated by the longitudinal muscles: stylopharyngeus, salpingopharyngeus & palatopharyngeus; stylohyoid & digastric may also help
- Relaxation of the elevators allows the pharynx & bolus to descend while sequential contraction of the constrictors pushes the bolus towards the oesophagus
How is the epiglottis forced backwards like a lid over the already closed laryngeal inlet (aryepiglottic folds) in swallowing?
As the tongue has been drawn posteriorly, the larynx effectively lies tucked under the back of the tongue - forces epiglottis backwards
Respiration is suspended during swallowing but when does it recommence?
After pharyngeal and laryngeal depression: relaxation of elevators and elastic recoil
