22 - Pharynx Flashcards
What are the divisions of the pharynx?
- nasopharynx
- oropharynx
- laryngopharynx
What are the borders of the pharynx?
Superior - nasal cavity, cranial base
Inferior - inferior border of cricoid cartilage (at the level of C6)
Describe the borders of the nasopharynx.
- extends from the posterior border of the nasal septum to the soft palate
- lined with respiratory epithelium (ciliated columnar) including mucous producing goblet cells
What is the phrayngotympanic tube?
Opening from the nasopharynx to the middle ear
What are the tubal tonsils?
Protect the airway from infection, posterior and inferior to pharyngotympanic tube
Describe the borders of the oropharynx.
- extends from the soft palate and base of tongue to the superior border of the epiglottis
- anterior border is the fauces
- lined with oral muscosa (stratified squamous)
What is the vallecula?
- “little valley”
- area behind the epiglottis
- foreign bodies often become lodged here
What is the function of the epiglottis?
- elastic cartilage
- folds over to protect the larynx and trachea from food bolus
Describe the borders of the laryngopharynx.
- superior border of epiglottis to inferior border of cricoid cartilage
- continuous with oesophagus
- posterior and lateral borders are the middle and inferior constrictor muscles
What is the piriform fossa?
- muscosa lined recess behind the laryngeal inlet
- foreign bodies often become lodged here
What tonsils make up Waldeyer’s ring?
- pharyngeal tonsils (“adenoids”) in nasopharynx
- tubal tonsils in nasopharynx
- palatine tonsils (“tonsils”) in oropharynx
- lingual tonsils on posterior 1/3 of tongue
What is the function of Waldeyer’s ring?
Protection of airways
What fascia is found in the nasopharynx?
- pharyngobasilar fascia
- blends with periosteum of cranial base
What muscles are associated with the pharynx?
- 3 pharyngeal constrictors
- 3 pharyngeal elevators
List the pharyngeal constrictor muscles.
- superior
- middle
- inferior
List the pharyngeal elevator muscles.
- salphingopharyngeus
- palatopharyngeus
- stylopharyngeus
What nerve supplies the pharyngeal constrictors?
Vagus nerve via pharyngeal plexus
Describe the inferior pharyngeal constrictor.
Lower circular part called the cricopharyngeus that forms a sphincter at the upper oesophagus
Describe the location of the pharyngeal elevators.
- originate and descend from the skull
- fan out into the inner surface of pharynx
- some fibres to thyroid cartilage
What is the action of the palatopharyngeus?
- elevates pharynx and larynx
- draws soft palate downwards
What is the action of stylopharyngeus?
- originates from styloid process
- elevates pharynx and larynx
What is the action of salphingopharyngeus?
- originates from auditory tube
- elevates pharynx and larynx
- opens auditory tube during swallowing for pressure equalisation
What is the innervation of palatopharyngeus?
Vagus nerve
What is the innervation of stylopharyngeus?
Glossophayrngeal nerve
What is the innervation of salphingopharyngeus?
Vagus nerve
What are the stages of swallowing?
- oral (voluntary)
- pharyngeal (involuntary)
- oesophageal (involuntary)
Describe the oral phase of swallowing.
- bolus is formed by mastication (tongue retracted)
- tongue then pushes bolus into oropharynx
- soft palate closes the nasopharynx
Describe the pharyngeal phase of swallowing.
- superior pharyngeal constrictor contraction and elevation of soft palate
- pharynx elevated to receive bolus by elevators
- pharynx contracts to push bolus towards oesophagus (constrictors)
- epiglottis closes laryngeal inlet
Describe the oesophageal phase of swallowing.
- inferior pharyngeal constrictor contracts, upper oesophageal sphincter relaxes
- peristaltic movements move bolus to stomach
