The Pharynx Flashcards
What is the pharynx?
Muscular tube that enables multiple areas to interconnect
Tube is not rigid, it is highly mobile + distensible + can undergo peristalsis
Hangs from base of skull to where oesophagus begins connecting nasal + oral cavities with larynx + oesophagus
What are the 3 regions of the pharynx? What is their sensory innervation?
Nasopharynx (Cn Vb + IX)
Oropharynx (CN IX)
Laryngopharynx (CN IX + X)
What travels through our pharynx? What route do they take?
Air: goes down larynx/tracheobronchial tree route
Food/fluid: oesophagus (fluid can come out too e.g. in vomiting)
What major structures drain into the nasal cavity?
Frontal sinus Sphenoid sinus Maxillary sinus Ethmoidal sinus Nasolacrimal duct
What structure stops food going up our nose when we swallow?
Soft palate as it seperates nasopharynx + oropharynx -> moves posterior-inferiorly when you swallow to block off nasopharynx
What 2 muscles control the soft palate and auditory tube? What do they do?
Tensor veli palatini: tenses palate laterally
Levetor veli palatini: elevates palate superiorly
Also open auditory tube when contracted as its normally closed
What is the structure posterior to the nasal cavity called?
Choanae = body of C1 + lower border of soft palate
What are the borders of the 3 sub-structures of the pharynx?
Nasopharynx: choanae + lower border of soft palate
Oropharynx: upper border of soft palate, palatal arches (muscles covered in mucosa that sit either side of tonsils)+ lower border of epiglottis
Laryngopharynx: base of tongue/upper epiglottis + cricopharyngeus muscle
What is the epiglottis?
Cartilage of larynx
Covers laryngeal inlet during swallowing
As you move down the pharynx, the regions get larger. What epithelium transition occurs?
Pseudostratified ciliated columnar epithelium(respiratory mucosa) -> stratified squamous epithelium (stops abrasions when you eat)
What is the cricopharyngeus muscle?
Circular strong muscle considered true oesophageal sphincter -> not a true anatomical sphincter but a physiological one as it has to relax to allow food to pass down
What cranial nerve carries sensory information from all portions of the pharynx, middle ear, auditory tube and inner side of tympanic membrane? Why is this relevant?
Glossopharyngeal nerve (CN IX)
Pain can refer from and to all of these structures
What are the 3 muscles of the pharynx? What do they do?
- Superior constrictor
- Middle constrictor
- Inferior constrictor
- Lined by continuous internal fascia + mucosa - End at cricopharyngeus
- > supplied by vagus nerve (CN X) to contract = reduce diameter of pharynx squeezing food down (peristalsis)
What 2 nerves control the gag reflex?
Vagus (CN X) - motor
Glossopharyngeal (CN IX) - sensory
If there is a vagus nerve (CN X) lesion and the pharyngeal muscles are paralysed, what symptoms might this lead to?
Dysphagia (uncoordinated/difficult swallowing)
Gag reflex compromised
Increased risk of aspiration
Describe the bony and ligamentous attachments to the pharyngeal muscles.
Styloid process -> attached to stylohyoid ligament -> stabilises hyoid bone + muscles
Also, pterygomandibular raphe, thyroid cartilage + cricoid cartilage
What is eagle syndrome? How would patients present?
Styloid processes grow exceptionally long so they poke into soft tissue of pharynx
Leads to: Dysphagia Feeling of something stuck in throat Facial pain on head rotation Carotid artery compression
Why does the pharynx have a weak spot?
Pharyngeal constrictors overlap each other forming a functional unit + attaching posteriorly along a midline raphe (long tendon) which extends from base of skull to ‘weak spot’
Weak spot between inferior constrictor + cricopharyngeus as direction of muscle fibres change -> herniation can occur here posteriorly
What 3 processes have to occur for normal swallowing to happen?
- Coordinated peristalsis of all pharyngeal constrictor muscles
- Relaxation of cricopharyngeus muscle
- Drop in intrapharyngeal pressure to allow food to progress downwards
What is a Zenker (pharyngeal) diverticulum? What can this cause?
Posteriorly herniated pharyngeal lining at ‘weak spot’ forming a pouch
-> food/liquid will collect in pouch as oesophagus in front of it = halitosis+ coughing up of old food
What is the piriform fossae? What is their function?
Mucosal lined pouch with walls formed by laryngeal structures i.e. recess between central larynx + lateral thyroid cartilage (CN IX)
Permits passage of food/liquids during swallowing in a directive route alongside larynx (foreign bodies e.g. bones can get stuck here -> pain referral to ear)
What is the vallecula of the piriform fossa useful for?
Blade of laryngoscope can be placed in vallecula to pull tongue forward, opening up beginning of larynx if trying to intubate the trachea
What motor nerve innervates all pharyngeal muscles? What are the 2 exceptions?
Vagus (CN X)
EXCEPT
Stylopharyngeus (CN IX) + tensor veli palatini (Cn Vc)
What are longitudinal internal muscles called that elevate, shorten + widen the pharynx?
Stylopharyngeus
Salpingopharyngeus
Palatopharyngeus
All attach to soft palate + go down
What is the salpingopharyngeus muscle? What does it do?
Longitudinal, internal muscle that arises from auditory tube to pharynx
It helps open tube on swallowing + equalizes pressure
Aids in elevating, shortening + widening pharynx in swallowing
What are the palatoglossus and palatopharyngeus muscles? What do they do?
Both hang down from soft palate joining tongue + pharynx at entrance of oropharynx (surround palatine tonsils) - called ‘arches’ when covered with mucosa
When contracted, elevate the pharynx helping to cover food bolus
What will happen if there is damage to CN X or Vc?
Ipsilateral soft palate paralysis - if this is on the right, soft palate will contract towards left (uvula will point to working side) -> issues aspirating food/liquid + also food/liquid will go into nasopharynx
Gag reflex often diminished in the ___.
Elderly
How do you text the gag reflex?
- Inspect soft palate + oropharynx for asymmetry
- Ask patient to phonate; if there is a weak side, palate + uvula will pull away from weak side
- Touch pharynx to elicit reflex:
- Motor loss - sensation but unilateral/no contraction = CN X lesion
- Sensory loss - no gag reflex when touching side with sensory loss but full gag when touching other side = CN IX lesion - Assess swallowing + character of voice (if appropriate)
What 4 bits of lymphoid tissue make up the Waldeyer Ring in the nasopharynx + oropharynx? Why do we need these?
- Pharyngeal (adenoid)
- Tubal
- Palatine
- Lingual
Need these here as there are lots of thins going in/out of this region
What happens if any of the Waldeyer Ring lymphoid tissues increase in size?
Enlarged adenoids/tonsils
Tonsilitis
Adenoids can get so big breathing problems can ensue, auditory tube gets blocked so more prone to inner ear infections or tonsillitis repeatedly
Impedes swallowing, coordination + changes voice (can happen if tonsils taken out too)
