9. Pharynx & swallowing Flashcards
what does the posterior wall of the pharynx consist of and which structure is posterior to this
- consists of buccopharyngeal fascia (ie posterior pre-vertebral layer of deep cervical fascia)
- located anterior to retropharyngeal space
describe the limits and contents of the 3 parts of the pharynx
- nasopharynx
- skull base to soft palate (upper border) at C1/2
- nasal cavity anteriorly
- contains: pharyngeal tonsils and ET opening - oropharynx
- soft palate to epiglottis (superior border) at C2/3
- oral cavity anteriorly
- contains: palatine tonsils (between palatoglossal and glossopharyngeal arches) - laryngopharynx
- epiglottis to cricoid cartilage (inferior border) at C6
- laryngeal inlet anteriorly
which structure is found on either side of laryngeal inlet
piriform recesses (when swallowing, epiglottis closes to protect trachea and divert bolus into recesses)
describe the motor and sensory innervation to the pharynx
- motor = vagus n. (exc. stylopharyngeus = CN IX)
- sensory
- nasopharynx = maxillary n. (CN Vb)
- oropharynx = glossopharyngeal n.
- laryngopharynx = vagus n.
name the 3 phases of swallowing, describing the 1st and 3rd
- ORAL (voluntary)
- Preparatory phase: makes bolus
- Transit phase: bolus compressed against palate and pushed into oropharynx by tongue (CN XII) and soft palate - PHARYNGEAL (involuntary)
- OESOPHAGEAL (involuntary)
- peristaltic contraction of upper striated oesophageal muscles (CN X) and lower SM
describe the pharyngeal phase of swallowing
- CN IX sensory afferents sense presence of bolus
- Tongue positioned against hard palate to prevent food re-entry into mouth (CN XII), and soft palate elevated to seal off nasopharynx (tensor palatini CN Vc and levator palatini CN X)
- Larynx elevated, epiglottis closes and vocal cords adduct (CN X)
- Suprahyoid and longitudinal muscles (CN IX and X) shorten… pharynx widens and shortens to receive bolus
- Bolus moves through pharynx by sequential contraction of constrictors
- Relaxation of UOS
name and describe the function of the internal pharynx muscles
3 longitudinal muscles within pharynx wall that i) shorten and widen pharynx, and ii) elevate larynx, during swallowing
- stylopharyngeus - styloid process to thyroid cartilage
- palatopharyngeus - hard palate to thyroid cartilage
- salpingopharyngeus - cartilaginous part of ET to merge with palatopharyngeus
name and describe the function of the external pharyngeal muscles
Circular superior, middle and inferior constrictors - relax and contract sequentially from above to below to propel food into oesophagus
describe the innervation of the pharyngeal muscles
all internal and external pharyngeal muscles innervated by vagus n. except stylopharyngeus (glossopharyngeal n.)
which part of the pharynx is a point of potential weakness and what can be the clinical consequence of this
- Inferior pharyngeal constrictor made of 2 parts (thyropharyngeal and cricopharyngeal) between which is point of potential weakness - KILIAN’S DEHISCENCE
- If incoordination of pharynx during swallowing… muscles attempt to constrict against closed UOS… increased pressure in pharynx… part of pharyngeal mucosa herniates through Kilian’s dehiscence = PHARYNGEAL POUCH (Zenker’s diverticulum)… food material may be trapped.
what are the symptoms of pharyngeal pouches
Small pouches may be asymptomatic but others can cause:
- dysphagia
- food regurgitation
- halitosis
how can neurological causes for dysphagia be differentiated from upper GI causes
- difficulty swallowing prominent with fluids as well as/more than solids
name 5 signs/symptoms suggesting CN IX or X palsy
- loss of gag reflex
- uvula deviation (away from lesion) - soft palate should rise when P says Ahhh due to rise of arches
- dysphagia
- taste impairment (post. tongue)
- loss of oropharynx sensation
name 3 signs suggesting CN XII palsy
- wasted tongue
- tongue deviation (towards lesion) on protrusion
- fasiculations
describe the gag relex
Afferent limb = glossopharyngeal n. (sensory to oropharynx)
Efferent limb = vagus n. (motor to muscles of pharynx)
