The Pharynx Flashcards
Where is the oropharynx located?
space between the oral cavity, laryngopharynx, and nasopharynx
Dorsal boundary of the oropharynx?
Soft palate
Ventral boundary of the oropharynx?
Root of the tongue
The palatopharyngeal muscles extend as arches laterally to create the A) and act as a sphincter between what 3 structures?
A) intrapharyngeal ostium
- oropharynx, nasopharynx and laryngopharynx.
The soft palate protects against food entering the nasopharynx by contraction of what muscles?
The tensor and levator veli palatini muscles
What happens to the tensor and levator veli palatini muscles to cause the free edge of the palate to press against the pharyngeal wall, sealing off the nasopharynx?
These tighten and elevate the palate
What nerves control the function of the soft palate? (2)
Glossopharyngeal n
Vagal n
The minor palatine artery (a branch of the ? artery) supplies the soft palate.
Maxillary
What control is swallowing under? (2)
Cranial n and brainstem
Any alterations in normal swallowing process, can lead to what? (3)
dysphagia, aspiration, or regurgitation
What are the 3 phases of deglutition?
oropharyngeal,
oesophageal
gastroesophagea
3 actions of the oropharyngeal phase?
- Oral
- Pharyngeal
- pharyngoesophageal
What is involved in the oral phase of oropharyngeal phase?
This is the formation of a food bolus by compression of food between the tongue and soft palate. The bolus is then propelled to the base of the tongue at the entrance to pharynx.
hat control i the oral phase of oropharyngeal phase under?
Voluntary control
Which nerves is the oral phase of oropharyngeal phase under?
Trigeminal
Facial
Hypoglossal
Pharyngeal phase of the oropharyngeal phase:
What is it stimulated by?
The presence of the bolus at the base of the tongue under reflex (involuntary)
Pharyngeal phase of the oropharyngeal phase:
What is it controlled by?
Swallowing centre
Pharyngeal phase of the oropharyngeal phase:
What nerves is it controlled by (2)
Glossopharyngeal n
Vagal n
Pharyngeal phase of the oropharyngeal phase:
What muscles transport the bolus in a peristaltic manner through pharynx? (2)
Tongue
Pharyngeal constrictor muscles
Pharyngoesophageal phase of oropharyngeal phase;
What is involved in this?
This is the passage of food from pharynx, through the cricopharyngeal sphincter into the oesophagus. As soon as the pharyngeal muscles contract, sphincter relaxation occurs to allow the movement to occur.
Pharyngoesophageal phase of oropharyngeal phase;
What is the end of this phase marked by?
Closure of the sphincter and relaxation of the pharyngeal muscles.
Pharyngoesophageal phase of oropharyngeal phase;
Under what control?
(involuntary) control
Pharyngoesophageal phase of oropharyngeal phase;
Which nerves? (2)
Glossopharyngeal
Vaga
Peristalsis moves food in the oesophageal phase to gasatro-oesopheal sphincter. What happens if primary phase weakens?
The distension of the oesophagus also stimulates secondary peristalsis which helps to continue propulsion
What mechanism causes Relaxation of the gastro-oesophageal sphincter occurs just prior to the bolus reaching it?
non-adrenergic, non-cholinergic mechanism
Does the following increase of decrease gastro-oesophageal sphincter tone?
Moderately elevated intra-gastric pressure
Increase
Does the following increase of decrease gastro-oesophageal sphincter tone?
Dietary fat
Reduce
Does the following increase of decrease gastro-oesophageal sphincter tone?
Marked increase increased intra gastric pressure
Reduce
Does the following increase of decrease gastro-oesophageal sphincter tone?
Dietary protein
Increase
Does the following increase of decrease gastro-oesophageal sphincter tone?
Gastric acid
Increase
Does the following increase of decrease gastro-oesophageal sphincter tone?
Postprandial hormone release of gastrin, histamine and ACh
Increase
Does the following increase of decrease gastro-oesophageal sphincter tone?
Distension of cardia by gas
Reduce
Define dysphasia
Difficulty swallowing at any stage of deglutition
How can dysphagia be classified?
oral or pharyngeal/pharyngoesophageal
What is seen with oral dysphagia? (5)
Difficulty prehending food or lapping water
Retention of food and water in the mouth
Failure to swallow saliva leading to drooling
Possible reduction in tongue mobility
Affected animals may throw their head back to assist with the movement of the food bolus towards the pharynx
What may assist patients with oral dysphagia at feeding?
Feeding from an elevated position may help these animals
Pharyngeal/pharyngoesophageal dysphagia:
What may be seen with a patient? (2)
Repeated unsuccessful attempts at swallowing
Food regurgitated into the mouth or retained in pharynx
Pharyngeal/pharyngoesophageal dysphagia:
Why are these patients at risk of aspirating?
Since the epiglottis relaxes at end of swallowing leaving the larynx unprotected
Pharyngeal/pharyngoesophageal dysphagia:
Effect on gag reflex?
Reduced or absent
Pharyngeal/pharyngoesophageal dysphagia:
What happens if you feed from height/place food at tongue base?
No improved function
How to identify conditions causing dysphgia?
Most seen at CE
Common conditions causing dysphasia? (3)
Palate defects
Tongue defects – ankyloglossia, macro-/micro-glossia
Tight lip syndrome
Which breed is tight lip syndrome seen in?
Shar pei
Pharyngeal mass ; how to identify extend of mass?
CT
What is recommended in the first instance to attain a diagnosis if possible with a pharyngeal mass?
FNA
Pharyngeal tumours are how common?
rare
Pharyngeal tumours that have been reported in dogs? (4)
SCC
Melanoma
Adenocarcinoma
Rhabdymyosarcoma
Tumours that have been reported in cat pharynx? (2)
Lymphoma
Polyps
How common are inflammatory polyps in dogs?
Rare
Clinical signs of nasopharyngeal disease include? (4)
Sneezing
Stertor
Nasal discharge
Open mouth breathing
How to diagnose a pharyngeal mass?
Diagnosis is made by evaluation under anaesthesia. Retraction of the soft palate using a probe or spay hook improves visualisation. Endoscopy can also be very helpful for improving visualisation
Best imaging for pharynx?
CT
To access the nasopharynx and achieve biopsy samples or remove benign tumours, how can this be accessed?
How to approach to aid reconstruction and reduce dehiscence?
The soft palate can be split through its midline.
he distal ends of the palate are left intact to assist
Pharynx abnormalities can be idiopathic or secondary to generalised neuropathy or neuromuscular conditions, including (4)
peripheral neuropathy,
myasthenia gravis,
brainstem lesions
intracranial abnormalities.
How to identify functional abnormaltiies of the pharynx?
Fluoroscopy; barium paste of suspension mixed with food.
What happens in Pharyngeal dysphagia?
The bolus forms but despite repeated swallowing attempts, it remains in the pharynx without passing through the pharyngeal constrictor muscles.
What happens in Pharyngoesophageal dysphagia?
The bolus moves normally through the pharynx but will not pass through the cricopharyngeal sphincter, remaining in the pharynx or moving towards the larynx.
What are the most common pharyngoesophageal disorders in the dog? (2)
Cricopharyngeal asynchrony
cricopharyngeal achalasia
Although rare, how would Cricopharyngeal achalasia be managed?
Surgically- Myotomy of the cricopharyngeal muscle is curativ
What is Cricopharyngeal achalasia characterised by?
failure of the upper oesophageal sphincter to open at the end of the oropharyngeal phase of swallowing, preventing the bolus of food from entering the oesophagus.
What is the main clinical sign of Cricopharyngeal achalasia
Regurgitation immediately after swallowing (after weaning) +/- secondary aspiration pneumonia.
Prior to surgery, what must Cricopharyngeal achalasia be differentiated from and why?
Pharyngeal dysphagia prior to surgery since cricopharyngeal myotomy will significantly worsen the latter.
How common is pharynx in cats?
Rare
Main cause of pharynx injury in dogs?
Stick injuries
Presenting signs of Pharyngeal Trauma? (6)
dysphagia:
drooling,
depression,
oral pain,
pain on neck flexion or mouth opening,
and blood in the saliva
What muscle involvement may cause pain when opening the mouth, with pharynx injury?
Temporal
Masseter
When do acute vs chronic pharynx injuries present?
Acute - within 7 days of trauma – cause often observed or a history of stick chasing/chewing.
Chronic - More than 7 days after trauma (approx. 88% cases in one study).
Most common sites of stick penetration (3)
Oesophagus
Lateral and dorsal pharyngeal walls
Sublingual region.
What imaging should be used for stick injury, and what are you looking for?
Plain cervical radiography may not identify foreign material but the presence of extraluminal gas between fascial planes in the cervical region will confirm penetration of the oropharynx or oesophagus.
Gas may track along fascial planes causing pneumomediastinum and pneumothorax making localisation of the injury challenging
If not - Advanced image
In penetrating stick trauma without pharyngeal involvement, What is the treatment?
Wound exploration, debridement, and lavage may be adequate.
What approach to exploration allows the evaluation of cervical and parapharyngeal tissues?
Ventral exporation
When performing ventral midline exploration:
A) CARE of which nerves?
B) Take sample; why?
A) Recurrent laryngeal
B) C+S
Retrobulbar injury is best treated how?
drained through the oral cavity and treated with broad-spectrum antibiotics in the first instance.
Stick injury;
Clinical signs are reported to resolve in what % of chronic cases?
62%
Which stick injuries have a higher mortaility?
Oesophagus penetration
Prognosis following correct treatment of acute stick injuries is ?
Excellent
