Session 9 - Oral Cavity, Tongue And Pharynx Flashcards
What are the borders of the oral cavity?
Lateral walls - buccinators
Roof - hard and soft palates
Floor - tongue and muscular diaphragm
What is the posterior limit of the oral cavity?
The oropharyngeal isthmus
What is the oropharyngeal isthmus?
An arch between the oral cavity and oropharynx, formed by the soft palate above and the upper surface of the tongue below.
What are the sides of the oropharyngeal isthmus formed by?
The anterior and posterior pillars of the fauces (palatoglossal fold and palatopharyngeal fold)
The folds of the fauces are formed by what two muscles?
Palatoglossus muscle (anterior) Palatopharyngeal muscle (posterior)
Where does the palatoglossus muscle run from and to?
From the soft palate to the tongue
Where does the palatopharyngeal muscle run from and to?
From the soft palate to the pharynx
When do the palatoglossus and palatopharyngeal muscles contract and what are their actions?
Contract during chewing. They act to pull the soft palate down, closing the oropharyngeal isthmus, therefore ensuring that food remains in the oral cavity while chewing.
What fossa is found between the palatoglossal and palatopharyngeal folds and what does it contain?
Tonsillar fossa, in which the palatine tonsil is found.
Which tonsils make up Waldeyer’s ring?
1 pharyngeal tonsil
2 tubal tonsils
2 palatine tonsils
1 lingual tonsil
Which tonsil is easily visible due to inflammation in tonsillitis?
Palatine tonsil
Name the salivary glands.
Sublingual
Submandibular
Parotid
Is salivary gland secretion stimulated by sympathetic or parasympathetic stimulation?
Parasympathetic
Salivary gland stones can form in the ducts draining the salivary glands into the oral cavity. Which salivary gland is most commonly affected by stones?
Submandibular gland
Are the intrinsic muscle of the tongue attached to bone?
No, they blend with the extrinsic muscles of the tongue.
What is the action of the intrinsic muscles of the tongue?
Act to alter the shape of the tongue
What are the actions of the extrinsic muscles of the tongue?
Act to change the position of the tongue - allow protrusion, retraction and side-to-side movement.
Anchor the tongue to the surrounding structures (hyoid bone and mandible below, styloid process and soft palate above).
Which extrinsic muscle of the tongue is most important to note and what is its action?
Genioglossus.
Protrudes the tongue.
How can the function of the hypoglossal nerve (CN XII) be tested?
Ask patient to stick out their tongue. (Action of genioglossus muscle)
All muscles of the tongue (except one) are innervated by what nerve?
Hypoglossal nerve (CN XII)
Which muscle of the tongue is not innervate by the hypoglossal nerve?
Palatoglossus (muscle forming the shape of the anterior arch)
Which nerve innervates the palatoglossus?
Vagus nerve (CN X)
Tongue has embryological origins from which pharyngeal arches?
Pharyngeal arches 1, 3 and 4.
General sensation to the anterior 2/3 of the tongue is carried by what nerve?
Trigeminal nerve, specifically the lingual nerve (a branch of CN Vc).
What nerve supplies special sensory fibres for taste to the anterior 2/3 of the tongue?
Chorda tympani (branch of facial nerve).
What nerve supplies both general sensation and taste sensation fibres to the posterior 1/3 of the tongue?
Glossopharyngeal nerve (CN IX)
The glossopharyngeal nerve also carries parasympathetic fibres to which salivary gland?
Parotid gland
Asking a patient to open their mouth and say ‘ahhh’ is a test of which cranial nerve?
Vagus nerve (CN X)
When asked to open their mouth and say ‘ahhh’ a patients uvula may deviate to one side. What does this indicate?
Deviation of the uvula to one side indicates weakness of the soft palate on the contralateral side (opposite side) to the deviation. This therefore indicates an vagus nerve (CN X) lesion.
The gag reflex tests the integrity of which nerves?
Glossopharyngeal nerve (CN IX) (afferent limb of the gag reflex) Vagus nerve (CN X) (efferent limb of the gag reflex)
Lesions affecting the hypoglossal nerve on one side of the tongue will cause the tongue to deviate in which direction when protruded?
Deviates towards the side of the lesion.
The pharynx extends down to which vertebral level?
C6
The posterior wall of the pharynx is covered by what type of fascia?
Buccopharyngeal fascia
What are the three parts of the pharynx?
Nasopharynx
Oropharynx
Laryngopharynx
The nasopharynx lies superiorly to what?
Soft palate
What structures are found in the nasopharynx?
The orifice of the Eustachian (Pharyngotympanic) tube. Pharyngeal tonsil (adenoids)
What are the upper and lower limits of the oropharynx?
The oropharynx extends from the soft palate to the superior border of the epiglottis.
Which vertebral body lies posteriorly to the nasopharynx?
C1
Which vertebral bodies lie posteriorly to the oropharynx?
C2 and C3
What are the upper and lower limits of the laryngopharynx?
Extends from the epiglottis to the oesophagus at the level of the lower border of the cricoid cartilage, and also extends behind the laryngeal inlet.
Which vertebral bodies lie posteriorly to the laryngopharynx?
C3-C6
What are the small depression found on either side of the laryngeal inlet called?
Piriform fossa
What muscles are the wall of the pharynx formed by?
Superior, middle and inferior constrictors.
What nerve are the circular constrictor muscles of the pharynx innervated by?
Vagus nerve (CN X)
What is the function of the constrictor muscles of the pharynx?
Sequential relaxation and contraction to propel food along the pharynx into the oesophagus.
What is Killian’s dehiscence?
A small area of weakness found between the two muscle bellies of the inferior constrictor.
What is a pharyngeal pouch (Zenker’s diverticulum) and how do they form?
A pharyngeal pouch is a herniation through Killian’s dehiscence.
If there is uncoordinated swallowing, pressure in the pharynx can increase due the the constrictor muscle contracting against a closed oesophageal sphincter. This can cause part of the pharyngeal mucosa to herniate through Killian’s dehiscence forming a pharyngeal pouch.
What symptoms are caused by a pharyngeal pouch?
May be asymptomatic
Dysphagia
Regurgitation of food
Halitosis (bad breath)
The vagus nerve supplies all muscles of the pharynx and soft palate except for which?
Stylopharyngeus (supplied by CN IX)
General sensory to the nasopharynx is supplied by what nerve?
Maxillary nerve (CN Vb)
General sensory to the oropharynx is supplied by what nerve?
Glossopharyngeal nerve (CN IX)
(The pharyngotympanic tube is also supplied by CN IX even though it is found in the nasopharynx).
The laryngopharynx receives general sensory innervation from what nerve?
Vagus nerve (CN X)
