Session 4: Face and Oral Cavity Flashcards
What is the main sensory nerve of the head?
Trigeminal nerve
it also has a motor component
What is a posable complication of a lollipop stick injury?
- lollipop stick becomes stuck in the back of the pharynx
- becomes infected
- the infection can travel down to the thoracic cavity
-> Know the fascia, know how things can spread!!
When inspecting the oral cavity, why does a doctor ask you to say “aaa”?
- to examine the functions of the vagus nerve
- when saying “aaa” the uvula should rise in the midline
- if it is deviating, this suggests that there could be something wrong with one of the vagus nerves.
- deviates away from the lesion
What happens to the epiglottis during swallowing?
- it retroflexed to cover the airway to prevent food from going down there.
Piriform Fossa
- food e.g. fish bones can become stuck in this area
- might have to be removed with forceps
Constrictor muscles in the pharynx
- superior, middle and inferior
- supplied by vagus and some fibers of the accessory nerve
- food is pushed down by a series of constrictor muscles - sequential contraction pushes food down
Sensory innervation of the pharynx
- pharyngeal plexus (vagus and glossopharyngeal)
Process of swallowing
- mastication
- Lift and retract tongue (styloglossus, intrinsic muscles)
- Bolus into oropharynx (palatoglossus)
- Close off nasopharynx by raising soft palate
- Raise the larynx, closed off by epiglottis
- Peristaltic wave of constrictor muscles
- Relax cricopharyngeus, open oesophagus
What are the 3 salivary glands?
- parotid
- submandibular
- sublingual
What is the parotid gland a landmark for?
- the emergence of the facial nerve (VII)
- however, it is not innervated by that nerve but by CNIX (glossopharyngeal)
Parotid gland
- serous saliva
- innervated by IX
Submandibular gland
- serous saliva
- innervated by CNVII
Sublingual gland
- mucous saliva
- innervated by CNVII
What are the muscles of the tongue?
- styloglossus
- hypoglossus
- genioglossus
- intrinsic muscles
Which nerve innervates the tongue?
- XII (hypoglossal)
Afferent innervation of the tongue
- anterior 2/3: trigeminal (normal sensation); Facial (VII) for taste -> these fibers go to the nucleus solitarius
- posterior 1/3” glossopharyngeal; also some vagus innervation.
What are the two superficial muscles of mastication?
- Masseter
- Temporalis
Masseter Muscle
- zygomatic arch to lat surface of ramus and angle of mandible
- elevates mandible (allows forced closure of mouth)
- superficial muscle of mastication
Temporalis Muscle
- superficial muscle of mastication
- temporal fossa to coronoid process of mandible
elevates and retracts mandible - thin muscle, harder to palpate than masseter
Buccinator muscle
- parotid duct passes through it
- innervated by the facial nerve
- pushes food to the middle of the mouth
- sucking in cheeks -> that is the action of buccinator pushing food to the middle
What is the innervation of the muscles of mastication?
- buccinator is innervated by the facial nerve
- all others are innervated by the trigeminal nerve
Lateral pterigoid muscles
- sphenoid /lat pterygoid plate to neck of mandible
- depresses and protracts mandible to open mouth
Medial pterygoid muscles
- lat pterygoid plate/ maxilla/palate to angle of mandible
- elevates, protracts and lateral movement of mandible for chewing
What are the deep muscles of mastication?
- lateral pterygoid
- medial pterygoid
- buccinator?
What are the 2 actions of the temporomandibular joint?
- hinge action: when you open your mouth slightly
- gliding movement when you open widely
What do you do when someone dislocates their jaw? (anteriorly)
- you have to push the mandible down and then move the jaw posteriorly
- (down and back)
What are the branches of the external carotid artery?
- Superior thyroid
- Ascending pharyngeal
- Lingual
- Facial
- Occipital
- Posterior auricular
- Maxillary
- Superficial temporal (forehead)
[some anatomists like freaking out poor medical students]
What is special about the facial artery?
- it forms a loop to allow movement as it goes around the mandible
- branch of the ECA
What is special about the maxillary artery?
- MMA branches off of it
- enters the skull through the foramen spinosum
What is the relationship between the parotid gland and the facial nerve?
- purely anatomical
- parotid gland is innervated by CN9
What are the different braches of the facial nerve?
- mandibular
- buccal
- zygomatic
- temporal (most superior)
- cervical (innervates the platysma muscle)
How does the facial nerve emerge from the cranial cavity?
- passes through internal acoustic meatus along with the vestibulocochlear nerve
- exits through the stylomastoid foramen
How can you test the function of the facial nerve?
- ask someone to look up and look for creasing of the forehead
(this is only 1 example)
What are the 3 branches of the mandibular nerve (V3)?
- inferior alveolar nerve
- lingual nerve (sensation of the tongue)
Inferior alveolar nerve
- sensory nerve for lower dentation
- passes through foramen ovale into the mandible
- terminal branch: mental nerve (chin)
- test function by testing sensation of the chin
Lingual nerve
- also receives fibres from the facial nerve (chorda tympani)
- it is a branch of the madibular nerve (V3)
- bidirectional information flow (PS innervation to submandibular ganglion -> salivary glands; also taste fibres in the chorda tympani)
=> multifunctional nerve with constituents from 2 different cranial nerves.
How does the facial nerve branch to joint the lingual nerve?
- facial nerve exits through the stylomastoid foramen
- runs anteriorly through prethrotympanic fissure
- joins the lingual nerve
