Session 4: Oral Cavity and Upper GI Tract Flashcards
List the 3 sets of tonsils found in the upper GI tract
Palatine
Pharyngeal
Lingual
Between which 2 folds do the palatine tonsils lie?
Palatopharyngeal Fold
Palatoglossal Fold
Why does the GP gets you to say ‘aaaaaah’ when he inspects the inside of your mouth?
It raises the soft palate + uvula + depresses the tongue
Tests motor function of the vagus nerve.
Uvula should be midline
Problem: uvula deviates away from lesion
Describe the borders of the pharynx.
Base of the skull + inferior border of cricoid cartilage
What are the 3 parts of the pharynx and what are their borders?
Nasopharynx: down to the soft palate (pharyngeal isthmus)
Oropharynx: between the soft palate + epiglottis
Laryngopharynx: between the epiglottis + cricoid cartilage
What happens to the epiglottis when you swallow?
Retroflexion to cover the laryngeal inlet
What is the role of the soft palate in swallowing?
It elevates to close off the nasopharynx so food doesn’t go into the nasal cavity
What is the Piriform Fossa and what is its clinical significance?
Depressions on either side of the laryngeal inlet where food (e.g. fish bones) get stuck
Which muscles aid the passage of a bolus of food down the oesophagus?
Superior, middle + inferior pharyngeal constrictor muscles
Which nerves provide sensory innervation of the pharyngeal wall?
Glossopharyngeal + Vagus (pharyngeal plexus)
Which nerves provide motor innervation of the pharyngeal constrictor muscles?
Vagus (+ a bit of accessory)
Describe the changes that occur during swallowing.
Lift + retract tongue (styloglossus + intrinsic muscles)
Bolus into oropharynx (palatoglossus)
Close off nasopharynx by raising soft palate
Raise the larynx– closed off by the epiglottis
Peristaltic wave of constrictor muscles
Relax cricopharyngeus, open oesophagus
Name the 3 salivary glands, describe their secretions and state the nerves that provide secretomotor innervation to them.
Parotid: serous, glossopharyngeal
Submandibular: serous, facial
Sublingual: mucous, facial
Which muscle does the parotid duct pierce and where does it open into the buccal cavity?
Buccinator
It opens next to the 2nd upper molar
Name the main muscles of the tongue. Which nerve innervates all of this?
Genioglossus Hyoglossus Styloglossus Intrinsic Muscles Innervated by hypoglossal nerve
What other muscle is associated with the tongue but isn’t innervated by the hypoglossal nerve?
Palatoglossus – innervated by the vagus
What tongue movements do the genioglossus and styloglossus perform?
Genioglossus: protracts the tongue
Styloglossus: retracts + elevates the tongue
To which side would the tongue move if a patient with a unilateral lesion in the hypoglossal nerve was asked to stick their tongue out?
Towards the side of the lesion because the genioglossus is used in protracting the tongue
What movement is palatoglossus responsible for?
Elevates the soft palate + moves the back of the tongue upwards
Where is the lingual nerve relative to the hypoglossal nerve?
Lingual nerve is superior to the hypoglossal nerve
Describe the sensory innervation of the tongue
Anterior 2/3 sensation: mandibular branch of trigeminal
Anterior 2/3 taste: facial
Posterior 1/3 everything: glossopharyngeal
To which structure in the brainstem do the neurons of taste go? It is considered the main taste centre within the brainstem.
Nucleus Solitarius
State the origin and insertion of the masseter and the movement that it is responsible for.
Zygomatic Arch to Lateral surface of the ramus of the mandible + angle of the mandible Elevates mandible (allows forced closure of the mouth)
State the origin and insertion of temporalis and the movement that it is responsible for.
Temporal Fossa to Coronoid Process of mandible
Elevates + retracts mandible
State the origin and insertion of the medial and lateral pterygoid muscles and the movements that they are responsible for.
Lateral: lateral pterygoid plate (+ greater wing of sphenoid) TO neck of the mandible
Depresses + protracts mandible to open the mouth
Medial: lateral pterygoid plate, maxilla, palate TO angle of the mandible
Elevates, protracts + allows lateral movement of mandible for chewing
Describe the structure of the temporomandibular joint.
= a capsular joint
Capsule has an articular plate splitting it in 2
Head of the mandible articulates with the articular tubercle of the temporal bone
Describe the movements around the temporomandibular joint when opening the mouth.
Open mouth slightly= hinge action
Open further= the head of the mandible glides anteriorly on the articular tubercle of the temporal bone
State the 8 branches of the external carotid artery.
Superior Thyroid Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary Superficial temporal
At the level of what anatomical landmark does the common carotid artery bifurcate.
At the level of the laryngeal prominence
Why does the facial artery have a wavy course across the mandible?
If taut, opening the mouth would cause rupture
Which branch of the external carotid artery gives rise to the middle meningeal artery?
Maxillary
Through which foramen does the middle meningeal artery enter the skull?
Foramen Spinosum
State the 5 branches of the facial nerve
Temporal Zygomatic Buccal Mandibular Cervical
What are the 2 main branches of the mandibular branch of the trigeminal nerve?
Lingual Nerve
Inferior Alveolar Nerve
What are the functions of the lingual and inferior alveolar nerve?
Inferior Alveolar: innervates lower teeth (tooth ache)
Lingual: sensation (touch + taste) to anterior 2/3 of the tongue + secretomotor to sublingual + submandibular salivary glands
What fibres join the lingual nerve?
Some fibres of the facial nerve via the Chorda Tympani (why the lingual nerve is responsible for taste)
Which cranial nerve provides all sensory innervation of the face?
Trigeminal Nerve
How many arteries and veins does the thyroid gland have?
2 pairs of arteries
3 pairs of veins
State where these arteries and veins originate from and drain to.
Superior thyroid artery: from the external carotid artery
Inferior thyroid artery: from the thyrocervical trunk
Superior thyroid vein: to the internal jugular vein
Middle thyroid vein: to the internal jugular vein
Inferior thyroid vein: to the brachiocephalic vein
Which muscle protects the carotid sheath when the head is turned?
Sternocleidomastoid
What is Bell’s Palsy and how may it present in a patient?
Facial nerve palsy
Inability to contract muscles of facial expression + altered taste
Which nerves innervate the following muscles:
a. Temporalis
b. Masseter
c. Buccinator
d. Medial and Lateral Pterygoids
e. Pharyngeal Constrictors
f. Digastric
g. Mylohoid
Temporalis: Mandibular (trigeminal)
Masseter: Mandibular (trigeminal)
Buccinator: Buccal (facial)
Medial + Lateral Pterygoids: Mandibular (trigeminal)
Pharyngeal Constrictors
Sensory = Glossopharyngeal (IX) + Vagus (X)
Motor = Vagus (X) (+ a bit of Accessory (XI))
Digastric
Anterior belly = Mandibular (trigeminal)
Posterior belly = Facial
Mylohyoid: branch of inferior alveolar nerve (branch of the mandibular)
What are the branches coming off the inferior alveolar nerve?
Mental nerve: terminal branch (sensation to front of chin)
Nerve to mylohyoid
What is the vallecula?
Depression just behind the root of the tongue: serve as spit traps
Saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex
Why are the tonsils clinically important?
Areas of lymphoid tissue so can get infected + inflamed
What is the simplest test of the glossopharyngeal nerve?
Test gag reflex by sticking something down their throat
How is the trigeminal nerve tested?
Sensory: touch jawline, cheek + forehead (to test the 3 divisions)
Motor: patient to clench teeth. Palpate bulge of the masseter + temporalis
How is the facial nerve tested?
Patient to crease up their forehead by raising their eyebrows
Patient to keep their eyes closed against resistance
How can dislocation occur at the temporomandibular joint?
If mouth opened far + over done, head of mandible glides past articular tubercle + dislocates into the temporal fossa
Where does the facial nerve emerge?
From anterior border of parotid gland
