Lecture 7 - Cranial Nerve V, VII, XIII-XII Flashcards
What is Cranial Nerve V?
Trigeminal nerve
What is Cranial Nerve VII?
Facial nerve
What is Cranial nerve VIII?
Vestibulocochlear
What is cranial nerve IX?
Glossopharyngeal nerve
What is cranial nerve X?
Vagus nerve
What is cranial nerve XI?
Accessory nerve
What is cranial nerve XII?
Hypoglossal nerve
What are all 12 cranial nerves?
I = olfactory
II = optic
III = occulomotor
IV = trochlea
V = Trigeminal
VI = Abducens
VII = Facial
VIII = vestibulocochlear
IX = Glossopharyngeal
X = vagus
XI = Accessory
XII = hypoglossal
If a lesion is affecting a cranial nerve leaving the left side of the brainstem what side of the patient will signs manifest in?
Left side of patient
What is a tract?
The pathways that connect the cortex to the cranial nerves
Why does a stroke often affect the contralateral side of the body?
Strokes often involve the tracts connecting the cortex to the cranial nerve
This means the connection between the for example right sided cortex and the left cranial nerve is damaged
What does the Trigeminal nerve generally supply?
Skin of face, scalp and deep structures of the face
What is the bulge called on the Trigeminal nerve called?
Trigeminal ganglion
What part of the brain does the Trigeminal nerve arise from?
Pons
What part of the pons does the Trigeminal nerve arise from?
Side of the pons
What are the target tissues which the Trigeminal nerve (V) supplies?
Skin of face
Part of scalp
Surface of eye
Deep facial structures
General sensation to Anterior 2/3 of tongue
Motor to Muscles of mastication
What branch of the Trigeminal nerve (V) supplies the muscles of mastication?
Mandibular division of Trigeminal nerve (V)
How do you assess if the Trigeminal nerve (V) is functional?
Light touch on the Dermatomes of Va (ophthalmic), Vb (maxillary) and Vc (mandibular)
Any muscle wastage of the muscles of mastication
Corneal reflex present or absent
What branch of the Trigeminal nerve (V) is affected if there is muscle of mastication wastage?
Mandibular division (Vc)
What is the corneal reflex?
When the one eye is touched it leads to both eyes blinking
What nerves are important in the corneal reflex?
Ophthalmic divsion of the Trigeminal nerve for sensory (afferent)
Facial nerve (VII) = motor/efferent to close the eye
What are some examples of causes of Trigeminal nerve (V) lesions?
Trigeminal herpes zoster/shingles in a Trigeminal ganglion
Trigeminal neuralgia
Orbital and mandibular fractures
Posterior cranial fossa tumours
What affects which part of the face is covered with vesicles with Trigeminal herpes zoster?
What branch of the Trigeminal nerve it goes down
What is Trigeminal neuralgia?
What causes it?
When you get extreme pain in the face/headaches
When a blood vessel near the brain stem compresses the Trigeminal nerve
What branches of the Trigeminal nerve (V) pass through the cavernous sinus?
Ophthalmic
Maxillary
What hole in the skull does the ophthalmic division of the Trigeminal nerve pass through after passing through the cavernous sinus?
Superior orbital fissure
What hole in the skull does the maxillary division of the Trigeminal nerve pass through after passing through the cavernous sinus?
Foramen rotundum
What hole in the skull does the mandibular division of the Trigeminal nerve pass through?
Foramen ovale
What 2 key nerves does the ophthalmic division of the Trigeminal (V) nerve branch to?
Frontal nerve -> supraorbital on forehead
Nasociliary nerve
Why is a case of Trigeminal herpes with vesicles on the tip of the nose a cause for concern?
Nasociliary branch of Trigeminal (V) nerve supplies sense to the surface of eye and dorsum of nose
So if you see vesicles around here its likely vesicles will develop on the eye, scar and cause blindness
What is Hutchinson’s sign?
When vesicles from Trigeminal herpes are found on the tip of the nose
Indicates likely the Nasociliary nerve involved so potential to lose sight
What 2 key nerves does the maxillary division of the Trigeminal (V) nerve branch to?
Infra-orbital and superior alveolar nerves
Where does the infraorbital nerve emerge from the skull>
The whole just under the orbit on the anterior face
What nerve can be damaged in an orbital blow-out fracture?
Infra orbital nerve
What 3 nerves branch from the mandibular division of the Trigeminal nerve (V)?
Auriculotemporal nerve
Lingual nerve
Inferior alveolar nerve and mental nerve
What does the Auriculotemporal nerve supply?
Temporal Mandibular Joint
What does the lingual nerve supply?
General sensation from anterior 2/3 of tongue
What nerve is often damaged in a mandibular fracture?
Inferior alveolar nerve
What part of the brain does the facial nerve (VII) come from?
Bottom of the pons
What does the Facial nerve (VII) supply?
Muscles of facial expression + stapedius (muscle in middle ear)
Parasympathetic to lacrimal gland, nasal gland, salivary glands except for the parotid gland
Taste to the anterior 2/3 tongue
How can you assess whether someone has a facial nerve (VII) lesion?
Unilateral facial drooping (innervates muscles of facial expression)
+
Symptoms of other facial nerve functions like lack of taste or affected lacrimation or salivation
What is the route of the facial nerve?
Bottom of pons through the internal acoustic meatus through the Petrous bone (gives off 3 branches in the Petrous bone) then emerges through the skull through the parotid gland to to stylomastoid foramen
What 3 branches does the facial nerve give off while running through the Petrous bone?
Greater Petrous all nerve
Nerve to stapedius
Chorda tympani
What is the function of the greater Petrosal nerve?
Carries parasympathetic to lacrimal and mucosal glands
What is the function of the nerve to stapedius?
Motor branch to stapedius
What is the function of the nerve chords tympani?
Carries taste
What are some causes of Facial nerve lesions?
Lesions in/around internal acoustic meatus and posterior cranial fossa tumours
Basal skull fracture (Petrous bone)
Middle ear disease
Inflammation in facial canal
Bells Palsy
Ramsay-hunt syndrome
What is Ramsay-hunt syndrome?
Facial nerve lesion (shingles) with facial droop and vesicles in ear
Where does the Vestibulocochlear nerve (VIII) arise from?
Pons
What is the route of the vestibulocochlear nerve (VIII)?
Pons ->internal acoustic meatus ->Petrous bone - target tissues of inner ear
What are the target tissues of the vestibulocochlear nerve (VIII)?
Cochlea (hearing)
Vestibular system (balance)
How can patients present with vestibulocochlear (VIII) nerve lesions present?
Dizziness (vertigo)
Hearing loss/tinnitus
What can cause vestibulocochlear nerve (VIII) lesions?
Vestibular schwannoma (benign)
Occlusion of labyrinthine artery
Base of skull fracture (involving Petrous bone)
What are the 4 nerves that arise from the medulla?
IX = Glossopharyngeal
X = Vagus
XI = accesssory
XII = Hypoglossal
What is the route of of the Glossopharyngeal (IX) and vagus nerve (X)?
Arise medulla
Runs through posterior cranial fossa
Exits through jugular foramen
Enter into carotid sheath
Glossopharyngeal exits carotid sheath proximally but vagus continues inferiorly down length of neck
What are the target tissues of the Glossopharyngeal nerve (IX)?
Sensory to oropharynx and sensation to middle ear
Post 1/3 of tongue (sensation and taste)
Parasympathetic to parotid
Afferent from carotid sinus + carotid body
What are the target tissues of the Vagus nerve (X)?
Muscles of larynx and most of pharynx (including soft palate)
Parasympathetic to many tissues
General sensory of parts of external ear
How May patients with Glossopharyngeal and/or vagus nerve (X) lesions present?
Difficulties with speech or changes in voice (CN X)
Difficulties with swallow (CN X)
Weak cough (CN X)
How can you test for the functionality of the vagus nerve (X)?
Speech and cough
Soft palate movement and uvula position
Swallow
Gag reflex (also tests glossopharynegal)
What can lead to pathology of the Glossopharyngeal and Vagus nerve (IX + X)?
Recurrent laryngeal nerve branch of CNX (thyroid pathology or surgery, superior thorax/mediastinal pathology)
Pathology involving carotid sheath structures
Posterior cranial fossa tumours
Base of skull fractures
Brainstem(medullary) lesions
How do both the accessory and the (XI) and the hypoglossal (XII) nerve run?
Arise from medulla and runs through posterior cranial fossa
Both enter into carotid sheath:
-hypoglossal exits and travels towards tongue
-accesssory exits and heads towards posterior triangle
What are the target tissues of the hypoglossal (XII) nerve?
How do you test for pathology?
Muscles of tongue on the same side as the nerve
Ask patient to move tongue side to side
What are some pathologies that can lead to Hypoglossal L nerve lesions?
Surgery/pathology in proximity to or involving upper carotid sheath , int and ext carotid artery
Posterior cranial fossa tumours
What way does the tongue bend if you have a right hypoglossal nerve (XII) injury?
Lick your wound
So would bend to right since right genioglossus would be weak or paralysed
What is the target tissues for the Accessory (XI)?
SCM
Trapezius
How can you test the functionally of Accessory nerve?
SCM turn head
Trapezius shrug shoulders
What pathologies can cause Accessory nerve lesions (XI)?
Injuries, surgery or pathology involving posterior triangle
Posterior cranial fossa tumours
How does the accessory nerve run?
Emerges deep to posterior border of SCM to enter posterior triangle
Runs superficially in posterior triangle to reach trapezius
What does sensation and taste to the anterior 2/3 of the tongue?
Sens = lingual (Vc)
Taste = Facial (chorda tympani)
What does sensation and taste to the posterior 1/3 of the tongue?
Glossopharyngeal does both Sens and taste to posterior 1/3 of tongue
