Session 5- Cranial Nerves continued Flashcards
what are the divisions of the trigeminal nerve
opthalmic
maxillary
mandibular
which branches of the trigeminal nerve pass through the cavernous sinus
opthalmic and maxillary
what does the opthalmic nerve pass through
superior orbital fissure
what does the maxillary pass through
foramen rotundum
what does the mandibular pass through
foramen ovale
what kind of nerve is the CN V
motor and general sensory
trigeminal
what are the distal branches of the Va branch of trigeminal
opthalmic
- frontal nerve- which gives rises to supraorbital/supratrochlear
- nasocillary nerve
what is the distal branch of the Vb
maxillary
=infra-orbital and superior alveolar nerves
what is the distal branch of Vc
- auriculotemporal nerve
- lingual nerve
- inferior alveolar nerve and mental nerve
where does the trigeminal nerve originate
pons
in varicella zoster infections where does it lie dormant
trigeminal ganglion then reactivates through one of the divisions usually opthalmic
causes a vescicular type rash that remains in the dermatome of the opthalmic branch
what is hutchinson sign
vescicular rash only extends down the nose if the nasocilary branch is involved
this increases the likelihood of eye being affected which threatens sight
what is CN VII
facial nerve
what kind of nerve is CN VII
motor, special sensory- taste, parasympathetic
which of the cranial nerves are parasympathetic
1973
X IX VII III
Where does the facial nerve originate
pons
specifically pontomedullary junction
target tissues of CN VII
muscles of facial expression
taste from ant 2/3 of the tongue
glands - lacrimal, salivary (not parotid), mucosal (nose) not sweat
how do we test if CN VII is intact
facial expressions
unilateral facial droop +/- reporting symptoms due to absence of the other facial nerve functions
route of facial nerve
pons- internal acoustic meatus - into petrous bone and here gives off 3 branches - enters through base of skull via sylomastoid foramen - gives off extra cranial branches= muscles of facial expression
what are the three intrapetrous branches of the facial nerve
greater petrousal nerve - supplies lacrimal, masal and oral glands
nerve to stapedius
corda tympani- carries special sensory info from ant 2/3 of tongue
parasymoathetic fibres run with it to get to yhe glands in the oral cavity- salivary
where does the facial nerve exit the skull
stylomastoid foramen
how do we differentiate between a stroke and nerve lesion in terms of facial drooping
forehead sparing in a stroke because forehead receives motor innervation from both hemispheres of the cerebral cortex. A stroke that compromised motor innervation of the face would therefore only result in paralysis of the lower half of the face
how does pathology involving the motor pathways anywhere along the path from the PMC to where synapse with facial nerve motor nuclei present- before it exists the brainstem
upper half of contralateral face spared- has back up from ipsilateral input due to dual innervation
forehead wrinkles
how does pathology or imjury of the facial nerve anywhere from exit from the brainstem present and along its way to muscle tissue
whole half ipsilateral face is drooped no back up as it has already exited the brainstem
CN VIII
Vesticulocochlear
what kind of nerve is CNVIII
special sensory
where does the CN VIII originate
pons
target tissues of CN VIII
vestibular system
cochlea
route of CN VIII
exits pons-pontomedullary junction- then travels through internal acoustic meatus into the inner ear to the vestibular system - balance- and cochlea- hearing
how do we test if the CN VIII works
hearing tests
route of CN IX and X
arise from medulla
run through posterior cranial fossa
exit through jugular foramen
enter into carotid sheath
what kind of nerve is CN IX
glossopharyngeal- mainly sensory
target tisses of CN IX
post 1/3 of tongue- Somatosensory and Genreal sensory
1 swallowin muscle
afferents from carotid sinus and body
parasymoathetic to parotid
what is the function of the soft palate
separates the nasal cavity from the oral cavity
what type of nerve is CN X
motor and sensory
target tissues of CN X
muscles of larynx/ pharynx- including soft palate
sensory- larynx and laryngopharynx
parasympathetic to many tissues
where do CN IX and X emergr
medulla
how do patients present if they have lesions to CN X and CN IX
difficulty swallowing
weak cough
difficulties with speech or changes to voice
how do we asesess if cranial nerve X and IX is working
speech
swallow
cough
soft palate movement and uvula position
uvula position if nerve lesion
if lesion is left side uvula goes off centre
where do CN XI XII emerge and what route do they take
medulla and run through the posterior cranial fossa they then enter the carotid sheath briefly
hypoglossal then exits and travels to the tongue
accesory exits and heads towards posterior triangle
what type of nerve is hypogolssal
motor
target tissue of CN XII
tongue
where does the hypoglossal nerv exit
hypoglossal canal and at the level of the mandible it superficially crosses the internal and external carotid arteries
if there is damage to the right CN XII where does the tongue deviate
lick your wound
deviates towards weaker side therefore right
what kind of nerve is teh accesory nerve
motor
where does CN XI emerge
medulla
target tissues of CN XI
SCM
Trapezius
