CN VII: Facial Nerve Flashcards
What are the four nuclei of the facial nerve?
Spinal trigeminal nucleus: GSA; skin of outer ear
Nucleus of solitary tract: SSA; taste, nasal cavity and soft palate
Superior salivatory nucleus: GVE; glands
Facial motor nucleus: SVE; facial expression and stapedius
What CN VII fibers are received from the spinal trigeminal nucleus?
Pain and temp from outer ear
What CN VII axons travel to the nucleus of the solitary tract?
Taste for anterior 2/3 of tongue
Sensory for soft palate and nasal cavity
What CN VII axons leave the superior salivatory nucleus?
Salivary glands (EXCEPT parotid) Lacrimal glands - tears
What CN VII axons leave the facial motor nucleus?
Muscles of facial expression
Stapedius - controls sound volume
Where do the afferent axons for the facial motor nucleus come from?
Precentral gyrus -> corticobulbar pathway -> facial motor nucleus
T/F: Corticobulbar pathway controls upper facial muscles contralateraly, but lower facial muscles bilaterally.
FALSE
Upper face: bilateral
Lower face: contralateral
If there is a unilateral damage to the corticobulbar pathway, what would result in facial muscles?
Inability to smile or bare teeth symetrically
Wrinkling forehead unaffected
If a patient was struggling with unilateral facial paralysis that eventually heals over a long period of time what would this likely be?
Bell’s palsy
What are some symptoms of Bell’s palsy?
Paresis of muscles above and below eye; irritation of cornea on affected eye; reduced lacrimation and salivation
Describe the corneal blink reflex.
Touch cornea -> afferent CN V via SpV tract -> VII motor from bilateral projections from SpV nucleus/RF
What clinical test tests both V and VII?
Corneal blink test
Which reflex involves all nuclei of CN V?
Jaw opening and closing
What nuclei does the jaw-jerk reflex test?
Mesencephalic V: tap jaw so masseter stretches
Trigeminal motor: triggers masseter to stay closed
MONOSYNAPTIC
