trigeminal and facial nerves Flashcards
three branches of trigeminal nerve
v1 ophthalmic
v2 maxillary
v3 mandibular
trigeminal is what type of innervation
motor and sensory
where are the cell bodies of the pseudounipolar sensory neurons of CNV?
trigeminal ganglion in middle cranial fossa
what muscles does CN V innervate?
muscles of mastication
where are the CNV cell bodies of motor neurons?
trigeminal motor nucleus in the pons
where is the trigeminal ganglion located?
meckels cave – between te dura of the middle cranial fossa and the petrous temporal bone
what foramen does each trigeminal branch leave cranial cavity through?
v1 - superior orbital fissure
v2 - foramen rotumdum
v3 - foramen ovale
what region is v1/v2/v3 associated w?
v1 - orbit
v2 - pterygopalatine fossa
v3 - infratemporal fossa
v1
branches
ophthalmic - ALL sensory for upper face/nasal cavity/cornea
NFLnerves
nasociliary –> long ciliary nerves, anterior and posterior ethmoid nerves, and infratrochlear nerve
frontal –> supraorbital (lateral) and supratrochlear (medial)
lacrimal
lacrimal nerve is joined by? why?
postganglionic parasympathetics from v2 for tear production
what branches from v1 enter eyeball?
long ciliary off the nasociliary nerve
what supplies sensory to skin on upper nose?
infratrochlear nerve
v2
maxillary - ALL sensory for middle face/upper teeth/hard and soft palate, sinuses
branches:
2 ganglionic –> greater and lesser palatine, pharyngeal, nasopalatine
zygomatic –> zygomaticotemporal and sygomaticofacial
infraorbital
superior alveolar –> posterior superior, middle superior, and anterior superior alveolar branches
which v2 branches pass through pterygopalatine ganglion withoUT synapsing?
ganglionic branches
what v2 branch is in lateral orbit/branch that ascends? two divisions?
zygomatic nerve
zygomaticotemporal
and zygomaticofacial
cutaneous sensory to cheek, lateral nose, and upper lip?
infraorbital nerve off v2
v2 supply to maxillary sinus and teeth?
posterior, middle, and anterior superior alveolar nerves
posterior superior comes off becore v2 becomes infraorbital nerve
anterior and middle superior come off v2 after it becomes the infraorbital nerve
v2 terminal branch (becomes) is?
infraorbital nerve
why is sinusitis often interpreted as a tooth ache?
because maxillary sinus is innervated by superior alveolar nerves which also innervate the maxillary teeth
v3
both motor and sensory! to mandible/floor of mouth, anterior 2/3 tongue, lower face skin
motor fibers to MMATT (muscles of mastication, mylohyoid, anterior digastric, tensor velipalatini and tensor tympani)
v3 innervates structures derived from which pharyngeal arch
1st
anterior v3 vs posterior v3
anterior is mostly motor
posterior is mostly sensory
v3 motor fibers innervate ?
MMATT
muscles of mastication
mylohyoid
anterior digastric
tensor veli palatini
tensor tympani
what two nerves come off main trunk v3 first?
meningeal branch (sensory) and medial pterygoid nerve (motor)
meningeal branch reenters the skull through
foramen spinosum
anterior division of v3
masseteric, deep temporal x2, lateral pterygoid (all motor) –> pass above upper head of lateral pterygoid m.
buccal (sensory)–> passes between heads of lateral pterygoid m
posterior div of v3
auriculotemporal, lingual, and inferior alveolar (all sensory)
inf. alveolar gives off nerve to mylohyoid (motor)
only motor branch in posterior v3 div?
only sensory branch in anterior v3 div?
nerve to mylohyoid
buccal nerve
loss of corneal reflex –> lesions where?
v1
which way will jaw deviate with weakness of muscles of mastication?
toward the side of weakness
trigeminal neuralgia
tic douloureux
CN V disorder with recurrent short (<15 min) episodes of pain, usually in v2/v3 areas
facial nerve VII has 4 components
lower motor neurons
parasympathetic fibers
taste fibers
somatosensory fibers
where do facial lower motor neurons originate, exit, and innervate?
facial motor nucleus of pons
cerebellopantine angle as motor root
muscles from 2nd pharyngeal arch FESS-P (muscles of facial expression, stapedius, stylohyoid, and posterior digastric)
facial nerve innervates
muscles of facial expression
stapedius
stylohyoid
posterior digastric
FESS-P
(2nd pharyngeal arch muscles)
where do facial nerve VII parasympathetic fibers originate and innervate?
superior salivary nucleus
submandibular, sublingual, and lacrimal glands
what innervates submandibular, sublingual, and lacrimal glands?
parasympathetic fibers from VII
VII taste fibers
innervate anterior 2/3 tongue
where are cell bodies of VII taste fibers? descend in? terminate in?
geniculate ganglion
solitary tract –> solitary nucleus
what part of VII descends in spinal V tract
somatosensory fibers
course of facial nerve
motor root and intermediate nerve enter internal acoustic meatus –> geniculate ganglion
at geniculate ganglion splits –> greater petrosal nerve and abrupt bend posteriorly
1) greater petrosal –> pterygopalatine ganglion –> lacrimal gland
2) VII at geniculate ganglion –> tympanic cavity –> nerve to the stapedius and chorda tympani come off –> nerve then exits petrous temporal bone through stylomastoid foramen –> parotid gland (superficial to retromandibular veina and ECA) –> divides into temporofacial and cericofacial branches –> terminal branches (temporal, zygomatic, upper and lower buccal, marginal mandibular, and cervical)
terminal branches of facial nerve are purely
motor
what is the sensory ganglion of CN VII?
geniculate ganglion
what nerve contains the preganglionic parasympatheric fibers for the lacrimal gland?
greater petrosal nerve
what nerve has the preganglionic parasympathetic fibers for submandibular and sublingual glands and taste fibers for ant. 2/3?
chorda tympani
lesion of facial nerve –>
paralysis/weakness of facial musculature
weakness of facial muscles on the entire ipsilateral side
peripheral facial nerve palsy
distorted appearance at rest and during movement
peripheral facial nerve palsy effects
dropped eyebrow and corner of mouth on affected side
smooth forehead on affected side
asymmetrical smile
food in cheek due to paralysis of buccinator
absent corneal reflex in ipsilateral eye, but corneal sensation is intact(V1)
where is lesion if taste is impaired?
proximal to chorda tympani origin
impaired salivary secretion
lesion is proximal to origin of chorda tympani
dmaged parasympathetic fibers for glands
impaired lacrimation (dry eye)
damage to parasympathetic fibers for lacrimal gland
lesion proximal to origin of the greater petrosal nerve
bells palsy
all divisions of facial nerve become impaired over hrs/days - usually unilateral
viral or inflammatory cause
recovers over 2-3 weeks, sometimes residual effects
voluntary central facial palsy
lesion to the corticobulbar system
upper MN palsy
corneal reflex stays intact and coluntary m of upper face are preserved due to bilateral input
unilateral corticobulbar lesion produces only weakness of muscles of contralateral lower face
unilateral lesion of the corticobulbar system produces
weakness of muscles of contralateral lower face
corneal reflex and movement of upper face intact!
