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155 Cards in this Set

  • Front
  • Back
which part of the nervous system are the cranial nerves?
components of PNS
what structures are supplied by the cranial nerves?
muscles
sensory structures of skin
subcutaneous and deeper tissues including viscera
smooth muscles, cardiac muscle, secretory glands (ANS)
what are the regions innervated by the cranial nerves?
head and neck, with viscera and oral, nasal cavities, pharynx, larynx, ear, orbit, salivary glands
thoracic
abdominal
pelvic viscera
what are the cranial nerves all attached to?
the brain stem - all three divisions of it
do cranial nerves have ventral or dorsal roots?
no
where do the motor fibers from those nerves that supply muscles come from?
motor nuclei - neurons in brainstem
what sensory info is conveyed by cranial nerve VIII and V for example?
info from skin, mucous linings of cavities
viscera in head and neck, thorax, abdomen and pelvis
where does sensory info go once collected from distal cranial nerves?
to sensory ganglia in brainstem - correspond to ganglia of spinal nerves
do CNs carry sympathetic fibers?
no - not pre- or postganglionic fibers
which cranial nerves contain preganglionic parasympathetic fibers?
CNs III, VII, IX, X
where do nerves III, VII, IX, X come from?
parasympathetic nuclei in brainstem
where are the parasympathetic ganglia on which CNs III, VII, IX and X synapse?
III, VII, IX synapse on ciliary, pterygopalatine, submandibular and otic ganglias - all in head or neck

parasympathetic ganglia for X are found in thorax and abdomen, by organs vagus innervates
where are the postganglionic parasympathetic fibers of CNs III, VII, IX, X
III, VII, IX - would be traveling along with CN V to target

X is still in thorax and abdomen
what are the names and associated numbers of all the cranial nerves?
CN I = Olfactory
CN II = optic
CN III = oculomotor
CN IV = trochlear
CN V = trigeminal
ophthalmic
maxillary
mandibular
CN VI = abducent
CN VII = facial nerve
CN VIII = vestibulocochlear
CN IX = glossopharyngeal
CN X = vagus
CN XI = accessory
CN XII = hypoglossal
what hole does the olfactory nerve come out of - and what CN is that?
is CN I
comes out of optic canal
what hole does the optic nerve come out of and what CN is it?
CN II
optic canal
what hole does the oculomotor nerve come out of and what CN number is it?
CN III
superior orbital fissure
what hole does the trochlear nerve come out of and what CN number is it?
CN IV
superior orbital fissure
what hole does the trigeminal nerve come out of and what is its CN number?
CN V -
ophthalmic division - superior orbital fissure
maxillary division - foramen rotundum
mandibular division - foramen ovale
what hole does the abducent nerve come out of and what CN number is it?
CN VI - superior orbital fissure
what hole does the facial nerve come out of and what is its CN number?
CN VII
internal acoustic meatus to the facial canal to the stylomastoid foramen
what hole does the vestiubulocochlear nerve come out of and what CN number is it?
VIII
internal acoustic meatus as well
DOESN'T LEAVE THE SKULL
what's the CN that doesn't leave the skull?
vestibulocochlear nerve - CN VIII
what's the glossopharyngeal nerve CN number and where in the skull does it come out?
IX
jugular foramen
where in the skull does the vagus nerve exit and what is its CN number?
CN X
jugular foramen
where does the accessory nerve come out of the skull and what CN number is it?
CN XI
jugular foramen
where in the skull does the hypoglossal nerve exit and what is its CN number?
CN XII
hypoglossal canal
what nerves share the superior orbital fissure?
4:
1. oculomotor = CN III
2. trochlear - CN IV
3. ophthalmic branch of trigeminal nerve = CN V1
4. abducent nerve = CN VI
what nerves share the internal acoustic meatus?
CN VII - facial nerve
CN VIII - vestibulocochlear nerve
what nerves come out of the jugular foramen?
1. CN IX - glossopharyngeal nerve
2. CN X - vagus nerve
3. CN XI - accessory nerve
what types of nerve fibers make up the olfactory nerve or CN I?
just sensory
what's the path of the olfactory nerve?
terminates in the nasal cavity on specialized receptors in olfactory mucosa
exits cranial cavity via olfactory foramena in cribriform plate
starts in olfactory bulb of brain
what's the major function of the olfactory nerve?
conveys sense of smell to brain for perception, discrimination
what types of fibers are in the optic nerve, CN II?
just sensory
what's the path of the optic nerve?
ends in retina
exits cranial cavity through optic canal
optic chiasm and tract is where nerve comes from
starts in brain (thalamus?)
what's the major function of the optic nerve, CN II?
carries visual sensations to brain for perception, discrimination
what kinds of fibers do the oculomotor, trochlear and abducent nerves carry? CN III, IV and VI respectively?
only motor
what common pathway do CNs III, IV and VI share?
all exit the cranial cavity via the superior orbital fissure
then enters orbit
what muscles are innervated by CN III, the oculomotor nerve?
LPS = levator palpebrae superioris
medial rectus
superior rectus
sphincter of pupillae
ciliary muscle
what kinds of muscles are innervated by CN III, the oculomotor nerve?
both smooth and skeletal
how are the smooth muscles of the eye innervated?
by parasympathetic preganglionic fibers from CN III, the oculomotor nerve
what muscles are innervated by CN IV, the trochlear nerve?
superior oblique
what muscles are innervated by CN VI, the abducent nerve?
Lateral rectus
what does the superior oblique do?
depresses eyeball
what does the lateral rectus do?
abducts eyeball
what muscles affects the size of the pupil?
the sphincter pupillae
what muscle changes the shape of the lens?
ciliary muscle
how many and what are the names of the skeletal muscles that move the eye?
7 total

1. superior rectus
2. inferior rectus
3. medial rectus
4. lateral rectus
5. superior oblique
6. inferior oblique
7. levator palpebrae superioris
where are the recti muscles of the eye inserted?
onto the front of the eyeball
where do the oblique muscles of the eye insert?
the back of the eyeball
what does the superior oblique do?
depresses eye by pulling up on the back
what does the inferior oblique do?
elevates eye by pulling down on the back
what does the LPS do and how does it do it?
opens eyes

pulls up on tarsus or cartilage of upper lid to elevate lid
what is accomodation?
eye focusing on close objects
what does accomodation involve?
1. pupillary constriction
2. convergence of eyes from contraction of both medial recti
3. increase in convexity of lens
what does it mean to say that the eyes have conjugate movements?
means that eye muscles work together in pairs
what muscles contract to move the eyes right?
left - medial rectus
right - lateral rectus
what muscles contract to move the eyes left?
left - lateral rectus
right - medial rectus
what muscles contract to move the eyes up or down when looking straight ahead?
up - superior recti AND INFERIOR OBLIQUE

down - inferior recti AND SUPERIOR OBLIQUE
do the recti and obliques work optimally when staring straight ahead? why or why not?
no, because they are at a 90 degree angle to each other
what muscles contract to move the eyes up and down when the eyes are looking to the right?
UP
left - IO
right - SR

DOWN
left - SO
right - IR
what's the rule to remember when deciding which muscles are being used for which movements?
eye that's on side to which gaze is directed just has to move up or down with recti

eye on opposite side to which gaze is directed has to move up or down AND at an angle, so uses obliques
when do the recti and obliques act optimally?
when one is not staring straight ahead and then looking either up or down
what muscles contract to move the eyes up or down when looking to the left?
UP
left - SR
right - IO

DOWN
left - IR
right - SO
what kinds of nerve fibers are in the trigeminal nerve?
both sensory and motor
NO PARASYMPATHETIC FIBERS
what are the roots of the trigeminal nerve and what are their relative sizes?
sensory root is large compared to motor root
where is the sensory ganglion used by the trigeminal CN V nerve?
apex of petrous part of temporal bone
which types of fibers are carried in each of the trigeminal nerve branches?
V1 - ophthalmic nerve = Sensory
V2 - maxillary nerve = Sensory
V3 - mandibular nerve = motor and sensory
which parasympathetic ganglia does the trigeminal nerve hook up with to pass along their postganglionic fibers?
4:
1. ciliary ganglion - from nasociliary branch of V1
2. pterygopalatine ganglion - from V2
3. submandibular ganglion - from lingual branch of V3
4. otic ganglion - from V3
what kinds of fibers are hitching rides on the trigeminal nerve?
POSTganglionic fibers
what's the course and distribution of the ophthalmic division of the trigeminal nerve? V1
1. enters orbit through superior orbital fissure
2. divides into frontal, nasociliary, lacrimal branches
3. supplies orbit and nasal cavity
4. becomes terminal cutaneous branches in scalp, upper lid, nose
what's the course and distribution of the maxillary division of the trigeminal nerve? V2
1. enters pterygopalatine fossa through foramen rotundum
2. travels through inferior orbital fissure
3. enters face through infraorbital foramen
4. becomes terminal cutaneous branch or infraorbital nerve once exiting the infraorbital foramen
what's the course and distribution of the mandibular division of the trigeminal nerve? V3
1. exits through foramen ovale
2. reaches infratemporal fossa
3. parts travel through mandible
4. enters face thru mental foramen as cutaneous branch - mental nerve
what's the major motor function of the mandibular branch of the trigeminal nerve? V3
motor innervation to muscles of mastication!!
1. temporalis
2. masseter
3. lateral pterygoid
4. medial pterygoid

also happens to innervate the mylohyoid, anterior belly of digastric, tensor tympani, and tensor palati, but apparently we're not worried about that right now
what kinds of perceptions can be felt by the trigeminal nerve?
pain from head, regardless of cause
examples; toothache, headache, sinus pain
what areas of the head and face are sensory innervated by the ophthalmic branch of CN V? V1?
TOP OF HEAD
meninges - top of head
orbit, including cornea and conjunctiva
lining of nasal cavity
skin of forehead and middle of nose
frontal air sinuses
what areas of head and face are sensory innervated by maxillary branch of trigeminal nerve? V2?
CHEEK
meninges - front, side of head
maxillary air sinus
gums and teeth of upper jaw
skin over bony part of cheek
what areas of head and face are sensory innervated by mandibular branch of trigeminal nerve? V3?
JAW
meninges - back, side of head
mucosa of oral cavity and palate
anterior two thirds of tongue (EXCEPT TASTE)
gums and teeth of lower jaw
skin over soft part of cheek and mandible EXCEPT for angle of mandible - that's sensory innervated by cervical spinal nerves
what kinds of fibers does the facial nerve contain?
all three
motor, sensory, parasympathetic preganglionic fibers
what's the course and distribution of the facial nerve, CN VII?
1. leaves cranial cavity via internal auditory meatus
2. passes geniculate ganglion, sensory ganglion of facial nerve
3. runs in bony facial canal IN temporal bone close to inner, middle ear cavities
4. exits base of skull through stylomastoid foramen
5. enters substance of parotid gland and divides into terminal branches on face
where's the sensory ganglion of the facial nerve located?
internal auditory meatus
what's the sensory ganglion of the facial nerve called?
geniculate ganglion
what nerve innervates the parotid gland?
facial nerve CN VII

edit - is another question stating innervation from CN 9 - glossopharyngeal
what are the major functions of the motor fibers of the facial nerve?
innervates muscles of facial expression, scalp muscles (then 3 random more)

important muscles to know:
those that help in smiling, frowning, blowing, whistling, lifting eyebrows, closing eye

muscles that aren't important -
posterior belly of digastric, stylomastoid, stapedius
what are the major functions of the sensory fibers of the facial nerve?
supplies TASTE BUDS in ANTERIOR two-thirds of tongue

supplies small area of skin lining external auditory meatus
what are the major functions of the parasympathetic fibers of the facial nerve?
1. preganglionic - synapse in:
a. pterygopalatine ganglion
b. submandibular ganglion
2. postganglionic - supply:
a. lacrimal gland via branch of V
b. sublingual
c. submandibular salivary glands by branches of V again


essential for secretory function of glands
what kind of nerve fibers does the vestibulocochlear nerve contain?
just sensory - but there are 2 components:
1. vestibular
2. cochlear nerves
what's the path of the vestibulocochlear nerve?
1. leaves cranial cavity by internal auditory meatus
2. ends in specialized receptors of inner ear in petrous temporal bone
what are the major functions of the vestibulocochlear nerve?
VESTIBULAR NERVE
maintains equilibrium by communicating
a. changes in position
b. movements of head

COCHLEAR NERVE
hearing, auditory
what kind of nerve fibers does the glossopharyngeal nerve contain?
ALL 3!
sensory, little motor, parasympathetic preganglionic fibers
what's the course and distribution of the glossopharyngeal nerve?
1. leaves cranial cavity via jugular foramen with vagus, accessory
2. divides into branches that then enter pharynx
what's the pharynx?
muscular chamber posterior to nasal and oral cavities

leading into larynx anteriorly and esophagus posteriorly
what are the major sensory functions of the glossopharyngeal nerve?
1. innervates mucosa of posterior third of tongue and pharynx including tonsillar area
in tongue, branches convey general sensation and taste

2. supplies specialized chemoreceptors in carotid body and baroreceptors in carotid sinus
these receptors are important in the reflex regulation of blood pressure and respiration
what are the major motor functions of the glossopharyngeal nerve?
supplies one muscle of pharynx, stylopharyngeus, which assists in swallowing
what are the major parasympathetic functions of the glossopharyngeal nerves?
preganglionic fibers end in otic ganglion
postganglionic fibers supply parotid salivary gland - necessary for secretion of saliva
edit - is another question stating facial nerve innervates parotid
what kinds of fibers does the vagus nerve contain?
ALL THREE kinds
sensory, motor, HUGE parasympathetic component
what's the course and distribution of the vagus nerve?
1. exits skull through jugular foramen
2. enters neck
3. divides into branches
4. motor, sensory fibers leave as branches of vagus in neck
5. parasympathetic and rest of sensory fibers go into thorax and abdomen
what nerve is the accessory nerve considered to be a part of?
CN X, vagus nerve
what's the function of the accessory nerve?
purely motor
innervates muscles also supplied by vagus in neck
what are the major motor functions of the vagus nerve?
1. supplies skeletal muscles of:
a. pharynx, except the stylopharyngeus
b. larynx
c. soft palate - except tensor palati
d. upper 2/3rds of esophagus
e. important for swallowing, phonation, articulation of speech
what are the major sensory functions of the vagus nerve?
supplies mucus membrane of larynx
small number of fibers conveys taste from epiglottic area
what are the major parasympathetic functions of the vagus nerve?
preganglionic fibers end in many unnamed parasympathetic ganglia along walls of viscera

postganglionic fibers supply:
a. heart
b. smooth muscles, secretory glands of thoracic and abdominal viscera
what's the course and distribution of the accessory nerve?
1. pops up below foramen magnum from upper cervical spinal cord
2. enters cranial cavity through foramen magnum
3. joins vagus
4. leaves through jugular foramen
5. separates from vagus
6. enters roof of posterior triangle
what are the major functions of the accessory nerve?
motor innervation to sternocleidomastoid and trapezius muscles
what type of fibers does the hypoglossal nerve contain?
only motor
what's the course and distribution of the hypoglossal nerve?
1. leaves cranial cavity via hypoglossal canal - also called anterior condylar canal
2. distributes out to tongue
what are the major functions of the hypoglossal nerve?
1. extrinsic (except palatoglossus) and
2. intrinsic muscles of tongue
3. changes shape of tongue and produces up/down, side to side and protruding movements
how do i test the olfactory nerve theoretically?
use simple odors under each nostril at a time to test smell
examples: peppermint, coffee
what's a normal finding of a test to the olfactory nerve?
correct identification of odor
how would i test the optic nerve?
visual acuity using standard eye chart
test visual fields using confrontation test
ophthalmoscope exam
what's a normal finding of an optic nerve test?
correct identification of letters
no visual field defects
normal fundus
how would i test the parasympathetic part of oculomotor nerve function?
flash a light in one eye at a time
what's a normal finding of the test for parasympathetic function of the oculomotor nerve?
ipsilateral (direct light reflex) and
contralateral (consensual light reflex)
pupils constrict
how would i test the motor function of the oculomotor nerve, as well as the trochlear and abducent nerves?
ask patient to follow finger as i move it right and left, up and down, and obliquely
what's a normal finding of a motor test to the oculomotor nerve, and a general test of the trochlear and abducent nerves?
both eyes follow finger in parallel - with conjugate deviation
how would i test the trigeminal nerve?
feel the two masseter muscles as patient bites down

have patient open his/her mouth

test tactile, pain sensation for all 3 divisions

jaw jerk and corneal reflexes
what's a normal finding of a test to the trigeminal nerve?
equal contraction of masseters and no deviation of mandible

normal sensory perception from entire face
how would i test the facial nerve?
ask patient to wrinkle forehead, close eyes, show teeth

apply small amount of sugar or salt to anterior 2/3rds of tongue
what's a normal finding for the facial nerve?
normal execution of facial movements

correct identification of substance
how would i test the glossopharyngeal nerve?
touch the pharynx with a cotton applicator
what's a normal finding for a test of the glossopharyngeal nerve?
gagging
how would i test the vagus nerve and accessory nerve?
ask patient to say "ah"

listen to person talk
what's a normal finding for a test of the vagus and accessory nerves
both sides of soft palate should rise and uvula should remain in midline

lack of hoarseness
how would i test the accessory nerve?
ask person to turn his/her head to each side and shrug shoulders while i resist movements
what would a normal finding be for a test of the accessory nerve?
strong contractions of sternocleidomastoid and trapezius muscles
how would i test the hypoglossal nerve?
ask person to stick out his/her tongue fully
what's a normal finding for a test of the hypoglossal nerve?
tongue protrudes in midline
what's the corneal reflex?
i ask patient to look to one side
i touch opposite cornea with a cotton wisp
normal response is bilateral closure of eyes
what would happen in the corneal reflex if a person had unilateral trigeminal sensory loss?
no response by stimulation of corresponding eye (where nerve problem is)
what are the afferent and efferent limbs of the corneal reflex?
afferent - V1
efferent - VII
what's a jaw jerk?
motor functions from V3 are tested
i ask patient to clench teeth, then palpate contraction of masseters and temporalis muscles
have patient open mouth just a little
tap on chin with tendon hammer

normally, reflex not prominent
in abnormal cases, mouth will close
what technically is the gag response and how does one stimulate it?
to stimulate: touch lateral walls of pharynx where tonsils located OR
posterior third of tongue, one side at a time - with tongue depressor

response = forceful contraction of pharyngeal muscles and elevation of soft palate
what are the sensory or afferent nerves for the gag reflex and what are the motor or efferent nerves?
afferent - IX
efferent - X
what nerves does the gag reflex test?
IX and X
what do i do if the gag reflex is absent?
test X further to see which of nerves IX or X is involved
what's a symptom of dysfunction in the olfactory nerve?
reduction or loss of smell
example: trauma from closed head injury or skull fracture
what's a symptom of dysfunction in the optic nerve?
visual deficits in corresponding eye, partial or complete
what are symptoms of dysfunction in oculomotor nerve?
1. downward/outward deviation of eyeball due to unopposed pulls of lateral rectus and superior oblique

2. diplopia due to images in two retinae falling on non-corresponding loci on two retinae

3. ptosis from paralysis of LPS

4. dilated and fixed (unresponsive to light) pupil with loss of accomodation due to paralysis of sphincter and ciliaris muscles
what muscles would be affected if a person could only look down and out?
medial rectus, inferior oblique
what are symptoms of dysfunction in trochlear nerve?
troubles moving eye down and in
diplopia
what are symptoms of dysfunction to trigeminal nerve?
no sensation in areas once innervated
loss of corneal reflex in both eyes when affected eye stimulated
paralysis of muscles of mastication
difficulty chewing
flatterning of one side of face
complete loss of function rarely encountered
what are symptoms of dysfunction of the abducent nerve?
failure to abduct affected eye - paralysis of LR
diplopia - same reason as for oculomotor nerve
abducent nerve has longest intracranial course - is subject to stretching when intracranial pressure increases
bilateral paralysis of LR would suggest problem caused by an increase in intracranial pressure from tumor, hemorrhage...
what are symptoms of dysfunction to the facial nerve?
inability to raise eyebrow and wrinkle forehead
failure of corner of mouth to elevate on smiling
widening of palpebral fissure, inability to close eye
constant dripping of tears out of eye
loss of nasolabial fold
inability to blow, whistle
what are symptoms of dysfunction to vestibulocochlear nerve?
problems in hearing, maintaining balance
what are symptoms of dysfunction in glossopharyngeal nerve?
loss of gag reflex when affected side of pharynx stimulated

can lead to loss of sensation of taste in posterior third of tongue
what are symptoms of dysfunction in the vagus nerve?
difficulty in swallowing = dysphagia
difficulty in speaking - dysphonia
these are both due to loss of motor function on corresponding side of pharynx, palate and larynx

voice hoarse

patients says "ah" and palatal arch on affected side can't rise - uvula deviates to normal side
what are symptoms of dysfunction of accessory nerve?
weakness of sternocleidomastoid and trapezius muscles on same side

best detected when patient shrugs shoulder, turns head to one side against resistance
what are symptoms of dysfunction of hypoglossal nerve?
paralysis and atrophy of tongue on corresponding side

when patient asked to protrude tongue, tongue deviates toward paralyzed side
if patient has double vision, drooping left eyelid, eyes deviated down and out, pupil dilated and fixed on left side, eyes can't converge and images are blurring, what should be suspected?
CN III paralysis on left side
patient comes in with normal left lateral gaze, both eyes can move together to left side

however, right eye can't abduct when looking to right, abnormal right lateral gaze

which cranial nerve is affected and on which side?
would pupillary reflexes be lost in this patient?
if this patient had bilateral loss of lateral gaze, what would be the cause?
CN VI on right side; would still have pupillary reflexes in this patient

bilateral loss - problems with both sides of CN VI
if patient complained of spontaneous, severe pain on right side of face - triggered by chewing, touching, drinking - localized to right lower eyelid, right side of nose and cheek and right upper lip, what would i suspect?
which division of V is involved?
would this condition be associated with motor deficits?
V2
no motor deficits
what would my major concern be for a patient who had lesions along sensory innervation of V1, V2?
don't know - hopefully i'll know after studying this
if patient comes in saying she woke up to find face distorted - couldn't close right eye
has difficulty speaking, eating, drinking, because she can't close her mouth completely
right eye tearing constantly

what's the common name for this condition?

would taste sensation to anterior 2/3rds of tongue be normal?
CN VII - right side
bell's palsy
no, taste sensation would not be normal
patient comes in with hoarseness, difficulty swallowing, difficulty speaking

palatal arches don't rise symmetrically - left side lower than right

does this patient have dysfunction of right or left nerve X?
left
patients comes in slurring speech, has difficulty swallowing

tongue deviates to right when protruded

surface of right half of tongue wrinkled with visible twitchings

which nerve on which side involved?
CN XII on right