Neuro Usmle Cards 2

Front 1

olfactory nerve (CN1)

pathway projects to ____ finally

lesion results in ?

parahippocampal uncus lesions cause?

Back 1

amygdala and primary olfactory cortex (piriform cortex that overlies the uncus)

lesion = ipsilateral anosmia

olfactory hallucinations with deja vu

Front 2

ipsilateral anosmia
ipsilateral optic atrophy
contralateral papilledema

Back 2

foster kennedy syndrome 2/2 anterior fossa meningioma

Front 3

functions of the oculomotor nerve (CN3)

eye movement is from ____ of rostral midbrain-->eom and levator palpebrae (lift eyelid)

______ projects parasympathetic fibers to the _____ and then to sphinctre pupillae (miosis) and ciliary muscle (accomodation)

what causes ocluomotor paralysis or 3rd Nerve palsy?

sx?

Back 3

constricts pupil
accomodates
converges
moves the eye

oculomotor nucleus

EW nucleus
ciliary ganglion

transtentorial herniation via tumor, subudral hematoma, or epidural hematoma

1. EOM: eye looks down and out >>diplopia when pt looks in the direction of the paretic muscle
2. levator palpebra = ptosis
3. parasymp interruption >>dilated fixed pupil (internal opthalmoplegia) + can't accomodate

Front 4

trantentorial/uncal herniation (usually from tumor) can cause what sx?

Back 4

stretches 3rd N by forcing the hippocampal uncous through the tentorial noth

dilated fixed pupil = 1st sx
external strabismus (exotropia)

Front 5

aneurysms (P comm artery and carotid) can cause palsy of which nerve

Back 5

3rd nerve palsy

dilated and fixed pupil = first sx

Front 6

diabetes mellitus can cause palsy of which nerve?

sx?

Back 6

3rd nerve

only damages central fibers and spares the sphincter pupillae fibers
(due to damage of small vessels supplying th eeye)

(damages only the somatic fibers and spares the parasympathetics)

leads to double vision, ptosis and pain behind the eye

Front 7

trochlear nerve arises from the ___________ and decussates in the ______. it exits the brainstem on the ____surface

Back 7

contralateral nucleus of the caudal midbrain

decussates dorsal to the aqueduct, be;low the inferior colliculi

exits dorsal surface on the opposite side of the original nucleus

Front 8

CN IV palsy

cause?
sx?

can be mid-dx as ____

Back 8

trauma
herniation

-extorsion of th eeye and weak down gaze
-vertical diplopia which increases when looking down
-head tilting to compensate for extortion

torticollis

Front 9

trigeminal nerve has both motor and sensory nuclei

lesion result in what 6 sx

Back 9

1. heminanesthesia of face and mucous membranes of the oral and nasal cavitis (ipsi)

2. loss of the corneal reflex (afferent limb)

3. flaccid paralysis - muscles of mastication

4. deviation of jaw to the weak side (ipsis)

5. partial deafness to low pitched sound (ipsi)

6. trigeminal neuralgia (tic doulareux)

6.

Front 10

abducens nerve (6) is th emost common isolated palsy resulting from the long peripheral course of th enerve

list 4 conditions that can cause this and what are the defects

Back 10

defects:
1. convergent (medial) strabismus (esotrophia) -- can't abduct the eye
2. horizontal diplopia -- images separate most when eye looks laterally toward defective side

conditions:
1. meningitis
2. SAH
3. late stage syphilis
4. trauma

Front 11

functions of the facial nerve (7)

Back 11

1. motor muscles of facial expression (note voluntary smile affected, but reflex/emotional smile is not)
2. efferent limb of the corneal reflex
3. anterior 2/3 taste
4. stapedius innervation
5. lacrimation/salivation
6. sensation of the external ear
7. closes the eyelid (orbicularis oris)

Front 12

all first order neruons of the 7th nerve originate in the _______ located in the _______

the facial nerve exits the brainstem at the ______

it then enters the _______

in then exits the facial canal and skull through the ______

Back 12

geniculate ganglion, temporal bone

internal auditory meatus and facial canal

stylomastoid foramen

Front 13

stroke of the internal capsule = UMN lesion of the corticobulbar tract

effect on face?

Back 13

supranuclear facial palsy (central)

contralateral weakness of the lower face, sparing the forehead and the eye (orbicularis oris)

A unilateral lesion of the corticobulbar fibers to motor VII, for example in the motor cortex, results in weakness of the muscles of expression of the face BELOW THE EYE ON THE SIDE CONTRALATERAL TO THE LESION. The frontalis muscle (wrinkles forehead) and the orbicularis oculi muscle (closes eyelid) are unaffected.

Front 14

LMN lesion of CN VII is typically caused by _____ and results in _____ palsy which is (peripheral or central)?

sx?

Back 14

trauma or infection

Bell's palsy
peripheral

A unilateral lesion interrupting the axons of C.N. VII results in the following: On the ipsilateral side, the forehead is immobile, the corner of the mouth sags, the nasolabial folds of the face are flattened, facial lines are lost, and saliva may drip from the corner of the mouth. The patient is unable to whistle or puff the cheek because the buccinator muscle is paralyzed. When the patient is smiling, the normal muscles draw the contralateral corner of the mouth up while the paralyzed corner continues to sag. Corneal sensitivity remains (C.N. V), but the patient is unable to blink or close the eyelid (CN VII). To protect the cornea from drying, therapeutic closure of the eyelids or other measures are taken (patient wears an eye mask, or lids are closed with sutures). Because of the paralysis of the stapedius muscle, which normally dampens the amplitude of the vibrations of the ear ossicles, the patient will experience sounds as uncomfortably loud.

paresis of the entire ipsilateral face

Front 15

bilateral facial nerve palsies are common with ____

what would happen if the left cerebral cortex were damaged?

Back 15

Guillan barre syndrome

nterrupts all CORTICOSPINAL fibers and CORTICOBULBAR fibers to motor VII, nucleus ambiguus and the hypoglossal nucleus.

There will be a RIGHT hemiplegia, the tongue will deviate to the RIGHT upon protrusion, and the lower facial muscles on the RIGHT will be weak. Any problems with swallowing? Will the uvula deviate when you say ahhh? THINK! THIS IS VERY IMPORTANT.

Front 16

aside from facial paralysis, what defects are involved with CN 7 lesions?

Back 16

1. loss of corneal reflex >> corneal ulceration
2. hyperacusis (increased acuity to sounds 2/2 stapedius paralysis)
3. crocodile tears (lacrimation during eating)

Front 17

congenital facial diplegia and convergent strabismus

name syndrome and nerves affected

Back 17

7 and 6

mobius syndrome

Front 18

which CN nuclei are found in the mid medulla? which nerves do they innervate and what structures?

Back 18

Nucleus ambiguous >> 9, 10
9: muscles of the pharynx
10: muscles of the uvula, pharynx, larynx

dorsal motor nucleus of vagus (parasympathetic)>>10
innervates viscera below the head

hypoglossal nucleus >>12
innervates intrinsic/extrinsic toungue

Front 19

CN8 = vestibulocochlear nerve

functions? (2)
exits the brainstem where?
confiened to the ____ bone

Back 19

1. equilibrium and balance (vestibular nerve) - maintains image on retina with head movements

2. mediates hearing (cochlear nerve)

exits at the cerebellopontine angle
confined to the temporal bone

Front 20

the vestibular nerve of 8 is functionally associated with the ______

1st order neuron found _____

lesions result in _____

tract associated with this nerve is the _____ tracts

Back 20

cerebellum (flocconodular lobe)

Internal auditory meatus (vestibular ganaglion)

LATERAL VESTIBULAR NUC.—LATERAL VESTIBULOSPINAL TRACT—UNCROSSED—ENTIRE LENGTH OF CORD—VENTRAL FUNICULUS—PROXIMAL MUSCLES—MAINTAINS BALANCE BY ACTING MAINLY ON LIMBS

REMEMBER—MEDIAL VESTIBULAR NUCLEUS—MEDIAL VESTIBULOSPINAL TRACT—BILATERAL—CERVICAL AND UPPER THORACIC SPINAL CORD ONLY—MAINTAINS HEAD ERECT.


disequilibrium
nystagmus
vertigo

vestibulospinal

Front 21

Lesions involving the vestibular nerve, nuclei, and descending pathways will result in problems such as stumbling or falling _____

how do you test for this?

Back 21

TOWARDS THE SIDE OF THE LESION.

At the very onset of vestibular problems there may be a Romberg sign. Postural instabilities are kept in check by visual inputs however, closing the eyes with the feet together will reveal the unstable condition.

Front 22

vestibulo-oculomotor reflex

rt vestibular nerve turns on (with moving head to the right) >> stimulates the ______ which is located in the ______. the function of this is to stimulate ______.

once stimulated, it sends projectsion to the _____ and _____ via which pathways?

end result?

Back 22

left PPRF (ventral to the abducens nucleus in the pons)

horizontal eye movement

Left abducens nucleus>>>Left lateral recturs to the turn the left eye left.

axons to the R oculomotor nucleus via decussation via MLF to stimulate medial rectus of right eye to turn left

end result: move head to the right, both eyes turn left

Front 23

what is the result of a left vestibular nerve lesion?

Back 23

Right vestibular nuc predominate
stimulates left PPRF>>
stimulates L abducens nucleus (left eye turns left) which project to the Left abducens nerve and the right oculomotor nucleus via MLF decussation)>>both eyes slowly turn left, when go as far as possible,reflex back to the right

Right beating nystagmus

Front 24

what stimulates the PPRF to move eyes laterally voluntarily (called horizontal saccades)?

if you have a stroke in the R cerebral hemisphere, what results

Back 24

frontal eye field
(right frontal eye field >>left PPRF>>move both eyes left or left saccades)

R sided stroke = no R frontal eye field so left predominates:

Contralateral hemiplegia (left) +
horizontal saccades to the right (toward the unaffected side)

Front 25

A lesion of the LEFT PPRF will result in ______.

is there atrophy or misalignment of the eyes?

If a lesion in the pons is big enough to also involve the corticospinal fibers (pyramidal fibers) on the same side, the deviating eyes will LOOK ______ THE HEMIPLEGIA.

Back 25

the inability to make a VOLUNTARY saccade that moves the eyes to the LEFT of the midline

no.
Sometimes the eyes will be deviated to the RIGHT due to the unopposed normal circuitry for making RIGHT horizontal saccades.

toward

Front 26

A lesion of the LEFT ABDUCENS NUCLEUS will result _______


Will convergence be in tact?

will eyes be misaligned?
will the pt see double vision?
is there any self-correction?

Back 26

1. atrophy of the left lateral rectus + inability to turn the left eye left (laterally) - left abducens neurons are dead! (thus the atrophy)
2. small neruons to the right oculomotor nucleus are gone too, so no ability to move eye left (medial) on attempted leftward gaze. NO ATROPHY of the MR muscle on the right b/c neurons innvervating it from oculomotor nucleus still there.

convergence = simultaneous contraction of the medial rectus muscles >>still in tact

misalignment and double vision:
left abducens nuc means nothing to unoppose the left MR>>slight misalignment of left eye toward the right (mediallY)>>double vision>>pt rotates head to the left (toward lesion) to move right eye toward rt also (evens things out)

Front 27

lesion of the left abducens nerve results in ____

Back 27

atrophy of the left LR

left eye deviates medially>>double vision (you see a false image to the LEFT of the true vision. false images move. the further the image moves toward the lesion -- from right to the left-- the more they separate = horizontal diplopia)

self correction = move head to the left

Front 28

when is diplopia the worst? what makes it better?

Back 28

when attempted gaze in the direction of the lesion

moving head toward the lesion, which makes eyes scoot away from the lesion

Front 29

comatose patients have horizontal saccades similar to a lesion in the ____ where saccades are ____ the hemiplegia

Back 29

frontal eye field lesion
saccades point away from hemiplegia

Front 30

right MLF lesion results in _____

is there diplopia?
what gets rid of it?

Back 30

INO
internuclear opthalmoplegia (between nuclei 6 and 3 [6+3]) = inability to turn the right eye medially + no atrophy + diplopia on leftward gaze + nystagmus of the left eye

yes on leftward gaze
eye is deviated to the right b/c it can't look left, want to move both to the righ, so look left.

Because the RIGHT medial rectus has lost its drive (from the LEFT abducens) the RIGHT eye will deviate a little to the RIGHT (laterally) when looking straight ahead and there will be diplopia.

Turning the head to the left will ameliorate the diplopia (turn head opposite direction of eye deviation)

Front 31

if a person is spinning to the right, which vestibular nucleus is "driving"?

what is the result?

Back 31

right side is driving
righ beating nystagmus (Rt>>L PPRF>>L Abd nuc>>eyes look left>>reflex right)

fall to the left (right driver means arms and legs are so active on the right that it pushes you to the left)

Front 32

caloric nystagmus occurs when warm or cool water is irrigated in ear when head placed back

which temp activates the nuc?

Back 32

warm activates
cool deactivates

warm to the right ear = activates rt vestib nuc>>eyes look left and reflex right>>right nystagmus

cool to the right = left nystagmus

COWS

cool=opposite
warm = same

Front 33

What fibers run very close to the STT and are often involved with STT lesions above T2

result?

Back 33

preganglionic sympathetic fibers from the hypothalamus

ipsilateral horner's syndrome

CONSTRICTED PUPIL (MIOSIS) in the ipsilateral eye since the parasympathetic input is now in control.

There would also be slight drooping (PTOSIS) of the ipsilateral upper eyelid due to the absence of sympathetic “drive” to the superior tarsal (smooth) muscle.

There is also lack of sweating (anhidrosis) and vasodilatation (flushed face). Remember, sympathetics innervate sweat glands and constrict vessels.

Front 34

While lesions of the dorsal columns (fasciculi gracilis and cuneatus) in the spinal cord result in______ deficits, lesions of the medial lemniscus, in the brain stem, result in ______ deficits.

The axons of the DCML pathway decussate at ____

Back 34

IPSILATERAL

CONTRALATERAL

the location of the synapse of dorsal column fibers and nucleus gracilius (below T6) and cuneatus (above T6) = caudal medulla

Front 35

Lesions of the cerebellum lead to defects in the coordination of movements, but NOT ______.

what are the inputs to the cerebellum?

lesions here would cause (ipsi or conta) deficits?

would you get a romberg sign?

Back 35

paresis or paralysis

Such cerebellar defects involve errors in the rate, range or direction of voluntary movements.

accessory nucleus cuneatus and the Clark's column = both use Inferior cerebellar peduncle to enter cerebellum

ipsilateral deficits
no romberg (no efferents involved in lesion)

Front 36

the inferior olive lies in the _______

function

rt inferior olive lesion leads to ____

Back 36

ventral medulla, behind the pyramids

cerebellar afferent - climing fibers
sends info to the contralateral cerebellum

left sided arm/leg ataxia/uncoordination

Front 37

the hypoglossal nerve nucleus is located in the ______

give the path of the corticobulbar tract (cortex to medulla from cerebrum to CN nuc)

UMN lesion?
LMN lesion?

Back 37

dorsal rostral medulla

Cortex-->caudal extension to medulla where they decussate>>hypoglossal nuc>>extends ventrally>>out between inf olive and pyramids in the medulla (still rostral medulla)>> out the hypoglaossal foramen near skull base to innervate the muscles of the tongue

UMN = supranuclear lesion = contralateral hemiplegia + weakneass of tongue contralateral to lessoin so tongue moves in the direction of the weakness (contraleral to lesion) when extended -- no atrophy or fasculations

LMN = weakness ipsi to lesion so tongue moves toward lesion + fasciculations + atrophy