B7.029 Brainstem and Cranial Nerves: From Symptoms to Lesion

Question 1

systems involved in horizontal eye movements

Answer 1

frontal eye fields
paramedian pontine reticular formation
abducens nucleus
CN VI
medial longitudinal fasiculus (MLF)
oculomotor nucleus
CN III

Question 2

muscle involved with incomplete adduction of the eye

Answer 2

medial rectus

Question 3

possible locations of a CN III lesion

Answer 3

intra-axial (affects nucleus within midbrain)

extra-axial (affects nerve itself)

Question 4

other symptoms that would accompany and intra-axial CN III lesion

Answer 4

contralateral hemiparesis and hemisensory loss

Question 5

most worrisome etiology of an extra-axial, unilateral CN III lesion

Answer 5

posterior communicating artery aneurysm (berry aneurysm)

Question 6

what is the MLF

Answer 6

medial longitudinal fasiculus
communication between abducens and oculomotor nucleus
coordinates lateral eye movements
suspected etiology of an isolated horizontal eye movement defect

Question 7

components of corticobulbar tract

Answer 7

bilateral cortical innervation of the medullary reticular formation
ambiguous nucleus
hypoglossal nucleus
solitary nucleus

Question 8

UMN corticobulbar tract lesion

Answer 8

pseudobulbar palsy

Question 9

LMN corticobulbar tract lesion

Answer 9

bulbar palsy

Question 10

motor nuclei in the corticobulbar tract

Answer 10

hypoglossal

ambiguous

Question 11

sensory nuclei in the corticobulbar tract

Answer 11

solitary

Question 12

relationship between sympathetic innervation of the eye and the corticobulbar tract

Answer 12

sympathetic chain travels up and crosses with CN IX and XII slightly below eye levels

Question 13

collateral tracts that run alongside the corticobulbar

Answer 13

spinothalamic
descending tract and nucleus of V
descending sympathetics

Question 14

lateral medullary syndrome

Answer 14

right palatal weakness (CN X ambiguous)
right palatal numbness (CN IX solitary)
right face numbness (CN V nucleus and tract)
left body numbness (spinothalamic tract)
Right Horners (sympathetic fibers)
vertigo (vestibular nucleus)
right sided ataxia (inferior cerebral peduncle)

Question 15

possible etiology of lateral medullary lesion

Answer 15

posterior inferior cerebellar artery (PICA) dissection

Question 16

structure involved in right facial numbness

Answer 16

right CN V or general sensory nucleus

Question 17

structure involved in right upper and lower facial weakness

Answer 17

right CN VII or facial nucleus

Question 18

structure involved in right taste discrepancy

Answer 18

right CN VII or gustatory nucleus

Question 19

structure involved in right bilateral eye incomplete abductions

Answer 19

bilateral CN VI or abducens nucleus

Question 20

structure involved in left body weakness in an UMN pattern

Answer 20

corticospinal tract

Question 21

brainstem level of CN V, VI, and VII

Answer 21

pons

Question 22

etiology of a pons lesion that can cross the midline

Answer 22

primary brain tumor

glioblastoma multiforme

Question 23

body weakness: cortex to motor nucleus

Answer 23

UMN lesion

Question 24

facial weakness: cortex to motor nucleus

Answer 24

central VIIth

Question 25

eye movement weakness: cortex to motor nucleus

Answer 25

supranucleus

Question 26

swallowing weakness: cortex to motor nucleus

Answer 26

pseudobulbar

Question 27

body weakness: motor neuron to muscle

Answer 27

LMN lesion

Question 28

facial weakness:motor neuron to muscle

Answer 28

peripheral VIIth

Question 29

eye movement weakness: motor neuron to muscle

Answer 29

infranuclear

Question 30

swallowing weakness: motor neuron to muscle

Answer 30

bulbar