(14) CN III, IV, VI

Question 1

Nucleus that serves the levator palpebrae superior muscle

Answer 1

central caudal nucleus

Question 2

Nucleus that serves the lateral rectus muscle

Answer 2

abducens nucleus

Question 3

Nucleus that serves the inferior rectus muscle

Answer 3

dorsal nucleus

Question 4

Nucleus that serves the medial rectus muscle

Answer 4

ventral nucleus

Question 5

Nucleus that serves the inferior oblique muscle

Answer 5

intermediate nucleus

Question 6

Nucleus that serves the superior oblique muscle

Answer 6

trochlear Nucleus

Question 7

Nucleus that serves the parasympathetics that control the constrictor muscle of iris

Answer 7

Edinger-Westphal Nucleus

Question 8

nuclei ventral to the quadrigeminal plate

Answer 8

CN III and IV

**quadrigeminal plate = superior and inferior colliculi

Question 9

CN nuclei in the caudal pons

Answer 9

CN VI

Question 10

What is the facial colliculus? Where is it found?

Answer 10

CN VII sends axons over CN IV which creates a bump on the floor of the 4th ventricle

Question 11

Which CN III nuclei provides bilateral input to their respective muscles

Answer 11

Caudal and Edinger-Westphal nuclei

Question 12

Medial or lateral midbrain lesions will cause unilateral eye movement and pupillary abnormalities?

Answer 12

lateral

**axons from CN III subnuclei join together and quickly lateralize after leaving the nucleii

Question 13

CN III exits the brain stem at …

Answer 13

the junction of the midbrain and the pons

Question 14

CN IV exits the brain stem….

Answer 14

just caudal to inferior colliculus

only CN to exit dorsally

Question 15

CN VI exits the brain stem …

Answer 15

at the pontomedullary junction (most medially)

Question 16

Which CN nuclei controlling eye movement serve contralateral eye muscles?

Answer 16

medial and trochlear

Question 17

passes between the superior cerebellar artery and the posterior cerebral artery

Answer 17

CN III

Question 18

the cavernous sinus is lateral to…

Answer 18

pituitary gland and the sphenoid sinus

Question 19

____ fibers travel with the ICA through the cavernous sinus

Answer 19

sympathetic fibers

Question 20

travels alongside posterior communicating artery and underneath the internal carotid artery

Answer 20

CN III

Question 21

muscle that provides autonomic elevation of the eyelid

Answer 21

tarsal muscle

Question 22

muscle that provides voluntary elevation of the upper eyelid

Answer 22

levator palpebra superioris by CN III

Question 23

muscle that contracts as the eyes converge (accommodation reflex)

Answer 23

ciliary muscle

Question 24

sympathetic pathway fibers take to get to the eye muscles

Answer 24

primary neurons originate in hypothalamus and travel down the lateral brainstem to synapse in interomedial grey area at C8-T2. Secondary neurons exit via the ventral root to synapse in paravertebral sympathetic chain ganglia with the tertiary neurons. The tertiary fibers travel with the ICA into the cranium. Then they join with the nasocilliary N to innervate superior tarsal muscle and the long and short cilliary nerves to innv the dilator muscle of the pupil

Question 25

Describe the pathway that results in the light reflex

Answer 25

light in one eye cuases afferent signal to travel down that optic N to the optic chiasm and optic tract to synapse in left and right pretectal nuclei (In midbrain). these secondary nerve axons go to the Edinger-Westphal nuclei. the parasympathetic fibers then travel with CN III to the left AND right pupillary contractor muscles

Question 26

Where is the accommodation reflex initiated?

Answer 26

prefrontal eye fields and occipital-parietal fields