(14) CN III, IV, VI Flashcards
Nucleus that serves the levator palpebrae superior muscle
central caudal nucleus
Nucleus that serves the lateral rectus muscle
abducens nucleus
Nucleus that serves the inferior rectus muscle
dorsal nucleus
Nucleus that serves the medial rectus muscle
ventral nucleus
Nucleus that serves the inferior oblique muscle
intermediate nucleus
Nucleus that serves the superior oblique muscle
trochlear Nucleus
Nucleus that serves the parasympathetics that control the constrictor muscle of iris
Edinger-Westphal Nucleus
nuclei ventral to the quadrigeminal plate
CN III and IV
**quadrigeminal plate = superior and inferior colliculi
CN nuclei in the caudal pons
CN VI
What is the facial colliculus? Where is it found?
CN VII sends axons over CN IV which creates a bump on the floor of the 4th ventricle
Which CN III nuclei provides bilateral input to their respective muscles
Caudal and Edinger-Westphal nuclei
Medial or lateral midbrain lesions will cause unilateral eye movement and pupillary abnormalities?
lateral
**axons from CN III subnuclei join together and quickly lateralize after leaving the nucleii
CN III exits the brain stem at …
the junction of the midbrain and the pons
CN IV exits the brain stem….
just caudal to inferior colliculus
only CN to exit dorsally
CN VI exits the brain stem …
at the pontomedullary junction (most medially)
Which CN nuclei controlling eye movement serve contralateral eye muscles?
medial and trochlear
passes between the superior cerebellar artery and the posterior cerebral artery
CN III
the cavernous sinus is lateral to…
pituitary gland and the sphenoid sinus
____ fibers travel with the ICA through the cavernous sinus
sympathetic fibers
travels alongside posterior communicating artery and underneath the internal carotid artery
CN III
muscle that provides autonomic elevation of the eyelid
tarsal muscle
muscle that provides voluntary elevation of the upper eyelid
levator palpebra superioris by CN III
muscle that contracts as the eyes converge (accommodation reflex)
ciliary muscle
sympathetic pathway fibers take to get to the eye muscles
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
Describe the pathway that results in the light reflex
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
Where is the accommodation reflex initiated?
prefrontal eye fields and occipital-parietal fields
