Week 2 Part 2

Question 1

Which cranial nerve raises the eyelid?

Answer 1

3; Levator muscle

Question 2

Where is the parasympathetic innervation of the CN3 going?

Answer 2

Iris sphincter: pupillary constriction.

Ciliary muscles: lens accommodation

Question 3

Where are the cells of the GSE component of CN3?

Answer 3

Oculomotor nucleus of midbrain.

Question 4

What is the location of the preganglionic neurons of CN3? Postganglionic?`

Answer 4

Preganglionic: Edinger-Westphal Nucleus of midbrain
Postganglionic: Ciliary ganglion

Question 5

What is the function of the CN3 muscles?

Answer 5

Superior rectus: elevate and adduct
Inferior rectus: Depress and adduct
Medial rectus: adduct
Inferior oblique: elevate and abduct

Question 6

What is the most common causes of CN3 injury?

Answer 6

Primary cause: Aneurysm at junction of posterior communicating and internal carotid artery
Secondary cause: aneurysm at junction of posterior communicating and posterior cerebral artery.

Question 7

What is affected first by a vascular insult to CN3?

Answer 7

Somatic fibers; Patient presents with eye position problems but pupil reflex is normal.

Question 8

What is affected first by a compressive insult to CN3?

Answer 8

Peripheral autonomic fibers; Patient presents with normal eye position/movements but pupil reflex is abnormal.

Question 9

Where are the primary neurons of the abducens nerve?

Answer 9

Abducen nucleus; just under the 4th ventricle

Question 10

How do you test the abducens nerve?

Answer 10

Tell patient to look laterally.

Question 11

What is Foville Syndrome?

Answer 11

Damage to paramedian fibers of Basilar artery; Damage to CN6 and adjacent CST and CBT fibers.