Flashcards in Week 2 Part 2 Deck (11):
Which cranial nerve raises the eyelid?
3; Levator muscle
Where is the parasympathetic innervation of the CN3 going?
Iris sphincter: pupillary constriction.
Ciliary muscles: lens accommodation
Where are the cells of the GSE component of CN3?
Oculomotor nucleus of midbrain.
What is the location of the preganglionic neurons of CN3? Postganglionic?`
Preganglionic: Edinger-Westphal Nucleus of midbrain
Postganglionic: Ciliary ganglion
What is the function of the CN3 muscles?
Superior rectus: elevate and adduct
Inferior rectus: Depress and adduct
Medial rectus: adduct
Inferior oblique: elevate and abduct
What is the most common causes of CN3 injury?
Primary cause: Aneurysm at junction of posterior communicating and internal carotid artery
Secondary cause: aneurysm at junction of posterior communicating and posterior cerebral artery.
What is affected first by a vascular insult to CN3?
Somatic fibers; Patient presents with eye position problems but pupil reflex is normal.
What is affected first by a compressive insult to CN3?
Peripheral autonomic fibers; Patient presents with normal eye position/movements but pupil reflex is abnormal.
Where are the primary neurons of the abducens nerve?
Abducen nucleus; just under the 4th ventricle
How do you test the abducens nerve?
Tell patient to look laterally.