Cranial Nerves III, IV, VI Flashcards
What structures are innervated by the abducens nerve
Lateral rectus muscle
What are the signs and symptoms of an abducens nerve lesion
Lateral rectus muscle will lose tone and the medial rectus will pull that eye to the midline.
-Pt will experience diplopia
Where is the cell body of origin of the abducens nerve
abducens nucleus - pontine tegmentum
What is the course of the abducens nerve
rootlets exit through anterior surface,
What structures are innervated by the trochlear nerve
Superior oblique muscle
What are the signs and symptoms of a trochlear nerve lesion
extorsion of eye (tips outward)
vertical diplopia
weakness trying to look down and towards the midline
Where is the cell body of origin of the trochlear nerve
Trochlear nucleus - midbrain tegmentum
What is the course of the trochlear nerve
rootlets exit posteriorly, fibers cross as they exit
What structures are innervated by the oculomotor nerve
Levator palpebrae muscle
all extraocular muscles except lateral rectus and superior oblique
Where is the cell body of origin of the oculomotor nerve
Edinger-Westphal nucleus = GVE
Oculomotor nucleus = SE
these make up the oculomotor nuclear complex and is found in the midbrain tegmentum
What is the course of the oculomotor nerve
rootlets exit into intepeduncular fossa
What are the signs and symptoms of a lesion of the occulomotor nerve
If SE component affected - ptosis(drooping eyelid)
- eye moves down and
out
If GVE component affected - Dilated fixed pupil
- accommodation response lost
How does ptosis caused by a lesion of the oculomotor nerve differ from ptosis caused by Horner syndrome
The ptosis cause by an oculomotor nerve lesion is much more pronounced than that caused by Horner syndrome
What is diplopia
Double vision
How can a patient minimize diplopia
by turning their head to one side
