Cranial nerves B6

Question 1

What are you testing when testing cranial nerves?

Answer 1

peripheral nerves, brainstem, and also upper motor neurons in cerebrum

Question 2

Left visual field is processed by what?

Answer 2

right optic tracts, right thalamus, and right cortex

Question 3

Right visual field is processed by what?

Answer 3

left optic tracts, left thalamus, and left cortex

Question 4

Shining light into eye makes both eyes constrict, why?

Answer 4

sensory arc following optic tracts bilaterally to Pretectal nucleus area in midbrain.

Question 5

What cranial nerves do what to the eye?

Answer 5

“In on 2 out on 3”
Sensory on 2
Parasympathetic fibers on CN3

Question 6

If there is a lesion to optic nerve on right side, what happens?

Answer 6

Both eyes constrict if shine in left eye

Both eyes stay dilated when you shine light into right eye

Question 7

If there is a lesion to right CN3 what happens?

Answer 7

Light in left eye: left eye constricts normally, right eye stays dilated
Light in right eye: right eye fails to constrict, normal left pupil constriction.

Question 8

If you have unequal pupil size what could be the 2 reasons?

Answer 8

Impaired pupillary constriction in larger pupil

Impaired pupillary dilation in smaller pupil

Question 9

If you have a lesion to lateral midbrain, lateral pons, lateral medulla, what will likely be the syndrome?

Answer 9

Horner’s syndrome

Question 10

What can be a reason for pin point pupils (really tiny pupils, bilaterally)?

Answer 10

Opiate drugs and opioid Rx