Opthalmogy

Question 1

Miosis

Answer 1

Constriction of the pupil parasympathetic

Question 2

Describe the parasymp nervous pathway to the pupil

Answer 2

1st neuron: edinger westphal nucleus to ciliary ganglia
Second neuron: Short ciliary nerves to pupillary sphincter

When light hits the eye, CNII works through pretectal nuclei to constrict the eye via edinger pathway bilaterally.

Question 3

Mydriasis

Answer 3

Dialation due to sympathetics

Question 4

Describe the nerve pathway for mydriasis

Answer 4

1st neuron: hypothalamus to ciliospinal center of budge
2nd neuron: exits T1 to superior cervial ganglion
3rd neuron: plexus along internal carotid through cavernous sinus enters orbit as long ciliary nerve to pupillary dilator muscles.

Sympathetics also minorly innervate the eyelid and swead glands of teh forehead and face.

Question 5

Marcus Gunn pupil

Answer 5

Afferent pupillary defect - Due to optic nerve damage or severe retinal injury.

wont have bulateral constriction when light flashed in eye via swinging flashlight test.

Question 6

Horner syndrome

Answer 6

Sympathetic denervation of the face.
Leads to:
ptosis/drooping of eyhelid (superior tarsal muscle)
Anhidrosis of the skin
Miosis
Skin flushin

associated with lesion of spinal cord above T1 so think pancoast tumor or brown sequard syndrome.

“PAM is horny”
Ptosis
Anhydrosis
Miosis

Question 7

What is the action of cranial nerve 4?

Answer 7

Superior oblique

Abducts, intorts and depresses while adducted.

Question 8

Which way does the head tilt with damage to cranial nerve 4?

Answer 8

Head will tilt toward the side of the lesion.

eye will move upward due to loss of the superior oblique that would normally pull it down and medial.

Question 9

Cranial nerve VI damage

Answer 9

Would result in the damaged eye being moved medially due to loss of the lateral rectus muscle.

Question 10

What occurs when the meyer loop (temporal lobe) is lesioned?

Lets say right

Answer 10

Left upper quadrantic anopia

Right temporal lesion or a right medial cerebral artery lesion

Question 11

What does the medial longitudinal fasciculus (MLF) do?

Answer 11

Pair of tracts that allows for crosstalk between CN 7 and CN 3 nuclei.

Coordinates both eyes to move in the same horizontal direction.

Question 12

How would a medial longitudinal fasciculus lesion present?

Answer 12

Internuclear opthalmopleia also known as a horizontal gaze palsy.

thus when CN VI activates the lateral rectus, the contralateral CN III does not stimulate the medial rectus to fire.

thus the abducting eye gets nystagmus.