Flashcards in Opthalmogy Deck (12)
Constriction of the pupil parasympathetic
Describe the parasymp nervous pathway to the pupil
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.
Dialation due to sympathetics
Describe the nerve pathway for mydriasis
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.
Marcus Gunn pupil
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.
Sympathetic denervation of the face.
ptosis/drooping of eyhelid (superior tarsal muscle)
Anhidrosis of the skin
associated with lesion of spinal cord above T1 so think pancoast tumor or brown sequard syndrome.
"PAM is horny"
What is the action of cranial nerve 4?
Abducts, intorts and depresses while adducted.
Which way does the head tilt with damage to cranial nerve 4?
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.
Cranial nerve VI damage
Would result in the damaged eye being moved medially due to loss of the lateral rectus muscle.
What occurs when the meyer loop (temporal lobe) is lesioned?
Lets say right
Left upper quadrantic anopia
(Right temporal lesion or a right medial cerebral artery lesion)
What does the medial longitudinal fasciculus (MLF) do?
Pair of tracts that allows for crosstalk between CN 7 and CN 3 nuclei.
Coordinates both eyes to move in the same horizontal direction.