Pupillary control - Horner syndrome Flashcards Preview

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Flashcards in Pupillary control - Horner syndrome Deck (23)
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1

miosis mechanism - 1st neuron

Edinger-Westphal nucleous to ciliary ganglion via CN III

2

miosis mechanism - 2st neuron

short ciliary nerves to pupillary sphincter muscles

3

pupillary sphincter muscles - receptors

M3

4

A consensual reflex is

any reflex observed on one side of the body when the other side has been stimulated

5

Pupillary light reflex - mechanim

Light in EITHER retina sends signals via CN II (and chiasm and tract) to pretectal nuclei in midbrain that activates bilateral Edinger-Westphal nucleous --> Pupils contract bilaterally (consensual reflex)

6

Pupillary light reflex - direction of the signal from retina to Edinger-Westphal nucleous

light --> retina --> optic nerve optic chiasm --> optic tract --> pretectal nuclei (midbrain) --> bilateral Edinger-Westphal nucleous

7

CN that participate in Pupillary light reflex

optic nerve (CN II)
Oculomotor nerve (CN III)

8

miosis - number of neurons

2

9

mydriasis - number of neurons

3

10

mydriasis - 1st neuron (beginning and end)

hypothalamus to ciliospinal center of Budge (C8-T2)
Synapse in the lateral horn

11

mydriasis - 2nd neuron - direction

exit T1 - travels along cervical sympathetic chain near lung apex, sublavian vessels - superior cervical ganglion

12

mydriasis - 3rd neuron - direction

superior cervical ganglion - plexus along internal carotid through cavernous sinus - enters orbit as LONG CILIARY NERVE - sypathetic fibers also innervate smooth muscle of eyelids (minor retractors) and sweat glands of forehead and face

13

mydriasis - 3rd neuron - innervate

1. pupillary dilator muscle
2. smooth muscle of eyelids (minor retractors)
3. sweat glands of forehead and face

14

mydriasis - 3rd neuron is going through

cavernous sinus

15

long vs short ciliary nerve - according to eye control

long: 3rd neuron of Mydriasis
short: 2nd neuron of Miosis

16

Marcus Gunn pupil - clinical finding

decreased bilateral pupillary constriction when light is shone in affected eye relative to unaffected eye

17

Marcus Gunn pupil - mechanism

Afferent pupillary defect due to optic nerve damage or severe retinal injury

18

Marcus Gunn pupil is tested with

swinging flashlight test

19

Some causes of Horner syndrome

1. spinal cord above T1: Brown-Sequard syndrome (cord hemisection), Late stage syringomegalia
2. Pancoast tumor
3. Lateral medullary (Wallenberg) syndrome
4. Infernal carotid dissection
5. Carvenous sinus syndrome

20

Horner syndrome - findings

1. ptosis
2. anhidrosis and flushing
3. Miosis

21

Area of pretectal nucleus

Upper midbrain

22

Long ciliary nerve is going to the eye next to

V1 (opthalmic division of trigeminal nerve)

23

Superior tarsal muscle is AKA

Müller's muscle.