Neuro18

Question 1

What nerves innervate the extraocular eye muscles?

Answer 1

Oculomotor n. (CN III)
Trochlear n. (CN IV)
Abducens n. (CN VI)

Question 2

What EOMs are innervated by CN III?

Answer 2

Superior Rectus m.
Medial Rectus m.
Inferior Rectus m.
Inferior Oblique m.

Question 3

What EOM is innervated by CN IV?

Answer 3

Superior Oblique m.

Question 4

What EOM is innervated by CN VI?

Answer 4

Lateral Rectus m.

Question 5

What is the “chemical formula” for remembering the innervation of the EOMs?

Answer 5

LR6SO4R3

Lateral Rectus - Abducens (CN VI)
Superior Oblique - Trochlear (CN IV)
the Rest - Oculomotor (CN III)

Question 6

CN III damage leads to -

Answer 6

Eye looks Down & Out
Ptosis
Pupillary dilation
Loss of Accomodation

Question 7

CN IV damage leads to -

Answer 7

Eye moves UPward

*particularly w/ contralateral gaze & ipsilateral head tilt (problems going down stairs)

Question 8

CN VI damage leads to -

Answer 8

Medially directed eye that cannot ABDUCT

Question 9

How do you test the Inferior Oblique m?

Answer 9

have patient look UP

“IOU: to test Inferior Oblique have pt look Up”

Question 10

Oblique eye muscles more the eye in the _________ direction

Answer 10

Opposite

Question 11

Constriction/Dilation & Para/Sympathetic:

• Miosis
• Mydriasis

Answer 11

Miosis - Constriction & Parasympathetic

Mydriasis - Dilation & Sympathetic

Question 12

What brainstem nucleus is involved in Miosis?

Answer 12

Edinger-Westphal nucleus

Question 13

Describe the pupillary light reflex.

Answer 13

1-Light in either retina sends signal via CN II to Pretectal nuclei in midbrain
2-Activate Bilateral Edinger-Westphal; pupils constrict bilaterally (consensual reflex)

Result: Illumination of 1 eye results in BILATERAL pupillary constriction

Question 14

What is Marcus Gunn Pupil?

Answer 14

• Afferent pupillary defect (d/t optic n. damage or retinal detachment
• DEcreased consenual light reflex when light is shone in Affected eye relative to unaffected eye

*tested w/ “swinging flashlight test”

Question 15

What layers are separated in Retinal Detachment?

Answer 15

Neurosensory layer of retina from Outermost Pigmented epithelium

Question 16

What is found in the neurosensory layer of the retina?

Answer 16

Rods & Cones (photoreceptor layer)

Question 17

What is the function of the outermost pigmented epithelium?

Answer 17

Shield excess light, supports retina

Question 18

What leads to vision loss in retinal detachment?

Answer 18

Degeneration of photoreceptors

Question 19

What are the two types of age-related macular degeneration?

Answer 19

Dry (nonexudative) - MOST COMMON >80%

Wet (exudative)

Question 20

Describe Dry macular degeneration.

Answer 20

Deposition of yellowish extracellular material beneath retinal pigment epithelium (“Drusen”) with Gradual loss in vision

Question 21

How can you prevent progression of dry macular degeneration?

Answer 21

mutivitamin and antioxidant supplements

Question 22

Describe Wet macular degeneration.

Answer 22

Rapid loss of vision d/t Bleeding secondary to Choroidal neovascularization

Question 23

How do you treat Wet macular degeneration?

Answer 23

Anti-VEGF injections or Laser

Question 24

What is the function of the Medial Longitudinal Fasciculus (MLF)?

Answer 24

• Allows for crosstalk between CN VI & III nuclei

- Coordinates both eyes to move in same horizontal direction

Question 25

A lesion of the Right MLF results in what?

Answer 25

Right Internuclear Opthalmoplegia

Right eye CANNOT adduct (look to the left)
Left eye has nystagmus

Question 26

In what condition is INO most common?

Answer 26

Multiple Sclerosis