CN & Neuro-ophtho

Question 1

cavernous sinus

Answer 1

CN III, IV, V1, V2, VI, ICA, sympathetics, optic chiasm

Question 2

superior orbital fissure
foramen Rotundum
foramen Ovale

Answer 2

“standing room only
SOF - CN III, IV, V1 , VI
Rotundum- CN V2
Ovale - CN V3

Question 3

jugular foramen
hypoglossal canal
foramen magnum

Answer 3

jugular forman - IX, X, XI
hypoglossal canal - CN XII
foramen magnum - meninges, vertebral As, medulla

Question 4

superior oblique

Answer 4

CN IV-decussate before exits dorsally ->innervates contralateral superior oblique
Depression; Intorsion
closed head trauma
which side?
-contralateral head tilt improves diplopia - look for head tilt on lateral gaze

Question 5

inferior oblique

Answer 5

CN III
Extorsion externally rotates, elevates, and abducts

Question 6

inferior rectus

Answer 6

CN III-inferior branch
depresses and extorts

Question 7

eyelid innervation

Answer 7

orbicularis oculi - upper and lower eyelids - CN VII

CN III-oculomotor-levator palpebrae superioris -upper eye lid

Muller’s muscles/superior inferior tarus - sympathetic innervation - upper eyelid elevation and lower eyelid depression- 1-2mm

Question 8

Horner’s

Answer 8

1. ptosis upper eyelid - superior tarsal/Muller muscles
2. elevation lower eyelid - impaired depressed from inferior tarsal
3. miosis - impaired pupillodilator fxn
4. anhydrosis if dissection proximal to carotid bifurcation b/c sweating fibers in the ECA
5. Enophthalmos - decrease in palpebral fissure

Question 9

Leber optic neuropathy

Answer 9

mitochondrial disease

-“pseudo-edematous” optic nerve with peripapillary telangiectasia

-optic nerve heads - no leakage on fluoresein angiogram vs inflammatory cause

Tx: Idebenone - Raxone-antioxidant (mitochondrial electron carrier)

(no steroids/plex/IVIG)

Question 10

Optic neuritis infectious etiology

Answer 10

Bartonella cat scratch
Lyme
Syphillis

Question 11

Adie pupil

Answer 11

cause: damage to ciliary ganglion

-ciliary ganglion: most parasympathetic fibers contribute to near reflex, <5% to light reflex->will response to near response very slowly

-cholinergic hypersensitivity over time->diluted pilocarpine (0.125% , cholinergic) causes constriction when it wouldn’t in normal pupils

If non-dilute pilocarpine fails to constrict the pupil, then the pupil is pharmacologically dilated

syphilis - Argyle Robertson - no constriction to light but constrict to accommodation- symmetrically small, brisk response to near focus, sluggish react to light

Question 12

Horner’s

Answer 12

cocaine drops->prevent reuptake norepi; dilation normal pupil, no movement of Horner pupil

-if Horner’s ->worsening anisicoria after cocaine drops

Question 13

sympathetic pathway to eye

Answer 13

1st order/central neuron start posterior hypothalamus->brainstem to synapse in C8-T2-ciliospinal center of Budge;

2nd order: exit SC, travel near lung apex, under subclavian A, synapse on superior cervical ganglion near bifurcation

facial anhidrosis if dissection is proximal to carotid bifurcation

Question 14

ipsilateral vs contralateral innervation oculomotor subnuclei

Answer 14

ipsilateral for all except superior rectus - innervates contralateral muscle

Question 15

pupillary light response start afferent response

Answer 15

START: pretectal nucleus- gets light input from contralateral visual hemifield
then synapse on Edinger-Westphal