Eye Orbit Flashcards

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1
Q

Where is the sclera normal visible

A

normally visible between iris and lower lid

not visible above iris

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2
Q

caruncle

A

tears accumulate here

in medial canthus

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3
Q

three V1 branches

A

frontal: forehead and scalp
lacrimal: sensory to gland, upper eyelid
nasociliary: medial orbit, upper nose

^all somatic sensory

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4
Q

lateral/medial canthus

A

where eyelids meet

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5
Q

only ___ provides sensory info to the eyeball

A

only NASOCILIARY N. provides sensory info to the eyeball

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6
Q

V2 supplies (inferior/superior?) eyelid

A

V2 supplies INFERIOR eyelid

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7
Q

the frontal n. branches into which nerves

A

supraorbital n.

supratrochlear n.

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8
Q

the nasociliary n. branches into which nerves

A

ant/post ethmoidal n.s

infratrochlear n.

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9
Q

orbicularis occuli m. have 2 parts

A

orbital parts: on bone itself

palpebral parts: on eyelid itself

innervated by facial n.

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10
Q

insertion point of orbicularis oculi m.

A

medial palpebral ligament

pushes tears medially to accumulate in lacrimal lake

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11
Q

tarsal plates

A

inert tissue, not many vessels

  • support for eyelids
  • anchors tarsal m.
  • contains tarsal glands
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12
Q

input must touch ___ to trigger blink reflex

A

cornea

felt via CN V1 (nasociliary n.)

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13
Q

blink reflex - motor response is via

A

CN VII

to orbicularis oculi, palpebral part

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14
Q

blink reflex - sensory input

n. and stimulus

A

CN V1 - touch cornea

CN II - visual threat/bright light

CN VIII - sudden sounds >50-60 dB

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15
Q

6 bones of orbit

A
frontal
sphenoid GW/LW
ethmoid
lacrimal
maxilla
zygomatic
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16
Q

lamina papyracea

A

“paper-thin bone”

orbital plate of ethmoid bone, has air cells

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17
Q

orbital blowout fractures

A

can be toward medial side or inferiorly (twd maxillary sinuses)

  • diplopia
  • infraorbital n. damage
  • infections
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18
Q

How can hydrocephalus lead to papilledema?

A

high CSF pressure (hydrocephalus) –> impedes venous drainage –> pressure on optic disc causes bulging —> papilledema

usually bilateral
(unilateral –> ocular pathology)

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19
Q

6 extraocular m. of eye that move eyeball

A
superior rectus
inferior rectus
medial rectus
lateral rectus
superior oblique
inferior oblique
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20
Q

which extraocular m. elevates the upper eyelid?

A

levator palpebrae superioris

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21
Q

recti m. of eye insert ____ to equator

A

recti m. of eye insert ANTERIOR to equator

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22
Q

oblique m. of eye insert _____ to the equator

A

oblique m. of eye insert POSTERIOR to the equator

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23
Q

CN III supplies which extraocular m.?

A
superior rectus
inferior rectus
medial rectus
inferior oblique
levator palpebrae superioris
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24
Q

CN IV supplies which extraocular m.?

A

superior oblique m.

LR6SO4

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25
Q

CN VI supplies which extraocular m.?

A

lateral rectus m.

LR6SO4

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26
Q

adduction of eye

A

medial rectus

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27
Q

aBduction of eye

A

lateral rectus

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28
Q

elevation + adduction of eye

A

superior rectus

29
Q

depression + adduction of eye

A

inferior rectus

30
Q

which m. compensate for adduction of superior/inferior rectus m.?

A

superior oblique/inferior oblique

31
Q

depression + aBduction

A

superior oblique

32
Q

elevation + aBduction

A

inferior oblique

33
Q

m. required to look straight down

A

inferior rectus + superior oblique

34
Q

m. required to look straight up

A

superior rectus + inferior oblique

35
Q

4 smooth muscles (intra and extraocular) are controlled by ANS

A

parasympathetic: ciliary m. and sphincter pupillae m.
sympathetic: dilator pupillae m. and superior tarsal m.

36
Q

causes of slow pupillary constriction

A
  • brainstem damage (to parasympathetic nucleus)
  • CN III compression (epidural hematoma, squished against petrous temporal bone)
  • depressants (barbiturates)
  • untreated syphilis
37
Q

temporal retina

A

receiving light from midline

fibers do NOT cross at optic chiasm

most go to motor cortex (some to midbrain pretectal nucleus –> Edinger-Westphal nucleus –> ciliary ganglion –> pupillary constriction)

38
Q

nasal retina

A

receiving light more laterally

fibers decussate at optic chiasm

most go to motor cortex (some to midbrain pretectal nucleus –> Edinger-Westphal nucleus –> ciliary ganglion –> pupillary constriction)

39
Q

how does ciliary m. accommodate for near vision?

A

ciliary m. contracts –> loosens lens zonules –> lens rounds up

40
Q

What input is needed to cause lens flattening?

A

lens default shape is FLAT

NO sympathetic input is needed to cause lens flattening, zolular tension is sufficient

41
Q

presbyopia

A

diminished ability of the lens to become round

need reading glasses

42
Q

mydriasis

A

pupil dilation

43
Q

superior tarsal (Muller’s) m.

A

SMOOTH muscle, in tarsal plates

helps pull eyelid up

damage –> ptosis

44
Q

left abducent nerve palsy

A

abducent n. affected (at risk w/ cavernous sinus pathology)

–> lateral rectus m. affected –> eye pulled medially by medial rectus

45
Q

left oculomotor nerve palsy

A
  • all extraocular m. affected EXCEPT superior orbital and lateral rectus
  • pupil dilation (lost parasymp to sphincter pupillae)
  • ptosis (lost LPS)
46
Q

ptosis could be due to loss of which m.

A

superior tarsal (Muller’s) m.

OR

levator palpebrae superioris

47
Q

bitemporal hemianopsia

A

could be due to compression of optic chiasm

fibers from nasal retina can’t decussate

results in bilateral half vision (vision lost on LATERAL) sides

48
Q

tear production is controlled by ______ fibers via CN ___

A

tear production is controlled by secretomotor fibers via CN VII

49
Q

glands responsible for tear production

A
  • lacrimal glands
  • meibomian glands
  • conjunctival glands (goblet cells)

all controlled by CN VII

50
Q

path of tear drainage

A

tears accumulate in lacrimal lake –> thru superior/inferior punctum –> lacrimal canaliculi –> lacrimal sac –> lacrimal duct –> inferior turbinate

51
Q

meibomian (tarsal) glands

A

visible thru palpebral conjunctiva

specialized sebaceous gland (oil surface layer for tear film)

lipids seal lid margin (holds tear film in place

waterproofs lids when closed

reduces evaporation from deeper, aqueous tear film layer (from lacrimal gland)

52
Q

punctual plugs

A

tx for dry eye

prevents evaporation of tears

53
Q

mucus layer of tear film produced via

A

conjunctival glands (goblet cells)

54
Q

aqueous layer of tear film produced via

A

lacrimal gland

55
Q

lipid layer of tear film produced via

A

meibomian glands

56
Q

tear film functions

A

flushes debris
protects cornea from drying
provides O2 and nutrients to cornea
contains antibacterial enzymes (lysozyme)

57
Q

ptosis (via superior tarsal damage) + constriction of pupil

possibly caused by ________

A

Horner Syndrome

58
Q

What gives rise to anterior meningeal a.s?

A

ethmoidal a.s go through ant/post ethmoidal foramina –> become anterior meningeal a.s

59
Q

Middle meningeal a. anastomoses w/ _____ a. to contribute to ICA/ECA anastomoses

A

Middle meningeal a. anastomoses w/ LACRIMAL a. to contribute to ICA/ECA anastomoses

60
Q

Which vessels supply INNER aspect of retina?

A

central a. of retina (goes thru optic disk and branches)

br. of ophthalmic a.

61
Q

When looking through funduscope, optic disc is always on ____ side of the eye

A

When looking through funduscope, optic disc is always on MEDIAL side of the eye

62
Q

Which vessels supply OUTER aspect of retina?

A

short posterior ciliary a.

form choriocapillaris (cluster of vessels, very dense –> red eye in pics)

63
Q

choroid

A

the pigmented vascular layer of the eyeball between the retina and the sclera.

64
Q

Which vessels supply anterior eye of retina?

A

long posterior ciliary arteries

65
Q

what contributes to risk of spreading infections on face to cavernous sinus

A

superior/inferior ophthalmic v. are continuous w/ v. that supply face
(angular v. and facial v.)

infections can work their way back to the cavernous sinus

66
Q

which n. is just deep to the periorbita?

A

frontal n. (largest V1 branch)

67
Q

which m. is just deep to frontal n.?

A

levator palpebrae superioris m.

68
Q

which m. is just deep to levator palpebrae superioris?

A

superior rectus m.