Eye Orbit

Question 1

Where is the sclera normal visible

Answer 1

normally visible between iris and lower lid

not visible above iris

Question 2

caruncle

Answer 2

tears accumulate here

in medial canthus

Question 3

three V1 branches

Answer 3

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

^all somatic sensory

Question 4

lateral/medial canthus

Answer 4

where eyelids meet

Question 5

only ___ provides sensory info to the eyeball

Answer 5

only NASOCILIARY N. provides sensory info to the eyeball

Question 6

V2 supplies (inferior/superior?) eyelid

Answer 6

V2 supplies INFERIOR eyelid

Question 7

the frontal n. branches into which nerves

Answer 7

supraorbital n.

supratrochlear n.

Question 8

the nasociliary n. branches into which nerves

Answer 8

ant/post ethmoidal n.s

infratrochlear n.

Question 9

orbicularis occuli m. have 2 parts

Answer 9

orbital parts: on bone itself

palpebral parts: on eyelid itself

innervated by facial n.

Question 10

insertion point of orbicularis oculi m.

Answer 10

medial palpebral ligament

pushes tears medially to accumulate in lacrimal lake

Question 11

tarsal plates

Answer 11

inert tissue, not many vessels

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

Question 12

input must touch ___ to trigger blink reflex

Answer 12

cornea

felt via CN V1 (nasociliary n.)

Question 13

blink reflex - motor response is via

Answer 13

CN VII

to orbicularis oculi, palpebral part

Question 14

blink reflex - sensory input

n. and stimulus

Answer 14

CN V1 - touch cornea

CN II - visual threat/bright light

CN VIII - sudden sounds >50-60 dB

Question 15

6 bones of orbit

Answer 15

frontal
sphenoid GW/LW
ethmoid
lacrimal
maxilla
zygomatic

Question 16

lamina papyracea

Answer 16

“paper-thin bone”

orbital plate of ethmoid bone, has air cells

Question 17

orbital blowout fractures

Answer 17

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

• diplopia
• infraorbital n. damage
• infections

Question 18

How can hydrocephalus lead to papilledema?

Answer 18

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

usually bilateral
(unilateral –> ocular pathology)

Question 19

6 extraocular m. of eye that move eyeball

Answer 19

superior rectus
inferior rectus
medial rectus
lateral rectus
superior oblique
inferior oblique

Question 20

which extraocular m. elevates the upper eyelid?

Answer 20

levator palpebrae superioris

Question 21

recti m. of eye insert ____ to equator

Answer 21

recti m. of eye insert ANTERIOR to equator

Question 22

oblique m. of eye insert _____ to the equator

Answer 22

oblique m. of eye insert POSTERIOR to the equator

Question 23

CN III supplies which extraocular m.?

Answer 23

superior rectus
inferior rectus
medial rectus
inferior oblique
levator palpebrae superioris

Question 24

CN IV supplies which extraocular m.?

Answer 24

superior oblique m.

LR6SO4

Question 25

CN VI supplies which extraocular m.?

Answer 25

lateral rectus m. | LR6SO4

Question 26

adduction of eye

Answer 26

medial rectus

Question 27

aBduction of eye

Answer 27

lateral rectus

Question 28

elevation + adduction of eye

Answer 28

superior rectus

Question 29

depression + adduction of eye

Answer 29

inferior rectus

Question 30

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

Answer 30

superior oblique/inferior oblique

Question 31

depression + aBduction

Answer 31

superior oblique

Question 32

elevation + aBduction

Answer 32

inferior oblique

Question 33

m. required to look straight down

Answer 33

inferior rectus + superior oblique

Question 34

m. required to look straight up

Answer 34

superior rectus + inferior oblique

Question 35

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

Answer 35

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

Question 36

causes of slow pupillary constriction

Answer 36

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

Question 37

temporal retina

Answer 37

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)

Question 38

nasal retina

Answer 38

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)

Question 39

how does ciliary m. accommodate for near vision?

Answer 39

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

Question 40

What input is needed to cause lens flattening?

Answer 40

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

Question 41

presbyopia

Answer 41

diminished ability of the lens to become round need reading glasses

Question 42

mydriasis

Answer 42

pupil dilation

Question 43

superior tarsal (Muller's) m.

Answer 43

SMOOTH muscle, in tarsal plates helps pull eyelid up damage --> ptosis

Question 44

left abducent nerve palsy

Answer 44

abducent n. affected (at risk w/ cavernous sinus pathology) --> lateral rectus m. affected --> eye pulled medially by medial rectus

Question 45

left oculomotor nerve palsy

Answer 45

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

Question 46

ptosis could be due to loss of which m.

Answer 46

superior tarsal (Muller's) m. OR levator palpebrae superioris

Question 47

bitemporal hemianopsia

Answer 47

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

Question 48

tear production is controlled by ______ fibers via CN ___

Answer 48

tear production is controlled by secretomotor fibers via CN VII

Question 49

glands responsible for tear production

Answer 49

- lacrimal glands - meibomian glands - conjunctival glands (goblet cells) all controlled by CN VII

Question 50

path of tear drainage

Answer 50

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

Question 51

meibomian (tarsal) glands

Answer 51

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)

Question 52

punctual plugs

Answer 52

tx for dry eye prevents evaporation of tears

Question 53

mucus layer of tear film produced via

Answer 53

conjunctival glands (goblet cells)

Question 54

aqueous layer of tear film produced via

Answer 54

lacrimal gland

Question 55

lipid layer of tear film produced via

Answer 55

meibomian glands

Question 56

tear film functions

Answer 56

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

Question 57

ptosis (via superior tarsal damage) + constriction of pupil possibly caused by ________

Answer 57

Horner Syndrome

Question 58

What gives rise to anterior meningeal a.s?

Answer 58

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

Question 59

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

Answer 59

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

Question 60

Which vessels supply INNER aspect of retina?

Answer 60

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

Question 61

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

Answer 61

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

Question 62

Which vessels supply OUTER aspect of retina?

Answer 62

short posterior ciliary a. form choriocapillaris (cluster of vessels, very dense --> red eye in pics)

Question 63

choroid

Answer 63

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

Question 64

Which vessels supply anterior eye of retina?

Answer 64

long posterior ciliary arteries

Question 65

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

Answer 65

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

Question 66

which n. is just deep to the periorbita?

Answer 66

frontal n. (largest V1 branch)

Question 67

which m. is just deep to frontal n.?

Answer 67

levator palpebrae superioris m.

Question 68

which m. is just deep to levator palpebrae superioris?

Answer 68

superior rectus m.