Eye Orbit Flashcards
Where is the sclera normal visible
normally visible between iris and lower lid
not visible above iris
caruncle
tears accumulate here
in medial canthus
three V1 branches
frontal: forehead and scalp
lacrimal: sensory to gland, upper eyelid
nasociliary: medial orbit, upper nose
^all somatic sensory
lateral/medial canthus
where eyelids meet
only ___ provides sensory info to the eyeball
only NASOCILIARY N. provides sensory info to the eyeball
V2 supplies (inferior/superior?) eyelid
V2 supplies INFERIOR eyelid
the frontal n. branches into which nerves
supraorbital n.
supratrochlear n.
the nasociliary n. branches into which nerves
ant/post ethmoidal n.s
infratrochlear n.
orbicularis occuli m. have 2 parts
orbital parts: on bone itself
palpebral parts: on eyelid itself
innervated by facial n.
insertion point of orbicularis oculi m.
medial palpebral ligament
pushes tears medially to accumulate in lacrimal lake
tarsal plates
inert tissue, not many vessels
- support for eyelids
- anchors tarsal m.
- contains tarsal glands
input must touch ___ to trigger blink reflex
cornea
felt via CN V1 (nasociliary n.)
blink reflex - motor response is via
CN VII
to orbicularis oculi, palpebral part
blink reflex - sensory input
n. and stimulus
CN V1 - touch cornea
CN II - visual threat/bright light
CN VIII - sudden sounds >50-60 dB
6 bones of orbit
frontal sphenoid GW/LW ethmoid lacrimal maxilla zygomatic
lamina papyracea
“paper-thin bone”
orbital plate of ethmoid bone, has air cells
orbital blowout fractures
can be toward medial side or inferiorly (twd maxillary sinuses)
- diplopia
- infraorbital n. damage
- infections
How can hydrocephalus lead to papilledema?
high CSF pressure (hydrocephalus) –> impedes venous drainage –> pressure on optic disc causes bulging —> papilledema
usually bilateral
(unilateral –> ocular pathology)
6 extraocular m. of eye that move eyeball
superior rectus inferior rectus medial rectus lateral rectus superior oblique inferior oblique
which extraocular m. elevates the upper eyelid?
levator palpebrae superioris
recti m. of eye insert ____ to equator
recti m. of eye insert ANTERIOR to equator
oblique m. of eye insert _____ to the equator
oblique m. of eye insert POSTERIOR to the equator
CN III supplies which extraocular m.?
superior rectus inferior rectus medial rectus inferior oblique levator palpebrae superioris
CN IV supplies which extraocular m.?
superior oblique m.
LR6SO4
CN VI supplies which extraocular m.?
lateral rectus m.
LR6SO4
adduction of eye
medial rectus
aBduction of eye
lateral rectus