6. eye: muscle and artery (lecture) Flashcards
which muscle is superior to superior rectus?
levator palpebrae superioris
which structures are (immediately) inferior to superior rectus?
optic nerve
ophthalmic artery
(both running through optic canal)
which structures are medial to lateral rectus and superior to inferior rectus?
superior and inferior division of oculomotor nerve (III)
nasociliary nerve
abducens nerve
(within superior orbital fissure)
which is a major artery supplying the eye?
ophthalmic artery
where is ophthalmic artery from?
internal carotid artery
what does ophthalmic artery give rise to?
central retinal artery
what are the terminal branches of ophthalmic artery?
end arteries
how does central retinal artery occlusion appear?
cherry red spot on pale background
why is central retinal artery occlusion dangerous?
no other blood supply to retina
what is the main venous drainage to the eye?
central retinal vein
where does central retinal vein drain to?
superior ophthalmic vein
what does superior ophthalmic vein drain into?
cavernous sinus
describe the venous drainage of the eye
central retinal vein –> superior ophthalmic vein –> cavernous sinus
what can happen to the central retinal vein?
central retinal vein occlusion
can settle by itself
can be due to dehydration
what is the conjunctiva?
thin clear film on top of all structures around eye
where is the conjunctiva?
sits on top of cornea
clear film front of eye
what is the area between cornea and sclera called?
limbus
both cornea and sclera are fibrous outer layer - continuous
what can happen to the conjunctiva?
inflamed
conjunctivitis
sclera still white, but just conjunctiva over it appears red
function of the eyelid?
protect against:
injury
excessive light
dryness
which structures do the eyelids contain?
Levator palpebrae superioris (+ superior tarsal muscle)
tarsal gland
ciliary glands
(eyelash)
what happens when the tarsal gland is inflamed?
meibomian cyst
what is the relationship between the tarsal gland and ciliary glands?
tarsal gland more superior within the eyelid
ciliary glands more inferior and closer to eyelash
what happens when the ciliary gland is inflamed?
sty
treat with warm salty compress
what are the differences between partial and complete ptosis?
complete: CN III lesion (levator palpebrae superioris)
partial: sympathetic lesion (superior tarsal muscle)
