The orbit 2
Terms
undefined, object
copy deck
- bones of the orbit
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frontal
ethmoid
lacrimal
maxilla
zygomatic
sphenoid
palatine - sclera
-
maintains shape of eyeball
insertion of extraocular m
peirced by optic n - cornea
-
major refractive structure
transparent and avascular
won't be rejected in transplants - fibrous tunic
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sclera
cornea - vascular tunic
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choroid
cillary body
iris - choroid
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dense capillary plexus with pigment cells
btwn sclera and retina - cillary body
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produces aqueous humor
suspends the lens via zonule fibers
contains cillary muscles - cillary muscles
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control lens shape
parasymp -> contraction -> dec tesion on zonule fibers -> inc lens curvature - iris
- highly pigmented diaphragm
- sphincter pubillae m & cillary m
-
preganglionic parasympathetic from edinger-westphal nuc
synapase in cillary ganglion
postganglionic fibers pass via short cillary V1
*pupil constriction & lens thickening for near vision - dilator pupillae & superior tarsal m
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sympathetic vis CN III & V1
dilate pupil adn widen palpebral fissure - nasolacrimal duct
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within nasolacrimal canal
carries lacrimal fluid to inferior nasal meatus - ophthalmic a
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branch of internal carotid
enters orbit via optic canal
crosses optic n - central a of retina
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internal carotid
runs w/in dural sheath of
optic n
supplies retina
enters optic n's inferior surface - lacrimal a
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internal carotid
supplies lacrimal gland,
conjunctiva & eyelids as
palpebral aa
anastomoses w zygoaticoorbial & facial aa branches of external carotid - supraorbital a
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internal carotid
passes through supraorbial fissure
supplies skin of forehead, scalp and frontal sinus - supratrochlear a
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internal carotidterminal branch
supplies skin & muscles of forehead, scalp & pericardium - dorsal nasal a
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internal carotidterminal branch
supplies lacrimal sac & skin of nose
anastomses w external carotid via infraorbital - posterior and anterior ethmoidal aa
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internal carotid
supply ethmoidal air sinus, frontal sinus, lateral nasal wall, nasal septum, meningeal branches - infraorbital a
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external carotid
branch of maxillary
branches w/in infraorbital canal to supply inferior rectus, inferor oblique & lacrimal sac
anastomoses w/ dorsal nasal & facial - zygomatico-orbital a
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external carotid
branch of superficial temporal
supplies orbicularis oculi m
anastomoses w/ lacrimal a - facial a
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external carotid
anastomoses w/ dorsal nasal and infrorbital - transverse facial a
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external carotid
anastomoses w/ infaorbital and lacrimal aa - central vein of retina
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w/in optic nerve
drains into cavernous sinus or superior ophthalmic v - superior ophthalmic vein
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communicates w/ facial & supraorbital vv
passes through superior orbital fissure
drains into cavernous sinus - inferior ophthalmic vein
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recieves blood from inferior & medial parts of orbit
connects w/ superior ophthalmic or drains via inferior orbital fissure into pterygoid plexus - sympathetic innervation of lacrimal gland
- vasoconstriction
- parasympathetic innervation of the lacrimal gland
- secretion
- Levator palpebrea
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raises upper eyelid
oculomotor - medial rectus
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adducts
oculomotor - lateral rectus
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abduction
abducent - superior rectus
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1 elevation
2 adduction
3 intorsion
oculomotor - inferior rectus
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1 depression
2 adduction
3 extorsion
oculomotor - superior oblique
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abduction, depression, intorsion
trochlear - inferior oblique
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abduction, elevation, extorsion
oculomotor - injury to greater petrosal n
- loss of lacrimation
- sympathetic nerve injury
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pupil constricion (miosis)
ptosis
anhydrosis (lack of sweating)
erythematosis (blushing) - parasympathetic nerve injury
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pupil dialation
loss of accommodation