Orbit & Eye Flashcards
what are the 4 features of the eyelid
palpebral conjuctiva
bulbar conjuctiva
conjuctival sac
fornices
where is the palpebral conjuctiva
membrane lining inner eyelid
where is the bulbar conjuctiva
membrane lining surface of eye
where is the conjuctival sac
potential space between these membranes
where is the fornices
conjuctival reflections from eyelid to eye
what provides form for eyelids?
superior and inferior tarsus
what sebaceous glands are seen through conjuctiva
tarsal glands
what tendon does CN III innervate
levator palperae superioris muscle
what are the bones of the orbit
frontal sphenoid ethmoid palatine lacrimal maxillary zygomatic
what arteries go through the anterior and posterior ethmoidal foramen
anterior and posterior ethmoidal arteries
Objects piercing roof enter ___
anterior cranial fossa
Objects piercing floor enter ?
maxillary sinus
Objects piercing medial wall enter ?
ethmoid air cells
Objects piercing lateral wall enter ?
temporal fossa
Objects piercing superior orbital fissure enter ?
middle cranial fossa
what is the floor of the orbit?
roof of maxillary sinus
what does a medial orbital wall injury affect?
ethmoidal air cells
what does a lateral orbital wall injury affect?
temporal fossa
what goes through the optic canal
CN II and opthalamic artery
what goes through the superior orbital fissure?
CN III, IV, V1, VI, and opthalamic vv
what goes through the supraorbital notch/foramen
supraorbital n (CN V1) & a
what goes through the inferior orbital fissure?
infraorbital and zygomatic n (CN V2) and a
what goes through the infraorbital foramen
infraorbital n (CN V2) and a
what goes through the anterior ethmoidal foramen?
anterior ethmoidal n and a (CNv1)
what goes through the posterior ethmoidal foramen?
posterior ethmoidal n (CNv1) and a
what goes through the foramen rotundum
maxillary nerve
what are the features of the external eye
conjuctiva
sclera
cornea
define conjuctiva
mucous membrane of eye and lids
define sclera
posterior 5/6 of outer layer (white part)
define cornea
anterior 1/6 of outer layer (transparent)
what are the 4 features of the middle eye
choroid
ciliary body
iris
pupil
define choroid
thin middle layer of ciliary aa & vorticose vv
define cilary body
smooth muscle around lens for accommodation
what controls focal point of lens?
ciliary body
define iris
colored smooth muscle behind cornea controlling pupil size
define pupil
adjustable aperture through which light enters eye
how does the ciliary body muscles affect the zonular fibers?
change the tension of the zonular fibers, change the focus of the lens
what are the 4 features of the internal eye
retina
macula lutea
fovea centralis
optic disc
define retina
neural layer of eye which receives a light rays
define macula lutea
oval region of retina for visual acuity
defina fovea centralis
most acute vision site at center of macula
define optic disc
regions where CN II and retinal vessels enter/exit
what represents a blind spot?
optic disc (no photo receptors)
why is the optic disc considered a blind spot?
no photoreceptors
T/F vessels are over the fovea centralis
False
how do the meningeal layers extend to the eye?
through the optic nerve
what are the 4 features of the refractive media of the eye
cornea
lens
aqueous humor
vitreous humor
define cornea
largely responsible for refraction of light in the eye
define lens
focuses light rays & near or distant objects on retina
define aqueous humor
watery filling anterior to lens
define vitreous humor (body)
gelatinous filling posterior to lens
what is the nervous “visual” layer
refractive media
what are the 4 features of the lacrimal apparatus
lacrimal gland
lacrimal canaliculi
lacrimal sac
nasolacrimal duct
whats is lacrimal gland function?
produces lacrimal fluid (tears), flows inferomedially
what is the lacrimal canaliculi function
transports tears to lacrimal sac
what is lacrimal sac function
drains tears to nasolacrimal duct
what is nasolacrimal duct
drains tears through nasolacrimal canal (under inferior nasal concha)
levator palpebrae superioris m action?
raises upper eyelid
superior rectus m action?
elevates and adducts eye
rotates eye medially
inferior rectus m action?
depresses and adducts eye
rotates eye laterally
lateral rectus m action?
abducts eye
medial rectus m action?
adducts eye
superior oblique m action
depresses and abducts eye
inferior oblique m action?
elevates and abducts eye
which muscle helps the eye look “down and out”
superior oblique m
what tendon is oriented with superior oblique m?
trochlea
which muscle makes the eye look up and out?
inferior oblique m
which muscles ABDUCT the eye?
obliques
which muscles ADDUCT the eye?
recti
which cranial nerve supplies superior oblique m
CN IV
which muscles does the CN III supply?
LPS SR MR IR IO
which cranial nerve supplies lateral rectus m?
CN VI
which cranial nerve carries p-symp to ciliary ganglion?
CN III
how can the eye be placed to test lateral and medial rectus mm?
neutrally
how can the eye be placed to test superior and inferior rectus mm?
abducted
how can the eye be placed to test superior and inferior oblique mm?
adducted
the position of ab/adduction is ____ of muscle action
opposite
what is the optic nerve sensory for?
special sense of sight
where are the optic nerve fibers?
between the eye and chiasm
what is the optic chiasm
intermingling of nerve fibers
what is the optic tract
nerve fibers from chiasm to brain
what are the two visual fields of the optic pathway
temporal
nasal
which visual field crosses over the chiasm?
temporal vision
which visual field remains ipsilateral?
nasal vision
what does visual field testing detect?
blindness
what does the optic nerve lesion result in?
total blindness in affected eye
what does the optic chiasm lesion produce?
loss of peripheral vision
what does the optic tract lesion result in?
ipsilateral nasal visual field loss and contralateral temporal field loss
pattern of optic tract lesion is due to ____ of ____ visual fields
crossing of temporal visual fields
what does the ciliary ganglion receive?
p-symp from CN III
what does the ciliary ganglion supply?
p-symps to ciliary muscle and pupillary sphincter muscle
what does pupillary dilator muscle receive?
sympathetics from internal carotid plexus
where are the preganglionic sympathetic cell bodies?
T1
what does the pupillary light reflex test?
CN II and CN III
how do we tell if there is a CN III p-symp lesion?
pupil remains dilated
what are the 3 divisions of the CN V1
“NFL”
Nasociliary n
Frontal n
Lacrimal n
what does the nasociliary n contain?
ethmoidal and infratrochlear nn
long ciliary nn (sensory and symp) to posterior eye
what does the frontal n branch to?
supraorbital and supratrochlear nn
what does the lacrimal n supply?
lacrimal gland and conjuctiva
what are the 7 arteries of the orbit and eye
ophthalmic a posterior ciliary aa central retinal a ethmoidal aa supraorbital a supratrochlear a lacrimal a
what does the ophthalmic a give rise to?
all arteries of the eye
what does the posterior ciliary aa supply?
outer and middle layers of the eye
what does the central retinal a supply?
inner layer of retina
what does the ethmoidal a supply
anterior cranial fossa, nose, and sinuses
what does the supraorbital a supply
central region of forehead
what does the supratrochlear a supply
medial region of forehead
what does lacrimal a supply
lacrimal gland
what are the 4 veins of the orbit and eye
superior ophthalmic v
inferior ophthalmic v
central retinal v
vorticose vv
what does the vorticose vv drain into?
superior and inferior opthalmic vv
where does central retina v drain?
cavernous sinus
what does the inferior ophthalmic v anastomose with and drain to?
anastomose with facial v and drain to cavernous sinus
what layer does the vorticose veins drain?
choroid layer
what layer does the central veins drain?
the retinal layer
