Anatomy Flashcards
what does the optic canal contain
optic nerve and opthalmic artery and vein
what bone is the optic canal in
sphenoid
what bone is the infraorbital foramen in
maxillary
what bone is the superior orbital fissure in
the sphenoid
what bone is the supraorbital notch in
frontal
why is the ethmoid bone weak
due to the presence of the ethmoid sinuses
what is the ‘apex’ of the bony orbit
the optic canal
what bones are most likely to break in a ‘blow out’ fracture
medial (ethmoid) and orbital floor (maxilla, )
what is a blow out fracture
when a direct blow to the eye increases pressure in eye and cause the fracture of bone/s in the orbit
what bones make up the orbital rim. margin
zygoma, frontal, maxilla
what sensory deficit can be caused an insult to the infraorbital structure
sensory deficit of the skin of the face (maxillary nerve)
what nerve passes through the infraorbital nerve
the maxillary nerve
what maintains the shape of the eyelids
the tarsal plate
what glands in the eyelids secrete lipids
meibomian glands
what is the innervation of the orbicularis occuli
the facial nerve (CNVII)
what is the function of the levator palparbi superioris
lifts the upper eyelid
what is the innervation of the levator palpabri superioris
occulor motor nerve
what is ptosis and what can cause it
inability to lift the upper eyelid
third nerve palsy
what happens when the orbicularus occuli contracts
eyes close
what covers the iris
the continuous layer of the cornea and sclera
what is the sclera covered by
conjunctiva
what is the limbus
the corneoscleral junction
what does the lacrimal gland produce
tears
what innervates the lacrimal gland
parasympathetic CN VII
what is the path of tears
secreted from lacrimal gland washes over eye pushed by blinking towards medial angle drains through lacromal puncta drains through nasolacromal duct into inferior meatus of the nasal cavity
what are the three layers of the eye ball
outer- fibrous
middle- uvea (vascular layer)
inner- retina (photosensitiv
what makes up the fibrous layer of the eyeball
sclera (white and fibrous)
cornea (refraction)
what makes up the uvea layer of the eyeball
iris
ciliary body
choriod
what are the roles of the ciliary body
control iris, shape of lens, secretion of aques humour
what is the role of the choroid body
nutrition and gas exchange
what makes up the retina
the optic disc
what is uveitis
inflammation of the uvea
describe the anterior segment of the eye
in front of lens
divided into:
anterior chamber- between cornea and iris, contains aqueous humour
posterior chamber- between iris and suspensory ligaments, contains aqueous humour
describe the posterior segment of the eye
behind the lens, 2/3rd of eye,
contains vitreous body
what is in the viteous body
vitreous humour
where is a common place for ‘floaters’ to be
vitreous humour
can you replace vitreous humour
no
which part of eye does increased pressure cause glaucoma
posterior chamber of anterior segment
what is the role of the vitreous humour
holds retina in place and keeps shape of eyeball
what is the path of aqueous fluid within the eye
produced by ciliary body
circulates within posterior chamber- nourishes lens
passes through pupil, into anterior chamber, nourishes cornea
reabsorbed into scleral venous sinus (canal of schlemm) at iridocroneal angle
what makes up the ciliary body
smooth muscle and blood vessels
what is the angle is open and closed angle glaucoma
iridocorneal
what can raised intra ocular pressure cause
ischaemia of the retina and glaucoma
what is the blood supply to the eye
(central artery (and vein) of the retina from the) opthalmic artery which is a branch of the internal carotid artery
ciliary arteries also come off the opthalamic artery
what is an end artery
an artery with insufficient anastomoses to maintain viability of the tissue supplied if arterial occlusion occurs
what is the venous drainage of the eye and orbit
superior and inferior opthalmic veins combine and go into cavernous sinus
also drain anteriorly into facial vein (e.g. veins may drain into this via maxillary sinus)
what is the fundus
posterior area where light is focused
what makes up the fundus
optic disc, macula, fovea
what is the optic disc
point of CN II formation
only point of entry/ exit for blood vessels and axons of CN II
(as there are no rods or cones overlying the optic disc)
ACTS AS A BLIND SPOT
what is the macula
part of the fundus which has the greatest density of cones
what is the fovea
centre of the macula
area of most acute vision
why does a star disappear when you look directly at it
as looking at it with cones (colour) not rods (low light)
what are the three layers of the retina (from anterior to posterior)
axons of the ganglion cells
ganglion cells
photoreceptors
where are the retinal veins and arteries in relation to the retina
anterior to the retina
what does complete interruption of flow in a retinal artery branch/ retinal vein
loss of an area of visual field corresponding to the area of ischaemia
what does complete interruption of flow of the central (end) artery or vein cause
monocular blindness
what crosses over at the optic chiasma
nasal retinae
where is light from the right visual field processed
left primary visual cortex
where is light from the lower visual field processed
in the upper part of the primary visual cortex
what are the extrinsic muscles of the eye
superior, medial, lateral and inferior rectus
inferior and superior oblique
where do the extrinsic muscles attach to the eye
to the sclera
what is the action of lateral rectus
abducts (laterally)
what is the action of medial rectus
adduction (medially)
what is the action of superior rectus
up and in (adduct)
what is the action of inferior rectus
down and in (adduct)
what is the action of superior oblique
down and out (oblique- out- abduct) (but test by down and in)
what is the action of inferior oblique
up and out (oblique-out-abduct)
what innervated the lateral rectus
abducens CN VI
what innervates the superior oblique
trochlear nerve
what does the superior oblique pass through before attaching to the eye
the trochlear
what innervates all the extrinsic eye muscles apart from the superior oblique and lateral rectus
CN III- oculomotor nerve
how do you test the superior oblique
adduct and down
how do you test the inferior rectus
out and down
how do you test the superior rectus
out and up
how do you test the inferior oblique
in and up
