eye and orbit Flashcards
name the bones of the orbit
frontal
lacrimal
ethmoid
sphenoid (greater and lesser wings)
maxilla
zygomatic
name the different openings into the orbit
superior orbital fissure
inferior orbital fissure
optical canal
nasolacrimal canal
what comes through superior orbital fissure
LFTSNIA
Lacrimal branch of ophthalmic nerve (branch of trigeminal CNV1)
Frontal branch of ophthalmic nerve (CNV1)
Trochlear CN IV
Superior branch of oculomotor nerve CN III
Nasociliary branch of ophthalmic nerve CNV1
Inferior branch of oculomotor CN III
Abduecent nerve CNVI
what comes through optic canal
optic nerve and opthalmic artery
what comes through inferior orbital fissure
inferior ophthalmic vein
where is superior orbital fissure located
between greater and lesser wings of sphenoid bone
what may cause tunnel vision
compression of optic chiasm (potentially from pituitary)
name the layers of optic nerve from outer to inner
dura mater
arachnoid mater
subarachnoid space (CSF)
pia mater
central retinal vein & artery
what happens if central retinal artery becomes occluded
amaruosis fugax - painless temporary loss of vision in affected eye
what happens if ICP is raised
it is transmitted to meninges and subarachnoid space around CN II that slows retinal venous drainage via the central retinal vein causing papilloedema - unclear edges around eye
what is preseptal cellulitis
Infection of the skin/subcutaneous tissue (superficial layers) anterior to the orbital septum
what is orbital cellulitis
Infection posterior to the orbital septum
Pain on movements of the eye that are restricted along with proptosis (bulging of the eye)
Threatens vision & there is risk of infection spread to cavernous sinus or meninges/brain
what provides sensory innervation to eyelids
CN V1 and V2
what provides blood supply to eyelids
external carotid (facial, transverse facial, superficial temporal)
internal carotid (supratrochlear, supraorbital, lacrimal)
what provides venous drainage from eyelids
veins following arteries
what provides lymphatic drainage
parotid nodes
where do tears come from
lacrimal gland into conjunctival sac
drainage pathway of tears
lacrimal caruncle
punctae
canaliculi
lacrimal sac
nasolacrimal duct
inferior nasal meatus
outline pathway for parasympathetic supply of lacrimal gland
facial nerve CN VII
greater petrosal nerve
pterygoid canal
pterygopalatine ganglion
hitchhike to zygomatic branch of CN V2
lacrimal gland
name the extraocular muscles
superior & inferior oblique
superior, inferior, lateral and medial rectus
levator palpebrae superioris
motor nerve supply of extraocular muscles
LR6 SO4 AO3
lateral rectus CN VI
superior oblique CN IV
all others CN III
what happens if injury to CN III
dilated pupil
ptosis
eye turned downwards and outwards
what arteries bdoes CN III pass by
posterior cerebral and superior cerebellar arteries and posterior communicating artery. aneurysms of those vessels may compress CN III
what happens in CN IV palsy
makes looking down difficult
what happens in CN VI palsy
eye will be pulled inwards
what do CN III, IV AND VI pass through
cavernous sinus
