eye and orbit

Question 1

name the bones of the orbit

Answer 1

frontal
lacrimal
ethmoid
sphenoid (greater and lesser wings)
maxilla
zygomatic

Question 2

name the different openings into the orbit

Answer 2

superior orbital fissure
inferior orbital fissure
optical canal
nasolacrimal canal

Question 3

what comes through superior orbital fissure

Answer 3

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

Question 4

what comes through optic canal

Answer 4

optic nerve and opthalmic artery

Question 5

what comes through inferior orbital fissure

Answer 5

inferior ophthalmic vein

Question 6

where is superior orbital fissure located

Answer 6

between greater and lesser wings of sphenoid bone

Question 7

what may cause tunnel vision

Answer 7

compression of optic chiasm (potentially from pituitary)

Question 8

name the layers of optic nerve from outer to inner

Answer 8

dura mater
arachnoid mater
subarachnoid space (CSF)
pia mater
central retinal vein & artery

Question 9

what happens if central retinal artery becomes occluded

Answer 9

amaruosis fugax - painless temporary loss of vision in affected eye

Question 10

what happens if ICP is raised

Answer 10

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

Question 11

what is preseptal cellulitis

Answer 11

Infection of the skin/subcutaneous tissue (superficial layers) anterior to the orbital septum

Question 12

what is orbital cellulitis

Answer 12

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

Question 13

what provides sensory innervation to eyelids

Answer 13

CN V1 and V2

Question 14

what provides blood supply to eyelids

Answer 14

external carotid (facial, transverse facial, superficial temporal)
internal carotid (supratrochlear, supraorbital, lacrimal)

Question 15

what provides venous drainage from eyelids

Answer 15

veins following arteries

Question 16

what provides lymphatic drainage

Answer 16

parotid nodes

Question 17

where do tears come from

Answer 17

lacrimal gland into conjunctival sac

Question 18

drainage pathway of tears

Answer 18

lacrimal caruncle
punctae
canaliculi
lacrimal sac
nasolacrimal duct
inferior nasal meatus

Question 19

outline pathway for parasympathetic supply of lacrimal gland

Answer 19

facial nerve CN VII
greater petrosal nerve
pterygoid canal
pterygopalatine ganglion
hitchhike to zygomatic branch of CN V2
lacrimal gland

Question 20

name the extraocular muscles

Answer 20

superior & inferior oblique
superior, inferior, lateral and medial rectus
levator palpebrae superioris

Question 21

motor nerve supply of extraocular muscles

Answer 21

LR6 SO4 AO3
lateral rectus CN VI
superior oblique CN IV
all others CN III

Question 22

what happens if injury to CN III

Answer 22

dilated pupil
ptosis
eye turned downwards and outwards

Question 23

what arteries bdoes CN III pass by

Answer 23

posterior cerebral and superior cerebellar arteries and posterior communicating artery. aneurysms of those vessels may compress CN III

Question 24

what happens in CN IV palsy

Answer 24

makes looking down difficult

Question 25

what happens in CN VI palsy

Answer 25

eye will be pulled inwards

Question 26

what do CN III, IV AND VI pass through

Answer 26

cavernous sinus