Orbit, Eye and Lacrimal Apparatus

Question 1

what are the main bones which form the margin of the orbit

Answer 1

frontal, maxilla, zygomatic

Question 2

what are the openings into the orbit

Answer 2

nasolacrimal canal, inferior and superior orbital fissures, optic canal for optic nerve

Question 3

what does the optic canal carry

Answer 3

optic nerve and ophthalmic artery

Question 4

what does the inferior orbital fissure carry

Answer 4

inferior ophthalmic vein

Question 5

what does the superior orbital fissure carry

Answer 5

ophthalmic, oculomotor, trochlear, abducens and superior ophthalmic vein

Question 6

what is the retrobulbar fat and what does it do

Answer 6

fatty tissue posterior to eyeball and optic nerve and it supports the eyeball

Question 7

what are the extraocular muscles

Answer 7

superior rectus, lateral rectus, medial rectus, inferior rectus, superior oblique, lateral oblique

Question 8

what do the extraorbital muscles do

Answer 8

move the eyeball

Question 9

what does the optic nerve contain at the centre of the nerve

Answer 9

vascular structure containing retinal artery and retinal vein

Question 10

what surrounds the optic nerve

Answer 10

cranial meninges

Question 11

what can trauma to the eye mean for the maxillary sinus

Answer 11

damage to the bony casing can cause contents of the orbit to be displaced into the maxillary sinus

Question 12

where does the optic chiasm lie

Answer 12

superior and anterior to pituitary gland

Question 13

where do fibres in the optic tract go

Answer 13

to the visual cortex in the occipital lobe

Question 14

what is the consequence of a tumour in the pituitary gland on the optic nerve

Answer 14

presses on the optic chiasm and causes issues with vision (tunnel vision)

Question 15

why can the central retinal artery become occluded

Answer 15

due to transient causes such as amaurosis fugax that leads to painless temporary loss of vision in affected eyes

Question 16

what causes papilledema

Answer 16

raised intracranial pressure transmitted to the meninges and subarachnoid space around the optic nerve slowing retinal venous drainage via central retinal vein

Question 17

what is papilledema

Answer 17

swelling of the optic disc making is look fuzzy

Question 18

what is used as a diagnostic sign for intracranial pressure

Answer 18

papilledema - optic disc looking fuzzy

Question 19

what happens if there is an injury to the left optic nerve

Answer 19

sight to the eye will be lost but right eye will be fine

Question 20

what happens if there is an injury to the left side of the optic chiasm

Answer 20

lateral side of each visual field is lost and causes tunnel vision so only the smaller medial side of visual fields still function

Question 21

what happens if there is an injury to the left optic tract

Answer 21

part of visual fields supplied by this will not work

Question 22

what is the action of the orbicularis oculi

Answer 22

close eyelids gently or tightly

Question 23

what innervates the orbicularis oculi

Answer 23

facial nerve

Question 24

what can malfunction of the facial nerve mean for orbicularis oculi

Answer 24

sagging of lower eyelid, leakage of tears and dry eyes with potential for corneal ulceration

Question 25

where are tears secreted from

Answer 25

lacrimal gland into conjunctival sacs

Question 26

where do tears drain to

Answer 26

puncta canaliculi lacrimal sac nasolacrimal duct inferior nasal meatus

Question 27

why does the nose run when crying

Answer 27

because the eye and nose are joined

Question 28

what is the preganglionic parasympathetic supply to the lacrimal gland

Answer 28

facial nerve via nervous intermedius and travel in greater petrosal nerve then then the nerve of the pterygoid canal

Question 29

what ganglion is associated with the parasympathetic supply of the lacrimal gland

Answer 29

pterygopalatine ganglion

Question 30

what is the postganglionic parasympathetic supply of the lacrimal gland

Answer 30

fibres hitch hike to zygomatic branch of CNV2 to reach the lacrimal gland

Question 31

what are the 6 extraocular muscles

Answer 31

superior oblique, inferior oblique, superior rectus, inferior rectus, medial rectus, lateral rectus

Question 32

what does levator palpebrae superioris do

Answer 32

elevates upper eyelid and allows to open eyelid and keep open

Question 33

what is the superior oblique muscle controlled by

Answer 33

a tendon called the trochlea which works on a pulley system

Question 34

what nerve runs over the muscles in the eye

Answer 34

supraorbital nerve (part of ophthalmic division)

Question 35

what muscle pulls the eye to the nose

Answer 35

medial rectus

Question 36

what muscle pulls the eye to the side of the head

Answer 36

lateral rectus

Question 37

what muscle pulls the eye upwards and medial

Answer 37

superior rectus

Question 38

what muscle pulls the eye downwards and medial

Answer 38

inferior rectus

Question 39

what muscle pulls the eye upwards and outwards

Answer 39

inferior oblique

Question 40

what muscle pulls the eye downwards and outwards

Answer 40

superior oblique

Question 41

what muscles are required to work together to look straight up or down

Answer 41

rectus and an oblique

Question 42

what nerves innervate the motor supply of eye

Answer 42

oculomotor, abducens, trochlear

Question 43

what muscles does the oculomotor supply

Answer 43

medial rectus, inferior rectus, superior rectus, inferior oblique, levator palpebrae

Question 44

what muscle does the abducens nerve supply

Answer 44

lateral rectus

Question 45

what muscle does the trochlear nerve supply

Answer 45

superior oblique

Question 46

what does the oculomotor nerve carry parasympathetic fibres for

Answer 46

pupil constriction and accommodation

Question 47

what does the oculomotor nerve carry sympathetic fibres for

Answer 47

smooth muscle of levator palpebrae superioris

Question 48

what does injury to the oculomotor nerve result in

Answer 48

dilated pupil (mydriasis), ptosis, and eye turned down and outwards

Question 49

if the pupil is dilated, what nerve has a problem

Answer 49

oculomotor

Question 50

if the pupil is constricted, what nerve has a problem

Answer 50

sympathetic trunk in neck

Question 51

what are the 3 layers of the eyeball

Answer 51

sclera, choroid, retina

Question 52

what separates the posterior and anterior chamber of the eyeball

Answer 52

iris

Question 53

how does the posterior and anterior chamber of the eyeball communicate

Answer 53

through the pupil

Question 54

what is the eyeball made of

Answer 54

vitreous humour

Question 55

what are the chambers of the eyeball made of

Answer 55

aqueous humour

Question 56

what does the choroid continue as

Answer 56

ciliary body

Question 57

what does the ciliary body form

Answer 57

a complete supportive ring around the lens and iris

Question 58

what happens when the ciliaris muscle contracts

Answer 58

ring shrinks, suspensory ligaments relax and lens become rounded

Question 59

what muscles does the iris contain

Answer 59

sphincter pupillae, dilator pupillae

Question 60

where is aqueous humour secreted from

Answer 60

ciliary body

Question 61

where is aqueous humour reabsobred

Answer 61

scleral venous sinus

Question 62

how does glaucoma happen

Answer 62

from excess pressure

Question 63

what helps glaucoma

Answer 63

drugs that constrict the pupil which can pull the venous sinus open

Question 64

what happens to the lens in the absence of nerve stimulation

Answer 64

ciliary muscle relaxed, zonular fibres under tension, lens stretched thin to refract light for distant vision

Question 65

what happens to the lens when there is parasympathetic stimulation

Answer 65

ciliary muscles contract, zonular fibres relax, internal tension causes lens to become more spherical to refract light for near vision