Orbit, Eye and Lacrimal Apparatus Flashcards

1
Q

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

A

frontal, maxilla, zygomatic

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2
Q

what are the openings into the orbit

A

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

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3
Q

what does the optic canal carry

A

optic nerve and ophthalmic artery

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4
Q

what does the inferior orbital fissure carry

A

inferior ophthalmic vein

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5
Q

what does the superior orbital fissure carry

A

ophthalmic, oculomotor, trochlear, abducens and superior ophthalmic vein

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6
Q

what is the retrobulbar fat and what does it do

A

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

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7
Q

what are the extraocular muscles

A

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

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8
Q

what do the extraorbital muscles do

A

move the eyeball

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9
Q

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

A

vascular structure containing retinal artery and retinal vein

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10
Q

what surrounds the optic nerve

A

cranial meninges

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11
Q

what can trauma to the eye mean for the maxillary sinus

A

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

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12
Q

where does the optic chiasm lie

A

superior and anterior to pituitary gland

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13
Q

where do fibres in the optic tract go

A

to the visual cortex in the occipital lobe

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14
Q

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

A

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

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15
Q

why can the central retinal artery become occluded

A

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

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16
Q

what causes papilledema

A

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

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17
Q

what is papilledema

A

swelling of the optic disc making is look fuzzy

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18
Q

what is used as a diagnostic sign for intracranial pressure

A

papilledema - optic disc looking fuzzy

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19
Q

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

A

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

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20
Q

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

A

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

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21
Q

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

A

part of visual fields supplied by this will not work

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22
Q

what is the action of the orbicularis oculi

A

close eyelids gently or tightly

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23
Q

what innervates the orbicularis oculi

A

facial nerve

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24
Q

what can malfunction of the facial nerve mean for orbicularis oculi

A

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

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25
Q

where are tears secreted from

A

lacrimal gland into conjunctival sacs

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26
Q

where do tears drain to

A

puncta
canaliculi
lacrimal sac
nasolacrimal duct
inferior nasal meatus

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27
Q

why does the nose run when crying

A

because the eye and nose are joined

28
Q

what is the preganglionic parasympathetic supply to the lacrimal gland

A

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

29
Q

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

A

pterygopalatine ganglion

30
Q

what is the postganglionic parasympathetic supply of the lacrimal gland

A

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

31
Q

what are the 6 extraocular muscles

A

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

32
Q

what does levator palpebrae superioris do

A

elevates upper eyelid and allows to open eyelid and keep open

33
Q

what is the superior oblique muscle controlled by

A

a tendon called the trochlea which works on a pulley system

34
Q

what nerve runs over the muscles in the eye

A

supraorbital nerve (part of ophthalmic division)

35
Q

what muscle pulls the eye to the nose

A

medial rectus

36
Q

what muscle pulls the eye to the side of the head

A

lateral rectus

37
Q

what muscle pulls the eye upwards and medial

A

superior rectus

38
Q

what muscle pulls the eye downwards and medial

A

inferior rectus

39
Q

what muscle pulls the eye upwards and outwards

A

inferior oblique

40
Q

what muscle pulls the eye downwards and outwards

A

superior oblique

41
Q

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

A

rectus and an oblique

42
Q

what nerves innervate the motor supply of eye

A

oculomotor, abducens, trochlear

43
Q

what muscles does the oculomotor supply

A

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

44
Q

what muscle does the abducens nerve supply

A

lateral rectus

45
Q

what muscle does the trochlear nerve supply

A

superior oblique

46
Q

what does the oculomotor nerve carry parasympathetic fibres for

A

pupil constriction and accommodation

47
Q

what does the oculomotor nerve carry sympathetic fibres for

A

smooth muscle of levator palpebrae superioris

48
Q

what does injury to the oculomotor nerve result in

A

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

49
Q

if the pupil is dilated, what nerve has a problem

A

oculomotor

50
Q

if the pupil is constricted, what nerve has a problem

A

sympathetic trunk in neck

51
Q

what are the 3 layers of the eyeball

A

sclera, choroid, retina

52
Q

what separates the posterior and anterior chamber of the eyeball

A

iris

53
Q

how does the posterior and anterior chamber of the eyeball communicate

A

through the pupil

54
Q

what is the eyeball made of

A

vitreous humour

55
Q

what are the chambers of the eyeball made of

A

aqueous humour

56
Q

what does the choroid continue as

A

ciliary body

57
Q

what does the ciliary body form

A

a complete supportive ring around the lens and iris

58
Q

what happens when the ciliaris muscle contracts

A

ring shrinks, suspensory ligaments relax and lens become rounded

59
Q

what muscles does the iris contain

A

sphincter pupillae, dilator pupillae

60
Q

where is aqueous humour secreted from

A

ciliary body

61
Q

where is aqueous humour reabsobred

A

scleral venous sinus

62
Q

how does glaucoma happen

A

from excess pressure

63
Q

what helps glaucoma

A

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

64
Q

what happens to the lens in the absence of nerve stimulation

A

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

65
Q

what happens to the lens when there is parasympathetic stimulation

A

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