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Neuroscience and Behaviour Emily > 021 the orbit and its contents > Flashcards

021 the orbit and its contents Flashcards

1
Q

what bones make up the orbit?

A
  • frontal
  • zygomatic
  • maxilla
  • lacrimal
  • ethmoid
    -sphenoid
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2
Q

describe the position of the eye in the orbit

A
  • medial orbital wall lies parallel to the midsagittal plane
  • the lateral wall of the orbit is angled with regards to the midsagittal plane
  • the orbital axis and visual axis of the eye do not overlap = consequences on how the eye muscles work
  • the orbital axis = dead between lateral and medial orbit wall plane
  • visual axis = parallel to midsagittal plane (looking straight ahead
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3
Q

what happens when the zygomatic bone is fractured?

A
  • makes up part of orbit, so if it is fractured, the eye will be out of place
  • can cause diplopia (double vision)
  • suspensory ligaments of the eye in the horizontal plane become loose or rupture
  • extra-ocular muscles can become obstructed or trapped, thus restricting eye movement/field of vision
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4
Q

what is a blowout fracture and what is its clinical significance?

A
  • when trauma/force causes fraction of the middle inferior bones, mostly ethmoid or maxillary
  • common symptoms = diplopia (double vision), sunken eye, loss of sensation of cheek, and upper gums due to infraorbital injury of CNVii
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5
Q

what are the 7 extraocular eye muscles?

A
  • levator palpebrae
  • superior tarsal
  • superior oblique
  • inferior oblique
  • superior rectus
  • inferior rectus
  • medial rectus
  • lateral rectus
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6
Q

what is the function of levator palpebrae and superior tarsal muscle?

A
  • elevate/raise the upper eyelid
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7
Q

what is a?

A

superior oblique muscle

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8
Q

what is b?

A

trochlea

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9
Q

what is c?

A

superior oblique tendon

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10
Q

what is d?

A

superior rectus

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11
Q

what is e?

A

lateral rectus

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12
Q

what is f?

A

inferior oblique

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13
Q

what is g?

A

inferior rectus

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14
Q

what is h?

A

common tendinous ring

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15
Q

what is i?

A

medial rectus

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16
Q

what is the function of superior rectus?

A

moving the eye upwards
- also contributes to adduction and medial rotation of eyeball

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17
Q

what is the innervation of levator palpebrae?

A

oculomotor nerve

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18
Q

what is the innervation of superior tarsal muscle?

A

sympathetic

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19
Q

what is the innervation of superior rectus?

A

oculomotor nerve

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20
Q

what is the function of inferior rectus?

A
  • moving the eye downwards
  • also contributes to adduction and lateral rotation of eyeball
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21
Q

what is the innervation of inferior rectus?

A

oculomotor nerve

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22
Q

what is the function of medial rectus?

A
  • adducts eye (moves medially)
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23
Q

what is the innervation of medial rectus?

A

oculomotor nerve

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24
Q

what is the function of lateral rectus?

A
  • abducts eye (moves laterally)
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25
Q

what is the innervation of lateral rectus?

A
  • abducens nerve
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26
Q

where do all the rectus eye muscles originate from?

A

common tendinous ring

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27
Q

what is the function of superior oblique muscle?

A
  • move eye down and outwards (abducts)
  • also medially rotates eye
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28
Q

what is the innervation of superior oblique muscle?

A

trochlear nerve

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29
Q

what is the function of inferior oblique muscle?

A
  • moves eye up and out and laterally rotates eye
30
Q

what is a?

A
  • greater wing of sphenoid
31
Q

what is b?

A

superior orbital fissure

32
Q

what is c?

A

lesser wing of sphenoid

33
Q

what is d?

A

frontal bone

34
Q

what is e?

A

optic canal

35
Q

what is f?

A

ethmoidal foramina

36
Q

what is g?

A

ethmoid bone

37
Q

what is h?

A

lacrimal groove

38
Q

what is i?

A

lacrimal bone

39
Q

what is j?

A

palatine bone

40
Q

what is k?

A

maxilla

41
Q

what is L?

A

inferior orbital fissure

42
Q

what is m?

A

zygomatic bone

43
Q

what is the function of orbicularis oculi?

A
  • closes the eyelids
44
Q

what is the orbicularis oculi innervated by?

A

facial nerve

45
Q

what is the best way to test all the extraocular muscles?

A
  • H test
  • have the patient track an object in a H pattern without moving their head
46
Q

what are the different canals, fissures and foramen in the orbit?

A
  • optic canal
  • superior orbital fissure
  • inferior orbital fissure
  • ethmoidal foramina
  • nasolacrimal canal
47
Q

what passes through the optic canal?

A
  • optic nerve
  • ophthalmic artery
48
Q

what passes through the superior orbital fissure?

A
  • oculomotor nerve (superior and inferior branches)
  • trochlear nerve
  • abducens nerve
  • ophthalmic nerve branches ( lacrimal, frontal, nasociliary)
  • superior ophthalmic vein
49
Q

what passes through the inferior orbital fissure?

A

inferior ophthalmic vein

50
Q

what is a?l

A

superior orbital fissure

51
Q

what is b?

A

lacrimal nerve (branch of ophthalmic division CNVi)

52
Q

what is c?

A

frontal nerve (branch of ophthalmic division CNVi)

53
Q

what is d?

A

trochlear nerve

54
Q

what is e?

A

superior rectus

55
Q

what is f?

A

levator palpebrae

56
Q

what is g?

A

optic nerve

57
Q

what is h?

A

superior oblique

58
Q

what is i?

A

ophthalmic artery

59
Q

what is j?

A

medial rectus

60
Q

what is k?

A

superior division of oculomotor nerve

61
Q

what is L?

A

nasociliary nerve (branch of ophthalmic division (CNVi)

62
Q

what is m?

A

abducent nerve

63
Q

what is n?

A

inferior division of oculomotor nerve

64
Q

what is o?

A

inferior rectus

65
Q

what is p?

A

inferior ophthalmic vein

66
Q

what is q?

A

inferior orbital fissure

67
Q

what is r?

A

lateral rectus

68
Q

describe the arterial supply to the orbit

A
  • ophthalmic artery enters through optic canal
  • then branches:
  • central retinal artery (enters optic nerve, damage causes blindness)
  • lacrimal artery = lateral to lacrimal gland, eye lids and conjunctiva
  • posterior ciliary arteries = central into eye
  • ethmoidal arteries = medial to ethmoidal air cells in nasal cavity
  • supra-orbital, supratrochlear and nasal arteries = medial, supply nose and forehead
69
Q

describe the venous drainage of the orbit

A
  • superior: supra-orbital vein from forehead –> superior ophthalmic vein –> cavernous sinus
  • inferior: angular vein from cheek –> infra-orbital/inferior ophthalmic veins –> pterygoid plexus/cavernous sinus
70
Q

what is the clinical significance of the cavernous sinus?

A
  • most facial veins drain into it
  • easily get infections spread through it
  • could spread to the brain

Neuroscience and Behaviour Emily (21 decks)

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