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Head and Neck Anatomy > Lectures 17 & 18 Eye & Orbit > Flashcards

Lectures 17 & 18 Eye & Orbit Flashcards

1
Q

List bones of orbit?

A
  • Frontal
  • Zygomatic
  • Maxillary
  • Lacrimal
  • Sphenoid - optic canal passes through sphenoid
  • Ethmoid (orbital plate)
  • Palatine bone (orbital process - a small contribution medial to inferior orbital fissure)
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2
Q

Superior orbital fissure is crossed by?

A

Oculomotor, branches of V1 (lacrimal, frontal, nasociliary), trochlear, abducens nerve

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3
Q

Openings of the orbit

A
  • superior orbital fissure
  • inferior orbital fissure
  • infraorbital groove & foramen
  • optic foramen
  • lacrimal canal
  • anterior & posterior ethmoid foramina
  • zygomatico-orbital foramin
  • supraorbital foramen
  • trochleal fovea or spine
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4
Q

Infraorbital groove & foramen are crossed by?

A

Maxillary/infraorbital nerve (CNV/2)

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5
Q

Optic foramen is for which nerve?

A

Optic nerve (CN2)

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6
Q

Trochleal fovea or spine is located where and for what?

A

Halfway between supraorbital notch/foramen & frontolacrimal suture, for superior oblique muscle

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7
Q

Where does levator palpebrae superioris arise?

A

Arises lesser wing sphenoid, above superior rectus & optic canal

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8
Q

Function of levator palpebrae superioris

A

Raises upper eyelid

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9
Q

Frontal nerve is inferior to levator palpebrae superioris

A

False, it is superior

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10
Q

Rectus muscles insert where?

A

Recti insert into sclera about 6mm behind cornea & anterior to insertion of obliques

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11
Q

Superior, inferior, and medial recti arise?

A

Arises tendinous ring around optic nerve

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12
Q

______ has two heads - from lateral part of tendinous ring and from adjoining margin of ___________ ( _____ )

A

Lateral rectus, superior orbital fissure (sphenoid)

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13
Q

Oblique extrinsic muscles insert?

A

Obliques insert further back, behind equator of eyeball

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14
Q

__________ arises from body of sphenoid superomedial to optic canal.

A

Superior oblique muscle

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15
Q

___________ passes forwards along medial wall of orbit to tendinous band (called a trochlea) attached to trochleal fovea

A

Superior oblique muscle tendon

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16
Q

Where does superior oblique tendon insert?

A

Inserts into sclera between superior and lateral rectus

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17
Q

___________ arises orbital surface of maxilla lateral to nasolacrimal groove.

A

Inferior oblique

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18
Q

Where does inferior oblique muscle pass ?

A

Passes between inferior rectus and orbital floor and then between orbit and rectus lateralis

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19
Q

Inferior oblique muscle inserts?

A

Behind equator between rectos inferior and rectus lateralis

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20
Q

Medial and lateral recti rotate eye around horizontal axis

A

False, it rotates around vertical axis

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21
Q

Eye movement of superior and inferior rectus?

A

Elevation and depression

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22
Q

Eye movement of superior obliques

A

Down and out

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23
Q

Eye movement of inferior oblique

A

Turns eye up and out

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24
Q

List the structures of palpebral area

A
  • tarsal plate
  • tendon of levator palpebrae superioris
  • lateral & medial palpebral ligaments
  • orbital septum
  • sebaceous tarsal glands
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25
Q

What is ‘orbital septum’?

A

Fascial sheet attached to periosteum of orbital rim & levator tendon

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26
Q

What are eyelids lined with?

A

Conjunctiva which is continuous with cornea

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27
Q

What does conjunctiva contain?

A

Goblet cells

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28
Q

Another name of sebaceous tarsal glands?

A

Meibom’s glands

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29
Q

Where do sebaceous tarsal glands empty into?

A

Free margin of the eyelid. The oily secretion spreads out over the tear film & contributes to its stability

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30
Q

Location of lacrimal glands

A

Mostly in superolateral orbit, some in eyelid lateral to tarsal plate between conjunctiva & palpebral fascia.

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31
Q

Composition of tears?

A

Mix of serous (from lacrimal glands), mucus (from conjunctiva goblet cells) and sebaceous (from sebaceous tarsal glands)

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32
Q

Where do tears drain?

A

Tears drain into medial corner of the eye & from there into the nasolarcimal duct via lacrimal canaliculi (one per eyelid, above & below plica semilunaris) & lacrimal sac

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33
Q

What is the canal of schlemm?

A
  • Scleral venous sinus (trabecular meshwork)

- drainage of aqueous humour

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34
Q

What is the ora serrata?

A
  • Junction of sensory and non-sensory retina
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35
Q

List the 3 layers of the wall of the eyeball?

A
  • Sclera/cornea
  • Uvea
  • Retina
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36
Q

What is the cornea/sclera?

A

Fibrous outer coat

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37
Q

What is the uvea?

A

Vascular intermediate coat, includes choroid (underlies sensory retina) & anterior parts of ciliary body & iris

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38
Q

Retina has two which parts?

A
  • Sensory retina

- non-sensory retina

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39
Q

Describe sensory retina

A

10 cell layers thick - photoreceptors (rods & cones) & other neurons

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40
Q

Describe non-sensory retina

A

2 cell layers thick - which forms the posterior parts of ciliary body & iris

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41
Q

Hollow centre of eyeball consists of anterior, posterior & vitreous chambers containing humours

A

True

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42
Q

Location of anterior chamber?

A

It’s between cornea & iris

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43
Q

Location of posterior chamber?

A

Behind iris and in front of lens

44
Q

Location of vitreous chamber

A

Behind lens

45
Q

Refractive media of eye includes?

A
  • Conrea,
  • Aqueous humour
  • Lens
  • Vitreous humour
46
Q

What is the main refractive apparatus (focusing light onto retina)?

A

Cornea

47
Q

Function of iris?

A

Variable aperture to control amount of light onto retina

48
Q

Structure of iris?

A

Anterior part - uvea

Posterior part - non sensory retina (just 2 cells thick)

49
Q

Which muscle contracts and expands iris?

A

Circular muscle around pupil contracts (sphincter) & expand (dilate)

50
Q

Innervation of iris?

A
  • Parasympathetic fibres of oculomotor origin - dilation via radial muscle extending outwards from pupil
  • Sympathetic innervation
51
Q

Two functions of ciliary body?

A
  • Production of aqueous humour

- Accommodation for far and near vision

52
Q

Structure of ciliary body?

A
  • Anterior part: uvea

- Posterior part: non-sensory retina (2 cell layers thick)

53
Q

Function of lens?

A

Accommodation for near & far vision

54
Q

Describe structure of lens

A
  • Flexible cellular structure

- Attached to ciliary body by zonule fibres

55
Q

What is ‘accommodation’?

A

Adjusting focus to be able to see near or far objects. Lens, ciliary body and zonule fibres are involved.

56
Q

How are lens attached to ciliary body?

A

Via zonule fibres (complex structure including collagen)

57
Q

When ________ (circular muscle) of ciliary body contracts (parasympathetic control) the diameter of the ciliary body is reduced & there is less tension on zonule fibres

A

Sphincter, this in turn means less ‘pull’ on lens which rounds out/becomes less fat

58
Q

A rounder lens accommodates for?

A

Near vision

59
Q

How many layers of sensory retina?

A

10 layers

60
Q

How to recognise sensory retina?

A

Thickened region on inner surface of posterior & lateral eyeball.

61
Q

Junction of sensory retina and non-sensory retina of ciliary body?

A

Ora serrata

62
Q

From outer to inner surface of sensory retina:

A

Pigment epithelium -> photoreceptors -> inner surface of retina

63
Q

How thick is pigment epithelium? Location and function?

A

1 cell thick, and lies outside rods and cones and phagocytoses worn out components of rods and cones

64
Q

What do photoreceptors consist of and location?

A

Rods and cones, and are in outer retina adjacent to posterior pigment epithelium

65
Q

In sensory retina, the visual signal first goes inwards through a chain of neurons then over the inner surface of retina to the optic nerve.

A

True

66
Q

What is the ‘blind spot’?

A

Special areas of the sensory retina include the optic disc at the site of the entry of the optic nerve (lacks photoreceptors)

67
Q

What is the ‘macula/fovea’?

A

Region adjacent to the optic disc where the elements of the retina except the cones are reduced - region of greatest visual acuity.

68
Q

There is an actual attachment between pigment epithelium & outer sensory retina which can become separated from the pigment epitheliulm (detached retina)

A

False, there is no actual attachment

69
Q

Which type of humours fill which chambers in the eye?

A
  • Aqueous humour fills anterior and posterior chambers.

- Vitreous humour fills vitreous chamber

70
Q

Describe properties of aqueous humour

A
  • Fluid similar to blood plasma, constantly renewed
  • Aqueous humour is produced in folds of ciliary body
  • Transported into posterior chamber
  • Passes through pupil and into anterior chamber
71
Q

Where does aqueous humour drain?

A

Drains from eye into scleral venous sinus (canal of Schlemm) & from there into OPTHALMIC VEINS

72
Q

Describe vitreous humour

A
  • Fluid connective tissue, not constantly renewed

- Stored in vitreous chamber, behind lens

73
Q

The nerves oculomotor, ophthalmic, trochlear, abducent nerves pass through ______ along with internal carotid ______________.

A

Cavernous sinus, carrying carotid sympathetic plexus

74
Q

Sympathetic fibres are transferred in the _______ from carotid plexus to other nerves crossing _______.

A

Cavernous sinus, cavernous sinus

75
Q

List the nerves supplying extrinsic eye muscles

A
  • Oculomotor
  • Trochlea
  • Abducent
76
Q

What does oculomotor nerve supply?

A

Supplies all but two muscles of orbit

  • superior division supplies superior rectus & levator palpebrae superioris
  • inferior division supplies inferior & medial rectus, inferior oblique
77
Q

What does trochlea nerve supply?

A

Superior oblique nerve

78
Q

What does abducens nerve supply?

A

Lateral rectus

79
Q

What does ophthalmic nerve supply?

A

Supplies structures within or near eyeball apart from intrinsic muscles & retina.

80
Q

List branches of ophthalmic nerve

A
  • Lacrimal
  • Frontal
  • Nasociliary
81
Q

How do branches of ophthalmic nerve arise?

A

Arise as sensory nerves but lacrimal & nasociliary carry hitchikers

82
Q

Lacrimal supplies lacrimal gland and skin

A

True

83
Q

Parasympathetic fibres from the greater petrosal branch of facial nerve via pterygopalatine ganglion & maxillary nerve also supply lacrimal gland

A

True

84
Q

Branches of frontal nerve?

A

Supratrochlear nerve, supraorbital nerve

85
Q

Where does supraorbital nerve pass over?

A

Supraorbital nerve passes over superior surface of levator palpebrae superioris.

86
Q

List branches of nasociliary branch of ophthalmic nerve

A
  • sensory ganglion branches
  • long ciliary nerves
  • posterior ethmoidal
  • infratrochlear nerve
  • anterior ethmoid nerve
87
Q

Sensory ganglion branches of nasociliary goes to parasympathetic ciliary ganglion

A

True

88
Q

___________ (sympathetic & sensory) via sclera to dilator muscles of pupil & cornea

A

Long ciliary nerves

89
Q

Posterior ethmoidal branches of nasociliary goes via posterior ethmoid foramina

A

True

90
Q

What are the two terminal branches of nasociliary?

A
  • Infratrochlear nerve

- Anterior ethmoid nerve

91
Q

Describe infratrochlear nerve

A

A cutaneous nerve which emerges just medial to inner corner of eye

92
Q

Describe anterior ethmoid nerve

A

Goes to anterior ethmoid sinuses, nasal cavity and has a cutaneous branch the external nasal nerve

93
Q

_________ is about 1cm in front of the tendinous ring & between lateral rectus & optic nerve

A

Ciliary ganglion

94
Q

Describe the roots of the ciliary ganglion

A
  • Sensory fibres from nasociliary nerve via the short ganglion branches
  • Preganglionic parasympathetic fibres from the (inferior division) of the oculomotor
  • Sympathetic fibres from the ophthalmic artery plexus
95
Q

What do ciliary ganglion branches supply and how many?

A

6-10 short ciliary nerves via sclera supply iris & ciliary body & to the cornea.

96
Q

Parasympathetic innervation of iris and ciliary body are required to:

A
  • contract sphincters of pupil & ciliary body
  • contraction of ciliary muscle -> decrease tension on zonule fibres connecting ciliary body & lens result in a decrease in the diameter of the ciliary body. This results in lens becoming more round and gives accommodation for near vision - focusing light onto retina.
97
Q

Sympathetic innervation is required to:

A
  • dilate pupil

- vasomotor (constriction) to blood vessels

98
Q

Describe the pupillary reflex

A

Light into one eye then both pupils should contract as retina sends fibres into optic tracts of both sides. If the parasympathetic supply to the sphincter of iris (oculomotor nerve) is compromised then sphincter is slow (“2 in, 3 out”)

99
Q

Describe the corneal reflex

A

Afferent via ophthalmic nerve, efferent via facial to orbicularis oculi (“5 in, 7 out”)

100
Q

________ is a branch of the internal carotid - enters optic canal with optic nerve.

A

Ophthalmic artery

101
Q

Ophthalmic artery supplies?

A

Both orbit & eyeball.

102
Q

Orbital branches of ophthalmic artery supply?

A
  • Orbital structures - lacrimal gland, sclera, choroid, iris & ciliary body
  • Supraorbital & supratrochlear branches to eyelids & skin of forehead
  • Branches to ethmoid, frontal & sphenoid sinuses
  • Some of the meninges
  • Retinal branch
103
Q

Define retinal branch and its supply

A

Central artery of retina (arises below optic nerve, enters retina at optic disc, divides into branches).

104
Q

Central artery is the only supply to retina, no anastomosis between branches.

A

True

105
Q

Describe the venous drainage of the retina

A
  • Retinal veins - converge on optic disc & enter optic nerve as central vein of retina. These drain into superior ophthalmic vein -> cavernous sinus
  • Inferior ophthalmic vein drains orbit -> cavernous sinus. Thus both ophthalmic veins have linkages with pterygoid venous plexus.

Head and Neck Anatomy (13 decks)

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