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Head And Neck > The Orbits > Flashcards

The Orbits Flashcards

1
Q

Purpose of the orbits

A

Contain and protect the eyeballs and their muscles, nerves and vessels, together with most of the lacrimal apparatus

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2
Q

All space in the orbits not occupied by structures is filled with:

A

Orbital fat

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3
Q

What is the periosteum that is lines with the bones of the orbit called

A

Periorbita

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4
Q

What is the sup wall of the orbit formed by?

A

Mainly by the orbital part of the frontal bone and lesser wing of the sphenoid

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5
Q

The sup wall anterolaterally consists of:

A

Lacrimal fossa that’s occupied by lacrimal gland

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6
Q

The medial wall of the orbit is formed by:

A

Ethmoid bone

Frontal

Lacrimal

Sphenoid

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7
Q

The medial wall anteriorly is indented by the:

A

Lacrimal groove and fossa for the lacrimal sac

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8
Q

The medial wall of the orbit is (THICK/THIN)

A

Paper-thin

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9
Q

In the medial wall of the orbit, the ethmoid air cells are often:

A

Visible through the bone of a dried cranium

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10
Q

The lateral wall of the orbits is formed by:

It is:

A

Frontal process of zygomatic bone

And greater wing of sphenoid

The strongest and thickest wall

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11
Q

The inf wall of the orbits is formed by:

A

Mainly by the maxilla

Partly by the zygomatic and palatine bones

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12
Q

The inf wall (floor) is demarcated from the lateral wall by the:

A

Inf orbital fissure

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13
Q

The inf wall of the orbit (floor) is shared by:

A

The orbit superiorly

And maxillary sinus inferiorly

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14
Q

Where is the apex of the orbit located?

A

At the optic canal in the lesser wing of the sphenoid— just medial to the sup orbital fissure

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15
Q

The base of the orbits is formed by:

A

Orbital openings

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16
Q

The eyelids are movable folds that are covered externally by __ ___ and internally by:

A

Thin skin

A transparent mucous membrane— palpebral conjunctiva

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17
Q

Palpebral conjunctiva is reflected onto the ____, where it is continuous with the

A

Bulbar conjunctiva

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18
Q

What are the lines of reflection of the palpebral conjunctiva onto the eyeball?

A

Superior and interest conjunctival fornices

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19
Q

What are superior and inferior tarsi

A

Dense connective tissue that strengthens the upper and lower eyelids

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20
Q

What are the tarsal glands

A

Lipid secretion of which lubricates the edges of the eyelids and prevents them from sticking together when they close.

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21
Q

Eyelashes are located:

A

In the margins of the eyelids

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22
Q

What are the ciliary glands

A

Large sebaceous Glands associated with the eyelashes

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23
Q

The lacrimal glands lie in the _____ part of each orbit. They secrete:

A

Superolateral

Tears

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24
Q

Production of lacrimal fluid is stimulated by:

A

Parasympathetic impulses from facial nerve

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25
Q

What conveys lacrimal fluid from the lacrimal glands to the conjunctival sac?

A

Lacrimal ducts

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26
Q

Lacrimal canaliculi each begins at a ____ ____ on the ____ ___ near the ___ angle of the eye.

A

Lacrimal punctum (opening)

Lacrimal papilla

Medial

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27
Q

Lacrimal canaliculi convey the lacrimal fluid from the ___ ____ to the _____ ___ (____).

A

Lacrimal lake

Lacrimal sac (the dilated sup part of the nasolacrimal duct)

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28
Q

What conveys the lacrimal fluid to the nasal cavity

A

Nasolacrimal duct

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29
Q

the eyeball is suspended by (#) extrinsic muscles that control movements

A

6

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30
Q

3 layers of eyeball muscles

A

Fibrous layer (outer coat)

Vascular layer (middle coat)

Inner layer (inner coat)

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31
Q

What does fibrous layer of eyeball muscles consist of

A

Sclera and cornea

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32
Q

The vascular layer (middle coat) of the eyelid consists of what

A

Choroid

Ciliary body

Iris

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33
Q

The inner layer (inner coat) of the eyeball consists of what

A

Retina

Which has both optic and non-visual parts

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34
Q

What is the sclera of the eyeball

A

Tough opaque part of the fibrous layer of the eyeball

Covers the post 5/6 of the eyeball.

The white of the eye

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35
Q

The sclera is relatively _____.

A

Avascular

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36
Q

What is the cornea

A

The transparent part of the fibrous layer covering the ant 1/6 of the eyeball.

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37
Q

The cornea is completely ______, receiving its nourishment from the ____ ___ and the _____ ___

A

Avasular

Lacrimal fluid

Aqueous humor

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38
Q

What is the choroid

A

Dark reddish brown later between the sclera and retina

Forms the largest part of the vascular layer of the eyeball aaaaand lines most of the sclera

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39
Q

The choroid attaches firmly to the ____ later of the ____ and is directly continuous with:

A

Pigment

Retina

The ciliary body

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40
Q

The ciliary body is ___ as well as ____

A

Muscular

Vascular

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41
Q

The ciliary body connects the ____ with the ____

It provides attachment for the ____

A

Choroid

Iris

Lens

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42
Q

What controls thickness of the lens

A

Contraction/relaxation of the circularly arranged smooth muscle of the ciliary body

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43
Q

Ciliary processes secrete ____ ______.

This fills the:

A

Aqueous humor

Anterior segment of the eyeball (ant to the lens, suspensory ligament and ciliary body

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44
Q

The Iris lays:

A

Just on the ant surface of the lens

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45
Q

What is the iris

A

Thin contractile diaphragm with a central opening (pupil) for transmitting light

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46
Q

Muscles controlling the size of the pupil

A

Sphincter pupillae

Dilator pupillae

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47
Q

The sphincter pupillae is ____ stimulates, _____ arranges and works to _____ the pupil (___ ___)

A

Parasympathetically

Circularly

Constrict

Pupillary miosis

48
Q

The dilator pupillae is _______ stimulated ____ arranged and _____ the pupil

A

Sympathetically

Radically

Dilates

49
Q

The retina consists of what two functional parts?

A

Optic and non-visual

50
Q

Which part of the retina is sensitive to visual light rays?

A

The optic part

51
Q

2 layers of the optic part of the retina

A

Neural layer (light receptive)

Pigmented layer (reduces the scattering of light in the eyeball)

52
Q

The non-visual retina is an anterior continuation of what?

A

The pigmented layer

53
Q

Posterior part of the eyeball where light enters. Part of the retina

A

Fundus of the eyeball

54
Q

The optic disc (part of retina) is where ___ ___ and ___ are located. They are conveyed by the ___ nerve.

It is _____ to light

A

Sensory fibers

Vessels

Optic

Insensitive (bling spot)

55
Q

Macula lutea (yellow spot) of the retina is lateral to the ___ ___. It is a ___ ___ area of the retina with special ____ _____ that is specialized for ____ of vision

A

Optic disc

Small oval

Photoreceptor cones

Acuity

56
Q

Depression at the center of the macula of the retina. Area of most acute vision

A

Fovea centralis

57
Q

What changes the shape of the lens

A

Accommodation of the ciliary muscle

58
Q

What causes contraction of the ciliary muscle (sphincter)?

A

Parasympathetic stimulation via the oculomotor nerve (CN III)

59
Q

What happens to the lens as it becomes smaller

A

Becomes more convex, bringing near objects into focus

60
Q

In absence of nerve stimulation, what happens to the lens

A

Becomes less convex and brings more distant objects into focus (far vision)

61
Q

What are the extra-ocular muscles of the orbit

What do they do?

A

Levator palpebral Superioris

Four recti

Two obliques

Work together to move the sup eyelids and eyeballs

62
Q

Eyeball rotates around was axes?

A

Vertical

Transverse

Anteroposterior

63
Q

What axis causes the eyeball to move medially (toward the midline, adduct ion) or laterally (away from midline, abduct ion)?

A

Vertical axis

64
Q

What axis does the pupil move superiorly (elevation) and inferiorly (depression)?

A

Transverse axis

65
Q

Movements around the anteroposterior axis

A

Moves the sup pole of the eyeball medially (medial rotation or intorsion) or laterally (lateral rotation, or extortion)

66
Q

The four recti muscles run ____ to the eyeball, arising from the ___ ___ ___

A

Anteriorly

Common tendinous ring

67
Q

The common tendinous ring surrounds the ___ ___ and part of the ___ ____ fissure at the ____ of the orbit

A

Optic canal

Superior orbital

Apex

68
Q

What are the primary actions of the four recti?

A

Elevation

Depression

Adduction

Abduction

69
Q

The apex of the orbit is _____ placed relative to the orbit, so that the ____ of the orbit foes not coincide with the ___ ___.

A

Medially

Axis

Optical axis

70
Q

Position of the superior and inferior rectus muscles when the eye is in the primary position

A

Approach the eyeball from its medial side.

Line of pull passing medial to the vertical axis

71
Q

OINA for levator palpebrae superioris

A

OR: lesser wing of sphenoid. Sup and ant to optic canal

INS: sup tarsus and skin of sup eyelid

NS: Oculomotor nerve; deep layer (sup tarsal muscle) supplies by sympathetic fibers

AC: elevates sup eyelid
Antagonist to the sup half of the orbicularis oculi

72
Q

Superior tarsal muscle- smooth muscle fibers supplied by ____ nerve

Produces additional ____ of the _____ fissure

Interruption of sympathetic supply produces:

A

Sympathetic

Widening

Palpebral

A constant ptosis (drooping of the upper eyelid)

73
Q

OINA for sup oblique

A

OR: body of sphenoid bone

INS: through trochlea to insert into sclera, deep to SR

NS: trochlear nerve (CN IV)

AC: abducts, depresses and rotates eyeball medially (intorsion)

74
Q

OINA for inf oblique

A

OR: ant part of the floor of orbit

INS: sclera deep to lateral rectus muscle

NS: Oculomotor nerve (CN III)

AC: Abducts, elevated, and rotates eyeball laterally (extortion)

75
Q

OINA for sup rectus

A

OR: Common tendinous ring

INS: Sclera just post to corneoscleral junction

NS: Oculomotor nerve (CN III)

AC: Elevates, adducts and rotates eyeball medially (intorsion)

76
Q

OINA for inf rectus

A

OR: common tendinous ring

INS: sclera post to corneoscleral junction

NS: Oculomotor nerve (CN III)

AC: depresses, adducts and rotates eyeball laterally

77
Q

OINA for medial rectus

A

OR: Common tendinous ring

INS: sclera post to corneoscleral junction

NS: Oculomotor (CN III)

AC: Adducts eyeball

78
Q

OINA for lateral rectus

A

OR: Common tendinous ring

INS: Sclera just post to corneoscleral junction

NS: Abducent Nerve (CN VI)

AC: abducts eyeball

79
Q

Nerves of orbit

A

Optic nerves

Oculomotor

Trochlear

Abducent

Opthalamic

Ciliary ganglion

80
Q

Optic nerves are purely ___ nerves that transmit impulses generated by ___ ___ and develop as paired ____ ____ of the _____

A

Sensory

Optical stimuli

Anterior extensions

Forebrain

81
Q

Optic nerves are surrounded by extensions of the ____ _____ and ___ ____, the latter occupied by a thin layer of ____

A

Cranial meninges

Subarachnoid space

CSF

82
Q

Oculomotor (CN III) divides into what branches?

A

Superior and inferior

83
Q

Superior branch of the oculomotor nerve (CN III) supplies what muscles

A

Sup rectus and levator palpebrae superioris

84
Q

Inf branch of the oculomotor nerve supplies:

It carries:

A

medial and inf rectus and inf oblique

Presynaptic fibers to the ciliary ganglion

85
Q

The trochlear nerve (CN IV) passes directly through the __ ___ fissure and enters the ___ surface of the:

A

Sup orbital

Superior

Sup oblique muscle

86
Q

The Abducent nerve (CN IV) passes directly through the ___ ___ fissure and Enters the ___ surface of the:

A

Superior orbital

Medial

Lateral rectus muscle

87
Q

The ophtalmic nerve (CN V1) passes through the ___ ____ fissure

A

Superior orbital

88
Q

Branches of the ophthalmic nerve

A

Lacrimal nerve

Frontal

Nasociliary

89
Q

The lacrimal nerve arises in the ____ wall of the ___ sinus. It passes to the _____ gland, giving sensory branches to the

A

Lateral

Cavernous

Lacrimal

Conjunctiva and skin of superior eyelid

90
Q

;the distal part of the lacrimal nerve carries ______ fibers conveyed to it from the _______ nerve

A

Secretomotor

Zygomatic (CV2)

91
Q

The frontal nerve enters through the ____ ____ fissure, and divides into the ___ ___ and ____ ___ nerves, providing _____ innervation to the:

A

Superior orbital

Supraorbital

Supratrochlear

Sensory

Sup eyelid, scalp and forehead

92
Q

What is the sensory nerve to the eyeball?

A

Nasociliary nerve

93
Q

The nasociliary nerve also supplies several branches to:

A

The orbit

Face

Paranasal sinuses

Nasal cavity

Anterior cranial fossa

94
Q

Branches of the nasociliary nerve

A

Infra trochlear nerve

Ethmoidal nerves

Long ciliary nerves

95
Q

Terminal branch of the nasociliary nerve

A

Infra trochlear nerve

96
Q

Infratrochlear nerve supplies:

A

Eyelids

Conjunctiva

Skin of the nose

Lacrimal sac

97
Q

The ethmoidal nerves supply:

A

Mucous membrane of sphenoidal and ethmoidal sinuses

Nasal cavities and dura mater of the ant cranial fossa

98
Q

Short ciliary nerves are branches of the:

A

Ciliary ganglion

99
Q

Small group of postsynaptic parasympathetic nerve cell bodies located between the optic nerve and lateral rectus close to the apex

A

Ciliary ganglion

100
Q

The ciliary ganglion receives nerve fibers from what 3 sources?

A

Sensory fibers from CN V1 via nasociliary nerve

Presynaptic parasympathetic fibers from CN III

Postsynaptic sympathetic from internal carotid plexus

101
Q

Long ciliary nerves convey _____ ____ fibers to that?

A

Postsynaptic sympathetic

Dilator pupillae and afferent fibers form the iris and cornea

102
Q

Arteries of the orbits are from what?

A

The ophthalmic artery

A branch of the internal carotid artery

ALSO, infra-orbital artery, from the external carotid artery

103
Q

The ophthalmic artery transverses _____ canal to reach ____ cavity

A

Optic

Orbital

104
Q

Branches of the ophthalmic artery

A

Central retinal artery

Supra-orbital artery

Supratrochlear artery

Lacrimal artery

Short and long post ciliaries

Ant and post ethmoidal art

Infra-orbital artery

105
Q

Central retinal art arises inf to the _____ nerve, pierces the ___ ___ of the ___ nerve and runs within the ___ to the __.

It emerges at the ___ ____, spread over the internal surface of the ____

A

Optic

Dural sheath

Optic nerve

Nerve to the eyeball

Optic disc

Retina

106
Q

The terminal branches of the central retinal artery are _____ arteries, with provide:

A

End

Only blood supply to the internal aspect of the retina (optic retina except cones and rods)

107
Q

The Supra-orbital artery passes ____ and ____ from ________ foramen to supply:

A

Sup and post

Supra-orbital

Forehead and scalp

108
Q

Supratrochlear passes from _____ margin to:

A

Supra-orbital

Forehead and scalp

109
Q

The lacrimal art passes along the _____ border of ____ ___ muscle so supply:

A

Super

Lateral rectus

Lacrimal gland

Conjunctiva

Eyelids

110
Q

Short and long post ciliaries art pierces _____ to supply

A

Sclera

Choroid

Ciliary body and iris

111
Q

And and Post ethmoidal arteries pass through ant and post _____ foramen to supply:

A

Ethmoidal

Ant, middle and post ethmoidal cells

112
Q

The infra-orbital art is the third part of the _____ artery

A

Maxillary

113
Q

The infr-orbital art passes along the ______ ____ and ___ to the:

A

Infra-orbital groove and foramen

Face

114
Q

Sup and inf ophthalmic veins pass through the ____ fissure and enter the _____ sinus

A

Sup orbital

Cavernous

115
Q

The inf ophthalmic vein drains to the:

A

Pterygoid venous plexus

116
Q

The central vin of the retinal usually enters:

A

The cavernous sinus directly,

May join one of the ophthalmic veins

117
Q

Sclera venous sinus is a vascular structure encircling the ____ chamber of the eyeball through which the ___ ___ is returned to the blood circulation

A

Anterior

Aqueous humor

Head And Neck (16 decks)

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