Orbit Flashcards

1
Q

Thickened funnel shaped fascial layer that lines the orbit

A

periorbita

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2
Q

What are the thinnest walls of the orbit?

A

The medial and lateral walls

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3
Q

Flow of tears

A

Lacrimal gland–> conjunctival sac–> lacrimal punctum–> nasolacrimal duct–>nasal cavity

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4
Q

Purpose of tarsal gland

A

secrete a fatty substance to prevent lids from sticking together when closed

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5
Q

What anchors the tarsal plates?

A

Medial and lateral palpebral ligaments

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6
Q

Function of levator palpebrae superioris

A

skeletal muscle that raises the eyelid. It can fatigue.

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7
Q

What is the superior tarsal muscle

A

A smooth muscle that is responsible for the tone of the eyelid

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8
Q

What innervates the superior tarsal muscle

A

Sympathetic fibers that travel with the frontal nerve

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9
Q

What can cause horner’s syndrome?

A

Lesion of superior cervical ganglion.

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10
Q

What is Horner’s syndrome

A

causes the tone of the upper eyelid to relax since superior tarsal is innervated by sympathetic fibers

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11
Q

What muscle abducts the eye

A

Lateral rectus

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12
Q

What muscle adducts the eye

A

medial rectus

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13
Q

What muscles elevate the eye

A

superior rectus, inferior oblique

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14
Q

What muscles depress the eye

A

Inferior rectus, superior oblique

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15
Q

What muscle intorts the eye

A

Superior oblique

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16
Q

What muscle extorts the eye

A

inferior oblique

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17
Q

Test lateral rectus

A

Abduct the eye

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18
Q

Test medial rectus

A

adduct the eye

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19
Q

Test superior rectus

A

abduct eye to the line of pull and look up

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20
Q

Test inferior rectus

A

abduct eye to the line of pull and look down

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21
Q

Test superior oblique

A

adduct the eye and look down

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22
Q

Test inferior oblique

A

adduct and look up

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23
Q

diplopia

A

double vision

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24
Q

What would cause diplopia

A

A cranial nerve IV-trochlear lesion because the inferior oblique is unopposed

25
Q

3 layers of the eyeball

A

Fibrous layer, vascular layer, retinal layer

26
Q

What composes the fibrous layer

A

cornea and sclera

27
Q

What composes the vascular layer

A

choroid, ciliary body, iris

28
Q

What composes the retinal layer

A

bipolar neurons, optic disc, macula lutea

29
Q

What is the optic disc

A

Where the optic nerve enters the eye and it’s fibers spread out. There are no receptors here so this is the blind spot

30
Q

Macula lutea

A

area lateral to the optic disc where there is the fovea centralis

31
Q

Describe the cornea

A

transparent and avascular

32
Q

Aqueous humor

A

a clear watery fluid in the anterior and posterior chambers of the eyeball.

33
Q

What produces the aqueous humor

A

The ciliary processes

34
Q

Describe flow of aqueous humor

A

Produced by ciliary processes that passes from the posterior chamber into the anterior chamber via the pupil. It is drained away through spaces at the filtration angle into a venous canal of Schlemm

35
Q

What can cause glaucoma

A

Blockage of aqueous humor drainage

36
Q

Purpose of aqueous humor

A

nutrients for avascular cornea and lens

37
Q

What is the purpose of the suspensory ligament of the lens

A

Contraction and relaxation controls the curvature of the lens

38
Q

What innervates the muscles responsible for eye accommodation

A

CN III

39
Q

How does eye accommodation work?

A

Idk. Look at notes.

40
Q

What process would be lost if CN III is damaged

A

Loss of accommodation/focus.

41
Q

Cataracts

A

Loss of transparency of the lens

42
Q

Vitreous body

A

jelly like matrix with a fine meshwork of collagen fibers that fills the vitreous chamber of the eyeball.

43
Q

What it the ophthalmic artery a branch of?

A

The internal carotid artery

44
Q

How does the ophthalmic artery enter the orbit and what is its relationship to the optic nerve

A

it enters via the optic canal and travels superior to the optic nerve

45
Q

Branches of the ophthalmic artery

A

Lacrimal artery, central artery of retina, ciliary arteries, supraorbital artery, anterior and posterior ethmoidal arteries, dorsal nasal arteries, and supratrochlear artery

46
Q

What does the infraorbital artery branch from and what does it supply

A

The maxillary artery and it supplies structures of the orbital floor

47
Q

Central vein of the retina

A

Travels with the central artery of the retina to drain to the cavernous sinus

48
Q

Flow of venous drainage from superior and inferior ophthalmic veins

A

They originate on the anterior aspect of the orbit from supraorbital and angular veins. They exit the orbit via the superior orbital fissure and enter the cavernous sinus.

49
Q

Branches of V1

A

Nasociliary, Facial, Lacrimal

50
Q

Frontal nerve

A

Branches into supraorbital and supratrochlear nerves that innervate the forehead and anterior region of the scalp

51
Q

Lacrimal nerve

A

passes to the lacrimal gland and provides sensory innervation to the lacrimal gland, conjunctiva of eye, and sensory over the upper eyelid.

52
Q

Nasociliary nerves

A

communicates with the ciliary ganglion. Branches into anterior and posterior ethmoidal air cells to innervate them in the nasal cavity and external aspect of the nose

53
Q

What do sympathetics hitchhike on to get to the dilator pupillae

A

(LSD) long ciliary nerves

54
Q

Long ciliary nerves

A

run in the choroid plexus to provide sensory innervation to iris and cornea.

55
Q

Where do short ciliary nerves originate?

A

Ciliary ganglion.

56
Q

What do postganglionic parasympathetic fibers from the ciliary ganglion traveling on the short ciliary nerve go to?

A

The sphincter papillae and the ciliaris muscle

57
Q

What nerve fibers travel through the ciliary ganglion without synapsing?

A

Sensory fiberis for the eye

58
Q

STUDY PARASYMPATHETIC INNERVATION OF THE LACRIMAL GLAND

A

STUDY PARASYMPATHETIC INNERVATION OF THE LACRIMAL GLAND