Orbit and the Eye Flashcards

1
Q

Identify the bones in the bony orbit

A
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2
Q

Identify features of the bony orbit

A
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3
Q

What is the apex of the bony orbit?

A

Optic canal

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4
Q

What are the sides of the orbital rim?

A

Superior, inferior, medial and lateral orbital margins

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5
Q

What kind of fracture can affect the medial wall and orbital floor?

A

Orbital blowout fracture

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6
Q

Which muscle forms the external layer of the eyelid?

A

Orbicularis oculi

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7
Q

What are the parts of the orbicularis oculi?

A

Orbital and palpebral

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8
Q

What are tarsal glands embedded in tarsi responsible for?

A

Lipid secretion

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9
Q

The iris is covered by conjunctiva/cornea and the sclera and lower eyelid is covered by conjunctiva/cornea

A

Cornea

Conjunctiva

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10
Q

What is the junction between cornea and sclera better known as?

A

The limbus

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11
Q

Outline the path of lacrimal fluid in the eye

A

Produced by lacrimal gland before washing over eye and being pushed toward the medial angle. Drain through lacrimal punctae before reaching inferior meatus

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12
Q

Which nerve provides parasympathetic innervation to the lacrimal gland?

A

CN VII (facial)

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13
Q

What are the three layers of the eye?

A

Fibrous

Uvea (vascular layer)

Retina (photosensitive)

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14
Q

What are the two parts of the fibrous layer?

A

Sclera and cornea

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15
Q

What are the three parts of the uvea?

A

Iris

Ciliary body

Choroid

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16
Q

What divides the eye into anterior and posterior segments?

A

Lens

17
Q

The anterior segment contains vitreous/aqueous humour while the posterior segment contains vitreous/aqueous humour

A

Anterior contains aqueous while posterior contains vitreous

18
Q

Outline the circulation of aqueous humour

A

Ciliary body secretes aqueous which nourishes lens within posterior chamber then cornea in anterior chamber. Passes into scleral venous sinus (canal of Schlemm) and is reabsorbed

19
Q

What is the main arterial supply to the eye and what is it a branch of?

A

Ophthalmic artery - branch of internal carotid

20
Q

The central artery of the retina is wholly encapsulated by what?

A

Optic nerve

21
Q

The majority of venous drainage of the eye comes from which vein?

A

Superior ophthalmic vein

22
Q

What is the importance of the danger triangle of the face?

A

Bacteria in this area can enter the venous system which can enter the cavernous sinus and meninges

23
Q

What is found within the fundus?

A

Optic disc

Macula

Fovea (centre of macula)

24
Q

The optic disc is the point of CN III formation. True/false?

A

False - site of CN II formation (optic nerve)

25
Q

Where is the blind spot of the eye? Why?

A

Optic disc - there are no photoreceptors

26
Q

The fovea within the macula has the greatest density of cones/rods

A

Cones

27
Q

From anterior to posterior, what are the layers of the retina?

A

Axons of ganglion cells

Ganglion cells

Photoreceptors

28
Q

Complete ischaemia of the central artery of the retina can lead to what?

A

Monocular blindness

29
Q

What are the 7 extraocular muscles of the eye?

A

Superior rectus

Inferior rectus

Medial rectus

Lateral rectus

Superior oblique

Inferior oblique

Levator palpebrae superioris

30
Q

Where do all rectus muscles originate and insert?

A

Originate from common tendinous ring and insert onto sclera

31
Q

What is the somatic motor innervation of the extraocular muscles?

A

LR6 - Lateral rectus CN VI

SO4 - Superior oblique CN IV

AO3 - All others CN III

32
Q

What are the only two eyeball muscles not to have a secondary movement?

A

Medial and lateral rectus

33
Q

The lateral rectus muscle can only abduct/adduct the eyeball and bring line of gaze into the same plane as superior and inferior rectus/oblique

A

Abduct

Rectus

34
Q

When in abduction, the superior rectus can only elevate/depress while the inferior rectus can only elevate/depress

A

Elevate

Depress

35
Q

The medial rectus can only abduct/adduct the eyeball and bring line of gaze to the same plane as superior and inferior rectus/oblique

A

Adduct

Oblique

36
Q

When in adduction, the superior oblique can only elevate/depress while the inferior oblique can only elevate/depress

A

Depress

Elevate

37
Q

Pure elevation of the eyes is carried out by which muscles acting synergistically?

A

Superior rectus and inferior oblique

38
Q

Pure depression of the eyes is carried out by which muscles acting synergistically?

A

Superior oblique and inferior rectus