3.1 The Orbit and the Eye Flashcards

1
Q

What are the 7 bones which form the Orbit?

A
  1. The Frontal Bone
  2. The Lesser Wing of the Sphenoid Bone
  3. The Greater Wing of the Sphenoid Bone
  4. The Zygomatic Bone
  5. The Maxilla
  6. The Lacrimal Bone
  7. The Ethmoid Bone
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2
Q

What are the 3 Foramina at the Apex of the Orbit?

A
  1. The Optic Foramen
  2. The Superior Orbital Fissure
  3. The Inferior Orbital Fissure
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3
Q

What passes through the Optic Foramen?

A
  1. The Optic Nerve

2. The Ophthalmic Artery

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4
Q

What passes through the Superior Orbital Fissure?

A
  1. The Occulomotor Nerve (Cranial Nerve III)
  2. The Trochlear Nerve (Cranial Nerve IX)
  3. The Abducens Nerve (Cranial Nerve XI)
  4. The Ophthalmic Division of the Trigeminal Nerve (Cranial Nerve V1)
  5. Ophthalmic Veins
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5
Q

What passes through the Inferior Orbital Fissure?

A

The Maxillary Division of the Trigeminal Nerve (Cranial Nerve V2)

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6
Q

Where do the Ethmoid Air Cells lie in relation to the Orbit?

A

Medially

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7
Q

Where do the Maxillary Sinus lie in relation to the Orbit?

A

Inferiorly

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8
Q

Where do the Frontal Sinus lie in relation to the Orbit?

A

Superomedially

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9
Q

What are the Main contents of the Orbit?

A
  1. The Eyeball
  2. Extrinsic Ocular Muscles
  3. Ligaments Supporting the Eye
  4. Cranial Nerves II, III, IV, V1, V2, VI
  5. Branches of the Ophthalmic Artery
  6. The Lacrimal (Tear) Apparatus
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10
Q

What are the 3 layers of the Eye?

A
  1. The Outer Fibrous Layer
  2. The Middle Vascular Layer
  3. The Inner Sensory Layer
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11
Q

What does the Outer Fibrous Layer of the Eye comprise of?

A
  1. The Opaque Sclera (5/6)

2. The Transparent Cornea (1/6)

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12
Q

What does the Middle Vascular Layer of the Eye comprise of?

A
  1. The Choroid
  2. The Ciliary Body
  3. The Iris
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13
Q

What does the Inner Sensory Layer of the Eye comprise of?

A

The Retina

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14
Q

Is the Outer Fibrous Layer of the Eye a complete layer?

A

Yes, It extends all of the way around the Eye

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15
Q

Is the Middle Vascular Layer of the Eye a complete layer?

A

No, it is incomplete anteriorly with an apperature in the Iris, known as the Pupil

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16
Q

Is the Inner Sensory Layer of the Eye a complete layer?

A

No, it is present posteriorly but anteriorly it stops just in front of the Equator of the Eye

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17
Q

What divides the Eye into an Anterior and a Posterior Segment?

A

The Crystalline Lens

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18
Q

What is the name given to the watery fluid in the Anterior Segment of the Eye?

A

Aqueous Humor

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19
Q

What is the name given to the gel in the Posterior Segment of the Eye?

A

Vitreous Humor

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20
Q

What is the significance of the Optic Nerve Head?

A

It is a blind spot of the

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21
Q

What is the significance of the Fovea Centralis?

A

It is the point where the “Cones” of the retina are most densely compact, so it is the point of best visison

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22
Q

What is the Ora Serrata?

A

This is a Serrated Junction between the Retina and the Ciliary Body, and so marks the end of the Photosensitive Area

23
Q

Does the Ciliary Body Circle the Eye?

24
Q

What part of the Eye produces (secretes) Aqueous Humor?

A

The Ciliary Processes of the Ciliary Body

25
What are the 3 Intrinsic Muscles of the Eye, and what are there actions?
1. The Ciliaris Muscle - Accommodation 2. The Constrictor Pupillae - Pupil Constriction 3. The Dilator Pupillae - Pupil Dilation
26
Where does the Ciliaris Muscle lie?
Within the Ciliary Body
27
Where does the Constrictor Pupillae lie?
In the Pupillary Border of the Iris
28
Where does the Dilator Pupillae lie?
It is a radially running muscle within the Iris
29
What innervated the Ciliaris Muscle?
It receives Parasympathetic Innervation via the Occulomotor Nerve (Cranial Nerve III)
30
What innervates the Constrictor Pupillae?
It receives Parasympathetic Innervation via the Occulomotor Nerve (Cranial Nerve III)
31
What innervates the Dilator Pupillae?
It receives Sympathetic Innervation from the Superior Cervical Ganglion
32
What produces the movements of the Eye?
The Extrinsic Muscles of the Eye
33
What are the Extrinsic Muscles of the Eye?
1. Superior Rectus 2. Inferior Rectus 3. Lateral Rectus 4. Medial Rectus 5. Superior Oblique 6. Inferior Oblique 7. Levator Palpebral Superioris
34
Which Extrinsic Muscle of the Eye does not attach to the Eyeball?
The Levator Palpebral Superioris attaches to the Upper Eyelid
35
What is the function of the Medial Rectus?
Adduction of the Eye
36
What is the function of the Lateral Rectus?
Abduction of the Eye
37
What is the function of the Superior Rectus?
1. Elevation of the Eye 2. Adduction of the Eye 3. Intortion of the Eye
38
What is the function of the Inferior Rectus?
1. Depression of the Eye 2. Abduction of the Eye 3. Extrotion of the Eye
39
What is the function of the Superior Oblique?
1. Depression of the Eye 2. Abduction of the Eye 3. Intortion of the Eye
40
What is the function of the Inferior Oblique?
1. Elevation of the Eye 2. Abduction of the Eye 3. Extortion of the Eye
41
What is the mnemonic for remembering the actions of the Superior / Inferior Extrinsic Muscles of the Eye?
RADSIN: RAD = Rectus Adduct (Superior/Inferior Recti) SIN = Superior Intort (Superior Rectus/Oblique)
42
What is the only Extrinsic Muscle of the Eye which does not arise from the posterior aspect of the Orbit?
The Inferior Oblique
43
What is the name of the Ligaments which prevent over-adduction and over-abduction?
The Medial / Lateral Check Ligaments of the Eye
44
What is the function of the Suspensory Ligament of the Eye?
This attaches to the Ciliary Body and the Lens, holding the Lens in place and allowing the Lens to alter its thickness
45
What branch of the Internal Carotid Artery supplies the Orbit and the Eye?
The Ophthalmic Artery
46
Which foramina do the Ophthalmic Veins pass through to enter the Cavernous Sinus within the Cranial Cavity?
The Superior Orbital Fissure
47
Are there any Lymphatics in the Orbit?
No
48
Does the Levator Palpebral Superioris lie Medially or Laterally?
Medially
49
Via which Cranial Nerve does the Orbit receive Parasympathetic Innervation?
The Occulomotor Nerve (Cranial Nerve III)
50
Into which Nasal Cavity does the Nasolacrimal Duct drain?
The Inferior Nasal Meatus
51
What is the Trochlea? And what is it's function?
The Trochlea is a pulley-like structure in the Superomedial part of the Orbit which converts the pulling action of the Superior Oblique Muscle from, what would be, elevation to Abduction and Intorsion
52
Which of the Extrinsic Muscles of the Eye are supplied by the Occulomotor Nerve (Cranial Nerve III)?
1. The Superior Rectus Muscle 2. The Inferior Rectus Muscle 3. The Medial Rectus Muscle 4. The Inferior Oblique Muscle 5. The Levator Palpebral Superioris Muscle
53
Which of the Extrinsic Muscles of the Eye are supplied by the Trochlear Nerve (Cranial Nerve IV)?
The Superior Oblique Muscle
54
Which of the Extrinsic Muscles of the Eye are supplied by the Abducens Nerve (Cranial Nerve VI)?
The Lateral Rectus