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Block 5 > Ocular: Osteology Or The Orbit > Flashcards

Ocular: Osteology Or The Orbit Flashcards

1
Q

How many bones are in the skull/cranium?

A

28

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2
Q

How many of the skull bones are immovable?

A

21

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3
Q

The skull can be divided into what two parts:

A

-Neurocranium
-viscerocranium

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4
Q

How many bones form the bony orbit/eye socket?

A

11

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5
Q

The orbits are…

A

Bony cavities that each contain the globe, EOM, nerves, fat tissue, and blood vessels

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6
Q

Base of the orbit is called the ________________

A

Orbital margin or orbital rim

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7
Q

Dimensions of orbital margin:

A

4cm wide and 3.5cm high

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8
Q

The apex of the orbit contains the…

A

Optic foramen

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9
Q

Depth from the base to the apex?

A

4.5 to 5cm in depth

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10
Q

Medial wall of the orbit are ____________ to each other and are ______ apart from each other

A

Parallel, 2.5cm apart

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11
Q

Medial to lateral wall of the orbit lie at a ___degree angle

A

45 degrees

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12
Q

Both lateral walls of the orbit lie at a ____degree angle to each other

A

90 degree angle

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13
Q

Bones that form the base of the bony orbit superiorly:

A

Frontal bone

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14
Q

Bones that form the base of the bony orbit inferiorly:

A

-zygomatic
-maxilla

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15
Q

Bones that form the base of the bony orbit laterally:

A

-frontal
-zygomatic

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16
Q

Bones that form the base of the bony orbit medially:

A

-maxilla
-frontal

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17
Q

Bones that form the roof of the orbit:

A

-orbital plate of Frontal
-lesser wing of sphenoid

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18
Q

Contents of the roof of the orbit:

A

-lacrimal gland fossa
-Trochlear fossa
-supraorbital foramen/notch

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19
Q

Bones forming the floor of the orbit:

A

-maxilla
-zygomatic
-palatine

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20
Q

Contents of the floor of the orbit:

A

Inferior orbital fissure

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21
Q

Inferior orbital fissure allows for transmission of:

A

-maxillary nerve
-ascending branches from pterygopalatine ganglion
-infraorbital vessels

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22
Q

Orbital floor is the __________ portion of the orbit

A

Thinnest

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23
Q

Clinical signs of orbital floor fracture:

A

-crepitus
-ptosis
-enophthalmos
-strabismus

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24
Q

Most common cause of orbital floor fracture

A

Blunt trauma

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25
Q

Bones forming the lateral wall of the bony orbit:

A

-zygomatic
-greater wing of sphenoid bone

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26
Q

Contents of lateral walls of the orbit:

A

-lateral orbital tubercle of the zygomatic bone

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27
Q

Whitnall’s tubercle

A

-lateral orbital tubercle found on the zygomatic bone
-an anchor for many structures

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28
Q

Four Ls that anchors to whitnall’s tubrecle

A

-lateral rectus check ligament
-Lockwood suspensory ligament
-lateral palpebral ligament
-levator aponeurosis

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29
Q

Bones forming the medial wall of the bony orbit:

A

-maxilla
-lacrimal
-orbital plate of ethmoid
-lesser wing of sphenoid

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30
Q

Contents of medial wall of the orbit:

A

-anterior and posterior ethmoidal foramina
-lacrimal groove

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31
Q

Superior orbital fissure is located between…

A

Greater wing of sphenoid and lesser wing of sphenoid

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32
Q

What is transmitted through the SOF?

A

-lacrimal nerve
-frontal nerve
-Trochlear nerve
-inferior and superior division of oculomotor nerve
-nasociliary nerve
-abducent nerve
-ophthalmic veins

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33
Q

Paranasal sinuses are:

A

Mucus lines air cavities within a skull bone that communicate with the nasal cavity

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34
Q

Function of paranasal sinuses

A

Produced mucus, lighten skull bones, act as resonance chambers

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35
Q

Frontal sinus is located in the _____________ behind the _____________________

A

Frontal none, superciliary arches

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36
Q

Frontal sinus opens into nasal meatus via __________

A

Infindibulum

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37
Q

Maxillary sinus is the __________ of the sinuses that lies within the ____________________

A

Largest, body of maxilla

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38
Q

Maxillary sinus communicates with the middle nasal meatus via ________________

A

Semilunar hiatus

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39
Q

Superior relationship to maxillary sinus

A

Orbit and its contents

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40
Q

Medial relationship to maxillary sinus

A

-Nasal cavity
-maxillary ostium located high in medial wall

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41
Q

Inferior relationship to maxillary sinus

A

-maxillary alveolar process
-roots of maxillary teeth

42
Q

Temporal relationship to maxillary sinus

A

-bony arch of the cheek formed by connection of zygomatic and temporal bones

43
Q

Ethmoidal air cells

A

-Thin-walled spaces within ethmoidal labyrinths
-cell count varies from 3-18

44
Q

Anterior ethmoidal air cells open into…

A

Infundibulum of middle nasal meatus

45
Q

Middle ethmoidal air cells open on surface of…

A

Ethmoidal bulla of middle nasal meatus

46
Q

Posterior ethmoidal air cells open into…

A

Superior nasal meatus

47
Q

Sphenoidal sinus are located ___________ to the upper part of the nasal cavity within the sphenoid bone

48
Q

Sphenoidal sinuses are related superiorly to:

A

-pituitary gland
-optic chiasm

49
Q

Sphenoidal sinus is related laterally to the:

A

-cavernous sinus
-internal carotid artery

50
Q

Superior boundaries of the bony orbit:

A

Frontal paranasal sinus and anterior cranial fossa

51
Q

Inferior boundary of bony orbit:

A

Maxillary paranasal sinus

52
Q

Lateral boundary of the bony orbit:

A

-Temporal fossa
-middle cranial fossa

53
Q

Medial boundaries of the bony orbit:

A

-ethmoidal paranasal sinus
-sphenoid paranasal sinus

54
Q

Lefort fractures:

A

Fracture patterns secondary to blunt force trauma that involve the pterygoid plate

55
Q

Lefort fracture can result in…

A

A separation of the facial skeleton from the base and involve the orbit

56
Q

Type I Lefort fracture:

A

-Classically occur from downward force against the upper teeth
-no portion of bony orbit is fractured

57
Q

Type II Lefort fracture:

A

-from force delivered at the level of nasal bones
-portions of the medial, and inferior orbital walls are fractured

58
Q

Type III Lefort fracture:

A

-From force delivered at the level of the nasal bridge and orbit
-portions of medial, lateral, and inferior orbital walls are fractured

59
Q

5 layers of the eyelid:

A
  1. Skin
  2. Subcutaneous tissue
  3. Muscular layer
  4. Tarso-fascial layer
  5. Conjunctiva
60
Q

Tarso-fascial layer includes the:

A

-tarsal plate
-orbital septum

61
Q

Conjunctiva is a…

A

Thin membrane deep to the palpebral part of the orbicularis oculi muscle

62
Q

Conj is an extension of the _____________________ located inside and outside the bony orbit

A

Periosteum

63
Q

Conj attaches to the…

A

Levator palpebral superioris muscle tendon in the superior eyelid and attaches to the tarsal pate of the inferior eyelid

64
Q

Periorbita lines the bony orbit via…

A

Loose adherence to the bones (name change to periosteum)

65
Q

Periorbita is continuous with the ____________ at the rim of the bony orbit

A

Periosteum

66
Q

Periorbita has extensions known as _______________ which attaches…

A

Orbital septa, upper eyelid and lower eyelid

67
Q

Periorbita encases the…

A

Contents of the bony orbit

68
Q

Orbital cellulitis:

A

-infection of soft tissues of the orbit behind the orbital septum

69
Q

Preseptal cellulitis

A

Infection located anterior to the orbital septum

70
Q

Over half of orbital cellulitis infections are secondary infections from a…

A

Sinus infection

71
Q

Symptoms of orbital cellulitis

A

Swelling
-redness
-pain, -tenderness to touch
-pain of eye movements
sometimes diplopia

72
Q

Orbital cellulitis can lead to:

A

-meningitis
-loss of vision
-brain abscess

73
Q

Four segments of the optic nerve:

A

-intraocular
-intraorbital
-intracanalicular
-intracranial

74
Q

The intraocular portion of the optic nerve is the portion that:

A

-is evaluated by funduscope exam
-within the orbit
-1mm in length here

75
Q

Intraorbital segment of the optic nerve starts from…

A

Posterior part of scleral surface until BEFORE entering the optic canal

76
Q

Intraorbital segment is about _______ long and is the ________ portion

A

25-30mm, longest

77
Q

Intraorbital being the longest is important as it allows for…

A

Unimpeded rotation and axial displacement

78
Q

Intracanalicular segment of optic nerve begins at the…

A

Optic canal at the sphenoid bone

79
Q

Intracanalicular segment of optic nerve is ___ long and tightly fixed to the ___________ and fuses with the ____________

A

9mm, dura mater, periosteum

80
Q

Trauma to the brow can cause…

A

Optic neuropathy due to shifting between the dura and periosteum in the intracanalicular portion of optic nerve

81
Q

Intracranial segment of optic nerve is _____ in length and goes all the way to the _____________

A

12-16mm, optic chiasm

82
Q

Optic chiasm is about _____ wide and ____ antero-posterior in length

83
Q

Compact bone:

A

-80%
-dense
-closely packed osteons
-solid mass

84
Q

Spongy bone:

A

-20%
-less dense
-consists of trabeculae and bares of bone
-irregular cavities that contain red bone marrow

85
Q

Compact bone location:

A

Outer layer of bones

86
Q

Compact bone structure

A

Densely packed osteons

87
Q

Compact bone appearance

A

Solid and dense

88
Q

Compact bone function

A

Strength and support

89
Q

Blood supply of compact bone through…

A

Central canals

90
Q

Location of compact bone in bones

A

Diaphysis (shaft) and outer layer

91
Q

Location of spongy bone

A

Interior of bone

92
Q

True true of spongy bone

A

Network of trabeculae

93
Q

Appearance of spongy bone

A

Honeycomb like or spongy

94
Q

Function of spongy bone

A

Metabolic needs and bone marrow production

95
Q

Blood supply to spongy bone from….

A

Spaces between trabeculae

96
Q

Location of spongy bone in bones:

A

Epiphysis (ends) and interior of flat/irregular bones

97
Q

Eye muscles in the bony orbit:

A

-LPS
-SR
-MR
-LR
-IR
-IO
-SO

98
Q

Nerves of the bony orbit:

A

-CN 2
-CN 3
-CN 4
-V1
-CN 6

99
Q

Vessels of bony orbit:

A

Ophthalmic artery and veins

100
Q

Supporting tissues of bony orbit:

A

-Periorbita
-muscular fascia
-ligaments
-orbital fat

101
Q

Lacrimal contents in bony orbit:

A

-lacrimal gland
-lacrimal sac
-lacrimal canal

Block 5 (46 decks)

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