Orbit and eye Flashcards

1
Q

orbital cavity (ORBIT)

A

Orbit: quadrangular pyramid, with base anteriorly, apex posteriorly, and 4 walls

  • lacrimal bone
  • orbital plate of ethmoidal lamina (lamina papyracea)
  • frontal bone
  • sphenoid bone
  • orbital process of palatine bone
  • zygomatic bone
  • maxilla
  • superior orbital fissue
  • inferior orbital fissure
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2
Q

*orbit

A
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3
Q

lacrimal bone

A
  • contribute to medial wall of orbit.
  • contains fossa for lacrimal sac
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4
Q

orbital plate of ethmoid lamina (lamina papyracea)

A
  • posterior to the lacrimal bone, very thin bone.
  • contribute to medial wall of the orbit
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5
Q

frontal bone

A

contribute to superior wall (roof) of the orbit

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6
Q

sphenoid bone

A
  • greater wing contribute to lateral wall, while lesser wing contribute to superior wall near the apex of the orbit
  • optic canal: though the lesser wing
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7
Q

orbital process of palatine bone

A

contribute slightly to apex of orbit

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8
Q

zygomatic bone

A

contribute significantly to lateral wall of orbit

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9
Q

maxilla

A

contribute significantly to inferior wall of orbit

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10
Q

superior orbital fissure

A

located between the greater and lesser wings of the sphenoid

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11
Q

inferior orbital fissure

A

between maxilla, zygomatic, and greater wing of the sphenoid

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12
Q

orbital content

A
  • eyelids
  • extraocular mm
  • nerves and vessels
  • orbital fascia
  • muscous membrane (conjuctiva)
  • (rest of the orbital space is occupied by orbital fat, embedding structures)
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13
Q

eyelids

A

bound orbit anteriorly, limiting exposure of anterior eyeball

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14
Q

extraocular mm

A

position the eyeball and raise superior eyelid

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15
Q

orbital fascia

A

surrounds eyeball and mm

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16
Q

conjunctiva

A
  • mucous membrane
  • lining of the anterior aspect of the eyeballs, interior aspect of eyelids, and most of the lacrimal apparatus
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17
Q

eyelid components

A
  • Moveable folds covering and protecting the eyeball anteriorly
  • Keep cornea moist by spreading lacrimal fluid
  • Components
    • Skin
    • connective tissue: contains eyelashes
    • skeletal mm: orbicularis oculi mm
    • tarsofascial layer
    • conjunctiva: inner layer of eyelid
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18
Q

sphincter of the eye

A

orbicularis oculi mm

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19
Q

tarsofascial layer:

A
  • superior and inferior tarsi
  • orbital septum
  • tarsal glands
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20
Q

dense bands of connective tissue, strengthening the eyelids

A

superior and inferior tarsi

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21
Q

continuation of the periosteum of the bones surrounding the orbit (frontal, zygomatic, and maxillary). attached to the tarsi

A

orbital septum

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22
Q

sebaceous glands, whose lipid secretion resists the overflow of tear

A

tarsal gland

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23
Q

inner layer of eyelid and its 2 parts

A
  • conjuctiva:
    1. palpebrae conjunctiva: closer to eyelid and it is opaque
    1. bulbar conjuctiva: overlies the cornea and it is transparent. receives sensory innervation from the long ciliary n.
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24
Q

space bund by the bulbar and palpebral conjuctiva

A

conjunctival sac

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25
Q

junctions of the superior and inferior eyelids. Form the medial and lateral angles (canthi) of the eye

A

medial and lateral palpebra commissures

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26
Q

connects tarsi to medial margin of orbit

A

medial palpebral ligament

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27
Q

connects tarsi to lateral margin of orbit

A

Lateral palpebral ligament

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28
Q

*eyelid (lateral view)

A
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29
Q

*eyelid (anterior view)

A
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30
Q

lacrimal appartus (includes):

A
  • lacrimal glands
  • excretory ducts
  • lacrimal canaliculi
  • lacrimal sac
  • nasolacrimal duct
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31
Q

*lacrimal apparatus

A
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32
Q

secretes lacrimal fluid and is divided into superior (orbital) and inferior (palpebral) parts

A

lacrimal glands

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33
Q

location of lacrimal glands

A

in the superior lateral part of the orbit. in a little depression in the frontal bone called the lacrimal fossa (about 2 cm in diameter and oval-shaped)

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34
Q

a watery physiological saline solution secreted though 8-12 excreotry ducts

A

lacrimal fluid

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35
Q

convey lacrimal fluid to the conjunctival sac

A

excretory ducts

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36
Q

small canals that begin at the lacrimal punctum (opening) on the lacrimal papilla in the medial angle of the eye

A

lacrimal canaliculi

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37
Q

dilated superior part of nasolacrimal duct that lies in the medial wall of orbit, in the depression of the lacrimal bone

A

lacrimal sac

38
Q

conveys lacrimal fluid inferiorly to the inferior nasal meatus in the nasal cavity

A

nasolacrimal duct

39
Q

eyeball

A
  • Contains optic apparatus and occupies most of the anterior portion of orbit
  • Suspended by 6 extrinsic muscles and a fascial suspensory apparatus
40
Q

3 layers of the eyeball

A
  • Fibrous layer: external fibrous skeleton, providing shape and resistance
  • Vascular layer
  • Inner: is the retina, which is the sensory neural layer of the eyeball. Divided in two (2) layers
41
Q

*eyeball

A
42
Q

tough opaque part that covers the posterior 5/6th of the eyeball, providing attachment for muscles of the eye. Relatively avascular

A

sclera (found in the fibrous layer)

43
Q

transparent part that covers the anterior 1/6th of the eyeball. Completely avascular, nourishment is provided by the lacrimal fluid (O2 absorbed from air) and aqueous humor.

A

cornea located in the fibrous layer

44
Q

cornea is innervated by CN

A

CN V1

ophthalmic nerve (branch of trigeminal)

45
Q

dark reddish brown color, pigmented layer between sclera and retina. Largest part of vascular layer, with vessels located externally (near the sclera). Responsible for “red eye” reflection present in flash photography

A

choroid

46
Q

provides attachment for the lens. Contraction of smooth muscles of the ciliary body controls accommodation of the lens

A

ciliary body (found in the vasuclar layer of eyeball)

47
Q

folds on the internal surface of the ciliary body that secrete aqueous humor, which fill anterior segment of eyeball

A

ciliary processes

48
Q

connect the ciliary body to the lens

A

suspensory ligaments

49
Q

thin contractile diaphragm, with a central aperture (pupil)

A

iris (found in the visceral layer)

50
Q

circular, constrict pupil.

(parasympathetically stimulated via ___)

A

Sphincter pupillae m.: circular, constrict pupil (parasympathetically stimulated via ciliary ganglion)

51
Q

radial, dilate pupil.

(sympathetically stimulated via __)

A

Dilator pupillae m.: radial, dilate pupil (sympathetically stimulated via superior cervical ganglion)

52
Q

optic part of retina. What layer is defined as: single layer of cells, reinforcing the light-absorbing properties of the choroid by reducing the scattering of light in the eyeball.

A

pigmented layer

53
Q

optic part of retina. what layer is defined as: light receptive

A

neural layer

54
Q

extends anteriorly over the ciliary body and posterior surface of the iris

A

Non-visual retina

55
Q

internal aspect of the posterior of the eyeball, where the light entering the eyeball is focused

A

fundus of eyeball

56
Q

where the optic nerve enters the eyeball, and is insensitive to light

A

optic disk

57
Q

area specialized for acuity of vision

A

macula of retina

58
Q

~ 1.5mm at the center of the macula is the area of most acute vision

A

fovea centralis

59
Q

refractive media conains:

A

cornea

aqueous humor

lens

vitreous humor

60
Q

refracts light entering the eye, focusing an inverted image on the light-sensitive retina of the optic fundus

A

cornea

61
Q

occupies Anterior (between cornea and iris) and Posterior (between iris and lens) chambers of the eye. Produced in posterior chamber by ciliary processes of ciliary body and provides nutrients for the avascular cornea and lens

A

aqueous humor

62
Q

transparent, biconvex structure, anchored by the suspensory ligaments of the lens to the ciliary processes. Lens curvature is modified by the ciliary muscle, which is parasympathetically stimulated via the ciliary ganglion

A

lens

63
Q

watery fluid enclosed in the vitreous body, which is located posterior to the lens. The vitreous humor holds the retina in place and supports the lens

A

Vitreous humor

64
Q

*extraocular mm

A
65
Q

*extraocular movements

A
66
Q

nerves of orbit

A

CNII oculomotor n.

CN VI abducent n.

CN IV trochlear

CN V1 opthalmic division

CN II optic n.

67
Q

*nerves of orbit

A
68
Q

CN ?

travels in lateral wall of cavernous sinus -> enters through superior orbital fissure. Superior and inferior divisions. All other muscles

A

CN III

oculomotor n

69
Q

CN ?

travels in the cavernous sinus -> enters through superior orbital fissure. Innervates lateral rectus

A

CN VI

abducent n.

70
Q

CN ?

travels in lateral wall of cavernous sinus -> enters through superior orbital fissure. Innervates superior oblique

A

CN IV

trochlear

71
Q

CN ?

travels in lateral wall of cavernous sinus -> enters through superior orbital fissure. Frontal, lacrimal, nasociliary. Ciliary ganglion via short ciliary nerves to ciliary body and iris. Long ciliary nerve to dilator pupillae m., iris, and cornea

A

CN V1

Ophthalmic division

72
Q

arteries of orbit

A
  • ophthalmic a.
    • central a.
    • ciliary a.
    • lacrimal a.
    • anterior & posterior ethmoidal a.
    • muscular a.
    • supreorbital a.
    • supratrochlear a.
    • dorsal nasal a.
  • infra-orbital a.
73
Q

*arteris of orbit (intracranial view)

A
74
Q

*arteries of orbit (frontal view)

A
75
Q

route of ophthalmic artery

A

from internal carotid after emerging from cavernous sinus -> runs parallel to the optic nerve through optic canal

76
Q

central artery (branches off of opthalmic artery) begins and ends?

A

pierces sheath of optic nerve and runs with the optic nerve to the eyeball. terminal branches are end arteries supplying the internal aspect of retina.

77
Q

occlusion of this arteries results in blindness

A

central artery (branch of ophthalmic a)

78
Q

ciliary artery (branches off of ophthalmic a.) goes to

A

sclera, ciliary body, iris, coroid

79
Q

lacrimal a. (branches off of ophthalmic a.) goes to

A

lacrimal, conjunctiva, eyelids

80
Q

anterior & posterior ethmoidal a. (branches off of ophthalmic a.) goes to

A

sinuses

81
Q

muscular a. supply

A

orbital mm

82
Q

supraorbital a. emerges

A

onto the face together with nerve of same name

83
Q

supratrochlear a. emerge

A

onto the face together with nerve of same name

84
Q

dorsal nasal a.

A

on medial side of orbit

85
Q

branch of the maxillary a. that supplies the orbital floor is:

A

infra-orbital a.

86
Q

veins of orbit

A
  • sup. ophthalmic v.
  • inferior ophthalmic v.
  • vorticose v.
87
Q

*veins of orbit

A
88
Q

pathway & function of superior ophthalmic vein

A
  • it is continuous with the facial vein anteriorly -> crosses diagonally from medial to lateral above optic nerve -> exits through superior orbital fissure ->terminates in the cavernous sinus.
  • Drains structures within the orbit
89
Q

which vein : runs on floor of orbit. It begins at the plexus of veins on floor of orbit. Communicates with pterygoid venous plexus inferiorly and the superior ophthalmic before going into cavernous sinus

A

inferior ophthalmic vein

90
Q

drain vascular layer of the eyeball and are tributaries of the ophthalmic veins

A

vorticose veins