Orbit Eye Flashcards
(152 cards)
1
Q
What is the shape of the orbit
A
quadrangular pyramid with base facing anterolateral and apex posteromedial
2
Q
desribe how the orbital walls are oriented
A
the contralateral medial orbital walls are parallel
the contralateral lateral orbital walls are perpendicular
3
Q
Describe the orbital axis orientation
A
long axis through orbit
oriented at 45 degrees to one another
4
Q
describe the optical axes orientation
A
long axis through globe
parallel to medial walls
5
Q
What bones make up the orbit
A
frontal, maxilla, sphenoid, lacrimal, ethmoid, palatine and sygomatic
6
Q
describe the apex of the orbit
A
lesser wing of sphenoid surrounding optic canal
7
Q
describe the base of the orbit
A
orbital margin and orbital opening
8
Q
what bones form the orbital margin
A
frontal zygomatic and maxillar
9
Q
what is the function of orbital margin
A
thickened to provide support and protection to eyeball
10
Q
describe bones of the roof of the orbit
A
frontal and some sphenoid separating orbit from anterior cranial fossa
also contains fossa for lacrimal gland
11
Q
describe bones that form the floor of the orbit
A
maxilla- separates orbit from maxillary sinus
zygomatic bone
palatine bone
12
Q
what bones of the orbit form the medial wall
A
ethmoid, lacrimal, maxilla
13
Q
what is the function of medial wall of the orbit
A
separates orbit from sphenoidal and ethmoidal air sinuses
lacrimal fossa
14
Q
describe bones that form the lateral wall of the orbit
A
zygomatic
sphenoid- greater wing
15
Q
What foramina are in the orbit
A
optic canal superior orbital fissure inferior orbital fissure anterior ethmoidal foramen posterior ethmoidal foramen nasolacrimal canal
16
Q
what runs through the optic canal
A
optic n and ophthalmic a
17
Q
what runs through superior orbital fissure
A
III IV V1 and VI superior ophthalmic v
18
Q
what runs through inferior orbital fissure
A
inferior ophthalmic v
infraorbital avn
zygomatic nn
19
Q
what runs through anterior ethmoidal foramen
A
anterior ethmoidal avn
20
Q
what runs through posterior ethmoidal foramen
A
posterior ethmoidal avn
21
Q
What runs in the nasolacrimal canal
A
nasolacrimal duct
22
Q
What is a blowout fracture
A
fracture of the orbital walls
usually inferior or medial
23
Q
what can be damaged by a blowout fracture is there is damage to the floor
A
involve maxillary sinus, intraocular fat and bleeding can then spread to maxillary sinus
24
Q
What are other structures at risk in a blowout fracture
A
inferior rectus m gets trapped and can cause diplopia
exophthalmos due to fat in surrounding spaces of mm entrapment
globe can be damaged(detached retina)
25
what sinuses can be involved in a medial wall blowout fracture
sphenoidal and ethmoidal air sinuses
26
what are orbital tumors
malignant tumors originating in the sphenoidal and ethmoidal sinuses, middle cranial or infratermporal fossa car erodes through the thin walls of the orbit or pass directly through foramina
27
What can be a sign of an orbital tumor
exophthalmos
28
what fascia lines the bones of the orbit
periorbital fascia
29
what fascia is the periorbital fascia continuous with
periosteal dura at optic canal and superior orbital fissure
orbital septum anteriorly
muscular fascias of the EOM
30
What are the check ligaments of the orbit
medial and lateral attach to the orbital walls
limit ADduction and ABduction of the eye
prevent posterior retraction of the eyeball by rectus mm
31
What is tenon's capsule
the fascial sheath of eyeball
| continuous with muscular fascia of EOM
32
what is the function of orbital fat
cushion, lubrication, protection
33
why do eyes become sunken in in starvation
loss of orbital fat
| enophthalmos
34
What are the components of the eyelid
skin, loose CT, muscle, tarsal plate and palpebral conjunctiva
35
what are the mm associated with eyelids
orbicularis oculi and levator palpebrae superioris
36
what is the structure of the tarsal plate in eyelid
desnse CT
has orbital septum to contain fat in orbit and to limit spread of infection
has medial and lateral palpebral ligaments
37
what glands are assoc with the eyelid
Tarsal glands (sebaceous)
Glands of Zeis (smaller sebaceous)
Glands of Moll (sweat)
38
What happens if glands of eyelid become inflamed or obstructed
chalazion (meibomian cast)
| hordeoum (cyst of eyelash glands)
39
describe action and inn orbicularis oculie
sphincter m of eyelid
| VII
40
what happens with VII impairment
eyelid that cannot close completely
| inferior eyelid tends to fall away from eyeball and result in dryness and irritation of cornea and sclera
41
What is the origin and insertion of levator palpaebrae superioris
origin: lesser wing of sphenoid
insertion: skin of superior eyelid
42
what is the function and inn of levator palpebrae superioris
elevates superior eyelid
| CN III
43
where does the superior tarsal portion of levator palpebrae superioris attach
superior tarsal plate
44
What can impairment of CN III lead to
inability to open upper eyelid (ptosis)
45
What is horners syndrome
loss of SANs to head
| ptosis, miosis and anhydrosis
46
What is the palpebral conjunctiva
epithelium of internal eyelid
47
what is the bulbar conjunctiva
outer epithelium of sclera
48
what is the conjunctival sac
between palpebral and bulbar conjunctiva
| opens at palpebral fissure
49
what are the conjunctival fornices
formed where bulbar and palpebral conjunctiva are continuous
50
What are the components of the lacrimal apparatus
lacrimal gland
lacrimal cannaliculi
lacrimal sac
nasolacrimal duct
51
where is the lacrimal gland
compound tubuloalveolar gland
| located in lacrimal fossa in superolateral orbit
52
what does the lacrimal gland secrete
watery serous secretion into conjunctival sac
53
what is the function of lacrimal fluid
keeps sclera and cornea moist and contains an antibacterial agent for protection
54
where are the lacrimal canaliculi
located in medial angle of eye
| begin at lacrimal papilla (punctum is opening)
55
what is role of lacrimal sac
receives fluid from lacrimal cannaliculi
56
describe flow of tears
lacrimal gland to conjunctival sac to surface of eye to lacrimal papillae with punta to cannaliculae to lacrimal sac to nasolacrimal duct
57
What are the 3 tunics of eye
external cornea-scleral
middle uveal
inner neural
58
describe the sclera
tough opaque fibrous layer covering posterior 5/6 globe
| provides structural support and mm attachment
59
describe the cornea
avascular, dehydrated,
provides most eyes refractile capabilities
numerous pain R located here
60
What is corneal neovascularization
blood vessels grow into corneal stroma secondary to hypoxia
61
Describe the components in the uveal layer
choroid, iris and ciliary body
62
describe the choroid of eye
highly vascularized
loose CT
vascualr supply to fibrous layers and outermost layers of retina
contain melanocytes which produce melanin to absorb photons of light
63
describe the iris
central aperture forms pupil which controls amount of light
64
What are the mm of the iris
```
sphincter pupillae (closes pupil) miosis PANs CN III
dilator pupillae (opens pupil) mydriasis SANs
```
65
What are the ciliary processes
Finger like extensions from ciliary body
secrete aqueous humor into posteiror chamber
suspensory ligaments extend from ciliary proccesses to the lens
66
what inn the ciliary m
PANs CN III
67
what is the role of the ciliary mm
accommodation
distant it is relaxed
focused on nearby it is contracted to make lens more round
68
What is the ora serrata
anterior termination of retina
69
what is the macula lutea of eye
pigmented zone 2.5mm lateral to optic disk
70
what is the blood supply to retina
central retinal a supplies neural portion of retina except photoR
choroid vessels supplies pigmented epithelium and photoRlayer
71
What is retinal detachment
when pigmented epithelium separates from the underlying rods and cones layer
can cause blindness
72
Describe the characteristics of the lens
transparent, refractile, flexible, biconvex disk located posterior to iris
73
What is the function of the lens
refraction and accommodation
74
what is presbyopia
refers to hardening of lens
| inability to accommodate and focus on near objects
75
what are cataracts
proteins of lens aggregate
| produce opaque lens
76
Where is the anterior chamber?
| posterior?
anterior is located between cornea and iris
| posterior is located between iris and lens
77
where is the drainage from venous sinuses
vorticose and anterior ciliary vv
78
What causes glaucoma
excess aqueous humor in anterior and posterior chambers
decreased outflow of aqueous humor
or increased production of aqueous humor
79
What is the vitreous body
between lens and posterior surface eye
| filled with vitreous humor- transparent refractile jelly-like substance
80
What are the 3 sources of the eye in development
neural ectoderm (optic vesicles)
surface ectoderm
mesenchyme
81
What is neural ectoderm derived from
evaginations of the forebrain neuroectoderm
82
What forms the optic cup
optic vesicles invaginate on themselves
optic cup retains connection of forebrain at optic stalk
choroid fissure forms on central surface of optic cup- carries hyaloid vessels
83
what does the neural ectoderm become
retina, optic nerve
84
what does the surface ectoderm become
lens placode-->lens vesicle
85
what does the mesenchyme of the eye become
fibrous (sclera, cornea) and vascular (choroid, iris, ciliary body) layers
86
Which layer of the optic cup is pigmented
outer
87
when does the choroid fissure close
7th week
88
what causes congenital retinal detachment
inner and outer layer of optic cup fail to fuse
89
What is the choroid derived from
vascular layer of mesenchyme surrounding optic cup
90
The outer portion of the iris is derived from what
vascular mesenchyme surrounding optic cup
91
the inner potion of the iris is derived from what
optic cup
92
when do melanocytes migrate to the anterior iris
first 6-10 months
93
What is the iridopupillary membrane
vascular structure which originally separates anterior and posterior aqueous chambers
94
when does the iridopupillary membrane degenerate
15th week
95
What will happen if the iridopupillary membrane fails to degenerate
congenital atresia of the pupil
96
What is coloboma
failure of choroid fissure to fuse in 7th week
97
What layer of mesenchyme are the sclera and cornea derived from
fibrous layer of the mesenchyme surrounding optic cup
98
how do the aqueous and vitreous chambers of the eye form
eye chambers form in areas of cell death within eyeball
| vitreous humor is likely derived from neural crest cells
99
what is the lens derived from
lens vesicle
100
what is congenital aphakia
agenesis of lens placode
101
what are the extrinsic eye mm formed from
mesoderm of myotomes
102
What are the branches of the ophthalmic a
```
central retinal
short posterior ciliary
long posterior ciliary
anterior ciliary
lacrimal
supraorbital
posterior ethmoidal
anterior ethmoidal
medial palpebral
supratrochlear
dorsal nasal
```
103
where do the short posterior ciliary aa go? long?
short pierce sclera near optic n and supply choroid
| long pierce sclera anteriorly to supply ciliary body and iris
104
describe venous drainage of orbit and eyeball
central retinal v to cavernous sinus
vorticose vv to choroid, ciliary body and iris
superior and inferior ophthalmic vv to the cavernous sinue and pterygoid venous plexus
105
How can thrhomophlebitis of cavernous sinus lead to vision loss
can clot the central retinal v
106
What can causes retinal edema
occlusion of the central retinal v
107
What are the movements of the eye
```
ADduction
ABduction
eleveation
depression
extortion
intortion
```
108
what is extortion/intortion
extortion is the superior pole of eyeball rotates laterally
| intortion is the superior pole of the eyeball rotates medially
109
What is the origin and insertion action inn medial rectus
origin: common tendinous ring
i: medial surface eyeball
inn: CN III
ADduction
110
o i action inn lateral rectus
o: common tendinous ring
i: lateral surface of eyeball
ABducts
CN VI
111
what is the o i action inn of superior rectus
o: common tendinous ring
i: superior surface of eyeball
eleavtes, ADducts and intorsion
CN III
112
what is the o i action inn inferior rectus
o:common tendinous ring
i: inferior surface of eyeball
depresses ADducts and extorsion
CN III
113
o i action inn inferior oblique
o: anterior portion of floor of orbit
i: inferior surface of eyeball, posterior to vertical axis
elevates ABducts and extorsion
CN III
114
how do you test for loss of inferior oblique m
weakness of elevation
| loss of elevation when eye is fully ADducted
115
o i action inn superior oblique
o: common tendinous ring
i: superior surface eyeball, posterior to vertical axis
depresses ABdcuts and intorsion
IV
116
how do you test for loss of superior oblique
weakness of depression
| loss of depression when eye is fully ADducted
117
What type of info is CN III carrying
GSE and GVE-P
118
what mm does the superior division of CN III inn
levator palpabae superioris and superior rectus
119
what mm doe sthe inferior division of CN III inn
medial rectus, inferior rectus and inferior oblique
120
What other fibers are carried in the inferior division of CN III
preganglionic PANs to ciliary ganglia
121
What are signs of occulomotor nerve palsy
```
ptosis
diplopia
eye will be ABducted and depressed
dilation of pupil
loss of accomodation
```
122
What type of info is carried in CN IV
GSE to superior oblique
123
What are signs of trochlear n palsy
diplopia
eye is slightly elevated and ADducted
loss of depression when eye if fully ADducted
124
What type of info is carried in CN CI
GSE to lateral rectus m
125
what are signs of abducens n palsy
diplopia and loss of eye ABduction
126
What type of infor is carried in CN II
SSA vision
127
what meninges cover the optic n
dura, arachnoid and pia
128
where do the optic n fibers exit the sclera
lamina cribosa
129
What type of info is carried in ophthalmic V1
GSA
130
what are the branches of V1
nasociliary
frontal
lacrimal
131
what type of info do the short ciliary nn have
postganglionic SAN PAN and sensory fibers
| arise lateral to optic n
132
what type of info do the long ciliary nn have
postganglionic SANs and sensory
| arise medial to optic n
133
what are the branches of the nasociliary branch of V1
short ciliary, long ciliary, posterior ethmoidal, anterior ethmoidal, infratrochlea
134
what does the infratrochlear n inn
sensory skin at root of nose, eyelids, palpebral conjunctiva and lacrimal sac
135
what are the branches of the frontal n off V1
supratrochlear and supraorbital
136
what info is in the lacrimal branch of V1
sensory to lacrimal gland and lateral portion superior eyelid
postganglionic PAN and SAN to lacrimal gland
137
Where is the ciliary ganglion located
between lateral rectus and optic n
138
what type of cell bodies are in ciliary ganglion
postganglionic PANs
139
what are the 3 roots that enter ciliary ganglion
sensory from nasociliary
PAN motor from CN III
SAN from internal carotid plexus
140
Where are the preganglionic cells for the sphincter pupillae and cliliary m
edinger westphal nucleus
141
what n do postganglionic PAN run with
short ciliary nn to sphinter pupillae and ciliary m
142
Where are the preganglionic SAN cell bodies for dilator pupillae and superior tarsal m
T1-T2
143
describe path of postganglionic SAN to dilator pupillae and superior tarsal m
pass through ciliary ganglia without synapsing and distribute via long and short ciliary nn
144
Where are the preganglionic cell bodies for PAN to lacrimal gland and what n do they travel with
salivatory nucleus in brainstem
| travel with greater petrosal n from VII
145
where are the postganglionic cell bodies for PAN to lacrimal gland and what nn do they travel with
pterygopalatine glanglia
| zygomaticV2 and lacrimalV1 nn
146
where are the preganglionic cell bodies for SAN to lacrimal gland and what nn do they run with
T1-T4
| enter sympathetic chain and ascend
147
Where are the postganglionic cell bodies for SAN to lacrimal gland and what nn do they run with
superior cervical ganglia, some distrbute on deep petrosal and merge to form n of pterygoid canal
others go with zygomatic V2 and lacrimal V1
148
what is the result of SAN stimulation to lacrimal gland
more watery lacrimal fluid
| vasomotor
149
Describe componentes of pupillary light reflex
function to protect eye from excessive light exposure
afferent CN II
efferent CN III
150
describe components corneal reflex
afferend CN V1
efferent CN VII oribuclaris oculi
puff of air stimulates V1 and blink from VII
151
describe accommodation reflex
afferent II
| efferent III
152
what are the 3 events in accommodation reflex
ciliary mm contract lens rounds CN III GVE-P
pupils constrict CN III GVE-P
eyes adduct CN III GSE
