7 - Eye and Orbit Flashcards
1
Q
Palpebral conjuctiva –
A
membrane lining inner eyelid
2
Q
Bulbar conjuctiva –
A
membrane lining surface of eye
3
Q
Conjuctival sac
A
potential space between these membranes
4
Q
Fornices –
A
conjunctival reflections from eyelid to eye
5
Q
Space between eyelids when open =
A
palpebral fissure
6
Q
Tarsal glands embedded in
A
tarsal plates
7
Q
modified sebaceous glands –>
A
secretions increase viscosity of tears & decreases rate of evaporation
8
Q
Ciliary glands associated with :
A
eyelash follicles, sebaceous & sweat glands
9
Q
Orbital septum =
A
extension of periosteum into the upper & lower eyelids
extends into the eyelids
10
Q
Bony orbit Objects piercing roof enter
A
anterior cranial fossa
11
Q
Bony orbit Bony orbit Objects piercing floor enter
A
maxillary sinus
12
Q
Bony orbit Objects piercing medial wall enter
A
ethmoid air cells
13
Q
Bony orbit Objects piercing lateral wall enter
A
r temporal fossa
14
Q
Bony orbit Objects piercing superior orbital fissure enter
A
middle cranial fossa
15
Q
Supraorbital notch/foramen
A
Supraorbital n. (branch of CN V1) & a.
16
Q
Inferior orbital fissure
A
Infraorbital n. & zygomatic n. (branch of CN V2) & a.
17
Q
Infraorbital foramen
A
Infraorbital n. (branch of CN V2) & a.
18
Q
Ant. ethmoid foramen
A
Ant. ethmoidal n. (branch of CN V1) & a.
19
Q
Post. ethmoidal foramen
A
Post. ethmoidal n. (branch of CN V1) & a.
20
Q
Ophthalmic a. is a branch off the
A
the ICA
21
Q
Supraorbital a. branch off
A
ophthalmic a.
22
Q
Infraorbital a. branch off .
A
maxillary a
23
Q
The eyeball occupies the anterior part of the orbit.
Its rounded shape is disrupted
A
anteriorly, where it bulges outward.
This outward projection represents about 1/6 of the total area of the eyeball while the rest of the globe is approximately 5/6 of the total area
24
Q
The eyeball has three layers (or tunics)
A
fibrous (outer/external) layer
vascular (middle) layer
inner (internal) layer
25
Sclera
posterior 5/6 of outer layer (white part); the sclera is the important attachment point for the extrinsic eye muscles
26
Cornea
anterior 1/6 of outer layer (transparent)
27
Choroid - middle eye
thin middle layer of ciliary aa. & vorticose vv.
28
Ciliary body - middle eye
smooth m. around lens for accommodation
29
Iris - middle eye
colored smooth m. behind cornea controlling pupil size
30
Pupil - middle eye
adjustable aperture thru which light enters eye
31
middle eye
Remember this is the vascular layer
32
Vorticose vv. drain
choroid from each posterior quadrant – drain into superior and inferior ophthalmic vv.
33
Inner eye This is the nervous
visual” layer
34
Retina - inner eye
neural layer of eye which receives light rays
35
Macula lutea - inner eye
oval region of retina for visual acuity (yellow in color thus only visible with red-free light)
36
Optic disc – inner eye
regions where CN II & retinal vessels enter/exit
37
Fovea centralis - inner eye
most acute vision site at center of macula
38
Refractive Media of the Eye - Cornea
largely responsible for refraction of light in the eye
39
Refractive Media of the Eye - Lens focuses
light rays & near or distant objects on retina
40
Refractive Media of the Eye - Aqueous humor –
watery filling anterior to lens
41
Refractive Media of the Eye - Vitreous humor (body) –
gelatinous filling posterior to lens
42
Lacrimal Apparatus - Lacrimal gland – produces
lacrimal fluid (tears); flows across eye inferomedially to lubricate it
43
Lacrimal Apparatus - Lacrimal canaliculi
transports tears to lacrimal sac
44
Lacrimal Apparatus - Lacrimal sac
drains tears to nasolacrimal duct
45
Lacrimal Apparatus - Nasolacrimal duct – drains
tears thru nasolacrimal canal (under infr. nasal concha)
46
Levator palpebrae superioris m
raises upper eyelid
47
Superior rectus m. –
elevates & adducts eye
| intorsion - also rotates eyeball medially
48
Inferior rectus m. –
depresses & adducts eye
| extorsion - eye (also rotates eyeball laterally)
49
Lateral rectus m. –
abducts eye
50
Medial rectus m. –
adducts eye
51
Superior oblique m. –
depresses & abducts eye
| (Intorsion) eye (also rotates eyeball medially
52
Inferior oblique m. –
elevates & abducts eye
| extrosion) eye (also rotates eyeball laterally
53
All of these muscles, with the exception of
levator palpebrae superioris, insert into the sclera
54
CN III
Supplies LPS, SR, MR, IR, & IO mm.
| Carries parasymp. to ciliary ganglion
55
CN IV
Supplies SO m.
56
CN VI
Supplies LR m
57
Testing the Extraocular Muscles - each muscle tested
individually
Determines if damage is to CNs or single muscle, or single CN
58
Eye is placed in positions of strongest - test
individual m. pull
59
The position of abduction/adduction is opposite
of m. action
60
Part of the testing is in the
vision of seeing the light – CN II
61
Eye can be placed neutrally to test
lat. & med. rectus mm.
62
Eye must be abducted to test
supr. & infr. rectus mm.
63
Eye must be adducted to test
supr. & infr. oblique
64
Optic n
Nerve fibers between the eye & chiasm
65
Optic chiasm
X-shaped intermingling of nerve fibers
66
Optic tract
Nerve fibers from chiasm to brain
67
2 visual fields:
Temporal retina
| Nasal retina
68
Temporal vision crosses over at
chiasm
69
Nasal vision remains
ipsilateral
70
Visual field testing
detects blindness
| Location of lesion determines deficit
71
Optic n. lesion
results in total blindness in affected eye
72
Optic chiasm lesion
produces loss of peripheral vision
73
Optic tract lesion
results in ipsilateral nasal visual field loss & contralateral temporal visual field loss
74
Ciliary Ganglion receives p-symp from
from CN III
| Sends short ciliary nn. to posterior eye
75
Ciliary ganglion supplies p-symp to
Supplies p-symp. to:
Ciliary m.
Pupillary sphincter m.
76
Ciliary ganglion- supplies Symp. to
pupillary dilator m. via internal carotid plexus
77
Ciliary ganglion receives
3 types of fibers from 3 separate sources
Sensory fibers from CN V1 via the sensory or nasociliary root of the ciliary ganglion
Presynaptic parasympathetic fibers from CN III via the parasympathetic or oculomotor root of the ciliary ganglion
Postsynaptic sympathetic fibers from the internal carotid plexus via the sympathetic root of the ciliary ganglion
78
Pupillary Light Reflex tested with
pen light
79
Pupillary light reflex Tests
CN II & CN III pupillary responses
Eyes tested individually
Light enters 1 eye, both pupils should constrict
CN III p-symp. lesion
Pupil remains dilated
80
CN V1 in the Orbit- 3 divisions
Nasociliary n
Frontal n.
Lacrimal n.
81
Nasociliary n
Ethmoidal & infratrochlear nn.
| Long ciliary nn. (sensory & symp.) to posterior eye
82
Frontal n
Supraorbital & supratrochlear nn.
83
Lacrimal n.
Supplies lacrimal gland & conjunctiva
84
Arteries of the Orbit & Eye - Ophthalmic a. –
gives rise to all aa. of eye
85
Arteries of the Orbit & Eye - Posterior ciliary aa. –
supplies outer & middle layers of eye
86
Arteries of the Orbit & Eye - Central retinal a.
supplies inner layer of retina
87
Arteries of the Orbit & Eye - Ethmoidal aa. –
supply ant. cranial fossa, nose, & sinuses
88
Arteries of the Orbit & Eye - Supraorbital a. –
supplies central region of forehead
89
Arteries of the Orbit & Eye - Supratrochlear a. –
supplies medial region of forehead
90
Arteries of the Orbit & Eye - Lacrimal a.
Lacrimal a. – supplies lacrimal gland
91
Veins of the Orbit & Eye - Superior ophthalmic v. –
from upper med. orbit
92
Veins of the Orbit & Eye - Inferior ophthalmic v.
from lower med. orbit
| Both anastomose with facial v. & drain to cavernous sinus
93
Veins of the Orbit & Eye - Central retinal v.
from retina & drains to cavernous sinus
94
Veins of the Orbit & Eye - Vorticose vv. –
from vascular layer of eye
| Drains into superior & inferior ophthalmic vv.
95
Support for eyelids mainly
connective tissue
96
Orbital septum extension of
periosteum
97
Superior tarsus
dense connective tissue for eyelid support. Superior has muscle fibers from levator palpebrae superioris (smooth muscle portion) Inserts into orbital septum
98
Tarsus lateral attachemnt
lateral palpebral ligament - goes onto zygomatic bone
99
Ciliary glands
associated with eyelashes.
100
Autonomics get to lacrimal gland via
optic tract
101
Parasymp to lacrimal gland:
greater petrusal --> pterygopalatine ganglia (here it becomes postganglionic) --> maxillary nerve --> zygomatic nerve --> lacrimal nerve
102
Sympathetics to lacrimal gland
Pre to post occurs in superior cervical ganglion. Postsynaptic ride on internal carotid plexus, go to deep petrusal nerve, joins with greater petrusal.
103
Sympathetics
anywhere there are blood vessels
104
Presynaptic sympathetics lcated in
T1
105
Nerve of pterygoid canal has
both symp and parasymp.
106
Sympathetic control
Dilator pupilae - attention.
107
retina
11 or 12 layers
108
Meningeal layers continue on
optic nerve to eye
109
lens flips the
image
110
Vitreous humor
not remade
111
Periorbita
periosteum lining orbit
112
Horner's syndrome
loss of symp function in head. Pupilllary constriction, absence of sweating (also under symp).
113
Trochlear continues overtop of
levator palpebrae... splits
114
P-symp in eye
for ciliary muscle and pup sphincter.
