Orientation and the Eye Flashcards
Lecture 1 and 2
1
Q
layers of the eye
A
1) outer tunic
2) middle tunic
3) inner tunic
2
Q
outer tunic
A
- cornea
- limbus
- sclera
3
Q
cornea
A
2/3 of refractive power of eye for distance
4
Q
sclera
A
whites of eye, tough outer shell, region where EOMs attach to eyeball
5
Q
middle tunic
A
- iris
- ciliary body
- choroid
6
Q
iris
A
controls how much light enters the eye
7
Q
ciliary body
A
vascular, functions in accomodation (allowing the lens to change shape)
8
Q
choroid
A
vascular, photoreceptors
9
Q
inner tunic
A
- retina
- fovea
- ora serrata
- optic disc
10
Q
retina
A
pigmented epithelium (contains photoreceptors) and neural retina
11
Q
fovea
A
high density of cones
12
Q
ora serrata
A
where the retina ends
13
Q
optic disc
A
axos leave the eye here, no retina (or photoreceptors) so this is the blind spot
14
Q
aqueous humour
A
in anterior chamber and posterior chamber
15
Q
vitreous humour
A
in vitreous chamber
16
Q
A
17
Q
crystalline lens
A
1/3 of the refractive power of the eye, changes shape to accomodate and focus on objects both near and far
18
Q
visual pathway
A
1) optic nerve
2) optic chiasma
3) optic tract
4) lateral geniculate body - synapse occurs
5) optic radiations
6) visual cortex - synapse occurs again
19
Q
ceiling of orbit - bones
A
frontal bone and sphenoid bone (lesser wing)
20
Q
trochlear fossa
A
on medial side of orbit on frontal bone, contains the trochlear nerve (CN IV) and the superior oblique muscle
21
Q
lacrimal fossa
A
on lateral side of orbit on frontal bone, contains lacrimal gland
22
Q
medial orbital wall - bones
A
ethmoid, lacrimal, maxilla, sphenoid (body)
23
Q
nasolacrimal fossa
A
involves maxilla and lacrimal bone, contains nasolacrimal sac which is involved in tear drainage into the nose and throat
24
Q
floor of orbit - bones
A
maxilla, zygomatic, palatine
25
infraorbital groove
maxilla bone, continuous with infraorbital canal and infraorbital foramen, infraorbital nerve, artery, and vein (if real)
26
lateral wall of orbit - bonesit
zygomatic, sphenoid (greater wing)
27
bone of the apex of orbit
sphenoid
28
common tendinous ring / annulus of Zinn
site of attachment of extraocular muscles (EOMs)
29
extraocular muscles (EOMs)
- superior rectus
- inferior rectus
- medial rectus
- lateral rectus
- superior oblique
- inferior oblique
- levator muscle
30
cranial nerves
I: olfactory nerve (sensory)
II: optic nerve (sensory)
III: oculomotor nerve (motor)
IV: trochlear nerve (motor)
V: trigeminal nerve (mixed)
VI: abducen's nerve (motor)
VII: facial nerve (mixed)
VIII: vestibulocochlear nerve (sensory)
IX: glossopharyngeal nerve (mixed)
X: vagus nerve (mixed)
XI: accessory nerve (motor)
XII: hypoglossal nerve (motor)
31
trigeminal nerve branches
V1: ophthalmic nerve
V2: maxillary nerve
V3: mandibular nerve
32
V1 branches
- frontal nerve
- lacrimal nerve
- nasociliary nerve
33
frontal nerve branches
- supraorbital
- supratrochlear
34
nasociliary nerve branches
- long ciliary
- anterior and posterior ethmoidal
- infratrochlear
- sensory root of ciliary ganglion
35
V2 branches
- infraorbital
- zygomatic
36
zygomatic nerve branches
- zygomaticotemporal (ZT)
- zygomaticofacial (ZF)
37
major arteries of the orbit
- ophthalmic
- infraorbital artery
38
major veins of the orbit
- superior opthalmic vein
- inferior opthalmic vein
39
ophthalmic artery branches
- central retinal artery
- muscular branches (7 anterior ciliary)
- posterior ciliary arteries (2 long, 15-20 short)
- supraorbital
- anterior and posterior ethmoidal
- medial palpebral
- lacrimal artery (recurrent meningeal, zygomataic artery, lateral palpebral)
- supratrochlear artery
- dorsal nasal artery
40
infraorbital artery
form external carotid artery, branch of maxillary artery, runs along floor of orbit, exits infraorbital foramen
41
superior opthalmic vein
drains into cavernous sinus, receives blood from:
- supraorbital/facial/angular veins
- superior vortex veins (2)
- lacrimal vein
- muscle branches (14 anterior ciliary)
- conjunctival veins
- inferior ophthalmic (sometimes)
42
inferior opthlamic vein
drains into cavernous sinus, superior opthalmic vein, and ptyergoid plexus, receives blood from:
- facial/angular/supraorbital tributary (majority from facial and angular, supraorbital tends to go to SOV)
- inferior vortex veins (2)
- muscle branches (anterior ciliary)
- conjunctival veins
43
contents of optic canal
- optic nerve
- ophthalmic artery
44
contents of superior orbital fissure
- CN III, IV, V1, VI
- SOV
- recurrent middle meningeal artery
45
contents of inferior orbital fissure
- V2
- IOV
- infraorbital artery and vein
46
supraorbital foramen
frontal bone, supraorbital artery and nerve
47
anterior and posterior ethmoidal foramena
ethmoid bone, ethmoidal nerves, arteries, and veins (1 set each)
48
what exits through the orbit
- suprtrochlaer nerve
- infratrochlear nerve
- supratrochlera artery
- dorsal nasal artery
49
carotid-cavernous fistula
- internal carotid artery breaks within cavernous sinus
- III, IV, V1, V2, and VI are in walls or pass through cavernous sinus
- symptoms/implications: blood pressure changes, eye movement changes, visual acuity changes
50
periorbita and orbital septum
connective tissue, periorbita fuses with dura mater of optic nerve at optic foramen
51
Tenon's capsule
connective tissue, fuses with sheaths of EOMs and optic nerve, provides space for eye to move within the orbital socket, loosely attached to sclera
52
check ligaments (medial and lateral)
connective tissue, restricts eye movements to normal range, fuse with periorbita and Tenon's capsule
53
superior transverse ligament (Whitnall's ligament)
attaches to connective tussue of lacrimal fossa and trochlea
54
suspensory ligament (of Lockwood)
runs with Tenon's capsule in some areas
55
eye movement directions
1) elevation
2) depression
3) abduction - away from nose
4) adduction - toward nose
5) intorsion - internal rotation
6) extorsion - external rotation
56
rectus muscles origin and insertion
origin: annulus of Zinn
insertion: sclera
57
spiral of Tillaux
imaginary line connecting insertion points of rectus muscles
- medial rectus is closest to center of eye
58
superior rectus muscle
nerve supply: CN III superior division
actions:
- elevation
- intorsion
- adduction
59
inferior rectus muscle
nerve supply: CN III inferior division
actions:
- depression
- extorsion
- adduction
60
medial rectus muscle
nerve supply: CN III inferior division
action:
- adduction
61
lateral rectus muscle
nerve supply: CN VI
action:
- abduction
62
superior oblique muscle
origin: near annulus of Zinn
insertion: sclera - posterior to equator
nerve supply: CN IV
actions:
- intorsion
- depression
- abduction
63
inferior oblique muscle
origin: orbital plate of maxilla
insertion: sclera - posterior to equator
nerve supply: CN III inferior division
actions:
- extorsion
- elevation
- abduction
64
blood supply to EOMS
lateral muscular artery supplies the LR. SR. and SO
medial muscular artery supplies the MR, IF, and IO
65
anatomy of EOM
skeletal muscle, organised into bundles:
1) epimysium
2) perimysium
3) endomysium
66
histological structure of EOM
multinucleated, sarcolemma, sacroplasmic reticulum and T-tubules, myofibrils
67
neuromuscular junction
has multiple motor end plates, "en grappe" endings (unique to EOMs)
68
singly innervated fibres
contract in all or non manner, saccades (fast eye movements)
69
multiply innervated fibres
unique to EOMs, graded response, slow, controlled eye movements
70
eye position
- outflow (efferent) theory: position of eyes is known by motor commands sent to eye muscles
- inflow (afferent) theory: position of eyes is known by sensory signals from eye muscles
71
proprioception of the eye
EOMs do not have immature muscle spindles or golgi tendon organs, but rather have palisade endings (unique to EOMs), both motor and sensory functions
