Anatomy Flashcards
(95 cards)
1
Q
Position of optic canal in orbit
A
Medial
2
Q
The eye is protected by the _____________ from a direct blow
A
Orbital margins
3
Q
Which wall most often affeted in blowout fracture?
A
Medial wall
4
Q
Fractured zygoma rotates:
A
Medially
5
Q
What prevents spread of infection from periorbital to orbital cellulitis?
A
Orbital septum
6
Q
Below eyelids
A
Tarsal plates (attachment for LPS)
7
Q
Ligaments medial and lateral to eye
A
Medial and lateral palpebral ligaments
8
Q
Limbus
A
Corneoscleral junction (external)
9
Q
Conjunctival fornix
A
Where conjunctiva is reflected off sclera onto internal eyelid
10
Q
Para supply to lacrimal gland
A
CN VII
11
Q
Where do tears drain?
A
Superior and inferior puncta
Superior and inferior canaliculi
Lacrimal sac
Nasolacrimal duct
12
Q
Outer fibrous layer
A
Sclera
Cornea
13
Q
Vascular layer (uvea)
A
Iris
Ciliary body
Choroid
14
Q
Where is aqueous produced?
A
Ciliary body
15
Q
Anterior segment
A
Cornea Anterior chamber Iris Lens Ciliary body Posterior chamber
16
Q
Anterior chamber
A
between cornea and iris
contains aqueous
17
Q
Posterior chamber
A
Between iris and vitreous
Contains lens and aqueous
18
Q
Posterior segment
A
Vitreous body
19
Q
What are floaters?
A
Gel and clumping of collagen
20
Q
Iridocorneal angle
A
In anterior chamber
Between cornea and iris (internal)
Angle in glaucoma
21
Q
Raised IOP can cause:
A
Ischaemia of retina
22
Q
Where is aqueous reabsorbed?
A
Canal of Schlemm at iridocorneal angle and trabecular meshwork
23
Q
Area of greatest density of cones
A
Fovea (in centre of macula)
24
Q
Cones are responsible for:
A
Day vision, colour vision, central vision
25
Rods are responsible for:
Night vision, peripheral vision
26
Blood to eye
Ophthalmic artery off ICA (through cavernous sinus)
27
Contents of cavernous sinus
```
III
IV
V1
V2
ICA
VI
```
28
Carotid canal is in
temporal bone
29
Branches of ophthalmic artery
Central artery of retina
Nasal branches
Forehead branches
Ciliary arteries (choroid) = red eye
30
Venous drainage of eye
Superior ophthalmic vein to cavernous sinus (SOF)
Inferior ophthalmic vein to superior oph vein
Facial vein (valveless)
31
Layers of the retina
Photoreceptors
Bipolar cells
Ganglion cells
Axons of ganglion cells
32
Common tendinous ring of muscles attach round:
Optic canal
33
How to test superior and inferior rectus
Abduct eye
| Then elevate or depress
34
How to test superior and inferior oblique
Adduct eye
| Then elevate or depress
35
Pure elevation
SR and IO
| Antagonists as rotators
36
Pure depression
IR and SO
| Antagonists as add/abductors
37
Suspensory ligament of the eye
Fascial sling that holds the eye
| Diplopia if drops down
38
CNV1 supplies
Upper eyelid
Cornea
Conjunctiva
Tip of nose
39
CNV2 supplies
Lower eyelid
Maxilla
Alae
Upper lip
40
CNV3 supplies
Mandible
TMJ
NOT the angle of the mandible (C2,3)
41
Blink (corneal) reflex
V1 of cornea to trigeminal ganglion to V in the pons to VII to palpebral part of orbicularis oculi
42
How do symp axons get to organs of head?
```
Descend SC
Exit T1
Ascend symp trunk
Synapse in sup cervical ganglion
ICA plexus to opthalmic artery
```
43
Inferior cervical and 1st thoracic ganglia fuse to form
Stellate ganglion
44
How do para axons get to organs of head?
III (ciliary ganglion)
| VII, IX (otic ganglion), X, sacral spinal nerves
45
Where does CN III join brainstem?
Between midbrain and pons
46
What nerves supply autonomic axons to iris and lens?
Ciliary nerves
47
Which nerve forms 1st part of blink reflex?
Long ciliary nerve
48
Which type of nerve synapses in ciliary ganglion?
Para only
| Symp and somatic sensory pass through but don't synapse
49
Vestibulo-ocular reflex
Turns eyes in opposite direction of head movement
| III, IV, VI, VIII
50
Oculocardiac reflex
Reflex bradycardia in response to tension on extraocular muscles or pressure on eye
V1 and X
51
Type of muscle in LPS
Skeletal and smooth
52
Mydriatic pupil
Non-physiologically enlarged pupil
53
Origin and insertion of Dilator pupillae
Fixed origin
Mobile insertion
Radial fibres
54
Miotic pupil
Non-physiologically contracted pupil, e.g. opiates
55
Blown pupil
Fixed dilated pupil
| CN III pathology inhibiting para ciliary nerves
56
Sphincter pupillae
Circumferential, encricling
57
Pupillary light reflex
Retinal ganglion cells to optic nerve to chiasm to tract to pretectal nucleus in midbrain to EWN (now bilateral) to ciliary ganglion to sphincter pupillae of both eyes
58
Symp to lens
Ciliary muscle relaxes = suspensory ligament tightens = lens flattens for far vision
59
Para to lens
Ciliary muscle contracts = suspensory ligament relaxes = lens round for near vision
60
3 components of accommodation reflex
Bilateral pupillary constriction III
Bilateral convergence III
Bilateral relaxation of lens III
61
Types of lacrimation
Basal tears
Reflex tears (V1 and VII)
Emotional tears
62
How does VII get to lacrimal gland?
Greater petrosal nerve
presynaptic to pterygopalatine ganglion
postsynaptic to V2 to V1 to lacrimal gland
63
Monroe-Kellie hypothesis
To increase pressure in one place you have to decrease in another
64
Hydrocephalus
CSF overproduction
| Enlarged ventricles, sunset sign
65
Symptoms of raised ICP in the eye
```
Diplopia
LOV
Blurred vision
Papilloedema
Dilated pupil
```
66
Sensory supply to dura
CN V
67
Layers of dura`
Endosteal and meningeal
68
Where is CSF produced and reabsorbed?
Produced in choroid plexus
| Reabsorbed by arachnoid granulations
69
How do ventricles communicate?
IV foramen of monro (lateral to 3rd)
cerebral aqueduct (3rd to 4th)
2 medial and 1 lateral apertures (4th to central canal or subarachnoid space)
70
CN III palsy
```
Susceptible to compression in raised ICP (aneurysm, just posterior to post comm artery)
Down and out
Ptosis
Loss of pupillary reflex
Dilated pupil
```
71
Coning
Brain herniates through septa (folds of dura)
72
CN IV palsy
```
Long intracranial course = susceptible to damage, comes out posteriorly
Contralateral palsy
Eye can't move inferomedially
Gaze to right = moves up
Diplopia when looking down
```
73
CN VI palsy
Long intracranial course = raised ICP damages. Arises from pons
Medial deviation of eye
74
Types of conjunctiva
Palpebral
| Bulbar
75
pH of tear film
7.6
76
What nerve needs to be intact for reflex tear production?
V
77
Layers of tear film
Lipid phase
Aqueous phase
Mucus phase
78
Layers of cornea
```
Epithelium
Bowman's membrane
Stroma
Descements membrane
Endothelium
```
79
Lens is attached to ciliary body by
Zonules
80
Pancoast tumour
Compresses symp chain = symp III LPS compromised = ptosis
81
Stimulus for accommodation reflex
Blurred image
82
Hutchison's sign
Shingles vesicles on nose tip = V1 involvement = corneal involvement = acyclovir
83
Where does VI arise?
Pons
84
Through tendinous ring
```
Optic nerve and Ophthalmic artery (optic canal)
Sup and Inf divisions III
Nasociliary nerve
VI
(SOF)
```
85
Outside tendinous ring SOF
Lacrimal nerve
Frontal nerve
Superior ophthalmic vein
IV
86
Outside tendinous ring IOF
Inferior ophthalmic vein
87
Outside tendinous ring
LPS
| SO
88
In tendinous ring
All 4 rectus muscles
89
Symptom of optic neuritis
Pain on eye movements (muscles attach to tendinos ring)
Progressive unilateral visual loss
Usually MS (young)
90
Shortest and thickest of rectus muscles
MR
91
Blowout fracture traps what muscle?
IR
92
Type of epithelial in retinal pigmented cells
Simple cuboidal
93
Where is blind spot?
15 degrees temporal
94
How many fibres decussate?
53%
95
Symptom of blowout fracture
Pain on upgaze
