Orbits & Eyes

Question 1

What is a blow out fracture of orbit? How and what is fractured? what does patient report?

Answer 1

trauma

fracture to ethmoid or lacrimal bone with entrapment of ocular muscles = double vision

Question 2

What bones make the medial wall of orbit?

Answer 2

Maxilla
lacrimal
ethmoid
body of sphenoid

Question 3

What bones make the lateral wall of orbit?

Answer 3

zygomatic

greater wing sphenoid

Question 4

What bones make the floor of orbit?

Answer 4

maxilla

zygomatic

Question 5

What bones make the roof of orbit?

Answer 5

frontal

lesser wing sphenoid

Question 6

what are 3 layers to eye?

Answer 6

1. sclera/cornea
2. vascular
3. neural

Question 7

sclera means? How?

Answer 7

tough

predominantly collagen laid down in concentric circles

Question 8

What attaches to sclera?

Answer 8

extraoccular eye muscles

Question 9

What does the Cornea do?

Answer 9

principal refractor ~60%

Question 10

5 layers of cornea?

Answer 10

1. Epithelium (mucus membrane)
2. Bowman’s layer
3. stroma (collagen)
4. Descemet’s membrane
5. endothelium (cells don’t divide)

Question 11

describe cornea histologically?

Answer 11

avascular

transparent

Question 12

How is the cornea transparent?

Answer 12

very organized parallel collagen fibrils creating destructive interference

Question 13

is the sclera transparent or opaque? why?

Answer 13

opaque

non ordered/non-uniform size of collagen

Question 14

where is the anterior chamber?

Answer 14

between iris and cornea

Question 15

what is the anterior chamber angle for?

Answer 15

aqueous humour drains out

Question 16

Where in the anterior chamber angle does aqueous fluid drain out?

Answer 16

trabecular meshwork through the canal of Schlemm

Question 17

What is the Uvea? 3 things

Answer 17

1. Ciliary body (makes aqueous humour)
2. chroid
3. iris

Question 18

3 things ciliary body does: which cells do what?

Answer 18

1. make aqueous humour (epithelium)
2. tethers lens (ciliary processes)
3. accommodation (ciliary muscle)

Question 19

How is intraocular pressure created?

Answer 19

via ciliary body making aquenous humour

Question 20

What are zonules?

Answer 20

ligaments that attach ciliary processes to the lens.

Question 21

what does the ciliary muscle do? describe it’s neural connections

Answer 21

focuses by changing lens shape
parasympathetic
smooth muscle

Question 22

where do you find the ciliary muscle?

Answer 22

within ciliary body

Question 23

what is presbyopia?

Answer 23

loss of lens accommodation/flexibility with age

Question 24

2 muscles what control pupil: how innervated?

Answer 24

1. sphincter pupilae, ParaS, CNIII

2. dilator pupilae, Symp

Question 25

What is the choroid?

Answer 25

3 layers of blood vessels under the retina that keeps it alive

Question 26

what is the most important layer of choroid?

Answer 26

choriocapillaris just underneath retina

Question 27

What is the fovea?

Answer 27

highest area of concentrated cones, no rods, HIGH visual acuity

Question 28

what is the macula?

Answer 28

area around fovea with decreased vasculature, mostly from choroid

Question 29

what is the orra serrata?

Answer 29

junction between retina and ciliary body

Question 30

what is the lamina cribosa?

Answer 30

a structure continuous with the sclera that runs perpendicular and through the optic nerve, contains sieve-holes that transmit nerve fibres

Question 31

where are the retinal artery and vein located?

Answer 31

in or along the optic nerve

Question 32

curtain come down over someone's vision is most likely?

Answer 32

arterial ischemia/occlusion of central retinal artery

Question 33

what are the vessels you see in the fundoscope?

Answer 33

central retinal artery

Question 34

3 ciliary arteries are?

Answer 34

long posterior short posterior anterior ciliary

Question 35

What are the 2 arteries what supply the retina?

Answer 35

1. Central retinal artery: inner | 2. posterior ciliary: outer

Question 36

2 Muscles of the orbits and their innervation?

Answer 36

1. orbicularis oculi (CNVII) 2. levator palpebrae superiosis (CNIII) They work in opposition