Ocular: Sclera And Episclera

Question 1

What is apart of the fibrous tunic:

Answer 1

Sclera and cornea

Question 2

What is the tenon’s capsule?

Answer 2

-transparent layer of fascia on top of the episclera in the bulbar region
-“a potential space” between the conj and episclera (dr naja said this)

Question 3

What does the tenon’s capsule form?

Answer 3

A socket that allows the globe to move

Question 4

What is the episclera?

Answer 4

Thin but IMPORTANT vascular layer on top of the sclera

Question 5

What is the sclera?

Answer 5

dense connective tissue layer that provides the globe with structure and support

Question 6

What does the sclera provide attachment for?

Answer 6

EOM insertions into the globe

Question 7

What is the limbus?

Answer 7

Transitional band of tissue running 360 degrees around the cornea

Question 8

What does the limbus contain?

Answer 8

Corneal stem cells

Question 9

conjunctival does not course _________ AT ALL meaning that it does not cover the entire _____

Answer 9

Posteriorly, globe

Question 10

Is the sclera vascular?

Answer 10

NOOOO

Question 11

Is episclera vascular?

Answer 11

YESSSS

Question 12

Order of layers from anterior to posterior on the scleral side of the limbus:

Answer 12

-conj epithelium
-conj stroma
-tenons capsule
-episclera
-superficial episcleral plexus
-deep episcleral plexus
-sclera

Question 13

Another name for the tenon’s capsule:

Answer 13

Fascia bulbi

Question 14

What perforates the tenon’s capsule?

Answer 14

EOM tendons as well as vessels and nerves

Question 15

Where is the tenon’s capsule the thickest?

Answer 15

Equator

Question 16

How is equator situated?

Answer 16

Anterior to posterior NOT nasal to temporal

Question 17

Orbital fat prolapse:

Answer 17

Benign protrusion of intraconal and extraconal orbital fat
(“I would know this”)

Question 18

What is responsible for keeping the intraconal fat from migrating?

Answer 18

Tenon’s capsule

Question 19

If intraconal fat migrates anterior, what is likely responsible?

Answer 19

Weak tenon’s capsule

Question 20

Sub-tenon’s injection

Answer 20

An injection into the space between the episclera and sclera delivered when there is severe inflammation to the entire eye
-(we don’t do this in practice)

Question 21

Episclera is a _____, ______, _________ tissue layer

Answer 21

Slim, loose, connective tissue layer

Question 22

The episclera becomes _______ posterior to the rectus muscle insertions

Answer 22

Thinner

Question 23

What can make episcleral veins more prominent?

Answer 23

Elevated episcleral venous pressure

Question 24

When episcleral network becomes congested what happens?

Answer 24

-Limbus has a rose coloration
-corneal inflammation
-iris dysfunction

Question 25

Anterior episcleral vessels:

Answer 25

Anterior ciliary arterial branches

Question 26

Posterior episcleral vessels:

Answer 26

SPCA branches

Question 27

What do episcleral veins drain aside from blood? Where does it drain into?

Answer 27

Aqueous humor from schlemm’s canal, superior ophthalmic vein

Question 28

Episcleral arterial circle is ________ to MACI

Answer 28

Superficial

Question 29

What vessels are responsible for ciliary flush?

Answer 29

-anterior ciliary arteries connected to the episcleral arterial circle

Question 30

What is seen in ciliary flush?

Answer 30

Dilated, deep conjunctival and episcleral vessels around the cornea

Question 31

What is inflamed in conjunctivitis?

Answer 31

Conjunctival plexus

Question 32

What is inflamed in episcleritis?

Answer 32

Superficial episcleral plexus

Question 33

What is inflamed in scleritis?

Answer 33

Deep episcleral plexus

Question 34

How does sclera get the few nutrients that it needs?

Answer 34

Diffusion! -inner surface from uveal vessels -outer surface from deep episcleral vessels

Question 35

Are there capillary beds in the sclera?

Answer 35

NO, but many vessels pass through

Question 36

What are Anteiror scleral aperatures for and where are they?

Answer 36

Anterior ciliary vessels, at the limbus

Question 37

Anterior scleral foramen is a space for what?

Answer 37

Cornea

Question 38

Which muscle does not have two anterior ciliary arteries (ACAs)

Answer 38

Lateral rectus

Question 39

Intrascleral nerve loops

Answer 39

LPCN in the suprachoroidal space that flips on itself and forms a dark spot in the sclera

Question 40

Middle scleral aperatures are ______ _____ passageways

Answer 40

Vortex vein

Question 41

Posterior scleral aperatures allow what to pass through:

Answer 41

-SPCA -SCN

Question 42

Posterior scleral foramen is a passage for the ____ _____

Answer 42

Optic nerve

Question 43

Rectus muscles furthest to closest in relation to the limbus:

Answer 43

-SR -LR -IR -MR **SLIM

Question 44

Spiral of tillaux

Answer 44

Imaginary ring connecting the recti muscle insertion points

Question 45

SR insertion distance

Answer 45

7.7

Question 46

LR insertion distance

Answer 46

6.9

Question 47

IR insertion distance

Answer 47

6.5

Question 48

MR insertion distance

Answer 48

5.5

Question 49

Where is the thickest par tif the sclera and how thick is it?

Answer 49

Surrounding the optic nerve, 1mm

Question 50

Where is the thinnest part of the sclera and how thick is it?

Answer 50

Just posterior to rectus muscles, 0.3mm

Question 51

Thickness of sclera at the limbus:

Answer 51

0.75mm

Question 52

What is the path of the rectus tendons?

Answer 52

Penetrate the tenon’s capsule and episclera and merge with the sclera (EOM collagen and sclera collagen intertwine)

Question 53

Lamellae

Answer 53

Bundles of collagen fibrils

Question 54

Fibrils

Answer 54

Aggregates of parallel collagen

Question 55

What is the predominant collagen type in sclera stroma?

Answer 55

Type I

Question 56

Fibroblasts:

Answer 56

-Produce and degrade proeoglycans and collagen -pull fibrils into parallel bundle (lamellae)