Limbus

Question 1

___mm area of transition between the cornea and conjunctivca/Tenons capsule/sclera

Answer 1

1.5-2.0

Question 2

At the transition layer, conjunctival epithelium becomes

Answer 2

Bcomes corneal epithelium.

5-7 layers of squamous epithelial cells become 10-15 layers of columnar epithelial cells.

Question 3

At the transition layer, bowmans layer ___

Answer 3

Terminates. No counterpart in the conj, tenons capsule or sclera.

Question 4

At the transition layer, corneal stroma becomes

Answer 4

Sclera stroma. Gradual change from the highly organized corneal stroma to the irregularly arranged scleral stroma.

Question 5

At the transition layer, Descemets membrane __

Answer 5

Terminates. No counter part.

Question 6

At the transition layer, corneal endothelium becomes the __

Answer 6

Endothelial covering of the trabecular meshwork

Question 7

Boundaries of the limbus

Answer 7

1. Line connecting the termination of Bowman’s layer at the top and Descmet’s membrane at the bottom.
2. Line perpendicular to the surface of the globe passing through the posterior edge of the scleral spur.

Question 8

Which arteries form the episcleral arterial circle and where is it located?

Answer 8

The anterior ciliary arteries form the episcleral arterial circle. The anterior ciliary arteries are a brach off the muscular artery, which is a branch off the ophthalmic artery.

It is located just anterior to the rectus muscle insertion and located in the episclera.

Question 9

Composition of the episcleral arterial circle

Answer 9

Composed of a superficial and deep capillary plexus that supplies the sclera (episclera, stroma, lamina fusca).

Located in the episclera, just anterior to the rectus muscle insertions.

Question 10

Two divisions of the episcleral arterial circle and where is it located

Answer 10

Superficial capillary plexus- mobile with movement of the conj.
Deep capillary plexus- Firmly anchored into sclera stroma.

Both are in the episceral layer, and visible through the transparent conj.

These arteries continue on to form the limbal vessels.

Question 11

Limbal plexus/vessels

Answer 11

Formed by the muscular artery after it formed the episceral arterial circle.

Supplies the limbus and peripheral cornea.

Question 12

Palisades of Vogt

Answer 12

Composed of radial projections of conjunctival stroma. They project into the peripheral cornea.

Question 13

Limbal crypts

Answer 13

Are present between the palisades of vogt. They are composed of thickened conjunctival epithelium. Limbal stem cells (which replace corneal basal cells), malenocytes, and langerhan cells are found in this region.