Corneal Innervation

Question 1

Which nerve innervates the cornea

Answer 1

Long ciliary nerves of the nasociliary branch of the ophthalmic division of CN V

Question 2

How many sensory trigeminal neurons transmit nerve fibers via V1 and terminate in free nerve endings in the corneal epithelium

Answer 2

50-450. They travel from the trigeminal ganglion to the anterior portion of the eye. They travel in the suprachoiroidal space, which his between the sclera and choroid, to reach the limbus. Forms the limbal plexus.

Question 3

What forms the limbal plexus

Answer 3

Sensory trigeminal neurons travel in the suprachoroidal space (between sclera and cornea) to reach the limbus

Question 4

___ arise from the limbal plexus

Answer 4

Stromal nerve trunks

Question 5

Stromal nerve trunks

Answer 5

Arise from the limbal plexus and enter the peripheral corneal stroma radially and proceed centrally. They also form the anterior stromal plexus (sub epithelial plexus)

Question 6

How far away from the limbus do corneal nerve fibers lose their myelin sheaths?

Answer 6

~1mm. They continue on surrounded solely by Schwann cells.

Question 7

Subbasal plexus

Answer 7

Formed as the stromal nerves divide into smaller branches, nerves travel perpendicular to the cornea to penetrate Bowman’s layer and epithelium. These nerve fibers lose their schwann cell coverings.

Question 8

Intraepithelial plexus

Answer 8

Formed from nerves from the sub basal plexus. They continue to divide as they travel anteriorly to terminate just beneath the epithelial surface.

Question 9

No nerves in the __, ___, or __

Answer 9

Posterior stroma, Descemet’s membrane, or endothelium

Question 10

The cornea is __x denser than other epithelial tissue with __ nerve endings

Answer 10

400x
~2.2 million

^^ responsible for the sensations of touch, pain, and temperature. CN V is stimulated to produce tears and start wound healing.

Question 11

Limbal plexus enters into cornea in __-like fashion

Answer 11

Radial