OPTIC NERVES Flashcards
Which cranial nerve is it
no 2
Function
Carries visual and visual reflex signal from the retina to the rest of the visual pathway
how long is the optic nerve
40-50mm long
What is it surrounded by?
3 memnginal sheaths
P Pia mater
A Archnoid mater
D Dura mater
what changes in the structre of retina at the optic nerve head?
produces a thickening at the edge of the disc and central depression
What are the 4 sections of the optic nerve
Intraocular
intraorbital
intracanalicular
intracranial
What are the three sections within the intra ocular section
Prelamina
laminar
postlaminar
About the axons in the prelaminar
Axons are unmyelinated
Axons are about to enter the lamina cribrosa
What is the function of the lamina cribrosa
fills the posterior scleral foramen and provides supports to the nerve axons
What does the post laminar section do
increases the diameter of the nerve by 3mm
What is the infraorbital section covered by and how long is it
25mm long
the 3 meningeal sheaths
In the intracanaliicular section, the duramater is divided into two layers
Outer layer attaches to the periorbita and proximal tendon of rectus muscles. this anchors the nerve in the orbit
inner layer continuous through the optic canal and leaves orbit
What are the main 3 main structures of the blood supply
Circle of haller-zine
Ophthalmic Artery
Central Retinal artery
