The Optic Nerve (CN II)
The Optic Nerve (CN II)
- Last updated September 8, 2025
Objectives
By the end of these revision notes, you should be able to:
The Basics
The optic nerve is the second cranial nerve (CN II). It is a purely sensory nerve responsible for vision. The optic nerve may become relevant in dentistry in cases of infection, trauma or tumours.
Anatomy of the Optic Nerve
The optic nerve is actually surrounded by cranial meninges as compared to other nerves. The nerve carries sensory information from the retina to the primary visual cortex of the brain. The path of the nerve can be divided in to extracranial (outside the cranial cavity) and intracranial pathways.
Extracranial
The optic nerve originates from the retinal ganglion cells. These cells receive impulses from the photoreceptors (the rods and cones) of the eye. The axons of the retinal ganglion cells converge and form the optic nerve.
The nerve then leaves the orbit via the optic canal, which is present in the sphenoid bone. It then enters the cranial cavity and travels in close proximity to the pituitary gland.
Intracranial
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