Optic nerve

Nervus opticus

Begins at the optic disc where retinal ganglion cell axons converge. It exits the orbit through the optic canal and joins the opposite nerve at the optic chiasm, where nasal fibers cross. The optic tract continues to the lateral geniculate body and visual cortex.

種類 Nerve
器官系 Nervous
身体部位 Eye
ラテン語名 Nervus opticus
FMA ID 50863

機能

The second cranial nerve (CN II) that transmits visual information from the retina to the brain. It carries approximately 1.2 million nerve fibers from retinal ganglion cells to the lateral geniculate nucleus and superior colliculus.

臨床的意義

Optic neuritis causes acute vision loss and is associated with multiple sclerosis. Papilledema (optic disc swelling) indicates raised intracranial pressure. Glaucoma causes progressive optic nerve damage. Pituitary tumors can compress the optic chiasm causing bitemporal hemianopia.

よくある質問

What is the optic nerve?
The optic nerve is the second cranial nerve (CN II), formed by the axons of retinal ganglion cells converging at the optic disc. It transmits visual information from the retina to the brain's visual processing centers.
Where is the optic nerve located?
The optic nerve exits the posterior orbit through the optic canal and travels to the optic chiasm, where nasal fibers from each eye cross to the opposite side. The optic tract then continues to the lateral geniculate body and visual cortex.
What is the function of the optic nerve?
The optic nerve carries visual signals—in the form of action potentials from retinal ganglion cells—from the eye to the brain. This pathway enables the brain to process and interpret visual images.
What conditions may be associated with the optic nerve?
The optic nerve may be involved in conditions such as optic neuritis, glaucoma, and compressive lesions at the optic chiasm. Damage at the chiasm may be associated with visual field defects such as bitemporal hemianopia.
What does the optic nerve look like?
The optic nerve appears as a cord-like white structure about 5 cm long, surrounded by meningeal sheaths. On fundoscopy, its origin is visible as the optic disc—a pale, circular region at the back of the eye where retinal fibers converge.

関連構造

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.