Optic Nerve

The Optic nerve (CN II) has an intracranial portion extending approximately 10 cm from the optic chiasm. As the nerve enters the optic foramen, its dural sheath becomes continuous with the periorbita. The orbital portion of the optic nerve is 20 mm to 30 mm in length. The central artery of the retina perforates the optic nerve, and runs within the retina.

Optic nerve inflammation can be seen as papillary edema (papilledema).