The Intraorbital and Intracranial Portion of the Optic Nerve

The intraorbital portion begins after the nerve passes through a sieve-like plate of scleral connective tissue, the lamina cribrosa. Inside the orbit, the optic nerve describes an S-shaped course that allows extreme eye movements.

After the optic nerve passes through the optic canal, the short intracranial portion begins and extends as far as the optic chiasm. Like the brain, the intraorbital and intracranial portions of the optic nerve are surrounded by sheaths of dura mater, pia, and arachnoid (see Fig. 13.3). The nerve receives its blood supply through the vascular pia sheath.

362 13 Optic Nerve Vascular structures supplying the head of the optic nerve.

- Retina

Pigment epithelium Choroid Sclera Dura mater sheath Arachnoid sheath - Pia mater sheath

Vascular plexus of the pia sheath

Lamina cribrosa

362 13 Optic Nerve Vascular structures supplying the head of the optic nerve.

Ciliary Nerve Retina

Central retinal vein

Central retinal artery

- Ring of Zinn

Posterior ciliary artery

Short posterior ciliary arteries

Fig. 13.3 The optic nerve is supplied with blood from both the short posterior ciliary arteries and the central retinal artery.

Central retinal vein

Central retinal artery

- Ring of Zinn

Posterior ciliary artery

Short posterior ciliary arteries

Fig. 13.3 The optic nerve is supplied with blood from both the short posterior ciliary arteries and the central retinal artery.

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Responses

  • carola
    Why intraobital portion of optic nerve?
    9 months ago

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