Angioarchitecture of intraorbital part of human optic nerve.

The distribution of blood vessels in the intraorbital part of the human optic nerve was examined after injecting silicone rubber into the ophthalmic artery of eyes obtained after autopsy. Particular attention was focused on the possible existence of an end artery which might play an important role in ischemic optic neuropathy. In the anterior part of the optic nerve, the vascular architecture consisted of axial and peripheral vascular systems. The axial system was constituted of intraneural branches of the central retinal artery. The peripheral system was mostly branches derived from the intravaginal part of the central retinal artery. Few branches of the posterior ciliary arteries extending to the optic nerve were observed in this part. In the posterior part of the optic nerve, the vascular architecture was formed mostly by the peripheral system which consisted of the extravaginal and recurrent intravaginal branches of the central retinal artery and branches of the ophthalmic artery. These branches forming the peripheral system anastomosed with each other on the surface of the optic nerve. Within the anterior part of the optic nerve, intraneural branches of the central retinal artery and centripetal branches of the pial plexus anastomosed and formed a fine vascular network. The density of the intraneural vascular meshwork was sparse in the lamina cribrosa and the posterior part of the optic nerve. On the surface of the optic nerve and in its inner part, blood vessels anastomosed and formed a network: no end arteries appeared to exist.