Fibers of the optic nerve (CN II) extend posteriorly from each eye and intersect within the middle cranial fossa, forming the optic chiasm.
The optic chiasm is located at the base of the brain, just anterior and inferior to the location of the pituitary gland. It is formed by merging fibers from the optic nerves.
The optic chiasm contributes in conveying visual information from the eye to the cortex. It receives visual information from the optic nerve and transmits this information to the optic tracts. Nasal (medial) retinal fibers from each optic nerve (left and right) extend posteriorly from the eye, unite and decussate at the optic chiasm. Therefore, nasal retinal fibers from one optic nerve cross over to the contralateral optic tract.
The optic chiasm allows all right visual field information to travel to the left hemisphere of the brain via the left optic tract and all left visual field information to the right hemisphere of the brain via the right optic tract.
The optic chiasm is supplied by the branches of the anterior communicating artery, anterior cerebral, posterior communicating, posterior cerebral, and basilar arteries. The inferior portion of the optic chiasm also receives partial blood supply from the internal carotid artery.
English: Optic chiasm
Latin: Chiasma opticum
|Definition||Decussation of nasal retinal fibers of the optic nerve, which continue posteriorly as the optic tracts|
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