Optic nerve
- It is a nerve of sense for sight. This nerve is composed of medullated fibres devoid of neurilemma which are axons of the ganglion cells of retina.
- The fibres converge within the eyeball at the optic papilla, where they form the optic nerve.
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Distribution of III, IV &VI cranial nerves
FOR-Foramen orbito rotundum, LPS-Levator palpebrae superioris, DR-Dorsal rectus, MR-Medial rectus, VR-Ventral rectus, SO-Superior Oblique, IO-Inferior oblique, RO-retractor oculi, Cg-Ciliary ganglion
Note: The ciliary ganglion relays parasympathetic fibres to ciliary muscles and constrictor pupillae
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- Then it pierces through the choroid and sclera, emerges from the inferio-lateral quadrant of the eye and passes backward and inward to the optic foramen.
- On entering the cranium the two nerves decussate at the base of the brain and form the optic chiasma or commissure.
- From the optic commissure, the optic tract passes into the lateral geniculate body and anterior quadrigeminal body.
- The sheath of the nerve is formed by the prolongation of the meninges of the brain.
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Last modified: Wednesday, 2 May 2012, 7:00 AM