Optic canal

The optic canal is a funnel-shaped (narrowest anteriorly) structure as part of the sphenoid bone that extends from the optic foramen to the orbital apex, the posterior-most end of the orbit.  It is directed forward, laterally, and somewhat downward and conducts the optic nerve, the ophthalmic artery, and sympathetic fibers from the carotid plexus. The optic canal passes through the lesser wing of the sphenoid bone.

Note: The term "optic foramen" should be avoid for two reasons:

• For some authors the optic foramen would be a synonym of the optic canal but the International Nomenclature Committee (1955) felt that its use should not be perpetuated, as the optic canal is never a foramen but always a short bony canal

• For some authors the optic foramen would be the opening of the optic canal at the apex of the orbital cavity, but the use of this term is not officially validated.