Optic canal - Canalis opticus
The optic canal opens in the optic foramen.
The superior surface of the sphenoid bone is bounded behind by a ridge, which forms the anterior border of a narrow, transverse groove, the chiasmatic groove (optic groove), above and behind which lies the optic chiasma; the groove ends on either side in the optic foramen, which transmits the optic nerve and ophthalmic artery (with accompanying sympathetic nerve fibres) into the orbital cavity.
The left and right optic canals are 25mm apart posteriorly and 30mm apart anteriorly. They are funnel-shaped (narrowest anteriorly).
This definition incorporates text from a public domain edition of Gray's Anatomy (20th U.S. edition of Gray's Anatomy of the Human Body, published in 1918 – from http://www.bartleby.com/107/).
General Anatomy > Bones; Skeletal system > Axial skeleton > Cranium > Sphenoid bone > Lesser wing > Optic canal