The optic canal transmits the optic nerve (CN II) and ophthalmic artery. Which structure separates the optic canal from the superior orbital fissure?

• A Greater wing of sphenoid
• B Optic strut (a bony projection of the lesser wing of sphenoid) ✓
• C Anterior clinoid process
• D Frontal bone

Explanation

The optic canal is in the lesser wing of the sphenoid bone. The optic strut is a bony bridge (part of the lesser wing of sphenoid) that separates the optic canal medially from the superior orbital fissure laterally. The superior orbital fissure transmits CN III, IV, V1, VI, superior and inferior ophthalmic veins, and the sympathetic plexus. The optic canal transmits CN II and the ophthalmic artery (entering the orbit inferolaterally to the optic nerve). Knowledge of these foramina is essential for localizing orbital apex lesions.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.