View of orbital apex, right orbit. The ophthalmic artery enters the orbit through the optic canal, whereas the superior and inferior divisions of cranial nerve (CN) III, CN VI, and the nasociliary nerve enter the muscle cone through the oculomotor foramen. Cranial nerve IV, the frontal and lacrimal nerves, and the ophthalmic vein enter through the superior orbital fissure and thus lie within the periorbita but outside the muscle cone. Note that the presence of many nerves and arteries along the lateral side of the optic nerve mandates a superonasal surgical approach to the optic nerve in the orbital apex.