The Orbit and Superior Orbital Fissure. A, Superior view of the right orbit after removal of the orbital roof. The periorbita has been incised and retracted to expose the frontal, lacrimal, and trochlear nerves. B, The orbital fat has been removed to expose the main structures of the orbit. The frontal nerve arises in the lateral wall of the cavernous sinus and passes through the narrow lateral part of the SOF on the medial side of the lacrimal nerve and superior ophthalmic vein and below the trochlear nerve. It runs forward between the levator muscle and the periorbita. C, The levator palpebral and superior rectus muscles have been retracted posteromedially to expose optic, nasociliary, and abducens nerves. The nasociliary nerve passes forward above the optic nerve to reach the medial part of the orbit between the superior oblique and medial rectus muscles. D and E, Lateral view of the right SOF. The lesser wing of the sphenoid bone has been removed to open the SOF. At the level of the fissure, the nasociliary nerve ascends laterally to the inferior division of the oculomotor nerve and then crosses medially between the two divisions of the oculomotor nerve. (Images courtesy of AL Rhoton, Jr.)