Regional Aantomy of the Orbit and Superior Orbital Fissure. A, Posterior view of the right superior orbital fissure (SOF). The SOF is bounded above by the lesser wing of the sphenoid bone, below by the greater wing, and medially by the sphenoid body. The optic strut forms the upper medial border of the fissure. The SOF provides a communication between the orbit and the middle fossa. B, Lateral view of the right cavernous sinus. The lateral wall of the cavernous sinus and the anterior clinoid process have been removed. The oculomotor, trochlear, abducens, and ophthalmic division (V1) are situated within the cavernous sinus. They enter the orbit through the SOF. C, Superolateral view of the right frontotemporal area. After performing the frontotemporal craniotomy, the dura is elevated. The frontotemporal dural fold is located on the lateral side of the SOF, between the greater and lesser wings of the sphenoid bone. D, Resecting the dural fold allows further detachment of the dura from the surrounding structures, enabling extradural exposure of the anterior portion of the cavernous sinus and the third, fourth cranial nerves as well as the fifth cranial nerve. E, Superior view of the right orbit and the optic canal. At the SOF, the dura covering the optic nerve, middle fossa, and the cavernous sinus blends into the periorbita of the orbital apex. F, Anteroinferior view of the right orbit. The rectus muscles originate from the annular tendon. The annular tendon surrounds the orbital end of the optic foramen and the adjacent part of the SOF. The fibrous component, which blend together to form the annular tendon, are the periorbita covering the orbital apex, the dura lining the SOF and optic canal, and the optic sheath. G, Superior view of the right SOF. The dura covering the cavernous sinus and the optic sheath blend into the periorbita of the orbital apex and into annular tendon from which the rectus muscles arise. H, Schematic anterior view of the main structures passing through a right SOF. (Images courtesy of AL Rhoton, Jr.)