Superior view of right orbit and roof of infratemporal fossa. The greater and lesser wings of the sphenoid have been removed to expose the courses of the trigeminal nerve and its branches and other nerves to the orbit. The motor and sensory roots of the trigeminal nerve are visualized crossing the apex of the petrous bone. The mandibular nerve descends through the foramen ovale into the infratemporal fossa. Here, the superior head of the lateral pterygoid muscle is in view (surrounded by the pterygoid venous plexus), which inserts into the joint capsule and disc of the temporomandibular joint. At this plane between the temporal and infratemporal fossae, the temporalis muscle descends just medial to the zygomatic arch. The maxillary nerve passes through the foramen rotundum to enter the pterygopalatine fossa. The ophthalmic nerve approaches the orbit at the superior orbital fissure where it divides into its frontal, lacrimal, and nasociliary branches. Additional nerves coursing to the orbit along the lateral surface of the cavernous segment of the internal carotid artery include the oculomotor, trochlear, and abducens nerves, the latter of which passes beneath the petrosphenoidal ligament through Dorello's canal. The optic nerve and ophthalmic artery enter the orbit through the optic canal. The lateral rectus muscle follows along the lateral wall of the orbit while the superior oblique muscle follows along its medial wall before its tendon redirects at the trochlea to the eyeball. Medial to the medial wall are ethmoid air cells (ethmoid sinus). (Image courtesy of AL Rhoton, Jr.)