A, The inset shows the bicoronal scalp incision. A large bifrontal craniotomy and a fronto-orbitozygomatic osteotomy have been completed. The osteotomized segment may extend through the nasal bone and from one to the other lateral orbital rims, as shown. However, for most lesions, a more limited bone flap and osteotomy will suffice and can be tailored as needed to deal with the involvement of the cranial base, nasal cavity, paranasal sinuses, or orbit. For an orbital lesion, an orbitofrontal craniotomy, elevating only the superior orbital rim (yellow arrows) and orbital roof, is all that is needed. For a cavernous sinus or unilateral lesions of the anterior or middle fossa, an orbitozygomatic osteotomy will usually suffice (blue arrow). For a clival lesion, a more limited bifrontal approach (red arrow) will suffice. B, The periorbita has been separated from the walls of the orbit in preparation for the osteotomies. Division of the medial canthal ligament is not necessary for most lesions, but may be required for lesions extending into the lower nasal cavity or orbit. The ligaments should be re-approximated at the end of the operation. C, The right medial canthal ligament has been divided and the orbital contents retracted laterally to expose the nasolacrimal duct and the anterior ethmoidal branch of the ophthalmic artery at the anterior ethmoidal foramen. D, The osteotomies have been completed and the frontal dura elevated. The dura remains attached at the cribriform plate. The upper parts of both orbits are exposed. E, An osteotomy around the cribriform plate leaves it attached to the dura and olfactory bulbs, a maneuver that has been attempted to preserve olfaction but has not been commonly successful. The anterior face of the sphenoid sinus and both sphenoid ostia are exposed between the orbits. F, The sphenoid sinus has been opened to expose the septa within the sinus. The sphenopalatine arteries cross the anterior face of the sphenoid. (Images courtesy of AL Rhoton, Jr.)