Anterior Genu and Anterior Vertical Segment. A, Anterior view of a coronal section through the sphenoid sinus, nasal cavity, and orbits. The prominences over the anterior genu and anterior vertical segment are exposed in the lateral walls of this well-pneumatized sphenoid sinus. The medial part of the posterior wall of the left maxillary sinus has been removed to expose branches of the maxillary artery in the pterygopalatine fossa. B, Oblique view. The bony prominences overlying the anterior genu and anterior vertical segments, optic canal, superior orbital fissure, intracavernous carotid artery, and the V2 are exposed in the lateral wall of the sphenoid sinus. The bony depression between the carotid prominence and the optic canal, the opticocarotid recess, extends into the medial end of the optic strut. The broad round prominence below the opticocarotid recess overlies the structures passing through the superior orbital fissure. C, Oblique view. The anterior genu and anterior vertical segment are exposed below the cavernous carotid. The petrolingual ligament is not seen from this side because it is located laterally at the level of a line extending posteriorly along the upper edge of the V2. The pituitary gland; ophthalmic artery; and optic, ophthalmic, maxillary, oculomotor, and abducens nerves have been exposed. D, The junction of the petrous and cavernous carotid is exposed below the sella. A line extending posteriorly along the upper edge of the V2 approximates the upper edge of the petrolingual ligament and the junction of the petrous and cavernous carotid. The maxillary nerve passes through the foramen rotundum to enter the pterygopalatine fossa. The bone and dura covering the optic canal in the superolateral part of the sphenoid sinus have been opened to expose the optic nerve and ophthalmic artery in the optic canal. The terminal branches of the maxillary artery intermingle with the neural structures in the pterygopalatine fossa and exit the fossa to supply the tissues on the sphenoid face. The pterygopalatine ganglion and vidian nerve are positioned medial to the maxillary nerve. E and F, Endoscopic views of the transnasal transsphenoidal exposure of the left anterior genu and anterior vertical segments. E, The clivus has been opened to expose the pons and abducens nerve. The vidian nerve has been followed backward below the floor of the sphenoid sinus to the horizontal segment. The abducens nerve and V1, V2, and V3 are exposed on the lateral side of the carotid artery. The upper edge of the petrosphenoid ligament, which attaches to the lingual process of the sphenoid, is marked with an arrow. F, Enlarged view. The petrolingual ligament has been removed. The V3 and the trigeminal ganglion are in the lateral margin of the exposure. Bundles of the carotid neural plexus ascend along the petrous carotid to join the abducens nerve. (Images courtesy of AL Rhoton, Jr.)