Anterior view of the frontal and sphenoid bones. The frontal bone consists of two parts. The larger vertically directed squamous portion forms the forehead and anterior part of the neurocranium, and the horizontal orbital part forms the roof of the orbit and most of the floor of the anterior cranial fossa. The remainder of this floor is contributed by the lesser wings and planum sphenoidale of the sphenoid bone. The lateral margins of the frontal bone join the greater wings of the sphenoid. The sphenoid bone, a single bone, also consists of several parts: a midline body, and pairs of lesser wings, greater wings, and pterygoid processes. The superior orbital fissure is a space between the lesser and greater wings and transmits cranial nerves III, IV, V1, and VI, and the superior ophthalmic vein from the middle fossa to the orbit. The greater wing forms much of the lateral wall of the orbit. The paired pterygoid processes project inferiorly from the greater wings and in this view contain two foramina. The foramen rotundum for the maxillary nerve and Vidian canal for the Vidian nerve and artery. Both foramina open into the pterygopalatine fossa. The pterygoid processes give rise to lateral and medial pterygoid plates that are separated by the pterygoid fissure. (Image courtesy of AL Rhoton, Jr.)