I, Intracranial aspect of the right optic canal. The intracranial end of the optic canal has an ovoid shape with a slightly greater diameter in the mediolateral than in the superoinferior dimension. It is situated medial to the anterior clinoid and optic strut. The medial margin is formed by the sphenoid body. The upper margin is formed by the anterior root of the lesser sphenoid wing. The lateral margin is formed by the optic strut, which is also referred to as the posterior root of the lesser wing. The lower margin of the foramen is formed by the optic strut and the adjacent part of the sphenoid body. J, Intracranial aspect of the right superior orbital fissure. The superior orbital fissure provides a communication between the orbit and the middle fossa. It is bounded above by the lesser wing, below by the greater wing, and medially by the sphenoid body. A small portion of the lateral apex of the fissure is formed by the frontal bone. The midportion of the lateral margin of the fissure, at the junction of the fissure’s narrow lateral and larger medial part, is the site of a prominence that serves as the lateral attachment of the annular tendon. K, Orbital aspect of the right inferior orbital fissure. The inferior orbital fissure has long anterior and posterior borders and narrow medial and lateral ends. The long posterior edge is formed by the greater wing. The long anterior wall is formed by the orbital surface of the maxilla, except for a short posterior segment formed by the orbital process of the palatine bone. The narrow lateral end is formed by the zygomatic bone, and the narrow medial end is formed by the sphenoid body. The posteromedial part of the fissure communicates below with the pterygopalatine fossa, and the anterolateral part communicates with the infratemporal fossa. The orbital smooth muscle spans the upper part of the fissure. L, Anterior aspect of the right optic canal and an anomalous ophthalmic foramen. In this specimen there is a foramen in the optic strut, referred to as an ophthalmic foramen, that transmits the ophthalmic artery. M, Anterolateral view of the right zygomaticofacial foramina. The zygomaticofacial foramina transmit the zygomaticofacial branches of the maxillary nerve. The zygomatic nerve arises from the maxillary nerve in the pterygopalatine fossa and passes through the inferior orbital fissure to course along the lateral wall of the orbit, where it divides into zygomaticofacial and zygomaticotemporal branches. The branches enter the zygomatico-orbital foramina on the orbital surface of the zygomatic bone. The zygomaticofacial branches exit the zygomaticofacial foramina to supply the cheek. The zygomaticotemporal nerve gives a branch to the lacrimal nerve as it passes along the inferolateral margin of the orbit. It enters the zygomatico-orbital foramen on the orbital surface and exits the zygomaticotemporal foramina to reach the temporal fossa above the zygomatic arch where it is distributed to the skin of the temple. The lacrimal foramen transmits a branch of the recurrent branch of the ophthalmic or lacrimal artery, which exits the orbit through the superior orbital fissure, courses laterally below the sphenoid ridge, and turns forward through the lacrimal foramen to supply the periorbita. (Images courtesy of AL Rhoton, Jr.)