Step-by-step approach to the suprasellar region. The bone that forms the roof of the optic canal has been partially removed to expose the posterior-most aspect of the optic canal roof, the falciform ligament. This ligament is formed by the lateral extension of the dural fold of the limbus of the sphenoid. Consequently, the dura of the limbus represents an important anatomical landmark for identifying the location of the roof of the optic canal. (Image courtesy of JC Fernandez-Miranda)