Transcranial view of the optic canal region. The dura of the limbus of the sphenoid, planum sphenoidale, prechiasmatic sulcus, falciform ligament, roof of the optic canal, and anterior clinoid process has been removed bilaterally. Note the oblique shape of the optic canal, which makes the medial wall shorter than the lateral wall. The most common location of tumor invasion for tuberculum sella meningiomas is the medial and posterior aspect of the optic canal. This area is easily accessible from the endonasal route when the limbus dural fold and falciform ligament are transected. (Image courtesy of JC Fernandez-Miranda)