It is only recently that the use of the endoscope as the sole
visualizing tool has been introduced in transsphenoidal pituitary
surgery with its favorable related implications and minimal operative
trauma. Of course, microscopic and endoscopic anatomy are basically the
same, but the optical distorsion of endoscopic images is quite
substantial compared to microscopic depictions. An endoscope lens
produces images with maximal magnification at its center and severe
contraction at its periphery. Nearer images are disproportionally
enlarged and remote images are falsely miniaturized. This optical
illusion may disorientate a surgeon who is not familiar with this
peculiar condition at the skull base. This atlas acts as a guide through
the endoscopic anatomy and gives detailed descriptions of the
preoperative management and the surgical procedures.