This series of pictures only shows simple anatomy. In my advanced lectures for sinus surgeons, more complex topics can be covered. Here you can see an image-guided surgery system, similar to the kind used during real endoscopic operations. Wherever the pointer touches, the matching CAT scan slices are shown on screen. The CAT scan data can also be dropped right into the 3D scene, as shown here. The scan at the level of the sphenoid sinus is visible. The right sphenoid is partly see-through. A small anatomic landmark called the hiatus semilunaris superior is also pointed out.