A CT scan is a 3D block of data, but a screen is flat, so it gets shown as three sets of slices cut in three directions. Axial is cut across, as though looking down through the top of the head. Coronal is cut front-to-back, as though facing the person. Sagittal is cut side-on, like a profile.

This scan was requested for a breathing problem, and the front-facing coronal view is the one that shows the nasal passages and the wall between them most clearly. So it gets the most room.

The three panes are linked. Click anywhere in one and the other two jump to the exact same physical point in your head, seen from their own direction. That is what turns three separate stacks of pictures into one object you can actually navigate. It works in real millimetres, not in slice numbers, which is why it stays accurate across all three.

Scroll or drag inside a pane to move through its slices one at a time. Arrow keys do the same for whichever pane you last clicked.

The same X-ray exposure was processed by the scanner twice, in two different ways. The bone version makes hard structures crisp; the soft tissue version brings out muscle, fat and lining. Same instant, same dose, two different pictures — the toggle swaps between them.