Tomography is imaging by sections or sectioning. A device used in tomography is called a tomograph, while the image produced is a tomogram. The mathematical basis for tomographic imaging was laid down by Johann Radon. It is applied in computed tomography and magnetic resonance tomography (MRT) also called magnetic resonance imaging (MRI) to obtain cross-sectional images of slices through the body of patients. Each of that slices is defined by thickness and spatial resolution (see voxel).

A tomographic imaging direction, frontwards relative to a short axis of the human body from the back to the front.

A tomographic imaging direction, backwards relative to a short axis of the human body from the front to the back.

A tomographic imaging plane, parallel to the ground, perpendicular (rotated 90°) to the long axis of the human body; the axial plane separates the superior from the inferior part (the head from the feet).
Also called transaxial, transversal, transverse plane.

A tomographic imaging plane, perpendicular to the ground, the coronal plane separates the anterior from the posterior part (the front from the back).