Frankfort Horizontal / Occlusal Plane

Typically, the Frankfort plane (superior border of the external auditory meatus to the infraorbital rim) or plane of occlusion (vertical/up-down plane) is positioned parallel to the floor in panoramic imaging. (Figure 11) The tragal-canthus plane (tab in ear to outer corner of the eye), and the ala-tragus plane (corner of nose to tab in the ear) are used to align the vertical position of the head as well. Some machines provide a horizontal alignment light to help assess the proper vertical position of the head. The patient’s forehead and chin should be in the same vertical plane when viewing the patient’s head in profile.

Figure 11. Frankfort and Occlusal Planes.

Figure 11. Frankfort and Occlusal Planes.