This consists of aligning the focal spot with the center of the bucky so that the central ray will strike the center of the bucky at 90 degrees. The tube column is aligned with the bucky so that as the tube is moved the focal spot remains in alignment with the center of the bucky. Great care is taken in this procedure, and when properly done it results in a very close tolerance alignment. Headclamps are used to align the patient's skull and cervical region to the center of the bucky. Lateral, nasal and vertex films are made.
Great care is taken to insure that the films are made with a minimum of distortion.
Tube angle and tube distance are rigidly controlled. These films are then analyzed with respect to misalignment factors and bone contours. The patient is placed in the side posture position, measurements are made and a force is delivered into the atlas region. The ideal force is rectilinear in nature and has a minimum of curvilinearity. It may be applied by means of an adjusting machine, or by the employment of the musculo-skeletal framework of the doctor himself, using the pisiform bone as a contact point and aligning the various levers of his body in an attempt to deliver a rectilinear force.