Oblique lateral radiographs are extraoral views of the jaws that can be taken using a dental X-ray set (see Fig. 12.1). Before the development of panoramic equipment they were the routine extraoral radiographs used both in hospitals and in general practice. In recent years, their popularity has waned, but the limitations of panoramic radiographs (see Ch. 15) have ensured that oblique lateral radiographs still have an important role.
The differentiating adjectives true and oblique are used to indicate the relationship of the image receptor, patient and X-ray beam, as shown in Fig. 12.2.
The image receptor and the sagittal plane of the patient’s head are not parallel. The X-ray beam is aimed perpendicular to the image receptor but is oblique to the sagittal plane of the patient. A variety of different oblique lateral projections is possible with different head and X-ray beam positions.
Specially constructed angle boards, as shown in Fig. 12.3B, can be used to facilitate positioning, but are not considered necessary by the authors.