(2) Dorsal decubitus position. A right lateral projection is the radiographic
image produced when the patient assumes the dorsal decubitus position (figure 3-46).
Figure 3-46. A right lateral projection results when the patient is placed in the dorsal
(3) Ventral decubitus position. In the ventral decubitus position
(figure 3-47), a left lateral projection can be obtained.
Figure 3-47. A ventral decubitus position produces a left lateral projection.
3-22. CENTRAL RAY TERMINOLOGY
a. Central Ray. The central ray (CR) (figure 3-48) is the central or principal
beam of rays emanating from the X-ray tube. You will need to adjust the CR angle
according to the pan to be x-rayed and the protections that are desired. Accurate
positioning of the pan and accurate centering of the central ray are of equal importance
in securing a true structural projection.
central ray: the central or principal beam of rays emanates from the X-ray tube.
Figure 3-48. The CR is always centered on the film or portion of the film being used.