application anatomical Perhaps the oldest method of producing images of internal structures of the human body is sketching dissected specimens More recent technology has produced a number of advanced techniques of producing images of human structures One such technique first produced by Wilhelm Roentgen around the turn of the previous century is radiography This technique which is also called x ray photography uses radiation waves that pass through the specimen and onto photographic film Because the waves pass more easily through soft tissue than through dense tissue such as bone shadows of some structures are visible when the film is R A BRA B FIGURE 13 17 A Standard radiograph of the lumbar region notice the images developed Figure 13 17 A shows a radiograph or x ray photograph of the lumbar region Can you identify the structures indicated A more recent variation of this technique is computed tomogra phy CT A CT scanner emits a beam of x rays in a circular path around the subject After passing through the body the beams are processed by a computer that is able to reconstruct a three dimen sional image of internal structures The operator can view differen sections of the body on a video monitor Figure 13 17 B shows a CT image of a horizontal section of the upper abdomen A vertebr is clearly shown can you identify its parts 10 2 5 que perpective B CT image of the abdomen Label the structures