Figure 5.  Rib counting at CT with the xiphoid process as an anatomic landmark. Axial CT scan shows the xiphoid process (*), the seventh rib (7), and the relative position of the lower ribs (6–9). It is important to identify the transverse portion of the costal cartilage (arrows), at which point one stops counting down and starts counting up (ie, moves from medial to lateral). 5 = fifth rib.