Each vertebra has an anteriorly located body of cancellous bone, with a thin layer of surrounding cortical bone; and posterior elements, which are composed largely of cortical bone (pedicles, laminae, and spinous and transverse processes). The spinal canal is between these two components (Figure 1). Cancellous bone lesions often localize in the vertebral bodies, whereas cortical bone lesions preferentially affect the posterior elements. However, some bone lesions may show no preference for either of the two vertebral parts.