The preoperative assessment of sciatica secondary to a herniated intervertebral disk has been radically changed over recent years due to the development of percutaneous treatment techniques which now offer an alternative to surgery. After recalling the terminology used for the position of a herniated lumbar disk in relation to the posterior common vertebral ligament (subligamentous or transligamentous hernia) and to describe whether or not the hernia is detached from the original disk (excluded or non-excluded hernia), the authors review the current state of the art of imaging for each type of herniated lumbar intervertebral disk.