Retroperitoneum

Abstract

The retroperitoneum as defined in this chapter covers the central retroperitoneal area from the diaphragm to the region of the aortic bifurcation. It includes the major vessels and perivascular soft tissues exclusive of the pancreas which was covered in the preceding chapter. (The more lateral retro-peritoneal regions comprising mainly the kidneys and perirenal masses have been discussed in Chapter 4.) Below the level of the aortic bifurcation, retroperitoneal structures often cannot be seen by ultrasound because the overlying bowel may contain gas which prevents further ultrasound penetration. The only retroperitoneal structures in the lower abdomen that can be consistently imaged are those seen through the acoustic window of a full bladder.