Figure 1.

Compartments within the retroperitoneum as defined by fascial planes. Drawing of the abdominal compartments in the axial plane shows the peritoneal cavity (blue) separated from the retroperitoneum (various shades of green) by the posterior parietal peritoneum (straight white arrow). The retroperitoneal compartments include the anterior pararenal space (light green), the perirenal space (medium green) bounded by the Gerota fascia (*), and the posterior pararenal space (dark green). The fusion of the Gerota and Zuckerkandl fasciae forms the lateral conal fascia (curved white arrows), which separates the lateral anterior pararenal space from the posterior pararenal space. In the anterior abdominal wall, the rectus abdominis muscles (R) are in the midline and contained in the rectus sheath. The external oblique (E), internal oblique (I), and transverse abdominis (T) muscles form the muscular layers of the anterolateral abdominal wall.