The infraconal compartment: A multidirectional pathway for spread of disease between the extraperitoneal abdomen and pelvis

Purpose: The space below the kidneys where the anterior and posterior pararenal spaces converge has been defined only vaguely in the past. We describe observations on clinical CT cases and studies on cadavers that lead to a refinement in the terminology for this extraperitoneal compartment. Method: Abdominal/pelvic CT scans from 18 patients and the scans of 2 cadavers injected in the femoral region with iodinated contrast material were reviewed concerning the location and distribution of fluid or gas collections relative to the renal fascial enclosure. Results: Pathologic processes involving the anterior or posterior pararenal spaces in addition to the pelvic extraperitoneal spaces were always accompanied by collections in the space below the cone of renal fascia. Conclusion: The term infraconal compartment is a suggested term for the caudal continuation of the anterior and posterior pararenal spaces. This compartment serves as an important multidirectional pathway for the spread of disease between the extraperitoneal abdomen and the pelvis. Fluid collections within this compartment have a characteristic CT appearance.