Retroperitoneum

Last revised by Dr Henry Knipe on 17 Sep 2022

The retroperitoneum is the part of the abdominal cavity that lies between the posterior parietal peritoneum anteriorly and the posterior abdominal wall 4. It is C-shaped on axial cross-section with convexity projecting anteriorly in the mid-line. 

Gross anatomy

The retroperitoneum is variably defined, mostly by the lack of consensus definition for the posterior abdominal and whether the psoas muscles and quadratus lumborum are boundaries or contents 4. It can have up to five compartments depending on definition:

  • lateral compartments divided into three spaces by renal fascia 4 
  • great vessel compartment: from T12 to L4/5 between perirenal space 2,3
  • posterior compartment: containing psoas muscles, which join iliacus behind transversalis fascia, quadratus lumborum 4
Perirenal space
  • inverted cone shape with base resting on diaphragm and point directing towards the pelvis
  • boundaries 
    • anterior and posterior renal fascia continuous with each other (fascia of Gerota and Zuckerkandl respectively)
      • anterior renal fascia blends anteriorly with connective tissue around aorta and inferior vena cava
      • posterior renal fascia (thicker, two lamina) blends with quadratus lumborum fascia 
        • superficial lamina is made up of lateroconal fascia which extends anteriorly and attaches to peritoneum
  • contents : kidney, adrenal gland, renal pelvis, proximal ureter, renal hilar vessels, lymph nodes, fat 
  • relations
    • upper right perirenal space communicates with retrohepatic space at bare area of the liver
    • posterior pararenal space related posteriorly
    • anterior pararenal space related anteriorly
    • the Kneeland space is a theoretical communication between both perirenal spaces, anterior to the aorta and inferior vena cava
Anterior pararenal space
  • boundaries: posterior parietal peritoneum anteriorly, anterior renal fascia posteriorly and lateroconal fascia (continuation of posterior renal fascia) laterally
  • contents: duodenum (D2-D4), ascending and descending colon, pancreas, lymph nodes, fat 
  • relations: potentially continuous across mid-line, intraperitoneal space anteriorly, perirenal space posteriorly 
Posterior pararenal space
  • boundaries: posterior renal fascia anteriorly, transversalis fascia posteriorly 
  • contents: fat
  • relations 
    • communicates with properitoneal space in the anterior abdomen between peritoneum and transversalis fascia
    • communicates potentially with contralateral side
    • communicates with flank laterally (external to lateroconal fascia and deep to transversalis fascia); visualized as flank strip radiologically 
    • opens inferiorly towards pelvis following length of ureter
Great vessel compartment 
  • not well-defined by fascial planes
  • boundaries
    • laterally: perirenal space and ureter
    • posteriorly: vertebral body, psoas major muscle
    • superiorly: continuous with the posterior mediastinum
  • contents: aorta, inferior vena cava, fat, lymph nodes

Related pathology

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Cases and figures

  • Figure 1
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  • Figure 2: retroperitoneum (axial)
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  • Figure 3: retroperitoneum (anterior dissection)
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  • Figure 4: retroperitoneum (posterior dissection)
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  • Figure 5: retroperitoneum
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