Posterior Abdominal Wall

Atlas References

Netter: 265–269, 300, 311–323
McMinn: 253–261
Gray's Atlas: 183–196, 198–199

Exposing the Kidneys

o
Cut the white lines of Toldt (paracolic gutters) along the edges of the ascending and the descending colon, and reflect the large and small intestines to the left of the abdominal cavity ( Fig. 13.1 ).
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With your fingers, retract the duodenum and pancreas to the left, without disrupting their vascular supply ( Fig. 13.2 ).
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Palpate the abdominal aorta on the left and the inferior vena cava (IVC) on the right.
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With scissors, cut the peritoneum of the posterior abdominal wall and expose the IVC ( Fig. 13.3 ).
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To the right of the IVC, dissect out the perirenal (renal) fascia (of Gerota), which is filled predominantly with abundant perirenal fat ( Fig. 13.4 ).
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Trace the right ureter; expose its course from the kidney to the pelvic brim and as it crosses over the iliac arteries.
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Remove the fat posterior to the kidney, known as the pararenal fat ( Fig. 13.5 ).

Dissection Tip

For the removal of the perirenal and pararenal fat, use scissors or a probe and scrape it from the kidney capsule.

o
Remove enough fascia and adipose tissue to clearly expose the kidneys and suprarenal glands. Free up the margins of the suprarenal glands, taking care to preserve their blood vessels, especially along their medial borders.
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Remove all fat from the posterior part of the kidney capsule.

Liver

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Reflect the liver medially and expose the entire posterior abdominal wall.
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Cut the falciform, left triangular, and coronary ligaments.
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Place your fingertips underneath the lateral side of the liver, lift it up slightly, and cut the right triangular ligament ( Fig. 13.6 ).
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Pull the liver inferiorly, and in the space between the diaphragm and the liver, cut the IVC ( Fig. 13.7 ).
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Lift the liver upward and to the left; expose the infrahepatic portion of IVC away from the body wall ( Fig. 13.8 ).
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Gently pull the liver to the left; otherwise, you will damage the right suprarenal vein as it enters the IVC.
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With a scalpel, make an incision through the IVC superior to the level of the renal veins and reflect the liver to the left ( Fig. 13.9 ).
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The liver is attached to the abdominal cavity only by the portal vein, hepatic artery, and bile duct.
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On the reflected liver, identify the right and left lobes (divided by the falciform ligament), as well as the quadrate and caudate lobes of the right lobe.
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Identify the fissure for the ligamentum venosum and the ligamentum teres (round ligament) of the liver.
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Identify the round ligament, left triangular ligament, and coronary ligament ( Fig. 13.10 ).
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To identify the ligamentum venosum, reflect the caudate lobe and clean the fissure for the ligament ( Fig. 13.11 ).
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Reflect the inferior vena cava slightly inferiorly and expose the suprarenal gland and the bare area of the liver ( Fig. 13.12 ).

Kidneys and Suprarenal Glands

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Clean out the connective tissue and fat over the IVC and expose the right gonadal vein and right and left renal veins ( Figs. 13.13 and 13.14 ).
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Continue the exposure of the left renal vein to the left and clean away the fat and connective tissue over the abdominal aorta ( Fig. 13.15 ).
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Paying special attention, identify the gonadal artery arising from the aorta just inferior to the level of the right renal vein.
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In the space between the IVC and aorta, identify the right lymphatic trunk and the sympathetic fibers ascending from the superior hypogastric plexus. This plexus is located just anterior to the promontory of the sacrum ( Fig. 13.16 ).
o
Complete the dissection by exposing the branches of the inferior mesenteric artery ( Figs. 13.17 and 13.18 ).
o
Identify and expose the renal arteries and veins.

Anatomy Note

The left renal vein crosses over the aorta, inferior to the origin of the superior mesenteric artery, to reach the IVC. In contrast, the right renal artery passes posterior to the IVC ( Fig. 13.19 ).

Fig. 13.19, Locate and expose the renal arteries and veins.

Dissection Tip

Additional renal arteries are often seen arising from the aorta; these are normal variations.

o
Identify the right suprarenal gland with its connection between the right suprarenal vein and the IVC (see Fig. 13.12 ). This vein is very short.
o
Dissect out the right superior, middle, and inferior suprarenal arteries, typically arising from the inferior phrenic artery, aorta, and renal artery, respectively ( Fig. 13.20 ).
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Notice the drainage of the right gonadal vein directly into the IVC ( Plate 13.1 ).
o
Identify the left suprarenal gland, and expose the left suprarenal vein and left gonadal vein draining into the left renal vein.
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With a scalpel, make a coronal incision and expose the outer cortex, as well as the inner medulla, of the suprarenal gland.
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Hold one of the two kidneys in your hand. Make a vertical incision along its lateral border, and transect the kidney into two parts ( Fig. 13.21 ).
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Open and inspect the inner part of the kidney.
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Identify the outer layer, the renal cortex, and the inner layer, the renal medulla ( Plate 13.2 ).

Anatomy Note

Realize that the cortex sends extensions into the medulla, the renal columns. The renal medulla is composed of pyramids, projections of the renal papillae, which contain collecting ducts that drain urine into the minor calyces. About 10 minor calyces combine to form three major calyces; all major calyces combine to form the renal pelvis, located at the hilum of the kidney ( Fig. 13.22 ).

Fig. 13.22, Inside the kidney, note the cortex, medulla, calyces, pyramids, and columns.

o
Between the inferior vena cava and the abdominal aorta, at the level of the right renal vein, locate the right sympathetic trunk ( Fig. 13.23 ).
o
You also can trace the sympathetic trunk just underneath the IVC, between the psoas major muscle and the vertebral column ( Figs. 13.24 and 13.25 ). The sympathetic trunk contributes lumbar splanchnic nerves to the superior hypogastric plexus (see Fig. 13.24 ).
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The right and left renal arteries are surrounded by a dense network of neural fibers (see Fig. 13.22 ). Identify the aorticorenal ganglion.

Anatomy Note

This ganglion further connects with the celiac ganglion, occupying the area over the celiac trunk (see Fig. 13.22 ). Preganglionic sympathetic fibers reach the celiac, aorticorenal, and superior mesenteric ganglia by way of the greater, lesser, and least splanchnic nerves, respectively. These fibers synapse in the ganglia, and postganglionic fibers travel along the arteries of the abdomen.

o
Lift the kidney upward, and clean out the posterior surface of the renal hilum ( Fig. 13.26 ).
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Identify the psoas major muscle, and remove the fascia over the right crus of the diaphragm and psoas major muscle ( Fig. 13.27 ).