Peritoneal Cavity - Clinical Tree

Atlas References

Netter: 270–273, 276, 280, 284
McMinn: 226–233, 244, 249
Gray's Atlas: 152–156, 159, 164, 166–168, 172

Three Different Techniques for Opening the Peritoneal Cavity

Dissection Tip

All cuts with the scalpel should be made carefully to avoid cutting too deeply into the peritoneal cavity and underlying viscera.

Technique 1

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After removal of the skin over the anterior abdominal wall, palpate the most inferior costal cartilages and the xiphoid process ( Fig. 11.1 ).
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With scissors or a scalpel, cut the attachments of the rectus abdominis and external abdominal oblique muscles over the right and left hypochondriac areas ( Fig. 11.2 ).
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Continue the incision of the muscles from the xiphoid process toward the midaxillary line on both sides of the cadaver ( Fig. 11.3 ).
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Reflect the rectus abdominis and abdominal oblique muscles inferiorly ( Fig. 11.4 ).
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When necessary, use blunt dissection to expose the peritoneal cavity ( Fig. 11.5 ).
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Cut the attachments of the diaphragm, falciform ligament, and ligamentum teres (round ligament) of the liver to the abdominal wall.
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Reflect the anterior abdominal wall toward the pubic symphysis, and observe the contents of the abdominal cavity ( Figs. 11.6 and 11.7 ).

Technique 2

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Reflect the rectus sheath and expose the rectus abdominis muscle and the posterior lamina of the rectus sheath ( Figs. 11.8 and 11.9 ).
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Make a midline vertical incision at the linea alba from the xiphoid process to the pubic symphysis.
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Make a second horizontal incision from the xiphoid process to the midaxillary line, and reflect the muscle flap laterally ( Fig. 11.10 ).
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Use the same technique on the contralateral side, and expose the peritoneal cavity ( Fig. 11.11 ).

Technique 3

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Make a midline vertical incision on the linea alba from the xiphoid process to the pubic symphysis.
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Make a second horizontal incision from the right to the left midaxillary line, passing through the umbilicus, and laterally reflect the four muscle flaps ( Fig. 11.12 ).
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Identify and cut the falciform and round ligaments on the anterior surface of the liver.

Dissection Tip

In some specimens the peritoneal cavity is small. To expose it further, with a saw, cut the ribs in the midaxillary line on both sides of the cadaver. You also may extend the cuts with those made previously to expose the thoracic cavity.

In some cadavers, you will be able to separate the parietal peritoneum from the transversalis fascia. In most, however, these two layers are tightly adherent.

Peritoneal Structures

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Trace the round ligament of the liver along its pathway from the anterior surface of the liver to the median aspect of the anterior abdominal wall to the umbilicus.
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At the internal (posterior) surface of the anterior abdominal wall, identify five notable peritoneal folds: the lateral (right and left), the medial (right and left), and the single median umbilical folds ( Fig. 11.13 ).

Anatomy Note

The peritoneal fold covering the inferior epigastric artery and vein is the lateral umbilical peritoneal fold. The medial umbilical folds are formed by an elevation of the peritoneum over the obliterated umbilical arteries. Similarly, the median umbilical fold is an elevation of the peritoneum over the remnants of the urachus (intraabdominal part of allantois). The space between the medial umbilical fold and median umbilical fold is termed the supravesical fossa. The depressed region between the medial umbilical fold and the lateral umbilical fold is termed the medial inguinal fossa. The lateral inguinal fossa is the area lateral to the lateral inguinal fold.

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Make an incision at the posterior layer of the rectus sheath (and peritoneum) and expose the rectus abdominis muscle ( Fig. 11.14 ).
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Trace the course of the inferior epigastric artery and identify its origin from the external iliac artery ( Figs. 11.15 to 11.17 ).

Dissection Tip

In approximately 30% of cadavers, the inferior epigastric artery will give rise to the obturator artery, which travels medially over the pelvic brim.

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Remove the peritoneum covering the inferior epigastric artery and the base of the rectus abdominis muscle, and identify the inguinal ligament ( Fig. 11.18 ).

Anatomy Note

Notice the triangle of Hesselbach formed by the lateral border of the rectus abdominis muscle, the inguinal ligament, and the inferior epigastric vessels.

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Laterally to the inferior epigastric artery and vein, identify the deep inguinal ring and the ductus deferens (round ligament in females) passing within it.
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Continue the dissection by identifying the pubic tubercle and, lateral to it, a strong ligamentous band running over the periosteum of the pectineal line, the pectineal ligament (Cooper's ligament) (see Fig. 11.18 ).
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Note the medial one third of the inguinal ligament forming an aponeurotic expansion attaching to the pectineal line of the pubis and pectineal ligament, the lacunar ligament (Gimbernat's ligament) (see Fig. 11.18 ).
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Lateral to the lacunar ligament, expose the femoral vessels, and identify the femoral ring (lying medial to the femoral vein), the opening to the femoral canal.

Dissection Tip

Clean the adipose tissue and look for a large lymph node, the node of Cloquet .

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Retract the femoral vein medially and note a fascial partition under the inguinal ligament between the femoral vein and the iliopsoas muscle. This partition between the vascular portion (lacuna vasorum) and the muscular portion (lacuna musculorum) is called the iliopectineal ligament (see Fig. 11.18 ).
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Inspect the contents of the peritoneal cavity, and identify the liver, stomach (with its greater and lesser curvatures), small and large intestines, and greater omentum ( Fig. 11.19 ).

Anatomy Note

The peritoneal cavity is traditionally divided into two parts, the greater and lesser sacs, or into supracolic and infracolic compartments. The greater sac is the entire area of the peritoneal cavity with the exception of the area extending behind the stomach to the diaphragm at the left side, which is the lesser sac (omental bursa). Similarly, the supracolic compartment is the area of the peritoneal cavity that extends from the transverse mesocolon to the diaphragm. The infracolic compartment is the area of the peritoneal cavity extending from the transverse mesocolon below to the pelvic brim.

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Identify the greater curvature of the stomach, and lift the greater omentum ( Fig. 11.20 ).
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Expose the transverse colon with its transverse mesocolon, and identify the ileum, jejunum, cecum, ascending colon, transverse colon, and descending sigmoid colon ( Fig. 11.21 ).
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Observe the space between the liver and the stomach and identify the gallbladder and lesser omentum ( Fig. 11.22 ).
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With blunt dissection using your fingertips, separate any adhesions between the stomach and the liver ( Fig. 11.23 ).

Dissection Tip

Often you will find several adhesions between the contents of the peritoneal cavity. Take some time and separate these adhesions to restore the normal anatomy and position of the organs.

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Cut the greater omentum 3 to 4 cm away from the greater curvature, and leave its attachments to the transverse colon ( Fig. 11.24 ).
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Pull the stomach away from the transverse colon, and note the area of the lesser sac. Also notice the pancreas lying directly behind the stomach ( Fig. 11.25 ).
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Continue the dissection by pulling the stomach inferiorly from the liver, and note the epiploic foramen (of Winslow) ( Fig. 11.26 ).
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Pass a probe or scissors underneath the lesser omentum through the epiploic foramen ( Fig. 11.27 and Plate 11.1 ).