Retraction Of Herniated Loops

During the 10th week, herniated intestinal loops begin to return to the abdominal cavity Although the factors responsible for this return are not precisely known, it is thought that regression of the mesonephric kidney, reduced growth of the liver, and expansion of the abdominal cavity play important roles.

The proximal portion of the jejunum, the first part to reenter the abdominal cavity, comes to lie on the left side (Fig. 13.27A). The later returning loops gradually settle more and more to the right. The cecal bud, which appears at about the sixth week as a small conical dilation of the caudal limb of the abdominal cavity in the third month. B. Scanning electron micrograph of a lateral view of a mouse embryo at approximately the same stage as in A, with the body wall and amnion removed. The heart (H) occupies most of the thoracic region and the liver (L) most of the abdomen. Herniated midgut (M) is just beginning to coil and protrudes from the abdomen. C. Frontal view of the embryo in B. Note the extreme size of the liver, which is serving a hematopoietic function at this time, and the initial rotation of the herniated midgut. The diaphragm between the heart and liver has been removed.

Transverse

Transverse

Rotation Midgut

Figure 13.27 A. Anterior view of the intestinal loops after 270° counterclockwise rotation. Note the coiling of the small intestinal loops and the position of the cecal bud in the right upper quadrant of the abdomen. B. Similar view as in A, with the intestinal loops in their final position. Displacement of the cecum and appendix caudally places them in the right lower quadrant of the abdomen.

Figure 13.27 A. Anterior view of the intestinal loops after 270° counterclockwise rotation. Note the coiling of the small intestinal loops and the position of the cecal bud in the right upper quadrant of the abdomen. B. Similar view as in A, with the intestinal loops in their final position. Displacement of the cecum and appendix caudally places them in the right lower quadrant of the abdomen.

Primary Intestinal Loop
Figure 13.28 Successive stages in development of the cecum and appendix. A. 7 weeks. B. 8 weeks. C. Newborn.

primary intestinal loop, is the last part of the gut to reenter the abdominal cavity Temporarily it lies in the right upper quadrant directly below the right lobe of the liver (Fig. 13.27A). From here it descends into the right iliac fossa, placing the ascending colon and hepatic flexure on the right side of the abdominal cavity (Fig. 13.27B). During this process the distal end of the cecal bud forms a narrow diverticulum, the appendix (Fig. 13.28).

Since the appendix develops during descent of the colon, its final position frequently is posterior to the cecum or colon. These positions of the appendix are called retrocecal or retrocolic, respectively (Fig. 13.29).

Retrocecal Appendix
Figure 13.29 Various positions of the appendix. In about 50% of cases the appendix is retrocecal or retrocolic.

Dorsal mesogastrium fused with abdominal ■ wall

Dorsal mesoduodenum fused with abdominal wall

Ascending colon

Dorsal Mesogastrium

Dorsal mesogastrium fused with posterior

Greater abdominal wall curvature

Lesser curvature

Dorsal mesoduodenum fused with posterior abdominal wall

Greater omentum

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Responses

  • AMNA
    What is retrocecal appendix images?
    8 years ago
  • CHICA
    What is meant by the retraction of the herniated intestinal loops during development?
    2 months ago

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