Abdomen Objectives

Important Concepts about the Abdomen

You can understand a great deal about the basic structure and function of the abdomen if you learn some important concepts. Some of them may seem obvious, but if you keep them in mind it will save you some memorization.

  1. The abdominal wall musculature and innervation reflect the segmentation seen during development.
  2. Muscles in this region act on the vertebral column.
  3. Defects in the abdominal wall (hernias) occur where structures pass through the wall (e.g., testes, femoral vessels).
  4. The important layers of the abdominal wall from outside to inside are: superficial fascia (fatty and membranous layers) - muscle - deep fascia (e.g.,transversalis fascia) - subserous fascia - peritoneum.
  5. The vasculature is located in the subserous fascia.
  6. Viscera are located in the abdominal cavity, not the peritoneal cavity.
  7. Mesenteries and abodminal 'ligaments' are formed by peritoneal reflections.
  8. Intra-abdominal organs are completed enclosed by peritoneum in contrast to retroperitoneal organs that are incompleted covered.
  9. The relationships of intra-abdominal structures in the adult are the result of rotations of the GI tract during development.
  10. The lesser sac results from rotation of the GI tract. It communicates with the greater sac.
  11. Vascular anastomoses provide a redundant blood supply and drainage to many abdominal structures. This is very important functionally and clinically!
  12. Lymphatic drainage follows the venous drainage.
  13. Abdominal pain is poorly localized because it is transmitted by visceral afferents. It is often 'referred pain'.
  14. The abdominal aorta has both paired and unpaired branches.
    John A. McNulty, Ph.D.
    Last Updated: July 11, 2005
    Created: 1 March 1996