Abdomen is the region of body lying between the diaphragm above and pelvis below. It contains the contents of digestive system including stomach and intestine.

Walls of abdomen:

  • Superior Wall: The superior wall of abdomen is formed by the diaphragm. It is a strong muscular sheath that has a vital role in respiratory system. For detailed anatomy, visit the page: “Diaphragm”.
  • Inferior Wall: There is no inferior wall of the abdomen because the abdominal cavity is continuous with the pelvic cavity.
  • Anterior Wall: The anterior wall of abdomen is formed above by the lower part of thoracic cage. Below it is formed by Rectus abdominis, External oblique, Internal oblique and Transversus abdominis muscles along with their fasciae.
  • Posterior Wall: The posterior wall of abdomen is formed in the midline by the five lumbar vertebrae and their intervertebral discs. Laterally, it is formed by the twelfth rib, psoas muscle, quadratus lumborum muscle and the border of bony pelvis. The aponeurosis of origin of transversus abdominis muscle is also involved in the formation of posterior wall of the abdomen.