The Posterior Abdominal Wall and Related Structures

Abstract

The posterior abdominal wall consists of the five lumbar vertebrae in the midline and the psoas and quadratus lumborum muscles on either side. The forward curvature of the lumbar vertebrae brings the posterior wall very near to the anterior abdominal wall and in a thin individual the abdominal aorta can be seen pulsating near the umbilicus. The posterior part of the diaphragm with its crura also forms part of the posterior abdominal wall, and, lateral to the quadratus lumborum, the transversus abdominis is attached to the fascia related to that muscle (figures 63, 88). The kidneys with the suprarenal glands on their upper poles lie on either side on the muscles and extend above and below the level of the twelfth rib. The ureters run downwards at approximately the level of the tips of the transverse processes of the lumbar vertebrae, and the inferior vena cava and abdominal aorta lie to the right and left respectively of the bodies of the lumbar vertebrae. The branches of the lumbar plexus emerge from the psoas muscle and the autonomic nerves and lymph nodes are related mainly to the aorta.