An unusual peritoneal fossa: anatomic report and clinical implications

The peritoneal fossae are usually related to rotation and adhesion of the a bdominal viscera to the posterior abdominal wall during fetal development, and/or the presence of retroperitoneal vessels running just under the perit oneum and raising serosal folds. These fossae, therefore, are regarded as c ongenital and have been considered clinically and surgically as sites of in ternal abdominal hernias. The authors describe a peritoneal fossa interpose d between the fourth portion of the duodenum and the abdominal aorta. Due t o a scoliosis of the lumbar column, the abdominal aorta had shifted to the left of the duodenum, stretching two semilunar avascular peritoneal folds c onnecting the vessel with the ascending duodenum. These two folds bounded a bove and below an entrance into a fossa lined by the posterior parietal per itoneum and bordered by the fourth portion of the duodenum on the right and the aorta on the left. This recess extended as far as the anterior surface of the second and third lumbar vertebrae. On the basis of the anatomic fin dings, the authors suggest that acquired fossae, because of their size and topography, may play a part in the etiopathogenesis of internal abdominal h ernias.