The anterior abdominal wall constitutes a hexagonal area defined superiorly by the costal margins and xiphoid process; and inferiorly by the iliac crests, inguinal ligament, pubis and pubic symphysis. The wall extends posteriorly and incorporates the lateral aspect of the wall until the junction with the posterior abdominal wall approximately at the mid-axillary line. The wall is covered externally by skin and subcutaneous tissue: beneath this lies the superficial fascia (between the dermis and the muscles), which is conventionally divided into a superficial fatty layer (Camper's fascia) and a deep membranous layer (Scarpa's fascia); deep fascia; the rectus abdominis, pyramidalis, external oblique, internal oblique and transversus abdominis; and the extraperitoneal tissue and the parietal peritoneum. These tissues also form the umbilicus and the inguinal canal, which connects the abdominal cavity to the scrotum in males and the labia majora in females.