<P> The rectus abdominis muscles are long and flat . The muscle is crossed by three fibrous bands called the tendinous intersections . The rectus abdominis is enclosed in a thick sheath formed, as described above, by fibers from each of the three muscles of the lateral abdominal wall . They originate at the pubis bone, run up the abdomen on either side of the linea alba, and insert into the cartilages of the fifth, sixth, and seventh ribs . In the region of the groin, the inguinal canal, a passage through the layers . This gap is where the testes can drop through the wall and where the fibrous cord from the uterus in the female runs . This is also where weakness can form, and cause inguinal hernias . </P> <P> The pyramidalis muscle is small and triangular . It is located in the lower abdomen in front of the rectus abdominis . It originates at the pubic bone and is inserted into the linea alba halfway up to the navel . </P> <P> Functionally, the human abdomen is where most of the alimentary tract is placed and so most of the absorption and digestion of food occurs here . The alimentary tract in the abdomen consists of the lower esophagus, the stomach, the duodenum, the jejunum, ileum, the cecum and the appendix, the ascending, transverse and descending colons, the sigmoid colon and the rectum . Other vital organs inside the abdomen include the liver, the kidneys, the pancreas and the spleen . </P> <P> The abdominal wall is split into the posterior (back), lateral (sides), and anterior (front) walls . </P>

Are the kidneys located in the inguinal region of the abdomen