Abdomen.

The abdomen is the portion of the body’s trunk that begins immediately below the diaphragm, which is the main respiratory muscle in the chest cavity, and extends to the lower pelvic region. The abdominal area is defined by a muscular wall made up of fatty tissue and skin, which determines the general shape of the body from the chest to the lower pelvis. The entire abdominal cavity is lined by a membrane called the peritoneum. This membrane encloses the essential organs of the abdomen: the stomach, small and large intestines, liver, gallbladder, bladder, pancreas, and kidneys. In females, the abdominal casing also contains the uterus, ovaries, and Fallopian tubes. At the front of the abdomen is the navel, essentially a scar which forms following the cutting of the umbilical cord after birth.