The United States has by far the largest correctional system in the world. It is so large, in fact, so sprawling and dispersed, so administratively complex that just how many people are incarcerated is uncertain. The most commonly cited statistic is that are about 2.3 million inmates on any given day.
Most often, a lump in the abdomen is caused by a hernia. An abdominal hernia occurs when there is a weak spot in the abdominal wall. This allows the internal organs to bulge through the muscles of the abdomen. A hernia may appear after you strain, or lift something heavy, or after a long period of coughing. Inguinal hernia appears as a bulge in the groin or scrotum.
1 Umbilical hernias can appear later in life or in women who are pregnant or who have given birth (due to the added stress on the area). They usually do not cause abdominal pain.  Incisional hernia: Abdominal surgery causes a flaw in the abdominal wall. This flaw can create an area of weakness through which a hernia may develop. This occurs after 2%-10% of all abdominal surgeries, although some people are more at risk. Even after surgical repair, incisional hernias may return.