MODEL RELEASED. Incisional hernia in the abdomen of an 88-year-old man. A hernia occurs when an organ, such as a loop of the intestine, protrudes from a weak area in the abdominal wall. An incisional hernia occurs when weakened muscles of the abdominal wall allow the intestines to protrude through an old surgical incision. The previous operation in this case was a laparotomy, a general incision made for abdominal surgery.