a hernia is an actual defect in the muscles surrounding the abdominal cavity, through which contents can protrude and get stuck, creating the need for an operation. If the hernia is reduced (i.e. tissue is not bulging through the opening), it may not be seen on CAT scan. A diastasis is a separation of the muscles in the midline of the abdomen due to pregnancy or massive weight gain. This separation of the muscles can frequently be seen on CAT scan. Unlike a hernia, a diastasis does not require an operation but can be fixed as part of an abdominoplasty (tummy tuck) in order to tighten the muscular foundation of the abdominal wall and give a flatter overall appearance. The correction of hernias is usually considered medically necessary and covered by insurance. The correction of a diastasis is not considered medically necessary and therefore not covered by insurance