Incisional hernias may seem to appear and disappear, which is referred to as a "reducible" hernia. The hernia may not be noticeable unless the patient is involved in an activity that increases abdominal pressure, such as coughing, sneezing, pushing to have a bowel movement, or lifting a heavy object.
The visibility of a hernia makes it easily diagnosable, often requiring no testing outside of a physical examination by a physician. The physician may request that you cough or bear down in order to see the hernia while it is "out."
Routine testing can be done to determine what area of the body is pushing through the muscle. If the hernia is large enough to allow more than the lining of the abdominal cavity to bulge through, testing may be required.