An electrogastrogram (EGG) is a computer generated graphic produced by electrogastrography, which detects, analyzes and records the myoelectrical signal generated by the movement of the smooth muscle of the stomach, intestines and other smooth muscle containing organs. An electrogastroenterogram or electroviscerogram (or gastroenterogram) is a similar display of the recording of myoelectrical activity of gastrointestinal or other organs which are able to generate myoelectrical activity. These names are made of different parts: electro, because it is related to electrical activity, gastro, Greek for stomach, entero or viscero, Greek for intestines, gram, a Greek root meaning "to write". An electrogastrogram (EGG), electroviscerogram (EVG) or a gastroenterogram are similar in principle to an electrocardiogram (ECG) in that sensors on the skin detect electrical signals indicative of muscular activity within. Where the electrocardiogram detects muscular activity in various regions of the heart, the electrogastrogram or electroviscerogram detects the myoelectrical activity of the wave-like contractions of the stomach, intestines or other organs (peristalsis). Walter C. Alvarez discovered the EGG signal and pioneered early studies of electrogastrography in 1921–22. Physiological basis Motility of gastrointestinal tract (GI tract) results from coordinated contractions of smooth muscle, which in turn derive from two basic patterns of electrical activity across the membranes of smooth muscle cells—slow waves and action potentials. Slow waves are initiated by pacemakers—the interstitial cells of Cajal (ICC). Slow wave frequency varies in the different organs of the GI tract and is characteristic for that organ. They set the maximum frequency at which the muscle can contract: stomach – about 3 waves in a minute, duodenum – about 12 waves in a minute, jejunum – about 11 waves in a minute. ileum – about 8 waves in a minute, rectum – about 17 waves in a minute. The electrical activity or more properly termed myoelectrical activity of the GI tract can be subdivided into two categories: electrical control activity (ECA) and electrical response activity (ERA). ECA is characterized by regularly recurring electrical potentials, originating in the gastric pacemaker located in the body of stomach. The slow waves are not a direct reason of peristalsis of a GI tract, but a correlation between deviations of slow waves from norm and motility abnormalities however is proved. Cutaneous electrogastrography Recording of the Electrogastrogram can be made from either the gastrointestinal surface mucosa, serosa, or the external skin surface. The cutaneous electrogastrography provides an indirect representation of the electrical activity,