This section is from the book "Diseases Of The Intestines", by Max Einhorn. Also available from Amazon: Diseases Of The Intestines A Text-Book For Practitioners And Students Of Medicine.
Percussion is of less importance than palpation. In many instances it serves to confirm the results obtained by the latter. In percussing the intestines it is best to use the fingers. It should be done rather gently. Mild percussion permits the discernment of slight differences of sound much better than strong percussion. As is well known, percussion over empty intestinal coils or those filled with gas or air gives a tympanitic sound which is louder over the large than over the small bowel. Intestinal coils filled with liquid or solid substances give dulness. In meteorism of the intestines percussion will elicit a tympanitic sound of a deeper pitch than normally, and there will be besides some areas of dulness over the abdomen. The region of the liver and spleen will here show normal conditions with regard to the percussion sounds. Meteorism of the abdomen as a result of perforation will manifest an evenly diffused tympanitic sound all over the abdominal cavity. Usually the dulness over the region of the liver and spleen will have disappeared. In ascites percussion will reveal an area of dulness in the lower parts of the abdomen, and there will be a change in the character of the sound on altering the position of the patient. Tumors of the intestine give dulness on percussion.
Fecal accumulations and appendicular abscesses will also manifest dulness on percussion.
1 Kuhn: Deutsche med. Wochenschr., 1897, Nos. 36 and 37.