Percussion

Percussion can precede or be interspersed with palpation of each quadrant. It is a useful technique for:

Evaluating the size of the liver and sometimes the spleen.
Evaluating gas in the abdomen versus solid or fluid-filled structures.
Evaluating for focal areas of tenderness and peritoneal irritation.
Evaluating for the presence of ascites.

The anterior gas-filled abdomen normally has a tympanitic sound to percussion, which is replaced by dullness where solid viscera, fluid, or stool predominate. The flanks are duller as posterior solid structures predominate, and the right upper quadrant is somewhat duller over the liver. In contrast, the left upper quadrant may be tympanitic if there is an underlying gastric air bubble or splenic flexure of the colon filled with gas. There is good inter-rater reliability between clinicians in what represents a tympanitic note versus dull.

Percussion of the liver/spleen:

Percussion can be used to estimate the vertical span of the liver. In the midclavicular line, the liver span is generally between six and twelve centimeters. A liver span greater than 12 cms is generally considered abnormal and consistent with hepatomegaly. Variability in body habitus and certain disease states may influence where the liver is, and therefore where it is felt with palpation, but generally does not result in a change in span by percussion.

The spleen is a small, generally posterior structure, found just under the diaphragm and is often difficult to characterize with percussion. Percussion may be helpful when splenomegaly is suspected although palpation may provide more useful information.

Assessment of abdominal tenderness via percussion:

Percussion is a useful tool for evaluating abdominal tenderness. Lightly percuss the abdomen to determine the location of the pain. Localized pain is suggestive of peritoneal or intrabdominal inflammation, and is further discussed in the "Advanced Techniques" section.

Assessment of ascites via percussion:

One technique for evaluating ascites is assessment of shifting dullness. In the ascitic abdomen, gas-filled bowel loops float to the top while the ascitic fluid falls to the dependent portion of the abdomen. As a result, percussion notes are tympanitic over the bowel loops and dull over the surrounding fluid. With the patient lying on his back, map out these areas of dullness and tympany. Then, ask the patient to roll on his side and re-percuss. The ascites and thus dullness shifts to the side the patient is lying on, while the tympanitic area shifts to the top.

Click on the video icon to see a discussion and demonstration of the techniques for abdominal percussion.

Click on the interactive icon to practice percussion of the abdomen.