Liver span

The liver span is a measurement performed during physical examination to determine the size of the liver and identify possible hepatomegaly. It can be described as the distance between the lower border of the liver in the mid-clavicular line obtained by palpation, and the upper border of the liver in the mid-clavicular line detected by percussion ( i.e., as the upper border of the liver lies behind the ribs and can not be palpated.)

One technique to measure the span involves percussion.

Normal liver span is 6–12 cm.

...
Wikipedia