Final answer:
Percussion of the liver or spleen produces a dull noise, which is used in medical examinations to assess organ size and density. Kehr's sign, involving referred pain due to a ruptured spleen, demonstrates the relationship between these organs and the diaphragm.
Step-by-step explanation:
Percussion of the liver or spleen typically produces a dull noise due to the density of these organs. In the context of medical examinations, doctors perform percussion to assess the size and density of organs within the body. A normal liver has a dull sound because it is a solid organ. The spleen, located just inferior to the diaphragm in the upper-left quadrant of the abdominopelvic cavity, also produces a dull sound upon percussion.
In cases such as a ruptured spleen, where blood spills into the region and causes a hemorrhage, this may put pressure on the diaphragm and elicit Kehr's sign. This is characterized by referred pain felt in an area corresponding to the diaphragm - often the shoulder or back - instead of the actual site of the spleen. This phenomenon occurs because the visceral sensation is within the diaphragm, even though the spleen is the source of the problem.