In Germany, the surnames Mueller, Meyer and Schmidt are so common that in a lighter vein people say that they could feed pigs with them.
This joke is about a building housing practicing doctors with the above given names. By mistake, one patient landed up in the wrong doctor’s consulting room. The assistant asked him to undress and started the preliminaries. His poking finger invading his rectum made the patient quite uneasy, so when the doctor arrived, he asked, “Don’t you have an assistant with a longer fingers? My problem is with my throat!”