Epidemiology In the past viscera were considered insensitive to pain but now it is clear that pain from internal organs is widespread and that its social burden may surpass that of pain from superficial (somatic) sources.

Walter Rudolf Hess (March 17, 1881 August 12, 1973) was a Swiss physiologist who won the Nobel Prize in Physiology or Medicine in 1949 for mapping the areas of the brain involved in the control of internal organs.