What is pain?

Pain definitions:
  1. Pain is "An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage." - The International Association for the Study of Pain (IASP)

  2. "Pain is whatever the experiencing person says it is, existing whenever he says it does..." - McCaffery.

Pain theories

Pain classification

Pain is often described as acute or chronic. These terms provide more or less arbitrary indicators of duration but offer no information regarding underlying pathophysiology. The terms nociceptive and neuropathic are more indicative of the pathophysiology responsible for the electrical impulses interpreted by the brain as pain.