ABSTRACT
Only tissues and structures containing pain receptors can cause pain. There are only a few tissues that have these receptors–muscle, skin and nerves are the main ones. The number of possible causes of pain is even more limited. Injury, local pressure, inflammation, infection, loss of blood supply, and nerve damage are the main causes. Neuropathic pain is a special type of pain that does not need pain receptors. Neuropathic pain includes pains such as neuralgia in the face due to trigeminal nerve damage, or neuralgia that can develop after Herpes zoster infection. Any nerve damage can cause changes in spinal cord and brain. This can make unpleasant, painful sensations persist even though no pain receptors are involved. Being clear about what can cause pain and the different structures involved will help us to work out what causes of pain might be associated with some everyday activities. Understanding the different characteristics of pain is the basis for diagnosing pain.
