Editing Low back pain (section)

===Pain sensation===
Pain erupts in response to a [[Stimulus (physiology)|stimulus]] that either damages or can potentially damage the body's tissues. There are four main stages:  [[Transduction (physiology)|transduction]], transmission, [[perception]], and [[neuromodulation|modulation]].<ref name=salzberg_2012/> The nerve cells that detect pain have cell bodies located in the [[dorsal root ganglia]] and fibers that transmit these signals to the spinal cord.<ref name=patel_2010>{{cite book |title=Guide to Pain Management in Low-Resource Settings |chapter=Chapter 3: Physiology of Pain |vauthors=Patel NB |veditors=Kopf A, Patel NB |year=2010 |chapter-url=http://www.iasp-pain.org/AM/Template.cfm?Section=Guide_to_Pain_Management_in_Low_Resource_Settings&Template=/CM/ContentDisplay.cfm&ContentID=12162 |archive-url=https://web.archive.org/web/20131005010917/http://www.iasp-pain.org/AM/Template.cfm?Section=Guide_to_Pain_Management_in_Low_Resource_Settings&Template=%2FCM%2FContentDisplay.cfm&ContentID=12162 |archive-date=5 October 2013 |access-date=26 May 2017 }}</ref> The process of pain sensation starts when the pain-causing event triggers the endings of appropriate [[nociceptor|sensory nerve cells]]. This type of cell converts the event into an electrical signal by transduction. Several different types of nerve fibers carry out the transmission of the electrical signal from the transducing cell to the [[posterior horn of spinal cord]], from there to the [[brainstem|brain stem]], and then from the brain stem to the various parts of the brain such as the [[thalamus]] and the [[limbic system]]. In the brain, the pain signals are processed and given context in the process of pain [[perception]]. Through modulation, the brain can modify the sending of further nerve impulses by decreasing or increasing the release of [[neurotransmitter]]s.<ref name=salzberg_2012/>

Parts of the pain sensation and processing system may not function properly; creating the feeling of pain when no outside cause exists, signaling too much pain from a particular cause, or signaling pain from a normally non-painful event. Additionally, the pain modulation mechanisms may not function properly. These phenomena are involved in chronic pain.<ref name=salzberg_2012/>