Physical pain involves a complicated series of physiochemical responses leading to the perception of an unpleasant sensation which serves to protect the body. Pain elicits motor actions to move away from a noxious stimulus to avoid injury. It may arise from the actual tissue injury and (inflammation) or from damage to a portion of the nervous system. Inflammation serves to remove the injurious stimuli (pathogens, damaged cells, etc.) and initiate the healing process. During the inflammatory process, blood vessels dilate to facilitate the mobilization of healing factors to the injured site (e.g. white blood cells, plasma). Although the influx of these mediators is necessary in the healing process, the swelling that ensues may cause pain and could put pressure on nearby healthy tissue. Therefore, it is often important to reduce inflammation in order to alleviate pain.

Pain associated with neurological disease is often due to inflammation of the nerve roots, meninges, or disks, not the spinal cord itself. A thorough neurological examination is important since many signs of pain that appear neurological may actually be orthopedic or visceral. For example:

  • polyarthritis could appear to be cervical spinal pain.
  • panosteitis may resemble lumbar spinal pain.
  • certain abscesses of the jaw or bone could be mistaken for head pain.
  • pain from cruciate ligament ruptures often show similar signs as limb paresis.

Pain may also be referred, in that the discomfort is felt away from the actual area of irritation. For example:

  • neck pain may be due to an increase in intracranial pressure.
  • back pain may initially cause abdominal tension.
  • crying out
  • holding limb up
  • low head carriage
  • Head
    • brain swelling
    • inflammation
    • tumor
  • Spine
    • herniated disk
    • vertebral infections or tumors
    • meningitis
    • vertebral fractures or subluxations / luxations
    • neuritis
  • Limb
    • nerve root or peripheral nerve tumor
    • inflammation (neuritis)
    • myalgia (myositis)