The Science of Pain


Pain can be nociceptive, non-nociveptive, somatic, visceral, neuropathic, or sympathetic.


Studying Effects of Pain

There are several different classifications of pain. A Medical News Today article  provides a more in-depth view of what each type is and how they differ. 

Nociceptive Pain

In cases of nociceptive pain, the nervous system of your body is working properly. There is some sort of pain (ex. broken bone or cut) and specific pain receptors are stimulated. These receptors sense factors like temperature, vibration, stretch, and chemicals released from damaged cells.

Somatic Pain

A type of nociceptive pain. Pain felt on the skin, muscle, joints, bones and ligaments is called somatic pain. Somatic pain is synonymous with musculo-skeletal pain. The pain receptors are sensitive to temperature (hot/cold), vibration, and stretch (in the muscles). They are also sensitive to inflammation, as would happen if you cut yourself, sprain something that causes tissue damage. Somatic pain is generally sharp and well localized - if you touch it or move the affected area the pain will worsen.

Visceral Pain

A type of nociceptive pain. It is felt in the internal organs and main body cavities. The cavities are divided into the thorax (lungs and heart), abdomen (bowels, spleen, liver and kidneys), and the pelvis (ovaries, bladder, and the womb). Visceral pain is often more difficult to localize than somatic pain.  Visceral pain is diffuse, difficult to localize and often referred to a distant, ambiguous, deep ache. 

Nerve Pain or Neuropathic Pain

Nerve pain is also known as neuropathic pain. It is a type of non-nociceptive pain. It comes from within the nervous system itself. People often refer to it as pinched or trapped nerve. The pain can originate from the nerves between the tissues and the spinal cord (peripheral nervous system) and the nerves between the spinal cord and the brain (central nervous system, or CNS). Neuropathic pain can be continuous or episodic. 

Sympathetic Pain

The sympathetic nervous system controls our blood flow to our skin and muscles, perspiration, and how quickly the peripheral nervous system works. Sympathetic pain occurs generally after a bone fracture or a soft tissue injury of the limbs. This pain is non-nociceptive - there are no specific pain receptors. As with neuropathic pain, the nerve is injured, becomes unstable and fires off random, chaotic, abnormal signals to the brain, which interprets them as pain.
Usually with this kind of pain the skin and the area around the injury become extremely sensitive. Pain often becomes so intense that the sufferer is unable to use the affected limb, which can lead to other problems, such as muscle wasting, osteoporosis and joint stiffness overtime.