Chronic Pain - Classification

Classification

Chronic pain may be divided into "nociceptive" (caused by activation of nociceptors), and "neuropathic" (caused by damage to or malfunction of the nervous system).

Nociceptive pain may be divided into "superficial" and "deep", and deep pain into "deep somatic" and "visceral". Superficial pain is initiated by activation of nociceptors in the skin or superficial tissues. Deep somatic pain is initiated by stimulation of nociceptors in ligaments, tendons, bones, blood vessels, fasciae and muscles, and is dull, aching, poorly-localized pain. Visceral pain originates in the viscera (organs). Visceral pain may be well-localized, but often it is extremely difficult to locate, and several visceral regions produce "referred" pain when damaged or inflamed, where the sensation is located in an area distant from the site of pathology or injury.

Neuropathic pain is divided into "peripheral" (originating in the peripheral nervous system) and "central" (originating in the brain or spinal cord). Peripheral neuropathic pain is often described as “burning,” “tingling,” “electrical,” “stabbing,” or “pins and needles.”.