The Pain Pathway

From injury to "ouch" · Week 4
Pain is not instant magic. A signal has to be made, carried up to the brain, felt, and then turned up or down. Step through the four stages, from a stubbed toe to pain you feel.

Signal from toe to brain

Follow the pain signal from the injury, up the nerve and spinal cord, to the brain.
Press Advance to send the signal.

The 4 steps

Nociceptive

Normal "tissue damage" pain. Somatic pain comes from skin, muscle, or bone. Visceral pain comes from organs, and it may refer elsewhere. For example, a fracture or pancreatitis.

Neuropathic

Pain from nerve injury itself, in the PNS or CNS. It burns, shoots, or tingles. For example, diabetic neuropathy, shingles, carpal tunnel, or Guillain-Barré.
Acute vs chronic: acute pain is protective and immediate. It fades on its own, and it matches the injury. Chronic pain lasts beyond about three months. It does not match the first injury, and it drags along depression, anxiety, and fatigue.