What is referred pain?

Referred pain is pain that is felt at a site other than where the cause of the pain is situated.²⁸

What causes referred pain?

Specific pathways and neural connections in the brain are thought to lead to the possibility of pain referral. Convergence is one of the important neural phenomena that plays a critical role in pain referral. Information about touch and tissue damage is conveyed as action potentials along specific sensory nerve fibers that have their sensory receptors in the periphery. One group of nerve fibers conveys information about touch, and another group conveys information about tissue damage or noxious stimulation. Both types of nerve fibers convey action potentials into the brainstem to terminate on second order neurons in the trigeminal brainstem sensory nuclear complex. Some of these synaptic connections are ineffective or latent and action potentials arriving at these synaptic connections under normal circumstances. It appears that when there is prolonged and/or intense noxious stimulation, some of these ineffective synapses may become effective connections. Under these circumstances action potentials may be transmitted along pathways that convey information to unrelated to the source of the noxious peripheral stimulus.²⁸Murray GM. Guest Editorial: referred pain. J Appl Oral Sci. 2009;17(6). p1

Symptoms of referred pain

Symptoms of referred pain can vary according to the organ affected. An example is the pain from the thoracic and abdominal viscera, which is felt in the back. Pain in internal organs is often referred to sites distant from the organs themselves, such as the pancreas, which is felt in the back. Pain from the dissecting aortic aneurysm is referred to the upper back on the left side between the scapula and the spine.²⁹Kulkami R. Clincal Evaluation of Upper and Mid-Back Pain. Journal on Recent Advances in Pain. Sep-Dec 2015, p88.