Referred pain is defined as pain perceived in an area other than the location of the pathophysiology.
A common example of referred pain is that experienced in the arm, neck, or shoulder rather than the chest during a heart attack. The underlying mechanism of referred pain is not completely understood. Referred pain is often associated with anatomical areas, where nerve fibers from areas with high sensory innervation (e.g., skin and muscles of the arm) and nerve fibers from areas of low sensory innervation (e.g., the heart) enter at the same level of the spinal cord. Pain can also be referred from one skeletal muscle group to another. While the underlying mechanism is unclear, referred muscle pain may be related to central sensitization or increased sensitivity of specific muscle nociceptors.