Referred pain is best described as:

• A. Pain is localized strictly to the injury site
• B. Pain is felt in a different area due to diaphragmatic irritation
• C. Pain is felt in a different area (referred pain) such as shoulder from diaphragmatic irritation
• D. Pain disappears when the patient rests

Answer: (C)

Referred pain occurs when the brain perceives pain from an innervated structure as coming from a different, distant location. This happens because visceral and certain somatic nerves share the same spinal cord neurons, so signals can be mislocalized.

Diaphragmatic irritation is a classic cause: the diaphragm sends sensory signals via the phrenic nerves (C3–C5), and those inputs can be felt in the shoulder region. So pain can present in the shoulder even though the source is diaphragmatic irritation.

This description—pain felt in a different area such as the shoulder due to diaphragmatic irritation—best captures the phenomenon of referred pain.

The other statements don’t describe this concept. Pain localized strictly to the injury site is not referred pain but simple local pain. Pain that disappears with rest isn’t a defining feature of referred pain.