Question

Kehr's sign is a classic example of referred pain: irritation of the diaphragm is transmitted by the phrenic nerve to the tip of the left shoulder. Why does this pain refer to the shoulder?

Answer 1

The referred pain in Kehr's sign, where irritation of the diaphragm is felt in the tip of the left shoulder, is due to the connection of visceral and somatosensory fibers in the spinal cord.

Step-by-step explanation:

The referred pain in Kehr's sign, where irritation of the diaphragm is felt in the tip of the left shoulder, is due to the connection of visceral and somatosensory fibers in the spinal cord. Visceral sensory fibers from the diaphragm enter the spinal cord at the same level as the somatosensory fibers from the neck and shoulder. This leads to the brain misinterpreting the sensations from the diaphragm as coming from the shoulder, resulting in referred pain in that area.