Rovsing's Sign - Referral of Pain

Referral of Pain

This anomaly occurs because the pain nerves deep in the intestines do not localize well to an exact spot on the abdominal wall, unlike pain nerves in muscles. Pain from a stomach ulcer or gallstone can be interpreted by the brain as pain from the stomach, liver, gall bladder, duodenum, or first part of the small intestine. It will "refer" pain often to the mid upper abdomen.

Because the appendix is a piece of intestine, it follows a similar referral pattern. An appendix with some early inflammation may give a non-specific irritation somewhere near the umbilicus (belly button). Should the inflammation become severe, it may actually irritate the inner lining of the abdominal cavity called the peritoneum. This thin layer lies under or behind the abdominal wall muscles. Now the pain is "localized". If pressure is applied to the muscles of the right lower abdomen (or iliac fossa) near a very irritated appendix, then the muscle fibers in that area will be stretched and will hurt.