Rovsing's sign was first noted by Niels Thorkild Rovsing in 1907, and has been shown to be an uncommon sign of appendicitis (Davey, 1956). The presumptive mechanism has been that antiperistaltic pressure on the descending colon results in backflow of gas through the transverse and ascending colon resulting in appendiceal irritation and pain. Yasui (1958) demonstrated intraoperatively that pressure on the left iliac fossa does not result in pressure change in the caecum, suggesting that a different mechanism may be responsible. One hypothesis is that pressure on the left iliac fossa causes rubbing of the sigmoid colon against an inflamed appendix resulting in pain.