Correct answer:

Typically the pain commences as a central periumbilical colic, which shifts after approximately 6 hours to the right iliac fossa or, more accurately, to the site of the inflamed appendix as the adjacent peritoneum becomes inflamed. The appendix is a long tube (7–10 cm long), tethered proximally to the caecum near the ileocaecal junction; distally, the tip may lie anywhere from behind the caecum (retrocaecal), adjacent to the ileum, or down in the pelvis lying against the rectum or the bladder. Thus, if the appendix is in the pelvic position, the pain may become suprapubic, with urinary frequency as the bladder is irritated; if it is in the high retrocaecal position, the symptoms may become localized to the right loin with less tenderness on abdominal palpation. Rarely, the tip of the inflamed appendix extends over to the left iliac fossa and pain may localize there. The colicky central abdominal pain is visceral in origin, the shift of pain is due to later involvement of the sensitive parietal peritoneum by the inflammatory process. Typically, the pain is aggravated by movement and the patient prefers to lie still with the hips and knees flexed.