Expansion
Pressure in the left iliac fossa produces pain in the right iliac fossa
Expansion
Pressing in the left iliac fossa elicits pain in the right iliac fossa.
The traditional explanation is that colonic gas is displaced retrogradely towards the caecum, distending it. The more accepted explanation is simpler: the manoeuvre shifts the mobile viscera and stretches the inflamed parietal peritoneum on the right.
Companion signs, each localising the appendix:
- Psoas sign - pain on passive extension of the right hip, suggesting a retrocaecal appendix lying on psoas
- Obturator sign - pain on passive internal rotation of the flexed right hip, suggesting a pelvic appendix lying on obturator internus
- Rebound tenderness and guarding - generalised parietal peritoneal involvement
None is sufficiently sensitive to be used alone, but together they help localise the appendix and support the diagnosis.