Psoas sign - how to elicit, causes, mechanism

The psoas sign, also known as Cope's sign (or Cope's psoas test) or Obraztsova's sign, is a medical sign that indicates irritation to the iliopsoas group of hip flexors in the abdomen, and consequently indicates that the inflamed appendix is retrocaecal in orientation (as the iliopsoas muscle is retroperitoneal).

[@ryanlie6250]

So this is like modified Thomas test in a different angle