Psoas sign

If abdominal pain results, it is a "positive psoas sign".

A positive psoas sign may also be present in a patient with a psoas abscess.

The principles of the obturator sign in the diagnosis of appendicitis are similar to that of the psoas sign.

In particular, the right iliopsoas muscle lies under the appendix when the patient is supine, so a positive psoas sign on the right may suggest appendicitis.

Similarly this is the explanation for other signs of localised peritonitis such as Murphy's sign, Rovsing's sign or Psoas sign.

The psoas 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).