The psoas sign, also known as 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). It is elicited by performing the psoas test by passively extending the thigh of a patient lying on his side with knees extended, or asking the patient to flex his thigh at the hip. If abdominal pain results, it is a "positive psoas sign". The pain results because the psoas borders the peritoneal cavity, so stretching (by hyperextension at the hip) or contraction (by flexion of the hip) of the muscles causes friction against nearby inflamed tissues. 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. A positive psoas sign may also be present in a patient with a psoas abscess. It may also be positive with other sources of retroperitoneal irritation, e.g. as caused by hemorrhage of an iliac vessel.
- Bhat, Sriram; M, Sriram Bhat (30 December 2012). SRB's Manual of Surgery. JP Medical Ltd. p. 1279. ISBN 978-93-5025-944-3.
- Augustin, Goran (12 May 2014). Acute Abdomen During Pregnancy. Springer. p. 8. ISBN 978-3-319-05422-3.
- Bickley, Lynn S. Bates' Guide to Physical Exam and History Taking (9th ed.). Lippincott, Williams, and Wilkins. p. 390.
- Huang, Ih-Ping; Smith, C Daniel (August 2006). "Cope's Early Diagnosis of the Acute Abdomen, 21st Edition". Annals of Surgery. 244 (2): 322. doi:10.1097/01.sla.0000230276.84612.b4. PMC .
- Silen, William (revised by) (2005). Cope's early diagnosis of the acute abdomen. (21st ed.). Oxford: Oxford University Press. ISBN 0-19-517545-X.