What is the significance of a positive psoas (musculus psoas) sign?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 20, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Guidelines

The psoas sign is a valuable clinical indicator of appendicitis, particularly when the appendix is in a retrocecal position, and its presence, combined with other clinical findings such as fever and migratory pain to the right lower quadrant, suggests an increased likelihood of appendicitis. The psoas sign is tested by having the patient lie on their left side while the examiner extends the patient's right hip, or by having the patient lie supine and actively flex the right hip against resistance, with pain upon either maneuver indicating a positive sign 1. This sign is useful in the diagnostic work-up for intra-abdominal infections (IAIs), as it can help limit the differential diagnosis and guide decisions regarding further diagnostic testing and management, including the potential need for antimicrobial therapy or emergent intervention 1. Some key points to consider when evaluating the psoas sign include:

  • The sign is not always present in cases of appendicitis, and its absence does not rule out the diagnosis 1
  • The psoas sign should be interpreted alongside other clinical findings, such as right lower quadrant tenderness, fever, and elevated white blood cell count 1
  • Imaging studies, such as ultrasound (US) or computed tomography (CT), may be used to further evaluate patients with suspected IAIs, particularly when the diagnosis is unclear or when complications are suspected 1. The psoas sign is an important part of the physical examination in patients with suspected appendicitis, and its presence can help support the diagnosis and guide further management, as outlined in the 2016 consensus conference recommendations for the management of IAIs 1.

From the Research

Psoas Sign

  • The psoas sign is a clinical indicator used in the diagnosis of acute appendicitis 2.
  • It is one of the reliable signs for ruling in acute appendicitis in children, along with the obturator sign and Rovsing sign 2.
  • The psoas sign is not specifically mentioned as a reliable indicator for adults in the provided studies.
  • Acute appendicitis diagnosis is typically based on a combination of clinical findings, laboratory results, and imaging studies 2, 3.
  • Treatment options for acute appendicitis include appendectomy via open laparotomy or laparoscopy, as well as intravenous antibiotics in selected patients 2, 3, 4.

Related Conditions and Treatments

  • Gangrenous or perforated appendicitis requires antimicrobial management, with options including cefoxitin or a combination of clindamycin and gentamicin 5.
  • The use of antibiotics as first-line therapy for acute appendicitis has been explored in several studies, with evidence suggesting it can be an effective treatment option for uncomplicated cases 3, 4.

Unrelated Studies

  • A study on the effects of alcohol on glial cell differentiation is not relevant to the topic of psoas sign or acute appendicitis 6.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.