A positive psoas sign is indicated by increased abdominal pain when the patient moves the leg against resistance. It suggests direct or reflex irritation of the psoas muscle, most commonly due to appendicitis, but may also result from retroperitoneal abscesses or other localized abdominal infections.

Pathophysiology

• The psoas muscle lies in close proximity to the retrocecal appendix and retroperitoneal structures.

• Inflammation (e.g., appendicitis, abscess) irritates the psoas muscle directly or via adjacent peritoneum, causing pain during flexion or extension of the hip.

• Positive psoas sign reflects muscle contraction against inflammation, producing abdominal or lower back pain.

• In retroperitoneal abscess, inflammatory edema or pus accumulation compresses or inflames the psoas, eliciting a similar response.

Emergency Interventions

• Suspect appendicitis if positive.

• Assess vital signs promptly.

• Prepare patient for surgery:

  • Explain procedure

  • Restrict food and fluids

  • Withhold analgesics (may mask symptoms)

  • Administer IV fluids for hydration

  • Avoid cathartics/enemas (risk of rupture and peritonitis)

• Assess Rovsing’s sign: pain in RLQ with LLQ palpation indicates peritoneal irritation.

History and Physical Examination

History

• Onset, duration, and pattern of abdominal or lower back pain

• Previous episodes of prolonged pain and relief measures

• Urinary or bowel changes

• Relevant medical history: sickle cell anemia, infections, trauma

• Drug history

Physical Examination

• Abdominal inspection: rigidity, tenderness, rebound

• Palpate for masses in iliac, lumbar, or lower abdominal regions

• Monitor vital signs: fever, tachycardia, hypotension

Examination Tips: Eliciting a Psoas Sign

Supine Position

• Patient flexes leg and moves against resistance.

• Test both legs separately; increased pain is positive.

Lateral Position

• Test left psoas: patient on right side, pushes left leg upward from hip against hand

• Test right psoas: patient on left side, pushes right leg upward against hand

Medical causes

Special Considerations

• Monitor vital signs for complications like peritonitis or fascial plane spread

• Promote patient comfort with positioning (flex hip/leg)

• Prepare for diagnostic tests: electrolyte studies, abdominal X-rays

Pediatric Pointers

Elicit psoas sign by having child raise head while applying pressure on forehead; RLQ pain usually indicates appendicitis.

Geriatric Pointers

• Elderly may have reduced or absent psoas/peritoneal signs

• Differentiate from musculoskeletal or degenerative joint pain

References

1. Berkowitz, C. D. Berkowitz’s Pediatrics: A Primary Care Approach (4th ed.). USA: American Academy of Pediatrics; 2012.

2. Buttaro, T. M., Tybulski, J., Bailey, P. P., Sandberg-Cook, J. Primary Care: A Collaborative Practice (pp. 444–447). St. Louis, MO: Mosby Elsevier; 2008.

3. Colyar, M. R. Well-Child Assessment for Primary Care Providers. Philadelphia, PA: F.A. Davis; 2003.

4. Lehne, R. A. Pharmacology for Nursing Care (7th ed.). St. Louis, MO: Saunders Elsevier; 2010.

5. Sommers, M. S., Brunner, L. S. Pocket Diseases. Philadelphia, PA: F.A. Davis; 2012.