Aaron’s sign is defined as pain in the chest or epigastric area induced by gentle but progressively increasing pressure over McBurney’s point. A positive response is considered indicative of acute appendiceal inflammation.

Pathophysiology

The appendix, when inflamed, triggers localized irritation of the parietal peritoneum and visceral afferent fibers. The referred pain to the epigastrium or precordial region occurs due to the convergence of visceral afferent nerves with somatic fibers in the spinal cord, particularly at T8–T10 dermatomes. This mechanism explains the early, diffuse periumbilical pain seen in appendicitis and the elicited referred discomfort of Aaron’s sign.

Examination technique

1. Patient positioning: Supine, relaxed.

2. Locate McBurney’s point: One-third of the distance from the anterior superior iliac spine to the umbilicus on the right lower abdomen.

3. Palpation: Apply gentle, steadily increasing pressure at McBurney’s point.

4. Assessment: Ask the patient whether pain is felt in the epigastric or precordial region.

5. Interpretation: Pain radiating to the chest or epigastrium constitutes a positive Aaron’s sign.

Clinical utility

• Supportive, not definitive: Aaron’s sign should be interpreted alongside other appendicitis findings.

• Adjunct in ambiguous cases: Useful when classical RLQ pain is absent or atypical, particularly in children, elderly, or pregnant patients.

• Correlation with other signs: Commonly assessed with McBurney’s tenderness, Rovsing’s, Psoas, and Obturator signs.

Differential diagnosis

Pediatric considerations

• Children may describe diffuse abdominal or chest discomfort rather than localized pain.

• Gentle palpation is required to reduce distress and avoid false positives.

Geriatric considerations

• Older adults often present atypically, with less localized tenderness or vague abdominal symptoms.

• Aaron’s sign may be less sensitive, and imaging is often necessary to confirm appendicitis.

Limitations

• Not pathognomonic; a positive sign does not confirm appendicitis on its own.

• False negatives may occur in retrocecal appendicitis or in patients with obesity or thick abdominal walls.

• Sensitivity and specificity are lower compared to imaging modalities like ultrasound or CT scan.

Patient counseling

• Explain the purpose of palpation and the need to localize pain.

• Reassure the patient that referred pain is normal and expected during the assessment.

• Discuss potential further evaluation, including laboratory tests and imaging, if appendicitis is suspected.

Conclusion

Aaron’s sign remains a classic physical examination tool in the assessment of acute appendicitis. While it is not definitive, it provides valuable clinical information when interpreted alongside other signs and patient history. Awareness of its proper technique, indications, and limitations enhances diagnostic accuracy and supports timely surgical intervention.

References

1. McBurney C. The diagnosis of acute appendicitis. Ann Surg. 1898;27:38–46.

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

3. Colyar MR. Well-Child Assessment for Primary Care Providers. Philadelphia (PA): F.A. Davis; 2003.

4. Tintinalli JE, Stapczynski JS, Ma OJ, Yealy DM, Meckler GD, Cline DM. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide. 9th ed. New York (NY): McGraw-Hill; 2020.

5. Cameron JL. Current Surgical Therapy. 13th ed. Philadelphia (PA): Elsevier; 2021. p. 135–140.