Aaron sign

How to perform the Aaron sign

Apply continuous firm pressure with the ends of the first three fingers over McBurney point. The sign is positive when this produces referred pain or distress away from the site of pressure, particularly in the epigastrium, but also described in the left hypochondrium, umbilical, left inguinal or precordial regions.

The diagnostic accuracy of the Aaron sign has not been established. Sensitivity and specificity are unknown, and no validation study has been identified.

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History of Aaron sign

1898 – American gastroenterologist Charles Dettie Aaron (1866-1951) first observed the phenomenon in a patient presenting with persistent hyperchlorhydria and a history of recurrent attacks of appendicitis. Continuous firm pressure with the ends of the first three fingers over McBurney point produced referred distress or pain in the epigastrium or precordial region. The patient subsequently developed acute appendicitis requiring emergency surgery.

1913 – Aaron published A sign indicative of chronic appendicitis, describing the finding in four clinical cases and inviting other observers to help determine its diagnostic value. He distinguished the referred pain of his sign from local tenderness at McBurney point and described referred pain or distress in the epigastrium, left hypochondrium, umbilical, left inguinal or precordial region.

Chronic concealed appendicitis without active inflammation is difficult to diagnose. Ewald has well named this condition “appendicitis larvata.”

McBurney was the first to call our attention to the pain on pressure in the right inguinal region in acute appendicitis. This tender point may also be found in some eases of chronic appendicitis, though not in all. The referred distress or pain induced by continuous pressure over McBurney’s point seems to me to b a most valuable sign in arriving at the diagnosis chronic appendicitis.

I have been able to induce a referred pain or distress in the epigastrium, left hypochondrium, umbilical, left inguinal or precordial region by a continuous firm pressure over the appendix. I have found this test exceedingly valuable in deciding when and when not to recommend operation for chronic appendicitis

Aaron 1913

1915 – Aaron attempted to explain the phenomenon physiologically. During fluoroscopic examination of a patient with Chronic appendicitis, pressure over the appendiceal region appeared to produce spasm of the distal stomach and proximal duodenum, which relaxed when pressure was released. He proposed that the referred epigastric pain resulted from reflex pylorospasm mediated through visceral nerve connections.

1921 – In the third edition of Diseases of the Digestive Organs, Aaron incorporated the manoeuvre explicitly as “Aaron’s Sign”. He described it as referred pain or distress produced by continuous firm pressure over the appendix. He advocated its use in the diagnosis of chronic appendicitis and attributed the referred pain to reflex spasm of the pylorus or duodenum.

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Associated Persons

• Charles Heber McBurney (1845-1913)
• Charles Dettie Aaron (1866-1951)

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References

Original articles

• Aaron CD. A sign indicative of chronic appendicitis. JAMA. 1913; 60(5): 350-351. [Aaron sign]
• Aaron CD. Chronic appendicitis, pylorospasm and duodenal ulcer: a preliminary note. JAMA 1915;LXIV;(22):1845
• Aaron CD. Appendicitis In: Diseases of the Digestive Organs with special reference to their diagnosis and treatment. 1921

Article reviews

• Rastogi V, Singh D, Tekiner H, Ye F, Mazza J, Yale S. Abdominal Physical Signs and Medical Eponyms: Part II. Physical Examination of Palpation, 1907–1926. Clin Med Res. 2019;17(1-2):47-54.
• Yale SH, Tekiner H, Yale ES. Recurrent and chronic appendicitis: Diagnostic challenges and clinical insights. World J Gastrointest Surg. 2025 Nov 27;17(11):111404.
• Cadogan M. Appendicitis eponymous signs. LITFL