A Tale of Two Doctrines: Why Is the Monro-Kellie Hypothesis Still Called a Doctrine?
Luisa Figueredo1, Cesar Jara Silva Acosta1, Carlos Oliu2
1Larkin Community Hospital, 2Design Neuroscience Center
Objective:

To explore the historical and linguistic origins of the term “doctrine” in the Monro-Kellie Doctrine (MKD), assess why this terminology persists, and evaluate whether its endurance is linked to the contemporaneous and homophonic Monroe Doctrine in politics.


Background:
The Monro-Kellie Doctrine, proposed by Alexander Monro (1783) and expanded by George Kellie (1821–1824), describes the fixed intracranial volume shared by brain tissue, blood, and cerebrospinal fluid. Although now considered a dynamic physiological model, it remains termed a “doctrine.” The contemporaneous Monroe Doctrine (1823) may have reinforced its enduring use through linguistic and historical association.
Design/Methods:

A literature review of historical medical and political texts was conducted via PubMed, JSTOR, and Internet Archive to trace terminology trends related to the Monro-Kellie concept and comparable doctrines in neuroscience and politics.



Results:

Monro introduced the concept in 1783, which was later expanded in 1821 by Kellie’s dissections and further developed by Abercrombie in 1828. Abercrombie's work integrated cerebrospinal fluid dynamics, thereby strengthening the original Monro-Kellie hypothesis as a “doctrine”. In America, Harvey Cushing’s 1926 writings popularized the term “doctrine,” solidifying the MKD as a foundational element in neural science education. Even though subsequent revisions (MKD 2.0–4.0) have expanded the model. Yet, the title ‘doctrine” persists. The contemporaneous, and homophonic, Monroe Doctrine (1823) likely reinforced the word’s prestige and durability. In contrast to other physiological “doctrines,” such as Ramon y Cajal’s Neuron Doctrine, which have shifted mainly to historical context.



Conclusions:

The persistence of the term “doctrine” for the MKD illustrates how language, culture, and history shape scientific identity. Despite evolving understanding, the authoritative tone and historical resonance of “doctrine” continue to influence terminology in neurophysiology, education, and medical discourse.

10.1212/WNL.0000000000212862
Disclaimer: Abstracts were not reviewed by Neurology® and do not reflect the views of Neurology® editors or staff.