The hand pronation phenomenon: a franco-german tale

The hand pronation phenomenon due to a pyramidal tract lesion is a sign commonly used for identifying a mild paresis, but the first descriptions of this maneuver seem to have been only partially investigated by the historians of neuroscience. Here we illustrate that this sign was most probably originally described by Adolf Strümpell (1853–1925) in 1901 and subsequently re-proposed by the illustrious French neurologist Joseph Babinski (1857–1932) in 1907, although with a slightly different focus of application. Finally, the Pronationsphaenomen was analyzed in detail in the subsequent work of Nikolaus Gierlich (1865–1944), a less-known German neurologist who tried one of the first detailed reports of the phylogenetic significance of this sign, publishing a paper in 1925. These works are reported here, detailing the existing discrepancies, along with notes on the relevant surrounding historical context. In particular, the undervalued contribution of Gierlich to the history of neuroscience and to the phylogenetic approach to semeiotics is analyzed in more detail and acknowledged.