How Korotkoff, the surgeon, discovered the auscultatory method of measuring arterial pressure

The Korotkoff sounds that measure systolic and diastolic arterial pressure levels were described in a brief communication by N.C. Korotkoff in 1905. He did not state how it happened that he discovered this auscultatory method of measuring "blood" pressure. The search for information on this matter led to studying the thesis for his doctorate published in 1910 on Experiments for Determining the Efficiency of Arterial Collaterals. It seems that when he wanted to be sure that pressureonan artery (digital, or with an Esmarch ligature or a Riva-Rocci cuff) had completely obliterated its lumen, he listened over the artery below the area of pressure. The absence of any sounds meant complete obliteration; a sound appeared with each beat when some flow did occur during partial obliteration of the lumen and when no pulsation could be detected because of the small volume of flow.