Not Starling's first name: acknowledging Otto Frank's legacy in physiology education

The Frank-Starling law is a cornerstone of cardiovascular physiology, yet its name often leads to amusing misconceptions. Many students assume "Frank" refers to Starling's first name, overlooking the physiologist whose quantitative approach transformed the study of the heart. This article revisits Otto Frank's work within its historical and educational context. In his 1895 habilitation thesis, "Zur Dynamik des Herzmuskels," Frank introduced mathematical analysis of ventricular pressure-volume relationships, establishing a framework that underlies modern pressure-volume loop interpretation. In 1899, in "Die Grundform des arteriellen Pulses," he formalized the Windkessel model, representing the arterial system in terms of resistance and compliance and explaining how pulsatile ventricular ejection is converted into more continuous arterial flow. Beyond these theoretical contributions, Frank developed precision instruments, extended his work from frog heart preparations to mammalian physiology, and applied mechanical principles to cardiac function. His frameworks remain central to cardiovascular physiology and continue to support mechanism-based teaching through pressure-volume analysis and Windkessel modeling. Revisiting Frank's contributions highlights the enduring role of quantitative models in understanding and teaching physiological systems.NEW & NOTEWORTHY Otto Frank's contributions to cardiac mechanics are often overshadowed by Starling's work. We revisit Frank's 1895 pressure-volume analysis and 1899 Windkessel model, which established a quantitative framework for understanding ventricular function and arterial dynamics. His integration of mathematical modeling, experimental measurement, and physiological reasoning helped transform cardiovascular physiology from descriptive observation to predictive analysis. These frameworks remain central to contemporary physiology and continue to support mechanism-based teaching and interpretation of cardiovascular function.