This sign occurs as a result of blood from the aorta regurgitating into the left ventricle due to a defect in the aortic valve.[2][3] The nodding is an indication that the systolic pulse is being felt by the individual because of the increased pulse pressure resulting from the aortic insufficiency.
^ abYale, Steven H.; Tekiner, Halil; Mazza, Joseph J.; Yale, Eileen S.; Yale, Ryan C. (2021). "5. Aortic regurgitation murmurs". Cardiovascular Eponymic Signs: Diagnostic Skills Applied During the Physical Examination. Switzerland: Springer. pp. 122–123. ISBN978-3-030-67596-7.
^Gallo, Vittorio (2011). Unusual Signs and Symptoms in Internal Medicine (1st ed.). Torino: SEEd Srl. p. 44. ISBN9788897419044.
^Thomas, James; Monaghan, Tanya, eds. (2014). Oxford handbook of clinical examination and practical skills (Second ed.). [S.l.]: Oxford University Press. p. 131. ISBN9780199593972.