The examiner grasps the muscular part of the patient's forearm.
A water hammer pulse is felt as a tapping impulse that is transmitted through the bulk of the muscles.
This results in the artery emptying back into the heart during diastole, increasing preload, and therefore increasing cardiac output, (as per the Frank–Starling mechanism) so that systolic blood pressure increases and a stronger pulse pressure can be palpated.
[3] Water hammer pulse is commonly found when a patient has aortic regurgitation.
A more comprehensive list of causes follows:[4] "Watson's water hammer pulse" and "Corrigan's pulse" refer to similar observations.