Blood pumped into an already-full aorta during ventricular contraction creates a fluid wave that travels from the heart to the peripheral arteries. This recurring wave—called a pulse—can be palpated at locations on the body where an artery crosses over bone on firm tissue. In adults and children older than age 3 and in adults with a suspected cardiac disorder that affects the patient’s heart rate and rhythm, the radial artery in the wrist is the most common palpation site. (See Pulse points.) In infants and children
younger than age 3, a stethoscope is used to listen to the heart itself rather than palpating a pulse. Because auscultation is done at the heart’s apex, this is called the apical pulse.

An apical-radial pulse is taken by simultaneously counting apical and radial beats—the first by auscultation at the apex of the heart, the second by palpation at the radial artery. Some heartbeats detected at the apex can’t be detected at peripheral sites. When this occurs, the apical pulse rate is higher than the radial; the difference is the pulse deficit.

Pulse taking involves determining the rate (number of beats per minute), rhythm (pattern or regularity of the beats), and volume (amount of blood pumped with each beat). If the pulse is faint or weak, use a Doppler ultrasound blood flow detector if available.