In medicine, a person's pulse is the arterial palpation of a heartbeat. It can be palpated in any place that allows for an artery to be compressed against a bone, such as at the neck (carotid artery), at the wrist (radial artery), behind the knee (popliteal artery), on the inside of the elbow (brachial artery), and near the ankle joint (posterior tibial artery). The pulse rate can also be measured by measuring the heart beats directly (the apical pulse).
Pressure waves move along the artery walls, which are pliable; these waves are not caused by the forward movement of the blood itself, however. When the heart contracts, blood is ejected into the aorta and the aorta stretches. At this point, the wave of distention (pulse wave) is pronounced but relatively slow-moving (3–6 m/s).
As it travels towards the peripheral blood vessels, it gradually diminishes and becomes faster. In the large arterial branches, its velocity is 7–10 m/s; in the small arteries, it is 15–35 m/s. The pressure pulse is transmitted fifteen or more times more rapidly than the blood flow.
PULSE is also used to denote the frequency of the heart beat, usually measured in beats per minute. In most people, the pulse is an accurate measure of heart rate. Under certain circumstances, including arrhythmias, some of the heart beats are ineffective, and the aorta is not stretched enough to create a palpable pressure wave.
The pulse is too irregular and the heart rate can be (much) higher than the pulse rate. In this case, the heart rate should be determined by auscultation of the heart apex, in which case it is not the pulse. The pulse deficit (difference between heart beats and pulsations at the periphery) should be determined by simultaneous palpation at the radial artery and auscultation at the heart apex.