Palpatory - depends on the ability of an observer to detect the appearance of a weak pulse over an artery

which has been released from occlusion closer to the trunk; gives systolic pressure only.

Auscultatory - depends on the appearance and disappearance of Korotkow (Korotkoff) sounds, resulting from turbulence of blood flow

(not sounds of the heart). This is the current clinical method of measuring B.P.