S1 is the first heart sound that doctors can hear using a stethoscope. The vibrations that occur when the mitral and tricuspid valves in the heart close produce the S1 sound. There are two common ...
A third heart sound, or S3, is a low-frequency, extra heart sound that may be heard with a stethoscope right after the normal S1 and S2 heart sounds. S1 and S2 are the "lub-dub" sounds of a heartbeat ...
IT IS possible that the existence of the heart sounds was known to Hippocrates 1 and even that he made use of his knowledge for diagnostic purposes, but William Harvey 2 seems to have been the first ...