APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -The first sound (the lub) happens when the mitral and tricuspid valves close. The next sound (the dub) happens when the aortic and pulmonary valves close after the blood has been squeezed out of the heart.

Detailed explanation-2: -Normal heart sounds come in pairs. The sounds are often described as a constant “lub-dub, lub-dub.” The first “lub-dub” is the sound of the mitral and tricuspid valves closing. The second “lub-dub” is the sound of the aortic and pulmonary valves closing soon after.

Detailed explanation-3: -The familiar ‘lub-dub’ sound of the heartbeat is caused by the rhythmic closing of the heart valves as blood is pumped in and out of the chambers. A heart murmur is a sound caused by blood flow within the heart.

Detailed explanation-4: -The first heart sound, called S1, makes a “lub” sound caused by the closure of the mitral and tricuspid valves as ventricular systole begins. There is a very slight split between the closure of the mitral and tricuspid valves, but it is not long enough to create multiple sounds.