What is the timing, and more important, what is the significance of the movement at the lower left sternal edge? Let's take a look at the tips of the cotton swabs and remember that that at the upper left sternal edge is moving during systole and hence, we can determine very readily that that at the lower left sternal edge is also moving during systole and, in addition, there is an early diastolic movement. [Cut-away]

And, what does that mean? Again, simple anatomy related to the chest wall. The right ventricle lies below the mid-to-lower left sternal edge and during systole it is heaving up and moving the chest wall. It tells us hypertrophy and/or dilatation of the right ventricle and in addition, you've an early diastolic movement, and that's the palpable equivalent of a third heart sound. It tells us something about flow into the ventricle and/or the contractility of the right ventricle. So, we have two movements at the lower left sternal edge, a sustained systolic and an early diastolic movement.