The innocent murmur is best heard in children at:

Innocent murmurs Murmurs not associated with significant hemodynamic abnormalities. Aka functional/ normal or insignificant murmurs >30% of children have innocent murmur at some time in their lives; MC innocent murmur is a medium - pitched, vibratory or "musical," relatively sho systolic ejection murmur, best heard along left lower & mid-sternal border & has no significant radiation to the apex, base, or back. It is heard most frequently in children b/w 3 and 7 yr of age. Intensity of murmur often changes with respiration and position, may be attenuated in the sitting or prone position.