S3 and S4 heart sounds are best heard with which part of a stethoscope?

S3 and S4 heart sounds, also known as gallops, are best detected using the bell of the stethoscope. The bell is designed to pick up low-frequency sounds, which is crucial for distinguishing these specific heart sounds. S3 indicates a rapid ventricular filling during the early part of diastole, while S4 occurs just before S1 due to atrial contraction.

Using the bell allows for better sensitivity to the subtle vibrations associated with these sounds, enhancing the clinician's ability to monitor heart function and assess conditions such as heart failure or increased pressure in the heart. The diaphragm, on the other hand, is more suited for hearing high-frequency sounds such as normal heart sounds (S1 and S2) and certain respiratory sounds. The other options, such as the flat surface or acoustic tube, do not specifically pertain to the functionalities required for auscultating S3 and S4 effectively.