Which part of the stethoscope is best for low-pitched sounds such as S3, S4 and mitral stenosis?

Which part of the stethoscope is best for low-pitched sounds such as S3, S4 and mitral stenosis?

• A. Bell
• B. Diaphragm
• C. Both
• D. Otoscope

Answer: (A)

The bell is best for low-pitched sounds. The bell’s cupped, smaller membrane is most sensitive to low-frequency vibrations, especially when used with light pressure against the chest. Low-pitched heart sounds like S3 and S4, and the diastolic rumble of mitral stenosis, have more energy at lower frequencies, so they are more easily heard with the bell. The diaphragm, by contrast, is better for higher-frequency sounds (such as many normal heart sounds and higher-pitched murmurs) and breath sounds. The otoscope isn’t used for auscultation of the heart.

The bell is best for low-pitched sounds. The bell’s cupped, smaller membrane is most sensitive to low-frequency vibrations, especially when used with light pressure against the chest. Low-pitched heart sounds like S3 and S4, and the diastolic rumble of mitral stenosis, have more energy at lower frequencies, so they are more easily heard with the bell. The diaphragm, by contrast, is better for higher-frequency sounds (such as many normal heart sounds and higher-pitched murmurs) and breath sounds. The otoscope isn’t used for auscultation of the heart.