The stethoscope is a familiar medical instrument used by healthcare professionals for auscultation—listening to the internal sounds of the body. This device amplifies and clarifies sounds from the lungs, intestines, blood vessels, and especially the heart. A person can hear their own heartbeat using a stethoscope, but successfully isolating the distinct sounds requires specific technique and knowledge of the underlying anatomy.
Yes, But Proper Placement is Key
Hearing your own heart sounds is entirely possible, but simply pressing the chest piece anywhere on the chest will likely result in a muffled thumping sensation. To hear the clear, rhythmic sounds, the stethoscope must be placed over specific anatomical landmarks. These points are where the sounds generated by the heart valves are best transmitted to the surface of the chest wall.
The four primary areas for listening to the heart are named after the valves whose sounds are most audible there:
- The aortic valve sound is best heard in the second intercostal space just to the right of the sternum.
- The pulmonic valve sound is found in the same second intercostal space, but on the left side of the sternum.
- The tricuspid valve sound is best isolated in the fourth and fifth intercostal spaces near the left sternal border.
- The mitral valve sound, which corresponds to the heart’s apex beat, is heard most clearly in the fifth intercostal space at the mid-clavicular line.
Applying the stethoscope’s diaphragm—the flat, plastic side—firmly against the bare skin in these locations is necessary to pick up the distinct vibrations and transform them into audible sound.
The Mechanics of Heart Sounds
The sounds heard through a stethoscope are acoustic vibrations created by the snapping shut of the heart’s four valves, not the mechanical movement of the heart muscle. These sounds are traditionally described as a “lub-dub.” The first sound, “lub,” is known as S1, and it marks the beginning of ventricular contraction (systole). This lower-pitched sound is created by the near-simultaneous closure of the mitral and tricuspid valves.
The second sound, “dub,” is known as S2, and it is shorter and higher-pitched than S1. S2 immediately follows S1 and signals the beginning of ventricular relaxation (diastole). This sound is produced by the closure of the aortic and pulmonic valves. S2 can sometimes be heard as two distinct, closely spaced components, especially during inhalation, because the aortic valve typically closes slightly before the pulmonic valve.
The timing of S1 and S2 determines the duration of the heart’s two main phases. The time between S1 and S2 is the systolic period, when the ventricles contract to eject blood. The longer period between S2 and the next S1 is the diastolic period, during which the ventricles relax and fill with blood. These two fundamental sounds provide a rhythmic baseline that healthcare providers use to assess cardiac health, listening for variations like extra sounds or murmurs.
Why Self-Auscultation is Often Difficult
Successfully listening to your own heart presents several physical challenges. Self-auscultation often requires an awkward twisting or leaning motion to place the chest piece correctly, which can change the heart’s position and muffle sound transmission. Maintaining firm, consistent pressure on the chest wall while holding the ear pieces in place is physically demanding and prone to error.
External noise interference is a significant obstacle to hearing delicate heart sounds. Friction created by the stethoscope tubing rubbing against clothing or movement of hair on the chest can easily obscure the true sounds. Furthermore, the noise from one’s own breathing is difficult to isolate, and breath sounds can drown out the heart tones. The ear pieces must also be correctly angled forward in the ear canals to ensure the sound travels efficiently from the chest piece to the eardrum.