Auscultation

Auscultation is a clinical examination technique in which a healthcare provider listens to internal body sounds to assess the function of the heart, lungs, abdomen, and blood vessels. The practice relies on the acoustic amplification provided by a stethoscope, and it is a fundamental component of the physical examination. The stethoscope was invented by René Laennec in 1816, which facilitated indirect auscultation and became standard in medical practice.

Equipment and technique: Indirect auscultation uses a stethoscope, typically with a diaphragm for high-frequency sounds and a bell for lower-frequency sounds. The clinician places the chest piece on the skin and listens through the ear pieces, often in a quiet room. Direct auscultation—placing the ear directly on the body—is rarely used today.

Cardiac auscultation focuses on listening at the aortic, pulmonic, tricuspid, and mitral areas, in different patient positions, to assess heart sounds. Normal sounds include S1 and S2; abnormalities may include S3 or S4, murmurs, rubs, or clicks.

Pulmonary auscultation evaluates breath sounds. Normal sounds are vesicular over most of the lungs; bronchial and decreased or absent sounds can indicate disease. Adventitious sounds such as crackles, wheezes, rhonchi, and pleural friction rubs provide clues about underlying pathology and are often described in terms of timing and location.

Abdominal auscultation assesses bowel sounds and vascular sounds. Bowel sounds may be normoactive, hypoactive, or hyperactive. Vascular auscultation, including carotid or abdominal bruits, can suggest turbulent flow from stenosis or aneurysm.

Limitations include observer variability and reliance on patient factors such as body habitus and cooperation. Auscultation is most informative when integrated with history, examination, and confirmatory tests such as imaging and laboratory studies.