What instrument do doctors use to listen to the heart and lungs?

Doctors use a stethoscope to listen to the heart and lungs.

This examination technique is called auscultation. A stethoscope transmits internal body sounds through a chest piece, flexible tubing, and earpieces. By listening to heart sounds, physicians may assess rhythm and detect clues such as murmurs; lung sounds can reveal patterns associated with conditions including wheezing, crackles, or reduced airflow. The instrument can also help evaluate blood flow and intestinal sounds.

French physician René Laennec invented the first stethoscope in 1816. His original design was a wooden tube, developed partly because placing an ear directly on a patient’s chest was impractical and considered inappropriate. Later designs became binaural, using two earpieces; Arthur Leared introduced an early binaural version in 1851.

A stethoscope does not provide a complete diagnosis on its own. Sounds must be interpreted alongside symptoms, examination findings, and sometimes tests such as an electrocardiogram, chest imaging, or echocardiogram. An otoscope examines the ear, an ophthalmoscope examines the eye, and a thermometer measures temperature.