It was not until the early 1800’s that the stethoscope was “discovered” by Rene Laennec (1781 to 1826) who used a rolled cylinder of paper to listen to a patient’s chest. Robert Hooke (1635 to 1703)Įarly auscultation was performed by placing one’s ear directly on the patient’s body.

I have been able to hear very plainly the beating of a man’s heart… who knows, I say, but that it may be possible to discover the motions of the internal parts of bodies… by the sound they make. With each movement of the heart, when there is the delivery of a quantity of blood from the veins to the arteries, a pulse takes place and can be heard within the chest. You shall know by this that the chest contains water and not pus, if in applying the ear during a certain time on the side, you perceive a noise like that of boiling vinegar. There are several historical references to auscultation in medical literature. The intensity and character of breath sounds help determine the location and pathology of thoracic disease.Īuscultation, or listening to the sounds within the body, is a fundamental examination procedure in clinical medicine. Abnormal, or adventitious, sounds are classified as crackles, wheezes, stertor, and stridor. Normal breath sounds are classified as bronchial, bronchovesicular, and vesicular.

The character of the sound that is heard at the surface is determined by the factors influencing the production of the sound, and acoustical characteristics of the intervening tissues. Breath sounds originate in the large airways due to turbulence in airflow. Differences in the acoustical density of tissues result in attenuation, reflection, and refraction of these sound waves. Auscultable sounds originate as mechanical vibrations within compressible media that are then transmitted through the tissues as sound waves. Differences in the intensity and character of sounds can be useful in distinguishing underlying thoracic pathology. Many clues as to both respiratory and cardiac function and disease can be obtained through proper auscultation. Thoracic auscultation and percussion are two of the most useful and economical procedures of a physical examination.

Books & VINcyclopedia of Diseases (Formerly Associate).

VINcyclopedia of Diseases (Formerly Associate).

Normal and abnormal lung sounds