Physicians have used instrumentation from the earliest times to aid in their investigation of diseases, and similar interest in documenting the vital signs remains important in modern diagnosis.
treatise on the pulse by Wang Shu-ho (fourth century)
Ancient Chinese physicians made pulse diagnosis an important part of traditional Chinese medicine. There were twenty-eight different pulse patterns to be determined at eighteen different locations, six on each wrist occupying three different positions. It took between five and ten years of supervision in order to learn this diagnostic tool, and few “masters” were able to reach the highest levels of proficiency.
percussor and pleximeter by Hilliard of Edinburgh (mid nineteenth century)
Leopold Auenbrugger (1722-1809) grew up in Vienna in the middle of the eighteenth century and was the son of an innkeeper who had tapped on barrels to determine the level of the fluid by noting different pitches as the quantity changed. He played the flute and, with his ear for sound, Auenbrugger employed this tapping technique to help evaluate respiratory function in his patients. The percussor tapped on the pleximeter and gave the examiner different sounds to determine if there was underlying fluid. Percussion remains an important part of the modern physical examination.
mural painting of René Laënnec listening to a patient at the Necker Hospital by Theobald Chartran (1849-1907)
The discovery of the stethoscope, Greek for “I look into the chest,” is credited to Rene Laennec (1781-1826), a French physician who invented this instrument after examining a patient in 1816. In order to listen to her chest and at the same time preserve decorum, Laennec rolled up twenty-four sheets of paper and was surprised to find that the sounds were transmitted with more intensity than by simply placing his ear against his patient’s chest.
evolution of the stethoscope after Laennec
(left to right): rare cherry and ivory transition Laennec/Piorry (ca. 1830), ebony and ivory Piorry (ca. 1840), cased ivory monaural stethoscope by Maw (ca. 1860), aluminum stethoscope by Collin (ca. 1900), silk and ebony flexible stethoscope (ca. 1840), Cammann type by Leach and Green (ca. 1860)
(top) flexible stethoscope and (bottom) hearing horn
The stethoscope evolved into a more convenient “flexible” type made of woven silk, and are often confused with conversation tubes, though the former are usually less than eighteen inches in length and had ear pierces that were either straight or flat, but not curved.