History of Auscultation
Assessing the sounds of the human body was reported in the ancient medical literature. Amongst the earliest known medical manuscripts are the medical papyruses of ancient Egypt dating to the seventeenth century B.C., which referred to audible signs of disease within the body. Hippocrates, the Father of Medicine, advocated for the search of philosophical and practical instruments to improve medicine in 350 B.C.
He discussed a procedure for shaking a patient by the shoulders (succussion) and listening for sounds evoked by the chest. Hippocrates also used the method of applying the ear directly to the chest and found it useful to detect the accumulation of fluid within the chest. In the sixteenth century, the renown surgeon Ambroise Pare noted that "if there is matter or other humors in the thorax, one can hear a noise like that of a half-filled gurgling bottle."
The distinguished scientist William Harvey, in his 1616 lecture on the structure and function of the heart, described the heart's motion as "two clacks of a water-bellows to rayse water" and noted that "with each movement of the heart, when there is delivery of a quantity of blood from the veins or arteries, a pulse takes place and can be heard within the chest." The French physician Jean-Nicolas Corvisart, who is considered the founder of French clinical medicine, was accustomed to placing his ear over the cardiac region of the chest to listen to the heart.
Bayle and Double, who like Laennec were students of Corvisart, used the unaided ear to listen to the heart of their patients. Double suggested the regular use of this technique in his treatise on Semiologie published in early 1817, prior to the publication of Laennec's treatise on auscultation. He wrote "the ear should be brought against the thoracic wall" to appreciate the noises inside. Nevertheless, the evolution from listening with the unaided ear (immediate auscultation) to the aided ear (mediate auscultation) awaited Laennec's invention of the stethoscope.
Below is an engraving of a physician examining a patient by "immediate" auscultation, in which the doctor placed his ear on the chest of the patient to hear the sounds made by the lungs during breathing. The print shows a group of physicians, medical students and nurses observing the physician performing his exam. The print is entitled "A Visit to the Hospital" by the artist Luis Jimenez Aranda. It was copyrighted in 1894 and originally displayed at the Chicago World's Fair in 1893.
Invention of the Stethoscope
The stethoscope was conceived in 1816 when a young French physician named Rene Theophile Hyacinthe Laennec was examining a young female patient. Laennec was embarrassed to place his ear to her chest (Immediate Auscultation), which was the method of auscultation used by physicians at that time. He remembered a trick he learned as a child that sound travels through solids and thus he rolled up 24 sheets of paper, placed one end to his ear and the other end to the woman's chest. He was delighted to discover that the sounds were not only conveyed through the paper cone, but they were also loud and clear. The onset of Laennec's stethoscope research began in 1817 at the Necker hospital.
The first published observation documenting auscultation using the stethoscope (Mediate Auscultation) was in March 8, 1817, when Laennec noted examining a 40 year old chambermaid, Marie-Melanie Basset. Laennec's research activities about mediate auscultation were first brought to public attention with his consultation in June of 1817 for Mme de Stael, who was the daughter of the Neckers and an author who criticized the rise of Napoleon's empire. Her personal physician described Laennec's consultation: "Another well-known doctor [Laennec], using a horn of paper, which he placed with one end on a part of the thorax and the other in his ear, believed he diagnosed a hydrothorax, an could even hear a sort of undulation. One can well understand that I considered this method of investigating the interior of the chest to be very strange, and I did not share his opinion, in spite of the regard I might have for him."
Laennec began his study of medicine under his uncle who was a professor of the faculty of medicine in Nantes. Eventually he entered the Paris University where he studied medicine under Jean-Nicolas Corvisat, who was a proponent of immediate auscultation and percussion. He was a devout Catholic and his charity to the poor was proverbial, taking him to the Hospital Necker after his studies to care for the sick and poor. It was at the Hopital Necker that Laennec invented the stethoscope. His clinical work allowed him to correlate auscultation and post-mortem findings thus defining diagnoses of diseases of the chest.
On February 23, 1818, Dr. Laennec presented his findings in his Memoire sur L’Auscultation to the Academy of Medicine in Paris, later publishing his comprehensive treatise De L'Auscuatation Mediate of his work in 1819. In 1823, Laennec was appointed professor of clinical medicine at Paris University resigning from Necker hospital to preside over his former mentor Corvisat's Clinique Interne at the hospital Charite. A few years later just prior to his death he bequeathed his own stethoscope to his nephew, Dr. Meriadac Laennec, referring to it as the "greatest legacy of my life."
It is said that Meriadac diagnosed Laennec as having tuberculosis using his stethoscope. In his lecture on Laennec in 1883, the preeminent American authority on auscultation, Dr. Austin Flint said, "Laennec's life affords a striking incidence among others disproving the vulgar error that the pursuit of science is unfavorable to religious faith."
Rene Laennec
The faience buste shown in the middle photo was created by Georges Robin, HB-Henriot Quimper, in 1926 for the centennial of the death of Docteur Laennec. This reissue white enamel monochrome from the original mold has a height of 12.6 inches and is number 15 of a limited series of 100 pieces. The buste was based on the oil portrait on the left of Rene Theophile Hyacinthe Laennec by Paul Dubois, circa 1854.
This posthumous portrait was commissioned by the Medical Faculty of the Universite Paris Descartes and painted from the only full-length portrait of Dr. Laennec shown in the photographic print on the right by Alexandre Dubois, a struggling artist who painted Laennec as payment for his medical services in 1812. The original portrait did not display Laennec's stethoscope, and the family had the artist add the stethoscope to his portrait in 1825 after the invention of the instrument by Dr. Laennec in 1816.
Note Laennec's stethoscope shown in the lower left-hand corner of both portraits. The 1854 Paul Dubois painting changed Laennec's garb from the 1812 Alexandre Dubois original portrait, perhaps because the Faculty of Medicine wanted to show Laennec in their traditional faculty robe. In the 1854 portrait, Laennec is now wearing an academic robe with a matching hat on the table instead of a lamp, as well as two matching books on the table instead of the large book displayed in the original version. Laennec's treatise on auscultation was published in two volumes.
(Photo on the left courtesy of Museum of the History of Medicine, Paris University Descartes and on the right from the Wellcome Museum, London)
Evolution of the Stethoscope: Laennec to Littmann
The first advance in the Laennec stethoscope came in 1828, when Pierre Adolphe Piorry incorporated a pleximeter for mediate percussion into his stethoscope. Piorry was also interested in the stethoscope, and is usually credited with reducing its stem to the size of a finger. His book illustrated a beautiful instrument, which divided into two parts, and included a pleximeter and an ivory-headed chest-piece. After Piorry suggested his slenderer type of stethoscope, the stethoscopes gradually became shorter, and more slender.
In 1841, William Stroud published the design of a flexible, monaural stethoscope. It had an aural and pectoral end, connected by a tube which was made of a tigthly coiled wire covered by cloth. He cited Golding Bird's use of a flexible monaural stethoscope that he gave to him.
The idea for a binaural stethoscope was first introduced in 1829, just ten years after the publication of Laennec's text illustrated his original instrument. Nicholas Comins devised a stethoscope that he described as "a bent tube" that had several hinges, allowing the physician to not have to assume uncomfortable positions during the examination. He offered the suggestion of making his instrument binaural, but there are only sketches of his instrument. James Blasius Williams, one of Laennec's most brilliant pupils, also attempted to make a binaural instrument in 1829. It had a trumpet-shaped chest-piece of mahogany, the end of which screwed into a connection to which were added two bent lead pipes. Arthur Leared showed what he claimed was an improved form of Williams's stethoscope at the Great Exhibition in 1851, and this had two tubes of gutta-percha attached to the chestpieces at one end, and to the ear-pieces (which were just flat discs) at the other. Unfortunately, this instrument needed three hands to use it! In the same year N. B. Marsh, of Cincinatti, patented a form of binaural stethoscope which employed rubber tubes and rather inconvenient earpieces. However, it still required the use of both hands.
Dr. George Philip Camman of New York designed the first usable form of the binaural stethoscope. He developed this in 1851 and published an account of it in 1855. His instrument had woven tubing, a wooden chest-piece, ivory ear-pieces, plus a broad rubber band to hold the latter in place. This was an improvement, in the sense that it was self-adjusting and could be carried in the pocket. However, the old monaural instruments continued to be used in many forms long after Cammann described his binaural stethoscope.
Austin Flint was one of the first to use and advocate for the binaural stethoscope in the America, but in Europe most people still preferred one of the many variations of Laennec's original instrument.
In 1859, Somerville Scott Alison introduced his 'differential stethoscope' in Scotland, which allowed one to listen with each ear to the sounds through separate earpieces. Differential stethoscopes had quite a vogue, especially the Kerr Symballophone.
In 1894, R.M. Bowles, an engineer of Brookline, Mass., patented the modern form of diaphragmatic chest-piece. This was the first model to have a metal or celluloid diaphragm. It was sometimes described as a
'phonendoscope', or 'resonating stethoscope'.
The 'Sprague-Bowles' instrument, with a chest piece combining a bell and diaphragm, was described by Howard Sprague in 1926. Rappaport and Sprague of Boston published their paper on the physical laws which govern auscultation in 1941. They designed a stethoscope with a combined bell and diaphragm, short tubing with low internal volume and well fitting earpieces.
In 1961, Dr David Littman published his paper 'An approach to the ideal stethoscope.' Since then, his simple model, making use of Tygon tubing- the Y section being completely molded with a single length leading to a dual-headed chest-piece, is now the most widely used of modern type of stethoscopes. It included a closed chest piece with a stiff plastic diaphragm to filter-out low-pitched sounds. It also had an open chest piece bell to hear low frequency sounds.
Laennec's stethoscope, an instrument of the utmost simplicity, has had and continues to have, a profound effect on medicine. Sir James Kingston Fowler, a British physician and an expert in diseases of the lungs, once wrote: 'Those who advise that all stethoscopes should be "scrapped" may be influenced by the fact that they do not know how to use their own. A stethoscope is easier to carry than a cardiograph or X-ray installation.'