Stethoscope An invention of a medical device Nahrizul

Stethoscope An invention of a medical device Nahrizul Adib Kadri, Raha Mat Ghazali Biomedical Engineering Programme Faculty of Engineering University of Malaya

Contents Introduction n Monaural stethoscope n Binaural stethoscope n 20 th century n Stethoscope An invention of a medical device

Contents Introduction n Monaural stethoscope n Binaural stethoscope n 20 th century n Stethoscope An invention of a medical device

Introduction n Invented by French physician Rene Theophile Hyacinthe Laënnec in 1819 A portrait of RTH Laennec Stethoscope An invention of a medical device

Contents Introduction n Monaural stethoscope n Binaural stethoscope n 20 th century n Stethoscope An invention of a medical device

Monaural stethoscope n n 1816 Laennec was examining a young female patient He was embarrassed to place his ear to her chest Rolled up 24 sheets of paper, placed one end to his ear and the other end to the woman’s chest Discovered that the sounds were also louder and clearer Stethoscope An invention of a medical device Laennec examining a patient

Monaural stethoscope n n (cont. ) Laennec preferred to have his instrument simply called Le Cylindre, since he thought naming such an instrument was unnecessary Later decided to call stethoscope, derived from the Greek words for I see, and the chest A replica of Laennec’s stethoscope Stethoscope An invention of a medical device

Monaural stethoscope n n n Laennec set up a small shop, with a wood-turning lathe and many different materials He created a stethoscope from a turned piece of wood, hollow in the center, made of two pieces One end had a hole to place against the ear, and the other was hollowed out into a cone Stethoscope An invention of a medical device (cont. ) Laennec stethoscope, circa 1830

Monaural stethoscope n n (cont. ) 1828 Piorry incorporated pleximeter into his stethoscope His model about half the size of Laennec’s - made of wood with removable ivory earpiece and chest piece Combined Laennec-Piorry stethoscope Stethoscope An invention of a medical device

Monaural stethoscope n n (cont. ) 1828 C J B Williams used a two-piece monaural with removable end piece for examining the lungs Much smaller and more convenient instrument William’s stethoscope, circa 1845 Stethoscope An invention of a medical device

Monaural stethoscope n (cont. ) Other examples: Separable stethoscope Flexible stethoscope Stethoscope An invention of a medical device Cedar stethoscope with curved earpiece

Monaural stethoscope n Eventually physicians decided to find out if an instrument using both ears would be better – began quest for binaural stethoscope Stethoscope An invention of a medical device (cont. )

Contents Introduction n Monaural stethoscope n Binaural stethoscope n 20 th century n Stethoscope An invention of a medical device

Binaural stethoscope n n n 1829 Nicholas Comins suggested a binaural stethoscope Described a stethoscope as a bent tube with several hinges Allowing physician not to assume uncomfortable positions during the examination Stethoscope An invention of a medical device n n n 1851 Dr Marsh developed first commercial model Contained the first diaphragm chest piece Bulky and cumbersome

Binaural stethoscope n n (cont. ) 1855 Dr George Cammann produced the first usable binaural stethoscope Model - ivory earpieces connected to metal tubes, two tubes covered with wound silk, hollow ball to amplify the sound, bell-shaped chest piece Dr Cammann’s stethoscope Stethoscope An invention of a medical device

Binaural stethoscope n n n 1863 Scott Alison improved Dr Cammann’s stethoscope differential stethoscope Two independent chest pieces, to allow the listener to compare the sounds of two areas of the chest Impractical because it muffled certain sounds Stethoscope An invention of a medical device (cont. ) Differential stethoscope, circa 1870

Binaural stethoscope n n 1882 Bartlett made another improvement - Bartlett's Laennec stethoscope Used metal ear-tubes with the silk covered rubber tubes leading to a wooden chest piece Stethoscope An invention of a medical device (cont. ) Bartletts’ stethoscope, circa 1880

Binaural stethoscope n n (cont. ) 1885 Charles Denison came out with a new model, based on Bartlett's Came with three interchangeable chest pieces for hearing different types of sounds Denison’s sthetoscope Stethoscope An invention of a medical device

Binaural stethoscope n n 1885 invention of the Ford's Bell chest piece Funneled sound into two tubes, usually made of rubber, which led to the earpieces Stethoscope An invention of a medical device (cont. ) Snofton's stethoscope incorporating a Ford's Bell chest piece, circa 1890

Binaural stethoscope n Other examples: Leared's stethoscope Stethoscope An invention of a medical device (cont. ) Sheppard's folding stethoscope, circa 1890

Contents Introduction n Monaural stethoscope n Binaural stethoscope n 20 th century n Stethoscope An invention of a medical device

20 th century n n (cont. ) The bell chest piece was great for low-pitched sounds, however need to hear higher pitched sounds - enter the diaphragm chest piece The diaphragm became the standard for modern stethoscopes Stethoscope An invention of a medical device Early stethoscope with diaphragm

20 th century n n (cont. ) The stethoscope has remained unchanged since 1930's There were several experimental stethoscopes, including symballophone by Dr William Kerr Dr Kerr’s symballophone Stethoscope An invention of a medical device

20 th century n (cont. ) The newer models have both the bell and diaphragm interchangeable in the same chest piece Dr Kehler’s stethoscope Rieger-Bowles Stethoscope Fleisher stethoscope Stethoscope An invention of a medical device

20 th century n (cont. ) Latest models: Littmann Cardiology III stethoscope Welch Allyn electronic stethoscope Stethoscope An invention of a medical device

The End Thank you for your attention Stethoscope An invention of a medical device