Acoustic Parts of a binaural<unk>  Acoustic<unk> , with the bell upwards Acoustic<unk> s operate on the transmission of sound from the chest piece, via air-filled hollow tubes, to the listener's ears. The chestpiece usually consists of two sides that can be placed against the patient for sensing sound: a diaphragm (plastic disc) or bell (hollow cup). If the diaphragm is placed on the patient, body sounds vibrate the diaphragm, creating acoustic pressure waves which travel up the tubing to the listener's ears. If the bell is placed on the patient, the vibrations of the skin directly produce acoustic pressure waves traveling up to the listener's ears. The bell transmits low frequency sounds, while the diaphragm transmits higher frequency sounds. To deliver the acoustic energy primarily to either the bell or diaphragm, the tube connecting into the chamber between bell and diaphragm is open on only one side and can rotate. The opening is visible when connected into the bell. Rotating the tube 180 degrees in the head connects it to the diaphragm. This two-sided<unk>  was invented by Rappaport and Sprague in the early part of the 20th century. One problem with acoustic<unk> s was that the sound level was extremely low. This problem was surmounted in 1999 with the invention of the stratified continuous (inner) lumen, and the kinetic acoustic mechanism in 2002. Electronic An electronic<unk>  (or stethophone) overcomes the low sound levels by electronically amplifying body sounds. However, amplification of<unk>  contact artifacts, and component cutoffs (frequency response thresholds of electronic<unk>  microphones, pre-amps, amps, and speakers) limit electronically amplified<unk> s' overall utility by amplifying mid-range sounds, while simultaneously attenuating high- and low- frequency range sounds. Currently, a number of companies offer electronic<unk> s. Electronic<unk> s require conversion of acoustic sound waves to electrical signals which can then be amplified and processed for optimal listening. Unlike acoustic<unk> s, which are all based on the same physics, transducers in electronic<unk> s vary widely. The simplest and least effective method of sound detection is achieved by placing a microphone in the chestpiece. This method suffers from ambient noise interference and has fallen out of favor. Another method, used in Welch-Allyn's Meditron<unk> , comprises placement of a piezoelectric crystal at the head of a metal shaft, the bottom of the shaft making contact with a diaphragm. 3M also uses a piezo-electric crystal placed within foam behind a thick rubber-like diaphragm. The Thinklabs' Rhythm 32 uses an electromagnetic diaphragm with a conductive inner surface to form a capacitive sensor. This diaphragm responds to sound waves, with changes in an electric field replacing changes in air pressure. The Eko Core enables wireless transmission of heart sounds to a smartphone or tablet. Because the sounds are transmitted electronically, an electronic<unk>  can be a wireless device, can be a recording device, and can provide noise reduction, signal enhancement, and both visual and audio output. Around 2001, Stethographics introduced PC-based software which enabled a phonocardiograph, graphic representation of cardiologic and pulmonologic sounds to be generated, and interpreted according to related algorithms. All of these features are helpful for purposes of telemedicine (remote diagnosis) and teaching. Electronic<unk> s are also used with computer-aided auscultation programs to analyze the recorded heart sounds pathological or innocent heart murmurs. Recording Some electronic<unk> s feature direct audio output that can be used with an external recording device, such as a laptop or MP3 recorder. The same connection can be used to listen to the previously recorded auscultation through the<unk>  headphones, allowing for more detailed study for general research as well as evaluation and consultation regarding a particular patient's condition and telemedicine, or remote diagnosis. There are some smartphone apps that can use the phone as a<unk> . At least one uses the phone's own microphone to amplify sound, produce a visualization, and e-mail the results. These apps may be used for training purposes or as novelties, but have not yet gained acceptance for professional medical use. The first<unk>  that could work with a smartphone application was introduced in 2015 Fetal A Pinard horn used by a U.S. Army Reserve nurse in Uganda A fetal<unk>  or fetoscope is an acoustic<unk>  shaped like a listening trumpet. It is placed against the abdomen of a pregnant woman to listen to the heart sounds of the fetus. The fetal<unk>  is also known as a Pinard horn after French obstetrician Adolphe Pinard (1844–1934). Doppler A Doppler<unk>  is an electronic device that measures the Doppler effect of ultrasound waves reflected from organs within the body. Motion is detected by the change in frequency, due to the Doppler effect, of the reflected waves. Hence the Doppler<unk>  is particularly suited to deal with moving objects such as a beating heart. It was recently demonstrated that continuous Doppler enables the auscultation of valvular movements and blood flow sounds that are undetected during cardiac examination with a<unk>  in adults. The Doppler auscultation presented a sensitivity of 84% for the detection of aortic regurgitations while classic<unk>  auscultation presented a sensitivity of 58%. Moreover, Doppler auscultation was superior in the detection of impaired ventricular relaxation. Since the physics of Doppler auscultation and classic auscultation are different, it has been suggested that both methods could complement each other. A military noise-immune Doppler based<unk>  has recently been developed for auscultation of patients in loud sound environments (up to 110 dB). 3D-printed A 3D-printed<unk>  A 3D-printed<unk>  is an open-source medical device meant for auscultation and manufactured via means of 3D printing. The 3D<unk>  was developed by Dr. Tarek Loubani and a team of medical and technology specialists. The 3D-stethoscope was developed as part of the Glia project, and its design is open source from the outset. The<unk>  gained widespread media coverage in Summer 2015. The need for a 3D-stethoscope was borne out of a lack of<unk> s and other vital medical equipment because of the blockade of the Gaza Strip, where Loubani, a Palestinian-Canadian, worked as an emergency physician during the 2012 conflict in Gaza. The 1960s-era Littmann Cardiology 3<unk>  became the basis for the 3D-printed<unk>  developed by Loubani. Esophageal Prior to the 1960s, the esophageal<unk>  was a part of the routine intraoperative monitoring.
Stethoscope
Stroboscope
Endoscope
Videoscope
Fetoscope
Scope 
SurgiScope
Otoscope