How Does
Non-invasive Procedure
-
Stethoscopes make it possible for the physician to hear things going on in the body without having to resort to surgical procedures to make a diagnosis. Heart murmurs can be detected, as well as lung ailments and other cardiovascular ailments. To use a stethoscope properly, the doctor places the instrument either on the chest, abdomen or back and asks the patient to breathe normally, hold a breath or slowly inhale and exhale so that he can better hear the sounds made by the lungs themselves or by the heart during certain conditions. Stethoscopes can also be used during blood pressure monitoring to check for high or low blood pressure.
Acoustic Stethoscopes
-
Stethoscopes work by enhancing the sounds made within the human body and transmitting those sounds to the listener's ear. The doctor places the chest piece, which is either flat or bell-shaped, against the patient's skin. If the chest piece is flat it will have a thin, tightly stretched membrane over the end of the device, which is called a diaphragm. This membrane will vibrate much like the bones of the inner ear when sounds occur. The sound waves travel up the hollow plastic tubing into the metal earpieces, which are also hollow. Thus the doctor can hear what is happening inside the patient's body without an invasive surgical procedure. If the chest piece is shaped like a bell it will be hollow, with no diaphragm and work by transmitting the vibrations from the patient's skin. The bell chest piece transmits only the low frequency sounds while the flat diaphragm piece transmits only the higher frequency sounds.
Electronic Stethoscopes
-
Electronic stethoscopes are battery powered and have interchangeable frequencies that enable doctors to hear both high frequency and low frequency sounds with the same device. This type of stethoscope contains a microphone that picks up the sounds and amplifies them electronically before sending the sounds to the ear pieces. These stethoscopes pick up many more sounds than either of the other types. Unlike the simple acoustic devices however, the electronic stethoscope can randomly drop or distort some of the sounds, making it even more difficult at times for the doctor to make her diagnosis. For this reason, many doctors prefer to use acoustic stethoscopes.
eHow Article: How a Stethoscope Works
