A stethoscope is used to detect and study the heart, lung, stomach, and other sounds in human adults, children, and human fetuses. Using a best stethoscope, the listener can hear normal and abnormal respiratory, heart, pleural, arterial, venous, uterine, fetal, and intestinal sounds.
The stethoscope is an acoustic medical device for auscultation, or listening to the internal sounds of an animal or human body. It usually has a small disc-shaped resonator that sits against your chest, and two tubes connected to headphones. It is often used to listen to the sounds of the lung and heart. It is also used to listen to the intestines and the blood flow in the arteries and veins. In combination with a sphygmomanometer, it is commonly used for blood pressure measurements.
The stethoscope was invented in France in 1816 by René Laennec at the Necker-Enfants Malades Hospital in Paris. It consisted of a wooden tube and was monaural. Laennec invented the stethoscope because he felt uncomfortable placing his ear on women’s chests to listen to heart sounds. His device was similar to the common trumpet, a historical form of hearing aid; in fact, his invention was almost indistinguishable in structure and function from the trumpet, which was commonly called a “microphone.” Laennec called his device the “stethoscope,” and called its use “mediate auscultation,” because it was auscultation with an intermediate tool between the patient’s body and the doctor’s ear.
What are the advantages of owning a stethoscope?
It is practically the symbol of doctors and medical assistants. Most of us know the basics: you put the headphones in your ears, the other end in a sick person, and listen to the heartbeat. But stethoscopes can do much more than that for example: The following are some facts about this medical device, followed by a more complete list of its uses. If you are new to the field of medicine, being comfortable with your stethoscope and knowing how to use it properly will make you a better medical student and clinician. What can you do with it? If you learn the following, you will use yours more than 90% better in clinical use.
- Measure blood pressure. It is probably the most common use, but it is often done wrong. The placement of the blood pressure cuff is critical. Also, many students are taught that Systolic blood pressure (eg 120/80 mm / Hg) is normal and is the point where they can no longer hear the brachial artery bang. More precisely, Diastolic blood pressure is the number where the volume of the blow drops drastically. (This is often 4-10 mm Hg louder than when the sound disappears completely.
- Evaluation of lung sounds: allows you to identify the rate, rhythm and quality of breathing, airway obstructions, as well as smears indicating inflammation of the pleura. Don’t forget to start above the collarbone, as the lung tissue extends so high. Also, when listening to the back, have the patient lean slightly forward to expose the auscultation triangle. Remember that for lung sounds (according to the Bates Bible, “) we hear in six paired areas in the chest, and seven paired areas in the back. Remember this with the mnemonic “6AM – 7PM,” (6 pairs earlier, and 7 pairs later). Always listen to the left and right sides at the same level before going down to the next level – this way you will get a side by side comparison,
- Evaluation of heart sounds.We hear the frequency, type, and rhythm of the heart sound, as well as any sounds that shouldn’t be there (adventitious sounds), such as gallops, murmurs, or clicks. All hearts sound the same at first. But after listening to many hearts, eventually the sounds seem to jump at you. For heart sounds, we listen to the four main areas: left and right of the sternum at the level of the 2nd rib, to the left of the sternum Remember this with the mnemonic “2-2-4-5”. The names of the valves you are hearing in these places are: aortic (2 right), (2 left) pulmonary, (4) tricuspid, (5) mitral. Remember these with the mnemonic “All patients take Meds.
- Evaluation of intestinal sounds. This is easy to do, and important if there may be a bowel obstruction or paralytic ileus. The gurgling noises are called gurgling.
- Bruit detection. A murmur (pronounced “broo’-ee,”) is an abnormal sound of blood flow through an artery that usually indicates that the artery has narrowed, causing a turbulent flow, as in arteriosclerosis. Flare-ups are abnormal – if the patient is healthy and “normal,” he shouldn’t hear any bruits. Traces can be found in the neck (carotids), umbilicus (abdominal aortic kidneys), kidneys, femoral, iliac, and temporal arteries. The first true sound you should hear is an umbilical, just above a patient’s belly button, and when you hear it you know immediately that the patient has an abdominal aortic aneurysm (AAA).
- Measurement of the extent of the liver. Usually this is done by percussion (hitting the belly), but another neat way is to place the stethoscope under the right nipple, the other index finger just above the waist line in line with the nipple, and gently scratch skin to chest Piece of stethoscope. When you are over the liver, the sound will get duller. Marking the location where the begins and ends provides a decent measurement of liver size at that location. About 10 cm is normal for the nipple line.
- Headset. Lastly, the stethoscope makes a good hearing aid for hearing impaired patients. Put your ears to the patient’s ears and speak into the chest piece. Accessible in the ER! (Emergency)