This exercise is intended to teach students how a doctor uses a Stethoscope to diagnose disease. Learning to use a stethoscope takes considerable experience. If anything "abnormal" is heard during this exercise, this should not be taken as a sign of illness. Only a trained doctor can make that determination. Functional stethoscopes can be purchased from medical or nursing supply stores for as little as $10. More expensive models are not necessary for teaching purposes.
Stethoscopes are used to hear sounds generated from within the body. They are used to listen to the heart, lungs and intestinal tract. They are also used for measuring blood pressure.
The heart is located on the left side of the chest, between the 4th and 6th ribs, almost directly under the breast. Use the stethoscope to listen to your heart. Move it around and notice if it sounds any different in different places. Compare the sounds heard using the bell versus the diaphragm.
Normal heart sounds are "lub-dub". Each "lub-dub" represents one contraction of the heart. The noises are made when the valves snap shut. "Lub" is the closing of the atrioventricular valves; "dub" is the closing of the pulmonic and aortic valves (look 'em up in an anatomy book!)
Some people may have other heart sounds as well. If a quiet "whoosh" is heard after the "lub-dub", this is called a "murmur". Murmurs are the sounds of the blood itself moving through the heart. It makes noise when the blood flow has turbulence. This can be because a valve doesn't open or close all the way. Many people have heart murmurs without it affecting them at all. If someone in the class has a murmur, ask if you can listen and compare to your own heart's sounds.
Listen to your lungs by placing the stethoscope over your chest and breathing in and out deeply and slowly. Move the stethoscope around and compare the noises heard in different areas. Compare the sounds heard using the bell versus the diaphragm. Normal lung sounds should not have any crackles or wheezes in them. Place the stethoscope over your throat and listen to the sounds your trachea makes.
Percussion may be performed on the chest as well. Instead of listening for sounds made by the body, you are listening for sound reflected by sounds you make. For this exercise you need a partner. Place the stethoscope on your partners chest and lightly "thump" a finger against their chest all around the stethoscope. Normal sounding lungs sound slightly "hollow" because they have air in them. Compare this to holding the stethoscope over something solid like a shoulder blade. This sounds "dead". If a lung sounds dead on percussion, it can indicate that the lung has solidified, usually because of pneumonia.
Abnormal lung sounds include crackles and wheezes. If the lung rubs on the chest wall there may be friction rubs. Crackles sound just like the word sounds. They indicate that there is fluid in the lungs, such as happens with pneumonia or pulmonary edema. Wheezes are high pitched whistling noises, and are heard with some pneumonias and with airway diseases like bronchitis. Friction rubs are squeaky sounds that can be heard with pleuritis (an infection between the lung and the chest wall).
To mimic these sounds, create a model of the lung. Take a balloon and stretch the open end over one end of the tube. Take a sponge and shred it into small pieces. Push the pieces through the tube into the balloon, until the balloon is slightly stretched. Add enough water to moisten the sponge. Squeeze out any excess. Now hold the stethoscope to the balloon and blow in and out on one end of the tube to slightly inflate the balloon. The slight crackly noise you hear is similar to the crackles heard in patients with pneumonia. Wheezes can be simulated by pinching on the neck of the balloon, where it meets the tubing while blowing in and out. Friction rubs can be created by rubbing on the side of the balloon to make it squeak.
The abdomen can be listened to much like the chest. Holding the stethoscope over the upper left part of the abdomen, just under the ribs, you can hear the stomach gurgling. In the lower part of the abdomen you can hear the intestines. These noises are called "borborygmus". Borborygmus is normal. However, a doctor will listen to these noises and compare them with what is "normal" to decide if your intestinal tract is overactive or underactive.
Percussion can also be used to listen to the abdomen. Thumping over the upper right of the abdomen should sound "dead" as a solid organ, the liver, is below it. The stomach or lower abdomen may sound hollow if there is gas in the intestinal tract.
Using a stethoscope is an age-old art in medicine and is a very useful, non-invasive diagnostic tool to help localize problems. This is important to allow the doctor to determine what further tests are needed to diagnose disease.