Playing doctor as a kid always seemed the most fun when you had a toy stethoscope with which to listen to your patient’s lungs and heart. Curious how stethoscopes actually work? You might be surprised.
Parts of a Stethoscope
First, the basics of a stethoscope include several key pieces:
- Eartips and metal eartube – silicone or rubber ear tips sit at the very end of the stethoscope and should mold slightly to your inner ear when worn, to keep unwanted environmental sounds out. They have a clear hole in them and sit atop of metal or steel hollow ear tubes which form a wide “v” shape to connect down to the synthetic tubing of the stethoscope. The ear tubes help separate the sounds traveling up to the ear for clearer auditory analysis.
- Tubing – typically comprised of a synthetic or PVC-based material, a stethoscope’s tubing may include a single or dual lumen design. As sound travels up from the bell and diaphragm of the stethoscope, the tubing plays a critical role in maintaining the sound’s frequency and sending it up through the ear tips with as much accuracy as possible.
- Stem and chest piece – the metal or steel connector which joins the headset (eartips and tubing) to the chest piece is called the stem. The chest piece is made up of components including the stem, a tunable diaphragm, and/or a bell.
- Diaphragm and bell – the circular portion at the end of the chestpiece of the stethoscope which is placed against a patient’s skin to listen to the chest or stomach is called the diaphragm. It contains a metal circular frame with a thin piece of plastic stretched carefully across it. It picks up on higher frequency sounds and may feature a dual head design where a smaller circular end on its opposite side, called the bell, picks up lower frequency sounds.
The best stethoscopes often feature dual lumen tubing and both a bell and diaphragm components to provide the most accurate and helpful readings.
Using a Stethoscope
When a medical professional like a nurse or doctor goes to use a stethoscope, they are relying on it to detect and transfer internal sounds from the patient’s body to the professional’s ears to help evaluate symptoms and potentially make a diagnosis. For example, a doctor could listen to a patient’s lungs and if they hear crackling or bubbling sounds, know that their patient may have pneumonia.
Typically, a clinician will place the ear tips in their ears and then hold the diaphragm (or bell) against the skin of an area on the patient’s body depending on what they are looking to hear, i.e. the chest, back, abdomen, etc. The diaphragm will transmit the higher frequency sounds emitting from the inside of the patient’s body. Those sounds will travel up the tubing to the clinician’s ears. Stethoscopes may also be used in conjunction with a sphygmomanometers and blood pressure cuff to manually read a patient’s blood pressure.
Caring for a Stethoscope
Stethoscopes are somewhat of a delicate medical monitoring tool and their effectiveness can easily be damaged by dirt, scratches, and other items they might come into contact with on the job. Experts recommend storing a stethoscope in a stethoscope case when it is not specifically in use, or wearing it around your neck (i.e. on rounds at the hospital).
Stethoscopes can and should be frequently cleaned, but carefully. The diaphragm should never contact liquid, steam, oils, or solvents, but rather be wiped down with a 70% isopropyl alcohol solution which dries quickly. The ear tips and tubing on the other hand can be cleansed with mild soap and water. Separate all components prior to cleaning and allow them to dry before reassembling. Extreme heat and cold temperatures can potentially damage a stethoscope, so keep this in mind when storing and using yours.