WHAT MAKES A STETHOSCOPE?
The parts of a stethoscope work together to allow the user to hear the internal sounds of a patient’s body. These sounds are transferred from the stethoscope to the medical professional’s ears to enable proper diagnosis of a patient’s condition or illness.
To briefly describe how this happens, the head or chestpiece of the stethoscope is placed on the patient’s body—against the chest, stomach, or back—allowing the sounds from these areas to get picked up. The sounds move through the stethoscope tubing and into the binaural ear-tubes, where the user can hear the patient’s heartbeat, as well as lung and abdominal sounds.
A stethoscope has a chestpiece, diaphragm and/or bell, stem, tubing, headset, binaurals, and eartips. Let’s take a closer look at what each part does. First, we'll tell you about what makes an Ultrascope unique. Below that, you will find general stethoscope terminology to help you decide what type of stethoscope you need.
The Ultrascope employs an acrylic stethoscope head that blocks out more ambient noise than a metal-headed stethoscope. Acrylic doesn't conduct sound vibrations the same way. If your young patient is crying, or barking, you'll still hear your target. In addition, the properties of the acrylic ensure that the vibrations transmitted through the diaphragm membrane travel up the sound channel without the possibility any being lost through the head material.
If you are used to dual-sided stethoscope heads, you may think of the diaphragm as a portion that's limited to one range of frequencies. In our case, "Diaphragm" is simply the label for the membrane that makes contact with the patient.
Our binaurals are made from stainless steel and are threaded to receive our Screw-On ear tips. Our softer Push-On ear tips also grip securely to the binaural threading if you prefer the feel of that style. The binaurals and the ear tips point slightly towards the front of the tubing to match the angle of your ear canals. The angle can be adjusted slightly for best fit.
Our tubing is made from polyvinyl chloride and does not contain natural rubber latex. It is resistant to stretching and hardening. Tubing made of PVC will inevitably harden from contact with the lipids in your skin over a long period of time. Ultimately, we are talking about a span of years and a tubing set should last you close to a decade in regards to becoming stiff.
We offer 2 types of Ear Tips: Push-On (black, left) and Screw-On (grey, right). Our stainless steel Binaurals are threaded to receive the Screw-On variety but we were careful to ensure that the threading and the outer diameter would sufficiently allow the legacy Push-On style to securely grip and seal as well so that you have 2 options for comfort and fit. If you are having trouble unscrewing your Srew-On type Ear Tips, you can remove the grey PVC cover and grasp the internal metal cap with a pair of pliers or a jar opener to help break the seal.
The chestpiece, also known as the head, is the part of the stethoscope responsible for conducting sound. This is the part placed against a patient’s skin. Through technological advancements, some stethoscopes can now also conduct sounds through clothing and bandages, and even blankets and animal fur.
A stethoscope can have a one-sided or two-sided chestpiece, depending on the model. Some stethoscopes with one-sided chestpieces only have diaphragms. Some have tunable or pressure-sensitive diaphragms that can act as both a bell and a diaphragm. Those with two-sided chestpieces, on the other hand, have a diaphragm on one side and a bell when flipped over or rotated. This rotation allows the user to choose which side is appropriate.
Chestpieces are usually made of metal, but there are now also acrylic head stethoscopes which are great for blocking out ambient noise. The chestpiece is made up of the diaphragm and/or bell, and the stem. We’ll look into those parts in more detail below.
The diaphragm is the circular end of the chestpiece. On two-sided chestpieces, the diaphragm is the larger of the two ends. Its larger size allows the user to listen to a bigger area of the patient’s body. The diaphragm is designed to pick up sounds with higher frequencies compared to the bell. Diaphragms today are constructed to eliminate chill against the patient’s skin and to have better hypoallergenic properties, increasing comfort and safety for the patients examined.
The bell is another circular end of the chestpiece. On two-sided chestpieces, the bell is the smaller end. Due to its smaller diameter, it has a more restricted range that focuses on lower frequency sounds than the diaphragm. Similar to the diaphragm, today’s bells now come with features that provide better comfort for patients as they’re being examined. The smaller size of the bell makes it ideal for pediatric patients and skinnier patients. It is also used when dealing with bandaged areas or the carotid area.
The stem is the part that connects the chestpiece to the stethoscope tubing. It is usually made of metal or steel. On stethoscopes with two-sided chestpieces, it is also the part that allows the user to choose between the diaphragm and the bell. This is done by simply rotating the chestpiece and then clicking it into place with a ball bearing. Rotating the chestpiece determines whether the diaphragm or bell directs sound to the eartubes.
The tubing is responsible for transferring and relaying the frequencies or sounds picked up by the chestpiece. It directs the sounds to the eartubes so that the user can hear them.
Stethoscopes often come with either a single tube or dual lumen tube design. With dual lumen tubing, the tubing is actually split in half on the inside, creating two sound channels inside one outer tube. This creates left and right paths so that the sounds can reach the user’s ears with the greatest accuracy. Stethoscope tubing these days is designed to withstand skin oils and alcohol, making them longer-lasting and able to endure constant use and cleaning.
The headset is that half of the stethoscope often seen hanging from a healthcare professional’s neck. The headset is composed of two eartubes, tension springs, and eartips.
The eartubes connect the stethoscope tubing to the eartips. They are made of metal or steel and are designed to be at the optimal angle for the best fit into the user’s ear canals. The eartubes isolate and direct the sounds into left and right paths to provide the user a clearer and more accurate listening experience. They have ribbed ends where the eartips are then placed.
The eartips are the parts that actually go into the ear. They are usually made of rubber or silicone and have a hole in the middle for letting out sound. Eartips are placed on the ends of the eartubes to provide an acoustic seal as well as to improve user safety. Eartips should provide a snug but comfortable fit for the user. They often come in different sizes to accommodate different ears.
Advancements in science and medicine have given us a better understanding of the body now more than ever. We now have the best tools at our disposal for efficient and accurate diagnosis of patients’ conditions. The stethoscope seems so simple, but it is an indispensable part of every healthcare professional’s toolkit. It has endured as a symbol of medical practice and medical practitioners everywhere.
Getting the best stethoscope to suit your needs can help you become the best medical professional for your patients. The right stethoscope is what both you and your patients deserve. A stethoscope is an investment to last for years and years to come. With this guide, we hope that it will now be easier for you to make that choice.