While we’re showing a 3M™ Littmann® Cardiology III™ Stethoscope in these examples, please note that all current Littmann stethoscopes (with the exception of electronic models) have similar components.
Explore this page or for quick reference in your classroom or office, download our Anatomy of a Stethoscope poster (PDF, 180.62 KB).
Some Littmann stethoscope models have a one-sided chestpiece with a tunable diaphragm. Others have a two-sided chestpiece with a diaphragm on one side and a bell on the other. Some bells are always open, others are closed with a tunable diaphragm, depending on the model.
The larger diaphragm side is normally used for adult patients. The smaller-diameter bell is best for pediatric or thin patients, for maneuvering around bandages, and for carotid assessment. The closed bells on Littmann stethoscopes can be converted to traditional open bells by replacing the diaphragm with a nonchill bell sleeve or rim.
The stem connects the stethoscope tubing to the chestpiece. On Littmann stethoscopes with two-sided chestpieces, there can only be one acoustic path from the diaphragm to the eartips. Rotating the two-sided chestpiece on the stem selects or “indexes” which diaphragm is open to the acoustic path.
The tunable diaphragm is a 3M invention that can make auscultating a patient easier. It lets you easily hear different sounds simply by adjusting the pressure on the chestpiece. Here’s how a tunable diaphragm works:
Current Littmann stethoscopes feature next-generation tubing that provides improved resistance to skin oils and alcohol for longer tubing life. No natural rubber latex or phthalate plasticizers are used in the tubing or any other component—to help protect human health and the environment. All Littmann Cardiology stethoscopes have double lumen tubing: two sound paths inside one outer tube which helps eliminate the rubbing noise generated by traditional twin-tubed stethoscopes.
The headset is made up of two eartubes, tension springs and the eartips.
The eartubes are positioned at an anatomically correct angle, for a proper fit into your ear canals. The ribbed ends of the eartubes snap the eartips on tight for safety. Eartubes on a Littmann stethoscope are made of an aerospace aluminum alloy that provides both strength and lighter weight.
The headset tension is adjusted for individual fit and comfort by pulling the eartubes apart to reduce the tension, or squeezing them together (crossing them over) to increase tension.
All Littmann stethoscopes are fitted with eartips that snap tight onto the eartubes for safety. (In fact, they require some effort to remove.) The durable, soft-sealing eartips provide an excellent acoustic seal and comfortable fit. The eartips are available in small and large sizes, and black and gray versions. Many Littmann stethoscope models come with an extra set of soft-sealing eartips and a pair of firm tips.