Basics of Lung Sounds

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The goal of this basics in lung sounds module is to improve auscultation observational skills. We focus on describing important breath sounds and in providing recordings of each. Many students find that waveform tracings aid in learning lung sounds; we have included dynamic (moving cursor) waveforms with each lesson. The anatomy pages use illustrations to reveal an example of each lung sound (anatomy not yet available on smartphones).

Using this course

Each lesson in this course includes text describing the heart or lung abnormality and a simulated torso indicating the stethoscope chestpiece location. An audio recording of the sound is provided. Phonocardiograms or waveforms are included with each lesson. These waveforms can be a highly useful aid in learning to recognize heart murmurs. In addition, short videos clips illustrate the heart's motion for each abnormality. These animations indicate the origin of each murmur. Blood flow is also animated. For lung sounds, the source (location) of the sound can be revealed.

After completing a lesson, use the lesson table of contents to navigate to another lesson.

When all lessons have been completed, we recommend using the auscultation practice exercises or quiz. In order to gain a certificate of achievement, please complete the course lessons and practice drill during one session. Most users complete the course in 30-45 minutes.



Authors and Reviewers

Authored by Diane Wrigley, PA. Medically reviewed by Dr. Barbara Erickson, PhD, RN, CCRN.




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Lessons


Lesson #1: Vesicular - Normal


Vesicular breath sounds are soft and low-pitched with a rustling quality during inspiration and are even softer during expiration. These are the most commonly auscultated breath sounds, normally heard over most of the lung surface. They have an inspiration/expiratory ratio of 3 to 1 or I:E of 3:1.


Lesson #2: Crackles - Fine (Rales)


Fine crackles are brief, discontinuous, popping lung sounds that are high-pitched. Fine crackles are also similar to the sound of wood burning in a fireplace, or hook and loop fasteners being pulled apart or cellophane being crumpled. Crackles, previously termed rales, can be heard in both phases of respiration. Early inspiratory and expiratory crackles are the hallmark of chronic bronchitis. Late inspiratory crackles may mean pneumonia, CHF, or atelectasis.


Lesson #3: Crackles - Coarse (Rales)


Coarse crackles are discontinuous, brief, popping lung sounds. Compared to fine crackles they are louder, lower in pitch and last longer. They have also been described as a bubbling sound. You can simulate this sound by rolling strands of hair between your fingers near your ear.


Lesson #4: Wheeze


Wheezes are adventitious lung sounds that are continuous with a musical quality. Wheezes can be high or low-pitched. High-pitched wheezes may have an auscultation sound similar to squeaking. Lower pitched wheezes have a snoring or moaning quality. The proportion of the respiratory cycle occupied by the wheeze roughly corresponds to the degree of airway obstruction. Wheezes are caused by narrowing of the airways.


Lesson #5: Rhonchi - low-pitched Wheezes


Low-pitched wheezes (rhonchi) are continuous, both inspiratory and expiratory, low-pitched adventitious lung sounds that are similar to wheezes. They often have a snoring, gurgling or rattle-like quality. Rhonchi occur in the bronchi. Sounds defined as rhonchi are heard in the chest wall where bronchi occur, not over any alveoli. Rhonchi usually clear after coughing.


Lesson #6: Bronchial


Bronchial breath sounds are hollow, tubular sounds that are higher pitched compared to vesicular sounds. They can be auscultated over the trachea where they are considered normal. There is a distinct pause in the sound between inspiration and expiration. I:E ratio is 1:3.


Lesson #7: Pleural Rubs


Pleural rubs are discontinuous or continuous, creaking or grating sounds. The sound has been described as similar to walking on fresh snow or a leather-on-leather type of sound. Coughing will not alter the sound. They are produced because two inflamed surfaces are sliding by one another, such as in pleurisy. During auscultation, pleural rubs can usually be localized to a particular place on the chest wall. They also come and go. Because these sounds occur whenever the patient's chest wall moves, they appear on inspiration and expiration. Pleural rubs stop when the patient holds her breath. If the rubbing sound continues while the patient holds a breath, it may be a pericardial friction rub.


Lesson #8: Bronchovesicular


Inspiration to expiration periods are equal. These are normal sounds in the mid-chest area or in the posterior chest between the scapula. They reflect a mixture of the pitch of the bronchial breath sounds heard near the trachea and the alveoli with the vesicular sound. They have an I:E ratio of 1:1.


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