Breath sounds are the noises generated by air moving through the respiratory system during breathing. These sounds, which can be heard with a stethoscope, offer basic insights into lung function. Listening to breath sounds is a non-invasive procedure that can assist in identifying various respiratory issues. Auscultation, the practice of listening to internal body sounds, has been used for centuries to assess the respiratory system.
Key Anatomical Landmarks
To effectively listen to breath sounds, understanding the general anatomical regions of the chest and back is helpful. The bony structures of the body serve as guides, allowing for systematic assessment. On the front of the chest, the clavicles (collarbones) and sternum (breastbone) provide upper and central reference points. The ribs, which encircle the chest, define the intercostal spaces where listening occurs.
On the back, the scapulae (shoulder blades) and the vertebral column (spine) are important landmarks. The spaces between the ribs on the back, like those on the front, offer pathways to hear lung sounds. These landmarks help divide the chest and back into zones, guiding the placement of a listening device to cover the lung fields systematically. Avoiding listening directly over bones, such as the scapulae or clavicles, helps ensure clearer sound transmission.
Specific Listening Areas
Listening for breath sounds involves placing a stethoscope at precise points across the chest and back to capture the sounds of air moving through the lungs. On the anterior (front) chest, begin by placing the stethoscope slightly above the clavicles to assess the apex (top) of the lungs. Move downwards, listening in the second intercostal space (the space between the second and third ribs) along the midclavicular line, which is an imaginary line extending down from the middle of the clavicle. This area allows assessment of the upper lobes.
Continue listening down the anterior chest, moving to the fourth intercostal space, then down to the sixth intercostal space along the mid-axillary line, which is an imaginary line extending down from the center of the armpit. On the right side, the fourth intercostal space at the midclavicular line is also used to listen to the right middle lobe.
For the posterior (back) chest, instruct the individual to move their arms forward, perhaps by placing their hands on their lap, to shift the scapulae and expose more of the lung fields. Begin listening above the scapulae to assess the lung apices. Then, move to the areas between the scapulae, particularly between the T3 and T10 vertebrae, to listen to the superior and inferior lobes.
On the lateral (side) chest, listening points are typically found along the mid-axillary line, generally between the fourth and eighth ribs. These areas are helpful for assessing the lateral aspects of the lung lobes, including the right middle lobe and the lower lobes. A systematic approach, moving from top to bottom and comparing corresponding points on both sides of the body, helps ensure comprehensive coverage of the lung fields.
Effective Listening Techniques
Effective listening for breath sounds requires specific techniques to optimize sound clarity and consistency. A quiet environment minimizes ambient noise that could interfere with subtle lung sounds. Background noises, such as talking or nearby machinery, can significantly obscure the sounds being assessed.
Correct positioning is also helpful. Ideally, the individual should be sitting upright in a relaxed position, allowing for better lung expansion and easier access to listening points. If sitting upright is not possible, listening can be performed while the individual is lying on their side.
When using a stethoscope, place the diaphragm (the larger, flatter side) directly on the bare skin of the chest or back. Clothing, even thin layers, can muffle sounds or create artifact noises, making accurate assessment difficult. Apply firm but not excessive pressure to ensure complete contact with the skin without causing discomfort.
Instruct the individual to breathe deeper than normal through their mouth. Breathing through the mouth helps to reduce sounds produced in the nasal passages and allows for clearer airflow through the larger airways. Listening to at least one full cycle of inhalation and exhalation at each placement point provides a complete picture of the breath sound characteristics. Always compare sounds from symmetrical points on both sides of the chest and back to identify any differences.