Examining the Lungs

In this case of right hemothorax, the left lung will be clear while the right lung sounds will be muffled or absent in the lower half of the lung fields.

Fit the stethoscope earpiece to your ears. The tubing should angle slightly upward and toward the front of your head.

Instruct the patient to take slow, deep breaths through the mouth while you listen. The breaths should be deep so the air will completely fill the lungs. They should be slow to prevent hyperventilation. The mouth should be open to minimize the noisy turbulence created whenever air moves quickly through the nose.

Listen to each lung in several areas of the back. Compare the left side to the right side at the same level. Listen to the apex of each lung over the anterior chest. Avoid trying to listen through the scapula (shoulder blade) as sound does not conduct well through the bone. Avoid listening through chest hair or clothing as they introduce acoustic artifact.

Normal breath sounds are clear. Crackles (rales) are high-pitched sounds similar to the sound of hairs being rubbed together. Wheezes have a musical quality to them, reflecting narrowed air passages vibrating like the reeds on a musical instrument. Pleural friction rubs are the soft sounds with each breath that resembles two pieces of leather rubbing against each other. Stridor are the loud, coarse sounds coming from the upper airway indicating swelling or obstruction. These can be heard without a stethoscope, some distance from the patient.

• Listen to normal breath sounds
• Listen to wheezes (asthma)
• Listen to stridor 

Absent or significantly diminished breath sounds over part or all of the lung fields may indicate fluid (pleural effusion, hemothorax) in the chest, or a collapsed lung (air in the pleural space).

If you are connected to the Internet, you can hear additional breath sounds at this web site.