Interactive Guide to Physical Examination
Thorax & Lungs

Auscultation

Auscultation provides important information regarding the lungs and pleura. Auscultation evaluates air flow through the tracheopulmonary tree, the presence of added or adventitious breath sounds, and transmission of the patient's spoken voice. In conjunction with percussion, auscultation helps to evaluate the surrounding pulmonary parenchyma and pleural space.

During auscultation:

  • Have the patient sit upright if possible, breathing slowly and deeply through an open mouth.
  • Use the diaphragm of the stethoscope, placed firmly and directly on the skin. The presence of chest hair may require firmer pressure to eliminate any potential interference.
  • Auscultate all areas systematically including anterior, posterior, and lateral lung fields.
  • Compare sounds heard on one side to sounds heard in the same location on the opposite side. Compare sounds in the apices to sounds in the bases.
  • Listen to inspiration and expiration in each location. When abnormalities are found, listening to several breaths in that location may be necessary.
  • Note the inspiratory to expiratory ratio.
  • Lung sounds may be louder in areas where lung tissue is more dense.
  • Lung sounds may be diminished due to shallow breathing or hyperinflation, pleural disease, mucous plugging or obesity.
  • Lung sounds are absent over a pneumothorax.

Locations for auscultation.

Normal breath sounds:

Normal breath sounds differ over various portions of the lungs with regard to intensity, pitch, and relative duration of inspiratory and expiratory phases. Note these characteristics as you listen in different areas. Normal breath sounds are generally softer at the apices and become louder at the bases. Normal breath sounds include vesicular, bronchial and bronchovesicular breath sounds. It is important to know where these sounds are normally heard as hearing certain sounds in locations where they are not normally found may signify pathology.

View interactive module Click on the interactive icon for specific descriptions of these sounds, and for practice listening to these sounds.

Adventitious breath sounds:

Abnormal or adventitious breath sounds may indicate the presence of pathology and are generally divided into two categories: discontinuous and continuous sounds. Discontinuous adventitious breath sounds include crackles (also called rales). Continuous sounds include ronchi and wheezes. When describing adventitious sounds, the timing of these sounds in the respiratory cycle should be noted (e.g. "late inspiratory crackles" or "inspiratory and expiratory wheezes") as well as their location, and whether they clear with coughing or not.

View interactive module Click on the interactive icon for specific descriptions of these sounds, and for practice listening to these sounds.