• Pleural rub: a creaking sound caused by stiff pleural membranes such as with pleurisy.
• Stridor: harsh inspiratory sound caused by partial obstruction of a large airway.
• Vocal resonance:
• Place the stethoscope at various levels over the back and ask the patient to whisper "ninety-nine" each time. Note how well the sound is transmitted.
• The sound is muffled over a normal lung, increased if there is consolidation, and decreased or absent if there is effusion or collapse.