This patient's chest x-ray after lung biopsy shows a right pneumothorax, which is recognized by the continuous line in the right lung field with no visible lung markings peripheral to it.  This line is the outer edge of the collapsed right lung; the dark space peripheral to the lung represents air in the chest cavity.

The following characteristic physical examination findings are expected with pneumothorax:

• Tactile fremitus represents airway vibrations generated by vocalized sound (eg, saying "ninety-nine") and is measured by the examiner placing hands on the patient's back.  Because air in the chest cavity insulates and dampens airway vibrations before they reach the patient's back, decreased tactile fremitus is expected (Choice C).

• Breath sounds are caused by air movement within the airways, and the intensity varies by lung location.  Vesicular breath sounds are normal over the periphery; bronchial breath sounds are higher-intensity sounds that are normal over the hilum but indicate pathology (eg, lobar consolidation) over the periphery.  Because the lung is partially collapsed, leading to less air movement, and sounds from the airways are insulated by air in the chest cavity, decreased breath sound intensity is expected (Choices D and F).

• Resonance refers to the frequency of sound generated by percussion, and it varies with density.  Because air alone is less dense than a composite of lung parenchyma and air (ie, normal lung), higher-than-normal sound frequency to percussion (ie, hyperresonance) is expected.

(Choice A)  Like pneumothorax, fluid in the chest cavity (ie, pleural effusion) insulates airway vibrations and sounds, causing decreased tactile fremitus and breath sound intensity.  However, because fluid is more dense than normal lung, dullness to percussion is expected.  Atelectasis generates findings similar to those of pleural effusion; the collapsed lung reduces air movement and vibration within the airways, and the airless lung parenchyma is more dense than normal, air-filled lung.

(Choice B)  Consolidated, fluid-filled lung (eg, lobar pneumonia) is more dense than normal lung.  This leads to increased transmission of vibration and sound (ie, increased tactile fremitus and breath sound intensity) and dullness to percussion.

(Choice G)  Normal lung demonstrates resonance to percussion, baseline tactile fremitus, and vesicular (normal-intensity) breath sounds.

Educational objective:
Pneumothorax is recognized on chest x-ray by a continuous line without lung markings peripheral to it.  Decreased tactile fremitus, decreased breath sound intensity, and hyperresonance to percussion are expected on physical examination.