The most common cause of lung tissue consolidation (solidification) is pneumonia, a lung inflammation that can be caused by bacteria, viruses, or chemical insults (such as with aspiration). In this condition, fluid, leukocytes, and erythrocytes accumulate in spaces that are normally air-filled, producing a consolidated area. Clinical findings vary, depending on the location of the consolidated area and the causative agent. When classic consolidation is
present, decreased chest wall movement and a dull percussion note are apparent over the affected area. Bronchial breath sounds are heard over a dense, airless upper lobe, even without a patent bronchus (♦Sound 60), because the upper lobe surfaces are in direct contact with the trachea and loud tracheal breath sounds are transmitted directly to the dense, airless upper lobe tissues. In contrast, bronchial breath sounds are heard over a dense, airless lower lobe only when the bronchi are patent, because sound isn’t transmitted directly to the airless lower lobe tissues.

Atelectasis, incomplete expansion of a lung area, is typically diagnosed in postoperative or immobile patients and in some patients with bronchiectasis or pneumonia. It’s thought to result from prolonged shallow breathing (hypoventilation) or uncleared secretions that occlude the airway. Because no air enters the distal airways, the segmental or lobar bronchi collapse. If a large airway is occluded, clinical findings include decreased chest wall movement, a dull percussion note, regional changes in lung volume, and bronchial breath sounds over a dense, airless upper airway. (♦Sound 61) However, decreased chest wall movement and lung volume changes may be difficult to detect on clinical examination.