What condition involves the failure of the lungs to expand normally, leading to reduced lung volume?

Atelectasis is the condition characterized by the failure of the lungs to expand normally, which results in reduced lung volume. This can happen due to obstruction of the airways, pressure from neighboring organs or structures, or conditions affecting the lung tissue itself. When areas of the lung collapse or fail to inflate fully, it reduces the overall capacity for gas exchange, leading to symptoms such as shortness of breath and decreased oxygen levels in the blood.

In contrast, pneumothorax involves the presence of air in the pleural space, which can cause lung collapse but is not specifically about the inability of the lung tissue to expand. Chronic bronchitis and asthma, while they involve inflammation and narrowing of the airways, do not primarily lead to reduced lung volume through direct failure of lung expansion but rather through airway obstruction related to mucus production or bronchospasm. Thus, atelectasis directly correlates with the failure of lung expansion, making it the correct choice in this scenario.