A condition in which air enters the pleural cavity, causing the lung to collapse, is known as which of the following?

The condition in which air enters the pleural cavity, leading to the collapse of the lung, is known as pneumothorax. This occurs when air leaks into the space between the lung and the chest wall, which can disrupt the pressure balance that keeps the lung inflated. Depending on the severity and the amount of air that fills the pleural space, pneumothorax can lead to symptoms such as sudden chest pain and difficulty breathing.

In contrast, hemothorax involves the accumulation of blood in the pleural cavity, which can also lead to lung collapse but is a different pathological process. Pleural effusion refers to the buildup of excess fluid in the pleural space, which is distinct from air. Thoracentesis is a medical procedure used to remove fluid (or sometimes air) from the pleural space for diagnostic or therapeutic reasons, but it is not a condition that describes the presence of air. Understanding these differences is crucial for assessing respiratory issues and determining appropriate management strategies.