What is the term for the accumulation of air in the chest cavity?

Pneumothorax refers specifically to the presence of air in the pleural space, which is the area between the lungs and the chest wall. This condition can occur due to injury or spontaneous rupture of the lung tissue, leading to the collapse of part or all of a lung. The accumulation of air can cause symptoms like sharp chest pain and difficulty breathing, and it is a critical medical condition that may require intervention, such as needle decompression or chest tube placement, to restore normal pressure and lung function.

In contrast, hemothorax involves the accumulation of blood in the pleural space, while emphysema is a chronic lung condition that involves damage to the alveoli and results in difficulties with airflow. Atelectasis refers to the collapse of a lung or a portion of a lung due to lack of air, which isn't specifically related to air in the pleural space like a pneumothorax is. Therefore, pneumothorax is the correct term for the accumulation of air in the chest cavity.