Which term describes a condition where the lungs are not fully expanded?

Atelectasis refers to the partial or complete collapse of a lung or a section (lobe) of a lung, resulting in reduced lung capacity and insufficient air exchange. This condition occurs when the air sacs (alveoli) inside the lungs become deflated or filled with fluid, preventing them from fully expanding during inhalation. It can be caused by various factors, including obstruction of the airways, lack of surfactant (which helps keep the alveoli open), or pressure from outside the lung, such as tumors or fluid accumulation.

The term is relevant in clinical settings because it emphasizes the importance of lung expansion for adequate oxygenation and overall respiratory health. Understanding atelectasis is crucial for medical professionals, especially in emergency or intensive care situations, where ensuring proper lung function is vital for patient outcomes.