Pulmonary contusion
（重定向自Contusion of lung）
![](/Images/godic/202501/06/Pulmonary_contusion_CT_arrow4124.jpg")
![The alveoli](/Images/godic/202501/06/Alveolus_diagram.svg4124.png")
![Motor vehicle accidents are the most common cause of pulmonary contusion.](/Images/godic/202501/06/Crushed_Saturn4124.jpg")
![Normally, oxygen and carbon dioxide diffuse across the capillary and alveolar membranes and the interstitial space (top). Fluid impairs this diffusion, resulting in less oxygenated blood (bottom).](/Images/godic/202501/06/Fluid-filled_alveolus.svg4124.png")
A pulmonary contusion (or lung contusion) is a contusion (bruise) of the lung, caused by chest trauma. As a result of damage to capillaries, blood and other fluids accumulate in the lung tissue. The excess fluid interferes with gas exchange, potentially leading to inadequate oxygen levels (hypoxia). Unlike pulmonary laceration, another type of lung injury, pulmonary contusion does not involve a cut or tear of the lung tissue.