Are the lungs dorsal or ventral

 

The lack of ventilation of lung sections will Atelectasis called. At Dystelectasis there is only a reduced ventilation.

If the ventilation of the pulmonary air space is hindered by external pressure, by closure of the airways or by scarred loss of elasticity, the trapped air volume in the affected area is reduced by absorption.
The Volume reduction is less pronounced than expected because there is one in the non-ventilated part of the lung edema occurs. This can be seen in the computed tomogram as a zone of reduced density (water-like density) within the reduced ventilation (tissue-like density). In addition, an adult's lungs are stiffer than those of an infant and therefore do not collapse completely. In the extreme case of fibrosis, e.g. during a diagnostic puncture, it can coincide somewhat with the formation of a pneumothorax, but does not expand again completely under drainage suction treatment!

The characteristic figures of the flap atelectasis arise from the fact that the flaps are held by capillary forces on the thoracic wall, by the subpulmonary ligament on the diaphragm and on the hilus by the bronchovascular structures.
Due to the shift in the relation of air to tissue towards tissue density (due to decreasing air volume and inflowing liquid), the affected lung section becomes denser in the X-ray image.