Chest Radiology > Pathology > Atelectasis > General. Atelectasis is collapse or incomplete expansion of the lung or part of the lung. This is one of the most common findings on a chest x-ray. It is most often caused by an endobronchial lesion, such as mucus plug or tumor.
A Labradoodle, a crossbreed between a poodle and a retriever. A crossbreed or crossbred usually refers to an organism with purebred parents of two different breeds, varieties, or populations.
cross over, 1  Biology. (of a chromosome segment) to undergo crossing over. 2  to switch allegiance, as from one political party to another. 3  to change successfully from one field of endeavor, genre, etc., to another: to cross over from jazz to rock. 4  to die; pass away.