|Subcutaneous emphysema occurs when air gets into tissues under the skin. This usually occurs in the skin covering the chest wall or neck, but can also occur in other parts of the body. Subcutaneous emphysema is characterized by painless swelling of the tissues because of air tracking along tissue planes. It is commonly seen over the chest wall around drain sites, in the head and neck. Palpation elicits a characteristic tissue paper feeling beneath the fingers. Air may track deeper into the mediastinum, retroperitoneum, scrotum, and down into the limbs. It is rarely a problem clinically but may herald the presence of a pneumothorax or other visceral damage.
Scientific journal is a periodical publication intended to further progress of science, usually by reporting novel research. There are thousands of scientific journals in publication, and many more have been published at various points in the past. Most journals are highly specialized, although some of the oldest journals publish articles and scientific papers across a wide range of scientific fields. Scientific journals contain articles that are peer reviewed, to ensure that articles meet the journal's standards of quality, and scientific validity. The publication of the results of research is an essential part of the scientific method. If they are describing experiments or calculations, they must supply enough details that an independent researcher could repeat the experiment or calculation to verify the results. Each such journal article becomes part of the permanent scientific record.