Physical development of a person occurs in accordance with certain biological laws and principles and reflects in each age period the level of quantitative and qualitative changes in the body and its functional capabilities. The processes of growth and development occur unevenly and depend on a huge number of external and internal factors, the fundamental of which are heredity and social environment.
Mediastinum is in the center of the chest. Above it is bounded by the thorax, from below is the diaphragm, on the sides are the pleural cavities, in front - the sternum, behind - the ribs. Mediastinum is a cavity in which there are vital internal organs, a fatty layer, blood and lymphatic vessels.