ABSTRACT
The movement of air through the lungs has been recognized since the EgyptianBabylonian era of medicine as necessary for human life. The mechanism by which the air passes through the lungs was not mentioned until Galen (A.D. 138-201), who postulated "for in inspiration without obstruction, the animal inhales the air by means of the diaphragm alone, until the time when, should its inspiration meet with resistance, it brings into use the intercostal muscles besides the diaphragm." This is probably the first published work on the mode of pumping action of the chest wall-lungs system. Furthermore, Galen mentioned that the ribs move upwards and outwards (Duchenne, 1866).
