HISTORY OF DIAPHRAGM PHYSIOLOGY - THE ACHIEVEMENTS OF GALEN

Galen (129-200 AD) produced a large written output which was to remain one of the major basis of clinical medicine for centuries, His contri bution to respiration, reported in his own books and in those of Oriba sius, was that of a chest physician and of an experimental physiologis t. He described in minute details how to perform a remarkable series o f experiments by which he demonstrated the anatomy and function of the respiratory muscles, He described the actions of the diaphragm and ho w it moves the rib cage, in a series of spinal chord sections and musc le denervations. He investigated the passive or active nature of expir ation and made fine observations of lung movements through the exposed pleural space, He described the interaction between the lungs and che st wall and developed the concept of interaction between ribcage and a bdominal muscles in maintaining the position of the diaphragm, showing a clear understanding of the principle that the diaphragm can move up ward during an isovolume manoeuvre as long as the ribcage is allowed t o expand, A skillful clinician, Galen applied his theories of the anal ysis of problems at the bedside, particularly in patients affected wit h dyspnoea which he attributed to respiratory muscle dysfunction.