Diaphragm dysfunction

The thoracic diaphragm, or simply the diaphragm, is a sheet of internal skeletal muscle[2] in humans and other mammals that extends across the bottom of the thoracic cavity. The diaphragm separates the thoracic cavity, containing the heart and lungs, from the abdominal cavity and performs an important function in respiration: as the diaphragm contracts, the volume of the thoracic cavity increases, creating a negative pressure there, which draws air into the lungs. [Source: Wikipedia ]