diaphragm

it is attached at the crural portion to the upper lumbar vertebrae and at the costal portion to the inner aspect of the lower six ribs.on contraction (i.e. on inspiration),the diaphragm descends against the abdominal contents (pushing the abdominal wall outwards) so using the abdomen as a fulcrum on which to elevate the thoracic cage, causing a rise in intra-abdominal pressure.inward movement on the diaphragm on inspiration(paradoxical movement) is indicative of diaphragmatic fatigue/weakness/paralysis. higher lung volumes will reduce the resting length of the diaphragm and,therefore , provide a mechanical disadvantage to tension generation (as with hyperinflated states such as chronic airflow obstruction. these may result in an increased work of breathing and predispose diaphragmatic fatigue and respiratory muscle pump failure).