<prompt> The normal intrapleural pressure at the startbeginning of inspiration is ... cm of H207.55.02.00.5  <response>: The intrapleural pressure becomes more negative at the end of inspiration and less negative at expiration. It ranges between -3 and -6 mmHg. At the beginning of inspiration, the pressure is -3.8mmHg -5 cm of water, and at the end of inspiration beginning of expiration, it is -6mmHg -8 cm of water. The elasticity of lung and rib cage causes it to recoil and thus creating the negative pressure. The lymphatic drainage of the pleural fluid also creates a negative pressure. 